Electrochemical biosensors and power supplies for wearable health‐managing textile systems

In recent years, wearable electrochemical biosensors have received increasing attention, benefiting from the growing demand for continuous monitoring for personalized medicine and point‐of‐care medical assistance. Incorporating electrochemical biosensing and corresponding power supply into everyday textiles could be a promising strategy for next‐generation non‐invasive and comfort interaction mode with healthcare. This review starts with the manufacturing and structural design of electrochemical biosensing textiles and discusses a series of wearable electrochemical biosensing textiles monitoring various biomarkers (e.g., pH, electrolytes, metabolite, and cytokines) at the molecular level. The fiber‐shaped or textile‐based solar cells and aqueous batteries as corresponding energy harvesting and storage devices are further introduced as a complete power supply for electrochemical biosensing textiles. Finally, we discuss the challenges and prospects relating to sensing textile systems from wearability, durability, washability, sample collection and analysis, and clinical validation.


| INTRODUCTION
Recently, the rapid development of flexible functional electronics has laid the foundation for more comprehensive personalized healthcare and point-of-care medical assistance.The incorporation of wearability, comfortability, remote operation, and timely feedback in wearable devices allows natural interaction between electronics and the soft human body and enables continuous real-time physiological and biological monitoring. [1]Traditional diagnoses based on physical hospitals are typically based on periodic medical examinations, usually intervening only when patients exhibit symptoms or when a disease worsens.To achieve the next generation of personalized healthcare and telemedicine, it is evident that this model lacks more information related to the time dimension and individual convenience.With the advancement of flexible electronics, sensors for monitoring electrophysiological signals (such as heart rate, body temperature, and activity) have already been integrated into wearable devices or mobile devices. [2,3]However, the progression of human diseases and the fluctuations in emotions are highly complex and multidimensional.Simple physiological signal monitoring and single indicators cannot comprehensively assess real-time human status.In reality, evaluating normal physiological states and screening specific diseases can depend on biomarkers present in bodily fluids. [4]Over the years, the academic community has produced abundant research and findings concerning the association between biomarkers and the mechanisms of human diseases.Nevertheless, these potentials have not been fully realized due to technological gaps in sensing technologies and integrated systems.
Wearable biosensors, especially electrochemical biosensors, serving as a pivotal link in advancing medical developments and meeting the demands of personalized healthcare, can be equipped with wireless communication capabilities, enabling them to continuously monitor relevant biomarkers for more comprehensive health tracking and medical diagnostics. [5]While advancements in physiological monitoring using acoustic biosensing devices or optical methods such as fluorescence sensing and colorimetry, [6][7][8] electrochemical biosensors dominate in health monitoring and clinical diagnostics due to their advantages of rapid response, real-time monitoring, portability, and simplicity.With unprecedented advancements in information processing technology and biotechnology, universal access to professional health management is becoming feasible, and wearable electrochemical biosensors have emerged as a vital catalyst for this revolution to reach a new level.14][15][16][17][18][19] While certain essential features like bendability or stretchability have been widely achieved, there still exists a lack of properties akin to human wear, such as breathability, water absorption, softness, deformability, permeability, durability, and washability.These characteristics are indispensable for realizing a real "textile computer" that encompasses physiological sensing, power supply, information processing, logical computation, and wireless data transmission while imposing minimal psychological burden. [20]ndoubtedly, the emergence of smart textiles that integrate sensing and energy supply holds the potential to replace traditional plain-shaped biosensors and become the preferred platform for the next generation of interactive modes.First, everyone needs to wear clothes every day, and integrating electrochemical biosensors seamlessly with textiles makes it easy to collect and transmit data about the wearer's health management.Second, wearable electrochemical biosensing textile with breathability and flexibility allows for comfortable and flexible designs.
[23] Lastly, textiles consist of fibers that can effectively adapt to multidimensional motion deformation, which presents a significant opportunity to enhance the stability of wearable biosensors.
However, many challenges hinder the development and widespread use of smart textiles in personalized healthcare, such as advanced sensing mechanisms and materials, scalable fabrication methods, integrated communication for information exchange, user adoption and hardware and software limitations. [11]The continuous progress in flexible electronics and materials science has recently led to the emergence of fully integrated multifunctional smart textiles in health monitoring. [18,24][27] Moreover, the penetration of the new generation of information revolution and the Internet of Things addresses data relay and response time limitations.The growing consumer demand for personalized interaction experiences and the growing acceptance of wearable technology indicate an increasing need to expand the use of smart textiles in customized healthcare, i.e., sensing textiles.
This review first provides an overview of electronic textiles' general manufacturing techniques and structural design.Subsequently, we introduce fiber-shaped and textile-based electrochemical biosensors to monitor biomarkers (including pH, ion levels, metabolites, and other biological markers) in personalized healthcare.Since electrochemical biosensing textiles need the corresponding power supply modules to supply electricity, fiber-shaped and textile-based solar cells, and aqueous batteries for biosensors are further introduced.Finally, we discuss the challenges and prospects for the future development of sensing textile systems, providing insights for research on flexible electronic devices that integrate sensing and power supply.

