Interfacing Living and Synthetic Cells as an Emerging Frontier in Synthetic Biology

Abstract The construction of artificial cells from inanimate molecular building blocks is one of the grand challenges of our time. In addition to being used as simplified cell models to decipher the rules of life, artificial cells have the potential to be designed as micromachines deployed in a host of clinical and industrial applications. The attractions of engineering artificial cells from scratch, as opposed to re‐engineering living biological cells, are varied. However, it is clear that artificial cells cannot currently match the power and behavioural sophistication of their biological counterparts. Given this, many in the synthetic biology community have started to ask: is it possible to interface biological and artificial cells together to create hybrid living/synthetic systems that leverage the advantages of both? This article will discuss the motivation behind this cellular bionics approach, in which the boundaries between living and non‐living matter are blurred by bridging top‐down and bottom‐up synthetic biology. It details the state of play of this nascent field and introduces three generalised hybridisation modes that have emerged.


Introduction
Thef ield of synthetic biology concerns itself with the design of biological systems not found in the natural world. [1] This allows the power of biological systems,h oned over evolutionary history,t ob et apped into and ultimately engineered for functional applications.T his approach also leads to new insights into the "rules of life": understanding biology by building an ew biology. [2] Synthetic biology has been heralded as one of the critical emerging technologies of the 21st century,o ffering solutions to diverse real-world problems.F rom combatting climate change through the production of biofuels, [3] to removing pollutants via bioremediation, to using engineered cells as therapeutics [4] and in regenerative medicine. [1,5] Synthetic biology has traditionally been divided into two distinct approaches.T he first is "top-down", where cells are modified using molecular biology and metabolic/genetic engineering techniques.T he alternative approach is concerned with constructing cell-like structures known as artificial cells (also known as protocells or synthetic cells) from scratch out of non-living building blocks.T his endeavour is sometimes referred to as "bottom-up" synthetic biology. [6] Theu ltimate aim here is to engineer new cell-like entities from inanimate matter.This perspective focuses on the space in between the two approaches:the construction of composite structures in which biological and artificial cells are intermingled to create hybrid systems composed of living and synthetic components ( Figure 1).
As af ield, top-down synthetic biology is well developed and has already produced several breakthroughs including the biosynthesis of drug precursors, [7] thed evelopment of organisms for biofuel production, [3] engineered cell therapies, [8] and the creation of new responsive and multifunctional materials. [9] By contrast, the discipline of artificial cells is less mature in terms of demonstrated applications.C oncepts and methods in this area were first developed in the 1990s by pioneers such as Luisi, Yomo,a nd others, [10] who laid the foundations for the remarkable growth of this research area over the past decade.T here are now several dedicated large-scale international centres and initiatives devoted to building artificial cells from the bottom up. [11] Them ost dominant form of artificial cells involve cell-sized capsules, such as liposomes,p olymersomes,c oacervates,proteinosomes and hydrogel particles,w hich act as the chassis. [6a,12] These compartments can be functionalised with biomolecular components, including transmembrane channels, [13] enzymes, [14] cytoskeletal elements, [15] gene circuits, [16] and transcription/ translation machinery. [17] In doing so, cellular characteristics can be mimicked. [6,18] These include cellular processes and behaviours (e.g.s ignalling cascades, [19] communication, [16] motility, [20] energy generation, [21] replication, [22] and computation) [23] as well as architectural motifs (e.g.m embranes,organelles,and tissues). [24] Thep recise attributes that ac onstruct must have to be considered an artificial cell is still up for debate,a nd definitions vary between research groups.S ome consider any collection of functional biologically-relevant molecules encased in cell-sized capsules to be artificial cells.O thers emphasise the need to mimic cellular behaviours that are considered the hallmarks of life.O ther bones of contention are whether incorporation of genomic componentry are prerequisites,w hether artificial cells must be composed of biologically derived building blocks,o ri fm orphological resemblance is enough. Perhaps the strictest definitions are those which only class fully autonomous,a utopoietic,s elfsustaining,r eplicating and evolving biochemical microsystems as artificial cells;this is seen as one end goal of the field, and is yet to be achieved. Forthis reason, artificial cells cannot currently be considered "alive" which is one of their attractions,aswill be elaborated on later.
Beyond pure scientific curiosity,t hree classes of motivation drive artificial cell research. Thefirst is related to originof-life research, where building protocellular systems helps to The construction of artificial cells from inanimate molecular building blocks is one of the grand challenges of our time.Inaddition to being used as simplified cell models to decipher the rules of life,artificial cells have the potential to be designed as micromachines deployed in ahost of clinical and industrial applications.The attractions of engineering artificial cells from scratch,asopposed to re-engineering living biological cells,a re varied. However,iti sclear that artificial cells cannot currently matchthe power and behavioural sophistication of their biological counterparts.Given this,many in the synthetic biology community have started to ask:isitpossible to interface biological and artificial cells together to create hybrid living/synthetic systems that leverage the advantages of both?This article will discuss the motivation behind this cellular bionics approach, in whichthe boundaries between living and non-living matter are blurred by bridging top-down and bottom-up synthetic biology.I tdetails the state of playo fthis nascent field and introduces three generalised hybridisation modes that have emerged.
shed light on how life arose in the early earth; [25] this was an early driver for the research in this space.T he second is the use of artificial cells as models with which to study biology in as implified and highly controlled environment. [26] Thet hird lies in their potential applications as soft, responsive micromachines,s pecifically engineered to perform useful biotechnological functions.R apid developments in this area have meant that real-world applications of artificial cells-as therapeutic agents,s ensors,s elf-healing materials,a nd biochemical microreactors-are on the horizon.
Top-down and bottom-up synthetic biology have largely evolved in parallel to each other, and they still exist as distinct sub-fields with little by way of meaningful overlap.However, we are reaching ap oint where links between the two approaches can be made through the construction of hybrid cells composed of both living and synthetic components.This embryonic research space has emerged in part due to improved technological capabilities:platforms to form (i)adequately complex artificial cells (ii)robust enough engineered living cells,a nd (iii)tools to hybridise the two,h ave only recently come into their own. Themerits of this hybridisation strategy,sometimes referred to as cellular bionics,are derived from combining the advantages associated with both approaches,w hich will now be detailed.