| Manufacturing techniques of electrochemical biosensing textile
A wearable electrochemical biosensing textile system comprises a sensing area, an energy harvesting part and an energy storage part (Figure 1).The fundamental principle of the core sensing component often involves the utilization of specific bio-recognition elements, including ionophores, antibodies, aptamers and molecularly imprinted polymers (MIPs), incorporated onto flexible fibers or textile substrates, allowing selective in situ target recognition. [28]Specific electrical signals generated by the analysis of the concentration of the analyte are recorded as valuable physiological signal information.In addition, a biosensing textile system requires an adequate power supply to ensure long-term continuous operation.Therefore, energy harvesting devices or energy storage devices such as batteries are needed, and sometimes a combination of both in a hybrid energy supply integration. [29,30]Furthermore, logical computing units and wireless data transmission interfaces are also essential, guaranteeing data processing in the biosensing textile system and facilitating communication with other electronic devices or interactive tools.
There are two general ways to construct the electronic textile systems: one way is to first prepare the fibershaped essential functional elements based on conductive fiber and then weave them into commercial fabrics/ textiles (bottom-up strategy), and another way is to directly fabricate the functional devices based on the conductive textiles (top-down strategy).
For the bottom-up strategy, the preparation of conductive fibers is a prerequisite for constructing electrochemical biosensing textiles.So far, various conductive electrode materials, such as carbon nanomaterials, polymers and metals, have already been explored in conducting conductive fibers.Carbon nanomaterials, such as carbon nanotube (CNT) and graphene, with good electrical conductivity, high thermal stability, and ease of chemical functionalization, are widely manufactured into conductive fibers.Lightweight and mechanically strong CNT fibers can be prepared by chemical vapor deposition, [31] dry spinning [32] or wet spinning, [33] and flexible graphene fibers are usually prepared by wet spinning. [34]Besides, polymer-based conductive fibers, such as poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and polyaniline (PANI), are widely used materials for direct electrospinning into conductive nanofibers. [35,36]Furthermore, the direct utilization of commercial metallic fibers to prepare functional devices has garnered significant attention.
Generally, an electrochemical biosensor comprises either a two-electrode system featuring a working electrode and a reference electrode, or a three-electrode system incorporating an additional counter electrode.In this case, the fiber-shaped biosensor can be fabricated through structural designs such as coaxial, twisted, or parallel arrangements of two or three fiber-shaped electrodes. [11]For instance, Peng et al. [37] utilized different sensing components dipped onto the surface of CNT fibers to fabricate various single-ply sensing fibers and then twisted them together to ultimately form an electrochemical biosensing flexible fiber capable of multi-biomarker monitoring (Figure 2A).The fiber exhibited the capability of chemically detecting various biomarkers separately (H 2 O 2 , prostate-specific antigens, calcium ions [Ca 2+ ] and glucose).Recently, our group developed an all-in-one electrochemical fiber to achieve multifunctional detection and stretchability in one fiber through a novel structural design. [38]We arranged CNT strips side by side on pre-stretched silicon fibers, assembling them helically to form a core sensing fiber.Ultimately, this could detect six distinct molecules in real-time health monitoring even under a large strain of 300% (Figure 2B).
However, further sophisticated functionality on these extremely fine-level conductive fibers with minimal diameters is a significant challenge considering the largescale fabrication. [25]The top-down strategy involves embedding conductive materials directly into textiles, as well as the further deposited functional materials, through techniques such as electrochemical coating, [40] spray coating, [41] dip coating, [42] 3D-printing, [43] screen printing, [44] inkjet printing, [39] and laser processing, [45] or by incorporating microelectronic devices into textiles. [46]This strategy has the advantage of production efficiency.For instance, a reliable shape-preserving inkjet printing process was introduced, [39] in which particle-free functional inks create a conductive network within the fabric's structure, maintaining the fabric's texture and tactile qualities (Figure 2C).][49][50] For example, a sensor array based on silk fabric-derived intrinsically nitrogen-doped carbon textiles was fabricated by using a simple and economical laser processing strategy. [18]The intrinsically nitrogen-doped graphitic nanocarbon structure and the intricate hierarchical woven and porous design bestow the textile with good conductivity and enhanced reactant accessibility.The final integrated, flexible sweat analysis patch based on this silk fabric-derived carbon textile was developed for the monitoring of six healthrelated biomarkers (glucose, lactate, ascorbic acid, uric acid [UA], sodium ions [Na + ] and potassium ions [K + ]) (Figure 2D).
To sum up, the rational choice of conductive substrate' fabrication technologies is paramount in achieving various specific sensing functions in electrochemical biosensing textiles.In addition to being dependent on user-side application requirements and performance specifications, factors such as technological feasibility, cost-effectiveness, scalability, sustainability, and environmental considerations must be taken into account.

| Applications in electrochemical biosensing textile
Electrochemical biosensors are typically categorized into amperometry, potentiometry and impedance based on different sensing mechanisms, but overall, they all convert the chemical signals of the target analyte into electrical signals.Therefore, in this section, we will no longer emphasize specific sensing mechanisms but will instead take different biomarkers as entry points to discuss textile-based electrochemical sensors for continuous molecular monitoring.Details regarding the concentration and health condition of various analytes, sensing platforms, and sensing mechanisms of relevant applications are summarized in Table 1.

| pH-value-sensing devices
Measuring pH value and its trend among numerous physiological signals and biomarkers of biological health can unveil a wealth of information about an individual's physiological state.The pH value can reflect information related to the human body's local, regional, and even systemic acid-base balance.For instance, they can predict and monitor skin conditions, [62] offer indirect insights into blood glucose levels, [63] and track individual exercise intensity. [64]In addition, monitoring pH often reveals scenarios related to personal physiological activities and medical processes, such as wound healing, [65] the recovery and aggravation of ulcers, [66,67] and drug tracking. [68,69]he monitoring of pH in wearable devices is predominantly based on potentiometric sensors. [70]These pH sensors determine a target analyte's concentration by measuring the potential change between the working and reference electrodes.This method, known for its efficiency in quantitative analysis, features almost negligible bias current (on the order of 10 −15 A).This characteristic simplifies its design and compactness, requiring lower power than other sensor types, rendering it more resistant to interference effects and ohmic drop. [71,72]PANI was frequently employed in pH-value-sensing devices due to its relatively easy preparation, low cost, high chemical stability, tunable conductivity, and involvement of charge delocalization at multiple active sites. [73,74]These developed pH sensors exhibited satisfactory sensitivity of around 60 mV/pH, a linear range from 2.0 to 8.0, and could be stretchable above 100% by using elastic polymers through the PANI-coating method or coaxial electrospinning. [51,52,75]he fiber-shaped pH sensor can be further woven into the commercial fabric in practical usage.Wang et al. [54] achieved the integration of various sensing yarns including a pH sensor by embroidering them onto a fabric substrate (Figure 3A).These sensing yarns featured a multi-ply cotton sheath and a CNT-based sensing fiber core.Furthermore, whether in interfering ions or under physical strains like bending and twisting, the sensing yarns can maintain excellent selectivity for multiple target analytes detecting (pH, glucose, Na + , and K + ).In addition, a fulltextile biosensing platform was developed by utilizing natural and synthetic fibers, appropriately functionalized to enable sensing capabilities. [55]Specifically, the PEDOT:PSSbased two-terminal thread sensor was further functionalized by employing Ag/AgCl nanoparticles and bromothymol blue dye, enhancing its sensitivity for chloride ion (Cl − ) and pH, respectively.Various sensing fibers can operate in parallel without interference, precisely monitoring Cl − concentration and pH levels in body fluids, validating the possibility of weaving or sewing thread sensors into fabrics.78] T A B L E 1 A summary of wearable biosensors for real-time biomarkers monitoring.35.9 mV/dec CNT fiber [53]  (Continues)

| Ion-sensing devices
Electrolytes play a vital role in human metabolism and mineral balance.They coexist with trace heavy metal ions in intracellular, extracellular fluids, and metabolic products, intricately linked to overall human health.For instance, Na + and K + are pivotal in maintaining fluid osmolarity.81] Moreover, deviations from normal levels of soluble Ca 2+ within the human body can harm health, including The sweat capture process of the CSSY-EFS and EFS, respectively.Reproduced with permission. [54]Copyright 2022, Wiley.(B) (a) An electrochemical fabric composed of coaxial sensing fibers for real-time monitoring of various physiological signals.(b) Application and demonstration of the electrochemical fabric integrated into a garment for monitoring running processes through a smartphone.Reproduced with permission. [53]Copyright 2018, Wiley.(C) Design, composition and typical time trace plots for K + and Na + of the textile-based stretchable multi-ion potentiometric sensor.Reproduced with permission. [57]Copyright 2016, Wiley.(D) (a) A self-healing multi-ion sensor integrated with a flexible printed circuit board.(b) Stitch the ion-sensing thread electrodes with a needle, embedding multi-ion sensors into the textile.(c) Schematic diagram of ion-sensing and reference thread electrodes.Reproduced with permission. [56]Copyright 2019, American Chemical Society.CSSY-EFS, core-sheath sensing yarn-based electrochemical fabric sensor; EFS, electrochemical fabric sensor; ISM, ion-selective membranes; MWCNT, multi-walled carbon nanotube; SHP, self-healing polymers; PVB, poly(vinyl butyral).
impaired clotting function, acid-base balance disturbances, liver cirrhosis, kidney dysfunction and skeletal health issues. [82]Additionally, the total ion concentration in human sweat, such as Cl − levels, can serve as markers for cystic fibrosis and provide insights into the overall electrolyte balance in the body. [19,83,84]he ion-sensing microelectrodes, such as K + and Na + , were obtained by utilizing corresponding ion-selective membranes and an ion-electron converter (such as PEDOT:PSS) on the surface of the electrode so that specific ions can be selectively transported.As a result, a localized Faraday reaction takes place on the electrode surface.During this reaction, electrons flow towards the conductive substrate, and the potential difference change throughout this process is measured.Similarly, the principle of utilizing electrochemical interactions between ions and the material surface, leading to changes in electrical conductivity or current, is also employed in constructing biosensors. [48,56,58,85]The detection of multiple ions or biomarkers is usually integrated into a textile system.Wang et al. [53] fabricated multi-ions sensing fibers by coating CNT fibers with active materials to form coaxial structures, and integrated different sensing fibers into wearable electrochemical fabrics.Under repeated deformations, the textilebased platform effectively monitored five physiological signals (glucose, Na + , K + , Ca 2+ , and pH) (Figure 3B).A textile-based multi-ion potentiometric sensor was achieved to be stretchable up to 100%. [57]They selected an ionselective membrane based on stretchable polyurethane and combined it with developed stretchable printed electrodes and a serpentine sensor pattern for the real-time, noninvasive monitoring of Na + and K + levels (Figure 3C).
In addition, the durability of sensors has been emphasized because wearable devices may undergo mechanical wear and tear over time or suffer accidental damage in practical applications, potentially leading to possible breakdowns.[88][89][90] A fast self-healing and robust textile-based multiple K + and Na + ion sensors with a self-recovery capability within 20 s were reported. [56]This sensor was created by coating carbon fiber thread electrodes with a fast self-healing citrate-based supramolecular polymer to make ion-sensing threads, which were then woven into typical textiles (Figure 3D).
Despite the extremely low levels of heavy metal concentration in human body fluids (typically in the order of μg/L), imbalances can have severe consequences such as stunted growth, intellectual development issues, delayed sexual maturation and skeletal problems. [91]oreover, prolonged or high-level exposure to heavy metals such as lead (Pb) can also cause irreversible damage to the nervous system, organs, and reproductive and developmental problems. [92]For instance, a sensor for heavy metals detection based on a commercial textile had been developed using electrochemical plating combined with screen-printing technology using a Bi-based electrode. [93]Corresponding alloys (such as Pb(Bi), Cd(Bi), and Zn(Bi)) would be formed at a different negative potential in the solution containing Pb 2+ , Cd 2+ , and Zn 2+ .The concentration of heavy metals would be obtained during the corresponding stripping response for each element when the square-wave voltammetric stripping scan reached a certain potential.Detecting extremely low levels of heavy metals in bodily fluids is challenging, and integrating sensing platforms onto microfibers or flexible and adaptable textiles adds another layer of complexity.