Top-down vs. Bottom-up:AComparison
There are several advantages associated with engineering artificial cells from scratch rather than re-engineering living cells.F irst, the limitation of cellular burden-the tug of war associated with distributing energy and resources between natural and engineered cell functions-is not af eature of synthetic cells. [27] They do not have to devote resources to auxiliary processes associated with performing tasks that cells have evolved to undertake,a nd indeed, to staying alive. Engineered processes can thus potentially be more efficient if cells are fully synthetic.S econd, the fact that synthetic cells are not living means that one can engineer them to produce otherwise toxic compounds. [28] Moreover,asbiocompatibility issues are no longer critical with non-living cells,o ne can incorporate wholly non-biological building blocks,a llowing biological capabilities to be surpassed. These non-biological additions could include electronic components,f unctional nanoparticles,a nd novel molecular machines (e.g.D NA origami or nano-electrical elements). Third, the use of synthetic cells reduces biosafety,r egulatory,a nd public perception hurdles. [29] They do not replicate,a re not alive, are not autonomous,a nd are not functional for long periods without active human intervention-at least for the foreseeable future.I nt his respect, they have more in common with traditional nanotechnologies and microrobots than with living organisms.F or these reasons,they are not considered GMOs by either regulators or the public psyche.Finally,and perhaps most importantly,s ynthetic cells have av astly reduced molecular complexity compared to their biological counterparts,w hich makes them more programmable and predictable. [30] They are often composed of tens of distinct molecular species,c ompared to tens of thousands of species present in living cells.I nascenario where each biomolecule interacts with many others,t his yields an interaction network with exponentially increasing complexity for every new component added. Moreover,l iving cells may modify their internal biochemistries to resist changes imposed on them, often in an unpredictable manner.T hese factors make it difficult to effectively predict how living cells will respond when reengineered to have new functions.A dditionally,o ne knows (and can precisely control) the full molecular composition of synthetic cells-since they are constructed from scratchwhich is not the case with living cells.
However,d espite their promise,t he capabilities of artificial cells are inherently limited compared to living biological ones.B iological cells have dynamic metabolic, biosynthetic,and regulatory pathways.T heir molecular complexity means they are capable of energy conversion and of driving themselves out of equilibrium. They can self-repair, interact with one another to yield collective behaviours,selfreplicate and be cultured at scale.E xploiting these features has underpinned many biotechnological advances and is predicted to be am ajor driver behind the "fourth industrial Yuval Elani is aU KRI Future Leaders Fellow and Lecturera tt he Department of Chemical Engineeringa tI mperial College London. He is co-Founder of the fabriCELLc entre for artificial cell research and co-Director of the Membrane Biophysics Platform.Y uval received his PhD in 2015 from the Department of Chemistry at Imperial, which was followed by several independent fellowships. His undergraduate trainingw as at Cambridge, where he studied natural sciences. His research interests are in the development of artificial cell tools and technologies for clinical and industrial applications.