| Metabolite-sensing device
Human metabolites (e.g., glucose, lactate, and UA) are widespread in biological fluids such as blood, sweat, saliva and tears, which are directly related to some diseases.[101] Furthermore, measuring lactate levels and their temporal trends is invaluable for caring for noninfectious patients, such as individuals undergoing trauma or surgery. [102,103]UA, the final product of purine metabolic breakdown, can lead to gout disease, [104] hypertension, [105] hypertriglyceridemia, [106] cardiovascular diseases, [107] and Lesch-Nyhan syndrome when hyperuricemic, [108] while low UA levels may be associated with multiple sclerosis, Parkinson, and other diseases. [109]herefore, the development of non-invasive wearable biosensors for human metabolites is vital.
[112][113] Sweat is the primary method of lactate excretion, and textile-based sensing platforms targeting lactate monitoring in human sweat have been reported. [18,114]For instance, a thread-based lactate sensing patch using lactate oxidase for continuous and simultaneous monitoring of sweat on the skin was proposed (Figure 4A). [17]However, for enzymatic biosensors, addressing the limitations of their instability and reproducibility is necessary to expand their integration into wearable devices.Furthermore, enzymes are costly, limiting their use in large quantities.Surface modification of nano-fiber for multi-point attachment determines undesirable conformational changes of the enzyme in unfriendly environments, which contributes to the durability and stability of the textile-based sensor, such as the crosslinking method, [115,116] the covalent bonding method, [117,118] the adsorption method, [119,120] and the entrapping method. [121,122]Another issue that needs to be solved is that the enzymatic sensor is sensitive to pH, temperature, and time.Therefore, non-enzymatic sensors have been widely reported for direct electrocatalytic oxidation of metabolites at the electrode surface.For instance, hollow CuO/PANI nanofibers were reported for non-enzymatic electrochemical detection of H 2 O 2 and glucose. [59]The polyamide acid fibers used as a sacrificial template were employed to fabricate functional fiber via electrostatic spinning.The resulting three-electrode system exhibited a wide linear range and a low detection limit, with values of 0.005 mM for H 2 O 2 and 0.001 nM for glucose.A sweat-based biosensor for UA detection was reported based on electrospun carbon nanofibers with active sites, enabling efficient electron transmission. [123]The reliable and sensitive detection of UA can provide information on wound exudate under both static and flowing conditions.Furthermore, an organic electrochemical transistor configuration biosensor based on PEDOT:PSS and screen-printing technology was developed to fabricate a textile wound dressing for UA detection. [124]2.4 | Other biomarker-sensing devices Some other biomarkers (e.g., cytokines, nutrients, hormones, etc.) have a more direct role in some specific disease prevention and health monitoring.For instance, inflammatory cytokines (e.g.interleukins) play a crucial regulatory role in the human immune system.They can stimulate or inhibit the activity and influence the proliferation and differentiation of immune cells.Cortisol, which is referred to as the "stress hormone," and deficiency or excess of cortisol triggered by physical or psychological stress is associated with diseases, including post-traumatic stress disorder and primary adrenal insufficiency.[125][126][127] The prompt and precise detection of the steroid hormone cortisol plays a crucial role in diagnosing stress-related permission.[17] Copyright 2020, Springer Nature.(B) (a) Fabrication of the CNT/graphene composite fiber.(b) The mechanism of in situ detection of the fabric biosensor.Reproduced with permission.[60] Copyright 2023, Elsevier.(C) (a) Schematic of an application example of a MIP-based sensing fabric for cortisol monitoring.(b) Schematic of the composition of the core sensing fiber electrodes.Reproduced with permission.[61] Copyright 2024, Wiley.
adrenal disorders and chronic illnesses.However, research in related fields is constrained due to their extremely low concentration, stringent specificity requirements, and the need for sensors with high resistance to interference. [128]hese biomarkers typically lack corresponding antibody-antigen pairs like glucose-GOx, so alternative methods are required to detect such substances.One alternative approach is to utilize the specific binding of related aptamers to continuously monitor these trace amounts of biomarkers.So far, aptamer-based plainshaped biosensors have successfully developed, such as a flexible aptameric graphene-Nafion field-effect transistor biosensors to detect cytokine biomarkers, [129] and a flexible multi-channel immune sensor using aptamer to detect multiple inflammatory mediators (tumor necrosis factor-α, interleukin-6, interleukin-8, and transforming growth factor-β1). [130]Nevertheless, it remains a significant challenge to functionalize the aptamer on the curved surface of the fiber substrate to achieve better flexibility and wear comfort.Our team [60] recently made the first-ever report of an aptamer-based fabric wearable system with flexibility, anti-fatigue ability and breathability (Figure 4B).Specifically, this sensing fabric comprises the CNT/graphene composite fibers functionalized with aptamers, capable of real-time and in situ monitoring of interleukin-6.Moreover, this fiber functionalization method is universal and can be modified by changing the corresponding aptamers to detect other biomarkers (such as cortisol).
It is worth noting that washability is necessary for the sensing textile, which is hardly achieved by aptamer-based biosensors.In this case, MIPs, known as plastic polymers, hold a promising strategy to achieve a stable biosensor due to their stability under demanding chemical and physical conditions.A widely recognized application of MIPs is their capacity to extract cortisol from complex matrices such as biofluids due to their specific molecular recognition property.For this purpose, our group recently developed a washable sensing fabric for monitoring cortisol in sweat by functionalizing CNTs with MIP (Figure 4C). [61]The fabric exhibited satisfactory sensing capabilities (ranging from 1 pM to 10 μM) and a robust interface between MIP and the fiber electrode, benefiting from intricate channels within the CNTs.The sensing fabric retained its sensing capabilities even after undergoing 100 cycles of ethanol washing.

| POWER SUPPLY OF ELECTROCHEMICAL BIOSENSING TEXTILES
As the trend towards miniaturization, portability, and multifunctionality of wearable electronics becomes increasingly apparent, the demand for portable and secure sustainable power sources becomes pronounced. [131]The emergence of fiber-shaped and textile-based electronic devices is actively contributing to the breakthrough of the traditional rigid properties of energy-related devices, to meet the substantial demand in the flexible market.
Specifically, power supply devices for wearable electronics are generally divided into two types: energy harvesting devices and energy storage devices.In wearable scenarios, kinetic energy generated by body movements, biochemical energy from sweat-based biofuels, thermos energy from the body, and solar energy from the sun or artificial light can be harvested as energy sources to power the devices, which are known as triboelectric nanogenerators, piezoelectric nanogenerators, biofuel cells, thermoelectric nanogenerators, and solar cells. [11,132,133]In addition, energy storage devices represented by batteries, serving as a continuous and stable energy supply, can store the energy from household electricity or wearable energy conversion devices like solar cells.As a complete power supply for electrochemical biosensing textiles, an energy harvesting device and corresponding energy storage device are needed for overall energy conversion and storage.
Nanogenerators usually rely on extensive physical activity to generate pulsed electricity (generally several to hundreds of microamperes). [22]In addition, internal energy harvesting biofuel cells face challenges such as poor stability of the enzymes or redox mediator, low energy density, and biofouling, limiting their further application. [27,134]Solar cells stand out as promising devices for on-body powering owing to their easily accessible, renewable energy source from solar irradiance, higher energy conversion efficiency and output power. [135,136]Also, owing to the intermittent nature of solar energy from day-night cycles, it is necessary to equip suitable energy storage devices to maintain a continuous power supply.In this case, we will focus on fiber-shaped and textile-based solar cells and batteries.