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Minireviews 5604 www.angewandte.org revolution". [31] It is clear that biological cells have ab ehavioural sophistication that artificial cells cannot currently match. Moreover,w hen it comes to producing industrially relevant quantities of products in an economically acceptable manner,i ti su nlikely that the performance of "living" cells will be surpassed by synthetic ones.
It is important to note that the boundary between biological and synthetic cells is not always clear-cut, with the distinction between organism and machine being acentral topic in theoretical discussion in synthetic biology. [32] The border between the two is being approached from several directions,i ncluding artificial cells with increasing life-like characteristics,m inimal cells based on synthetic genomics, and genetically programmed bacterial/eukaryotic machines produced by bioengineering. [33]

Hybrid Cells
Thes imultaneous proliferation of microfluidics,c ell-free protein expression, gene circuit design, and membrane engineering technologies has meant that it is now possible to fuse living and synthetic cells together to form hybrid entities.T his in turn allows the advantages associated with each to be combined and the disadvantages to be tempered. One can envisage cells and organelles being used as functional modules that are coupled to artificial cells,a llowing them to harness the full power of biology.Directly using living cells as modules in an artificial cell context bypasses the limitations of making new modules from scratch. Instead, cellular components that have been sculpted through evolution can be hijacked, enabling as tep-change in artificial cell sophistication and capabilities.
Although this area of research is still in its infancy, several recent studies have emerged which have allowed some generalisation to be made regarding the different modes with which living and synthetic cells can be coupled. Overall Through these three hybridisation routes,itispossible to traverse length-scales:f rom the molecular to the organelle, cellular, and multi-cellular bulk material level. Now follows ar eview of some landmark examples which fall within these classes.

Population Hybridisation
Fairly diverse literature already exists on communication between various synthetic cells of different classes,i ncluding ones based on lipid vesicles, [16,34] proteinosomes [23] and polymersomes. [34] There have also been examples of engineered communication between two different species of artificial cells,i ncluding between vesicles and proteinosomes. [12a] Predator/prey [35] and response/retaliation [36] relationships between coacervates and proteinosomes have also been demonstrated.
There have been efforts to build on these examples and engineer communication between discrete populations of living and synthetic cells (Figure 3). Some of these have required the cells to be embedded in an agar gel matrix to protect the artificial cells from the destabilising effects of surrounding bacteria. [37] One early example involved the development of as ynthetic cell containing ap roto-metabolism capable of synthesising am olecule that elicited ac ellsignalling response in bacteria. [38] Thep roto-metabolism consisted of an autocatalytic sugar-synthesising formose reaction, the product of which was secreted from the synthetic cell and then engaged the natural quorum-sensing mechanism of Vibrio harveyi,yielding aluminescent output.
This concept was taken to an ew level by Lentini et al., who,i nstead of using enzymatic reactions,i ncorporated genetic elements and cell-free expression systems in artificial cells to establish the communication pathway ( Figure 3A). [39]  Their vesicle-based cells contained aD NA programme that coded for ar iboswitch that activated translation in response to the presence of as mall molecule,t heophylline.T his then initiated the synthesis of the pore-forming protein a-hemolysin (aHL), which led to the release of the inducer molecule IPTG,which in turn initiated GFP production in apopulation of E. coli. Theophylline is am olecule that E. coli would not normally respond to.The synthetic cells in effect were able to "translate" it into achemical signal that can be processed by bacteria, thus effectively expanding the sensory range of the E. coli. All this was done without significantly altering the genetic content of the bacteria.
Thes ame group, [40] as well as other researchers, [41] expanded on this work by engineering synthetic cells that could both send and receive chemical messages to/from bacteria, completing the communication loop.T his was done by reconstituting cellular quorum-sensing pathways in synthetic cells,t hus achieving two-way communication. [40] This principle was also used to engineer communication among three species of cells,w ith the artificial cells mediating communication between two different bacterial species (Fig-ure 3B). Interestingly,the authors used the ability of bacteria to recognise the synthetic cells as one of their own as ayardstick to determine how "life-like" the artificial cells are, in asimilar manner to the Tu ring test for artificial intelligence. Thea uthors proposed that the degree of response from the bacteria, ap rocess that can be quantified using analysis of RNAfrom transcription, can be used as aproxy for how "lifelike" the artificial cells are.T his nicely demonstrates some of the philosophical implications that can arise from hybridising living and synthetic cells.
Others have deployed communication between living and synthetic cell populations to demonstrate functional applications through feasibility studies.F or example,K rinsky et al. have shown potential therapeutic uses for this approach through the construction of artificial cells that synthesised anti-cancer proteins that inhibited tumour growth both in vitro and in vivo. [42] Successful attempts at engineering afeedback sense/response system between artificial and living cells have also led to the synthesis of antimicrobial peptides that killed surrounding bacteria through lysis. [41] Finally, Amidi et al. have explored the use of artificial cells as genetically programmable vaccine microreactors through cell-free protein expression of antigens. [43] When deployed in mice,these were shown to elicit an immune response.

Embedded Hybridisation
Thee mbedded hybridisation mode involves the creation of hybrid cells through physical encapsulation (Figure 4). This could either involve encapsulating living cells within synthetic ones,orvice versa. An analogy can be drawn with the origin of eukaryotic organelles,w here previously free-living organisms were taken up by ahost to yield eukaryotic cells through amutually beneficial symbiotic relationship between the two. Ther esulting organelles exist in ad istinct physicochemical environment, allowing them to be specialised to perform specific tasks.E mbedded organelle-like compartments have been used in ap urely artificial cell context, for example for spatially segregated transcription and translation, [44] for stimuli-responsive enzymatic reaction in vesicle-based cells, [45] and for engineering synthetic signalling cascades between compartments. [46] There is now an emerging trend to expand this concept for the creation of hybrid living/synthetic systems.

Biological Cells Encapsulated in Synthetic Cells:" Living-in-Synthetic"
There have been several demonstrations of living cells encapsulated in synthetic ones for the creation of hybrids.For example,d roplet microfluidics was used to encapsulate cells in giant lipid vesicles,w ith the encapsulated cells engineered to have an organelle-like function. [47] Specifically,c olon carcinoma cells were modified to express an enzyme which performed one step of am ulti-step enzymatic cascade (Figure 4A). Thee nzymatic product was then further processed by as ynthetic metabolism co-encapsulated in the vesicle.I n this way,t he encapsulated cell acted as ab ioreactor module

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Minireviews 5606 www.angewandte.org within the synthetic cells.This approach was expanded further through the encapsulation of genetically engineered E. coli designed to sense lactate within vesicles. [48] Thebacteria thus acted as abiosensor module,allowing the detection of lactate by the hybrid vesicle construct. In these examples,n ot only did the biological cell confer functionality to the synthetic cell, but the synthetic cell also shielded the encapsulated cell from at oxic exterior, demonstrating am utually beneficial relationship.Other researchers have encapsulated mitochondria in vesicles [49] and viable chloroplasts in coacervate-based synthetic cells (Figure 4B), [50] leading to the exciting possibility of these organelles being used as biobattery modules to power encapsulated biochemical processes.Finally,inarecent breakthrough paper, Altamura et al. extracted chromatophores from Rhodobacter sphaeroides and used them as photosynthesising organelles within artificial cells (Figure 4C). Under illumination, these converted ADP to ATP, which in turn sustained the transcription of DNAtomRNA, paving the way for continual regeneration of energy-carrying molecules using an external energy source. [51] Similarly,there have been recent efforts to appropriate thylakoid membranes and to couple these to as ynthetic enzymatic cycle that fixes carbon dioxide within water-in-oil droplets,t hus achieving ap hotosynthetic anabolic reaction in ac ell-like construct. [52] [50]. C) Schematic of achromatophore organelle extracted from ap hotosynthesising organism and inserted in asynthetic cell. Upon light irradiation, this led to the production of ATP, which powered the translation apparatus to produce mRNA. Figure modified with permission from Ref. [51]. Copyright 2020, the authors. D) An example of asynthetic cell encapsulatedi naliving one. The synthetic cells performed an organelle-like function by degradingH 2 O 2 ,t hus shielding the cell from the detrimentale ffects of this molecule. Image modified with permission from Ref. [54].