| Fiber-shaped solar cells
After experiencing the first-generation photovoltaics, such as crystalline silicon and the second-generation represented by thin-film photovoltaic devices, such as amorphous silicon and copper indium gallium selenide, recent developments in solar energy harvesting technology have centered around the third-generation photovoltaic devices.These include dye-sensitized solar cells (DSSCs), organic solar cells (OSCs), and perovskite solar cells (PSCs), serving as prominent representatives. [35,131,135]Fiber-shaped solar cells typically consist of two electrodes, and they are usually assembled into coaxial, twisting or interlaced configurations, each corresponding to distinct contacts between electrodes and functional layers, leading to various photoelectronic characteristics (Figure 5).
Fiber-shaped DSSCs were first reported in a coaxial configuration in 2001. [137]Because the initial versions of fiber-shaped DSSCs were hindered by the high resistance of the conductive polymer as the counter electrode, a voltage of only 0.35 V and a current of a few microamperes was achieved in a 10 cm long fiber cell.Over the years, researchers have extensively explored counterelectrode materials and electrolytes to enhance power conversion efficiency (PCE).139] However, the risk of leakage and volatility in the liquid electrolyte of DSSCs has consistently impeded their further application in wearable scenarios, warranting additional consideration.A stable semi-solid electrolyte was prepared utilizing polymer and hydrophobic ionic liquid. [140]This electrolyte could maintain its phase state below 98°C and combine the advantages of a nonleaking gel and a nonvolatile ionic liquid, broadening its utilization in specific scenarios (Figure 6A).Despite sacrificing some degree of PCE due to differences in conductivity and ion migration speed, quasi-solid or allsolid-state electrolytes are emerging as promising solutions in terms of safety.
Compared to DSSCs based on liquid electrolytes, allsolid-state fiber-shaped OSCs with an organic polymer donor material as the photoactive layer offer enhanced safety and stability for wearable electronic applications.Fiber-shaped OSCs were first reported in 2007 with an optical fiber serving as the substrate and Al film as the counter electrode in a coaxial configuration. [144]Due to the confined radiation within the active layer, it displays a PCE of only 1.1%.Moreover, choosing a suitable counter electrode in fiber-shaped OSCs is crucial for electron collection and injection.CNTs and graphene are the preferred counter-electrode materials for coaxial configuration due to their outstanding surface area, flexibility, and conductivity.A solid-state, polymer-based fiber OSC was developed using a layer of single-walled CNTs to replace conventional metal counter electrodes. [141]The OSC exhibited a higher PCE of 2.31% based on a coaxial configuration (Figure 6B).To further improve the electrical conductivity of counter electrodes by applying a single-layer graphene sheet doped with Au nanoparticles, a further increased PCE of 2.53% was obtained for fiber-shaped OSCs. [145]espite OSCs excelling in safety and stability, the low PCE has always been their most apparent weakness.PSCs have become a shining star in photovoltaic devices due to their outstanding PCE, and they have emerged as a strong candidate for addressing the low power supply caused by low light intensity in wearable scenarios.Qiu et al. reported, [142] for the first time, by coating a stainless steel wire with photoactive perovskite materials through a solution process, developed a PSC with a flexible fibershaped coaxial structure and exhibited a PCE of 3.3% F I G U R E 5 Schematic illustrations of different configurations of fiber-shaped solar cells.
(Figure 6C).Researchers have devoted significant effort to enhancing the PCE and enabling applications in wearable devices.For instance, addressing the compatibility issues between heat-sensitive flexible polymer substrates and compact TiO 2 layer requiring hightemperature annealing, we employed a mild solutionbased process and substituted the TiO 2 layer with obelisk-like ZnO arrays, leading to the further fabrication of perovskite photovoltaic fibers and textiles. [146]Later, Dong et al. [143] applied the vapor-assisted deposition method, commonly used for planar solar cells, to fabricate fiber-shaped PSCs.They achieved the fabrication of perovskite thin film layers on a titanium metal fiber substrate, combined with the utilization of gold thin film electrode, and the PCE reached 10.79% (Figure 6D).

| Textile-based solar cells
For textile-based solar cells, similar to the structural design of sensing textiles mentioned in Section 2.1 above, weaving, stitching, and knitting based on fiber-shaped solar cells stand as primary methods emphasizing flexibility, adaptability, and wearability.For instance, Zhang et al. [147] first manufactured fiber-shaped PSCs by twisting a modified Ti wire cathode and an aligned multiwalled CNT fiber anode.Subsequently, these were directly woven into a highly flexible photovoltaic textile without sealing, resulting in a lightweight power source suitable for wearable electronics (Figure 7A).
In addition, transferring prepared solar cells directly onto textile substrates or building solar cells on textile substrates by layer-by-layer coating or printing techniques is another strategy to avoid sliding between fibers to improve the interface stability and mechanical durability.However, when this structure was constructed in DSSCs (a PCE of 2.63%) [150] and OSCs (a PCE of 2.27%), [151] it only exhibited a low PCE of around 2%.Moreover, integrating planar-type solar cells directly into textile substrates will decrease breathability and wearability, conflicting with the primary purpose of wearable electronics.Therefore, a manufacturing approach that involves weaving before stacking was adopted. [148]The textile-based DSSCs were developed with modified Ti mesh as the working electrode and CNT textile woven by fibers as the counter electrode.Subsequently, these two Manufacturing and construction examples of fiber-shaped solar cells.(A) Constructing a flexible DSSC and the chemical constitution of ionic liquid gel electrolyte.Reproduced with permission. [140]Copyright 2015, Wiley.(B) The preparation process and constitute of a fiber solar cell.Reproduced with permission. [141]Copyright 2012, American Chemical Society.(C) The component material and structure of the flexible fiber-shaped PSC fabricated through a solution process.Reproduced with permission. [142]Copyright 2014, Wiley.(D) The chemical components and construction of the fiber-shaped PSC fabricated by the vapor-assisted deposition method.Reproduced with permission. [143]Copyright 2019, Wiley.
components and injected electrolytes were stacked before encapsulation (Figure 7B).As a result, the final DSSCs ensured close electrode contact while emphasizing the flexibility of the textile, achieving a PCE of 3.67%.
In addition to the strategies mentioned above that are based on fiber weaving and textile substrates, various other textile-based solar cells are also emerging.For instance, an interlaced fiber electrode-type solar cell was developed, wherein photovoltaic anodes and counter electrodes were seamlessly woven in an interlocking pattern to create a single-layer textile. [149]Furthermore, these textiles can be integrated into commercial garments to power portable electronic devices.Despite achieving a PCE of only 1.3% in the resulting single solar cell, this weave-interleaved manufacturing method offers advantages regarding the exposed surface area of photosensitive fibers and wearer comfort (Figure 7C).
Moreover, fiber-shaped DSSCs were directly sewn onto commercial clothing, creating customized patterns. [139]These DSSCs can also be integrated with fiber-shaped Li-ion batteries, achieving multifunctional smart clothing with health monitoring, display interaction, energy storage, and charging (Figure 7D).Despite resulting in different shapes and functionalities, the core F I G U R E 7 Construction and application examples of textile-based solar cells.(A) Photos of the fiber-shaped PSCs woven into a highly flexible textile and supply energy for an iPod.Reproduced with permission. [147]Copyright 2014, Wiley.(B) Images of the DSC textile and successfully glowing a light-emitting diode.Reproduced with permission. [148]Copyright 2014, Wiley.(C) Images of the fiber-shaped PSCs woven into flexible clothes.Reproduced with permission. [149]Copyright 2016, Wiley.(D) (a) The composition and working process of the smart healthcare garment.(b) Images of the fiber dye-sensitized solar cells and fiber Li-ion batteries woven into the sweater supplying energy for a smartwatch.Reproduced with permission. [139]Copyright 2022, Wiley.DSC, dye-sensitized solar cells.
objective remains the same: constructing more efficient textile-based solar cells that are less reliant on specific scenarios and offer increased flexibility and comfort.
Interdisciplinary research related to photovoltaic effects has been ongoing for several decades.However, the critical bottleneck problems in this field have always been energy efficiency and device stability.In addition, washability and resistance to strain performance of photovoltaic cells also need to be considered and improved. [136,152]In the context of self-powered wearable sensors and portable devices, the biocompatibility of photovoltaic cells also needs to be considered.While the challenges in this area have yet to be resolved, the substantial wearing surface area and readily available visible light present attractive opportunities for the next generation of energy harvesting and interactive experiences.

| Aqueous fiber batteries
Commercial batteries employing organic electrolytes pose a risk of combustibility and toxicity, raising safety concerns when applied in wearable cases and diminishing the potential of their usage for implantable devices.Since safety is particularly emphasized in wearable electronics, the aqueous electrolyte is one of the best candidates for wearable fiber-shaped battery systems with its high ionic conductivity, ease of handling, and safety features.Noteworthy, manufacturing batteries utilizing existing textiles has certain advantages regarding scalability and mechanical durability.However, sacrifices have been made in terms of wearing comfort and breathability.Additionally, building batteries on textile substrates via direct transfer, layer-by-layer coating, or printing is bound to face larger-scale encapsulation, which contradicts the concept of in-situ analysis in biosensing. [26,153]Therefore, constructing satisfactory batteries at the fiber level is more promising and, at the same time, more challenging.Here, our emphasis will be on introducing fiber-shaped aqueous batteries, categorized into liquid and gel electrolytes based on the physical state of the electrolyte.Details regarding the materials, cycling stability, energy density and power density of aqueous fiber batteries are summarized in Table 2.

| Liquid electrolyte
The primary advantages of using liquid electrolytes are their high ionic conductivity and safety.An early fiber-shaped aqueous Li-ion battery was developed using polyimide/CNT hybrid fibers as the anode and LiMn 2 O 4 /CNT hybrid fibers as the cathode (Figure 8A). [154]The battery exhibited a reversible discharge specific capacity of 134 mAh g −1 at 10 C.This battery's power density and energy density were 10217.74W kg −1 and 48.93 Wh kg −1 , respectively.][170] Nevertheless, the performance of fiber-shaped ASIBs showed a low voltage and energy density.For instance, a flexible ASIB using nano-NaTi 2 (PO 4 ) 3 @C as the anode, Na 0.44 MnO 2 as the cathode, and 1 M Na 2 SO 4 as the electrolyte, which had a dischargespecific capacity of 46 mAh g −1 at a current density of 0.1 A g −1 . [155]iber-shaped aqueous Zn-ion batteries (AZIBs) have emerged as promising energy storage systems to achieve a higher energy density in recent years. [9,171]For instance, a fiber-shaped AZIBs based on stainless steel conductive yarn, with Zn as the anode and nickel cobalt hydroxide nanosheets as the cathode (Figure 8B).It displayed a capacity of 16.6 mAh cm −3 (normalized to the sum of two yarn electrodes), and the capacity retention rate was 60% after 1000 cycles. [156]However, the battery had a limited deformation resistance.Under the deformation conditions of 95°bending and 360°twisting, 80% and 70% of the initial capacity were retained after 1000 cycles.The capacity decrease may be caused by cracks formed during the deformation process of the stainlesssteel electrode material.
Compared with metal fibers, carbon-based fiber such as CNT fiber or carbon fiber electrodes have superior flexibility, promising to enhance stability under deformation.For instance, the fiber-shaped AZIB was composed of a self-assembled Co 3 O 4 nanosheet array on CNT fibers as the cathode and Zn nanosheets deposited on the CNT fibers as the anode with a Co 2+ containing electrolyte (Figure 8C). [157]Such a prepared battery showed a reversible 158.7 mAh g −1 capacity at 1 A g −1 and a good cycling performance (97.27% capacity retention after 10,000 cycles).The capacity retention of the fiber-shaped battery was maintained at 90.72% after 2000 cycles of bending at 120°.Another example is that a fiber-shaped AZIB was constructed based on carbon fiber by utilizing the rich zincophilic N or O-containing functional groups to reduce the surface binding energy of Zn onto the anode (Figure 8D). [158]It demonstrated volumetric energy density (5.63 mWh cm −3 ) with a capacity retention of 90% after 2000 cycles.In addition, aligned CNT film can be employed as the surface protective layer for cathode materials to enhance stability. [159]The resulting flexible aqueous Zn-MnO 2 fiber batteries exhibited a long-term cycle life of 4000 cycles and discharge discharge-specific capacity of T A B L E 2 A summary of the performance of aqueous fiber batteries for portable power supply.Based on the active materials except for Guan et al. [158]   which is calculated by the total volume of ZFCF and Co 3 O 4 nanowires array material.332 mAh g −1 at 2 A g −1 .The fiber-shaped battery demonstrated mechanical and electrochemical stability under diverse deformations and then was woven into a flexible belt, powering an electronic watch.

Electrolyte
While aqueous batteries with liquid electrolytes have alleviated the problems of easy volatility and thermal runaway of organic electrolytes to some extent, they have not fundamentally addressed the risk of leakage. [172,173]his poses an obstacle to realizing flexible energy devices for practical applications.Thus, developing wide electrochemical windows and mechanically stable electrolytes is essential for using high-energy-density aqueous flexible energy storage systems. [174]

| Gel electrolyte
Gel electrolytes exhibit advantages in ionic conductivity and mechanical strength, effectively mitigating evaporation and leakage inherent in liquid electrolytes.Moreover, their mechanical flexibility and deformability make them ideal candidates for wearable electronic power supply modules. [175,176]Generally, gel electrolytes in aqueous batteries consist of a polymer matrix and an ionic conductor. [177]he polymeric matrix is essential because it provides superior mechanical flexibility and lowers the volatilization of water molecules. [178]Typical examples of polymeric matrixes are polyvinyl alcohol (PVA), [161,164,179,180] poly (ethylene oxide), [181] sodium alginate, [182] carboxymethylcellulose, [183] polyacrylamide, [184] and gelatin. [185]Considering the advantages of high theoretical capacity and easy assembly of Zn-ion batteries, most of the developed fibershaped aqueous batteries using gel electrolytes are fibershaped AZIBs with different assembly structures, including parallel, twisted, and coaxial structures.
A parallel-structured fiber-shaped battery was fabricated by two parallel and independent fiber electrodes separated by a quasi-solid-state electrolyte followed by encapsulation.Fiber-shaped AZIBs were reported using an aligned cathode and anode parallelly and then coated with PVA-KOH gel as the electrolyte and separator. [160]Based on this gel electrolyte, the fiber-shaped AZIBs achieved an energy density of 4.6 mWh cm −3 .In another work, graphene oxide flakes were introduced into the PVAbased gel to enhance ion conductivity, and the assembled fiber-shaped AZIB was sealed with a silicone layer (Figure 9A). [161]The integrated battery had a dischargespecific capacity of 467 mAh cm −2 at a current density of 0.8 A cm −2 , and the capacity retention rate was 75.4% after 1500 cycles.Furthermore, the battery exhibited excellent self-repairing capabilities due to the spontaneous attraction and reversibility of hydrogen bonds within PVA chains in the gel electrolyte.Similarly, CNTs were employed as the substrate, employing coating amorphous H 0.82 MoO 3.26 as the cathode material for fiber-shaped AZIBs, with Zn wire as the anode. [162]Finally, the fabricated batteries achieved an energy density of 32.1 mWh cm −3 with a retention of 67% after 5000 charge-discharge cycles, maintaining approximately 91% capacity even after 3500 bending cycles.In another example, the fiber-shaped AZIBs were assembled by employing Zn wire as the anode and mixedvalent manganese oxide (MnO x ) as the cathode, which Assembly examples of aqueous fiber batteries with liquid electrolyte.(A) Composition of a fiber-shaped aqueous Li-ion battery.Reproduced with permission. [154]Copyright 2016, Royal Society of Chemistry.(B) Composition of a fiber-shaped AZIB.Reproduced with permission. [156]Copyright 2017, American Chemical Society.(C) Composition of a carbon nanotube fiber-based AZIB.Reproduced with permission. [157]Copyright 2021, American Chemical Society.(D) Schematic illustration of the assembly of a fiber-shaped AZIB. [158]opyright 2019, Wiley.demonstrated a reversible capacity of 255.8 mAh g −1 , and maintained a capacity retention rate of 80% after 1000 bending deformations. [163]Moreover, a biomimetic helical structural design was utilized, winding PANI-Zn as the anode and elastic graphene as the cathode around a silver fiber with PVA/ZnSO 4 gel as the electrolyte. [164]The resulting battery can be stretched to 900%, maintaining a capacity retention rate of 71%.Furthermore, it demonstrated an excellent specific capacity (32.56 mAh cm −3 at 10 mA cm −3 ) and energy density (36.04 mWh cm −3 ), and had a specific capacity of 33 mAh cm −3 at a current density of 10 mA cm −3 and a retention rate of 76.5% after 1000 cycles.Nevertheless, this structure might cause short circuits when it deforms.Additionally, during electrochemical reactions, the kinetic reaction is slow due to the small effective contact area and long ion transport distance, which decreases the electrochemical performances.
Twisted structure fiber-shaped AZIBs were developed to increase the effective contact area and prevent cathode and anode separation.For example, a fiber-shaped AZIB with a twisted structure with a cathode consisting of Ag 2 O nanoparticles and an anode of Zn nanosheets was reported (Figure 9B), [165] whose energy density was 1.57 mW cm −2 , and the capacity retention rate was 79.5% after 200 cycles.Here, it is crucial to control the degree of twisting in the electrode.Insufficient twisting hinders the structure's advantages, while excessive twisting disrupts mechanical flexibility due to tight interactions between anode-cathode fibers.
Wrapping fiber electrodes around conductive fibers and coating them with gel electrolytes to create a coaxial structure is another assembly method for fiber-shaped AZIBs.Coaxial structures of fiber-shaped batteries offer the advantages of high contact area, uniform electric F I G U R E 9 Assembly and application examples of aqueous fiber batteries with gel electrolyte.(A-C) The assembly structures of fibershaped aqueous batteries with gel electrolytes: (A) Parallel structure.Reproduced with permission. [161]Copyright 2021, American Association for the Advancement of Science; (B) Twisted structure.Reproduced with permission. [165]Copyright 2019.Royal Society of Chemistry; (C) Coaxial structure.Reproduced with permission. [166]Copyright 2018, Wiley.Reproduced with permission. [167]Copyright 2022, Springer Nature.GPHE, graphene oxide-embedded polyvinyl alcohol hydrogel electrolytes; NCA, nanocarbon array field, and short ion transport channels for the most efficient utilization of active materials and good electrochemical performances.For instance, quasi-solid-state coaxial fiber-shaped AZIBs were assembled using Zn wire as the anode and polyaniline/carbon felt as the cathode (Figure 9C). [166]The discharge-specific capacity was 106 mAh g −1 , and the capacity retention was 94% after 50 cycles.Its capacity can still reach 97 mAh g −1 after 200 bending cycles, corresponding to a capacity retention of 91.5%.However, the difficulty in assembling coaxial structures and the issue with electrode short circuits impede the quick development of these devices.In addition, the direction of mechanical stress in this structure is parallel to the fiber device, which can easily cause stress concentration on the device and reduce mechanical flexibility.
Since fiber energy storage batteries have the energy storage function, unique flexibility, and knitting characteristics, they can be naturally constructed into energy storage fabrics, giving ordinary fabrics new functionality.Nevertheless, it is challenging to fulfill the large-scale needs of actual applications using the existing layer-bylayer coating method for batteries, which can only fabricate fiber-shaped batteries with low production rates.Peng et al. [167] created an all-in-one fiber-shaped battery via solution extrusion in a single process.The cathode, anode, and electrolyte are extruded from a three-channel nozzle, then the gel electrolyte coagulates around the anode and cathode fibers in a coagulation bath (Figure 9D).Here, electrodes and electrolytes for fiber batteries are simultaneously extruded and assembled in a highly productive three-channel industrial spinneret.A continuous fiber-shaped battery of 1500 km per spinneret unit may be produced using this approach.Finally, fiber-shaped batteries with an energy density of 550 mWh cm −2 were used to weave a smart tent of approximately 10 m 2 .
In summary, aqueous batteries, especially those composed of gel electrolytes, have garnered considerable attention in wearable electronics due to their significant water preservation and safety advantages.However, some necessary challenges also exist, such as irreversible electrolysis occurring when the operating voltage exceeds the thermodynamic decomposition voltage of water.Therefore, increasing the electrochemical voltage window is necessary.Additionally, achieving long-term stability of electrolytes during extended chargedischarge cycles and in complex physical environments of wearable devices and addressing effective packaging for aqueous batteries are crucial for further advancements in integrating aqueous batteries with wearable electronics.

| SUMMARY AND FUTURE PROSPECTS
Wearable biosensors used for health monitoring have already been widely recognized for their advantages: flexibility, comfort, non-invasive/minimally invasive, biocompatibility, and real-time continuous tracking.Textile-based wearable biosensors can be seamlessly combined with our daily clothes without any peculiar attention, physically or subjectively, and truly become an integral part of individual clothing.This paper starts with introducing fiber-shaped and textile-based electrochemical biosensors by adopting a bottom-up manufacturing strategy from fibers or a top-down strategy from textiles.Then, as for the energy supply for the wearable electrochemical biosensors, we have chosen solar cells and aqueous fiber batteries among numerous energy harvesting and storage devices as the primary subjects for review, considering key aspects such as energy sourcing, output power, safety, and environmental impact.The wearable electrochemical biosensing textile system is promising in medical technology and health management for continuous real-time monitoring of chemical molecules in human body fluids.The prospects for wearable electrochemical biosensing textile systems are as follows.

| Durability and washability
Wearable sensing devices face a variety of environmental and strain challenges.Therefore, preventing oxidation, moisture, corrosion, and mechanical deformation resistance are potential requirements for sensing devices to become "a true textile".Exploration of superhydrophobic and self-healing materials is a consideration for future processing and manufacturing techniques.Furthermore, taking wearable sweat biosensors as an example, the contact between the electrodes and sweat is not only essential for sense but is also a cause of corrosion and oxidation.Therefore, maintenance and cleaning of sensing devices are crucial for improving device durability and accuracy.
Textiles are not disposable items; intelligent textiles with expensive attached sensing devices should be even less so.Therefore, their washability in non-disassembled conditions should also be considered.In this case, encapsulation may be one solution for conductive materials on the surface of electronic fibers/textiles, especially those prepared by dipping or coating. [9,22,186]owever, encapsulation directly can lead to a decrease or failure in sensing functions.Therefore, long-term wearability and washability are the most significant challenges in future electrochemical biosensing textiles for personalized health monitoring.Moreover, due to the heterogeneity of academic solutions, conducting repeated washing and drying tests on smart textiles based on relevant unified international standards (such ISO 105/C10: 2006, AATCC 61-2013, or ISO/TC 38/SC 24) is a more meaningful evaluation of the washability.In conclusion, developing scientifically efficient manufacturing strategies and solutions that cater to the various intrinsic requirements of an "ordinary textile" is an essential step in developing electrochemical biosensing textiles.

| Multifunctional biomarker analysis in more demanding conditions
The next generation of wearable biosensors should avoid relying on overly ideal sensing conditions and aim to enhance their monitoring capabilities for multiple biomarkers, even across various bodily fluids.Taking the widely researched wearable sweat biosensor as an example, obtaining sweat samples with individuals at rest instead of being limited to some motion scenarios, analyzing multiple parameters in real-time and quickly, and preventing contamination and evaporation of sweat are all crucial challenges.One promising solution is microfluidics, which allows for minimally invasive or non-invasive sweat sampling on demand.Yang et al. [45] employed a laserengraved multi-entry microfluidic module with dynamic sweat sampling to minimize sweat contamination and skin evaporation.189] Moreover, researchers have explored techniques like iontophoresis or minimally invasive methods for active sweat collection.][192] Besides, while active chemical stimulation can obtain enough sweat samples, the metabolites present under these conditions may differ in composition and concentration from those induced by physical activity.Therefore, including active calibration functions in the next generation of biosensors becomes necessary.
In addition, although relevant research has already demonstrated a clear correlation between certain biomarkers in sweat and blood, offering feasible conditions for non-invasive health monitoring, the monitored physiological information often varies due to individual and environmental differences. [63]Therefore, the nextgeneration biosensors will require an emphasis on exhibiting exceptional adaptability and the ability to correct themselves using long-term, individual-specific health monitoring data.

| Aesthetics and portability
The focus of textile-based wearable biosensors is not solely on their sensing capabilities, the aesthetics and lightweight of coexisting with textiles are also important considerations.The choice of the wearable platform and location is highly relevant for sensing, energy harvesting, and comfort.Factors such as fabric color, shape, and size are key elements for wearers when selecting textiles and cannot be ignored when aiming for effective commercialization.
The fundamental development framework for wearable biosensors involves precise sensing, wireless communication, and human-machine interaction.Flexible electronics and wearable device science constitute an interdisciplinary field encompassing materials science, chemistry, electronic communication, and biology.The expandability of smart fibers and textiles in key functions such as sensing, power supply, and information storage and transmission holds the promise of fundamentally changing the landscape of personal healthcare.

| Monitoring data physiological correlation and clinical validation
The research and development of wearable biosensors often emphasize the relationship between analyte concentrations and output signals.However, the original intention of non-invasive health monitoring is to deliver reliable and interpretable physiological data to users.On the one hand, it requires extensive clinical validation by scientists and healthcare professionals to accurately assess an individual's health status based on molecular monitoring information.[195] This could serve as a valuable auxiliary approach to reduce the need for extensive clinical validation.Furthermore, compared to traditional in-person medical diagnostics, wearable biosensors can monitor long-term trends of specific physiological signals that short-term monitoring cannot achieve.Such personalized and long-term monitoring also presents opportunities and challenges in cloud storage and analysis of massive data.
As mentioned above, the next generation of wearable biosensors integrating multifunctional electronic components will inevitably require higher power demands.Relevant energy storage and harvesting strategies have already been extensively discussed and implemented.Leveraging the characteristics of textiles to integrate various energy harvesting devices into a single platform to enhance electrical power output is an inevitable trend.Additionally, safe and efficient energy storage devices and management units, along with effective thermal management techniques, are vital methods for alleviating the high-power consumption of these advanced devices.
While the large-scale commercialization of wearable biosensors is still a work in progress, thousands of scientists and scholars have already turned their attention to this interdisciplinary field filled with opportunities.The discovery of revolutionary materials is indeed exciting and highly anticipated, but the challenges and opportunities currently being faced are also being addressed and explored in parallel.Extensive scientific research and databases are driving progress in this field, with the potential to change traditional healthcare models and lifestyles fundamentally.

F
I G U R E 1 Schematic diagram of electrochemical biosensing textiles with energy supply units.

F I G U R E 3
Examples of ion-sensing fiber-based biosensors.(A) (a) The macro-and micro-structure of a core-sheath sensing yarn.(b)
(D) (a) Schematic diagram for large-scale production of fiber-shaped batteries.(b) The cross-sectional diagram of the produced battery.(c) Textile schematic integrating energy harvesting, storage, and display functions.(d) The photographs of the energy-generating textile and energy-storage textile produced.