Synthetic Cells Encapsulated in Biological Cells:"Synthetic-in-Living"
Thea rchitectural motif above can also be reversed, with synthetic organelles being introduced into living cells,a s aform of cellular implant. To date,synthetic organelles have relied on enzymatic processes and do not operate with DNA programmes coupled with cell-free protein expression. One impressive example of synthetic-in-living hybrids involved the creation of polymersome-based synthetic organelles that housed enzymes capable of producing afluorescent molecule from an on-fluorescent precursor. [53] These organelles were designed to be stimuli-responsive:molecular flow through the engineered protein pore OmpF (and hence activation of the organelle) was triggered when the structure experienced ac hange in redox potential as it entered the intracellular microenvironment. Impressively,i tw as shown that these organelles could respond to intracellular glutathione levels and were functional in vivo in zebrafish embryos.
Similarly,v an Oppen et al. used ap olymersome-based system that was functionalised with cell-penetrating peptides on its outer surface,w hich facilitated uptake by human embryonic kidney cells as well as human primary fibroblasts. [54] Theo rganelles housed the enzyme catalase in the interior,w hich allowed them to degrade externally added reactive oxidative species,s hielding the cell from their negative effects ( Figure 4D). As imilar approach, which relied on polymersomes functionalised with transmembrane channels and two coupled enzymes,w as used to mimic peroxisomes.T hese organelles were able to detoxify both superoxide radicals and H 2 O 2 .T hese examples are further demonstrations of the potential of organelle therapy,g iven that reactive oxidative species in general, and reduced catalase activity in particular,a re thought to play ar ole in ah ost of medical conditions including Alzheimers, Parkinsons, Huntingtons, acatalasemia, metabolic diseases,a nd cancer. [55] Other researchers have developed multi-layered synthetic organelles composed of both liposomes and polymersomes that housed distinct enzymes in different layers. [56] These were able to perform multi-step enzymatic cascades with glucose as afeedstock. Thesynthetic organelles could be internalised by macrophages,where they preserved their activity,utilising an intracellular source of glucose to initiate acontrolled foreign cascade reaction in the host cell. There has also been an example of synthetic organelles that were designed to reduce cell viability through the production of reactive oxidative species using the enzyme glucose oxidase and ag lucose feedstock. [57] Finally,inarecent study,asuite of synthetic vesicle-based organelles with diverse functionalities formed using droplet microfluidics were incorporated in living cells. [58] One organelle type mimicked peroxysomes through the incorporation of enzymatic modules.Asecond organelle type was engineered to act as an intracellular light-responsive signalling module that could release calcium stores,with the potential to act as an artificial regulatory element. Athird type of organelle was designed to impart the host with am agnetotactic sense, allowing cells to reorient themselves and move in response to am agnetic field. Thel atter example is ap owerful demonstration of the incorporation of entirely new,n on-intrinsic functionalities not otherwise found in host cells.

Networked Hybridisation
Then etworked hybridisation mode involves discrete artificial and biological cells physically interlinked with one another in adistinct spatial arrangement. To date,there have been only ahandful of examples of this,outlined below.T his is in contrast to interlinked networks of purely synthetic cells, of which there are more examples,i ncluding the creation of self-folding tissue-like networks composed of thousands of bilayer-linked compartments, [59] light-activated gene-expression in individual cells of as ynthetic tissue, [60] networked synthetic cell compartments for controlled prodrug activation and release, [61] and thermoresponsive proteinosome clusters capable of cyclical expansion and contraction. [30c] One of the few examples of hybrid living/synthetic networked structures involved artificial and biological cells that communicated with each other in amanner dependent on their precise geometrical connectivity. [62] In this work, the networked compartments were based on water-in-oil droplets that were connected in alinear chain. Droplets in the network either contained living E. coli or acell-free expression system and aD NA programme.B oth the synthetic and biological cells were engineered to possess genomes that could produce inducer molecules or respond to them through GFP expression, with the sensing mechanism regulated through the lux operon. Thea uthors were able to obtain position-dependent gene expression using am orphogen gradient, thus creating aform of artificial cell differentiation that was determined by their location in relation to their neighbours.
Another example involved the use of acoustic standing wave patterning to link up vesicle-based synthetic cells and bacteria. [63] Thet echnology enabled the geometries,l attice dimensions,and trap occupancyofstructures to be controlled. Using this setup,the authors could form networks of synthetic cells that produced H 2 O 2 through an enzymatic cascade.T his reaction product then diffused through embedded protein pores to adjacent E. coli cells,l eading to cell death. This approach was extended to engineer communication between 1D and 2D networks of synthetic cells and red blood cells. [64] Similar systems involving positively charged proteinosomes, which show ap rogrammed temperature-and salt-dependent interaction with living E. coli,have been developed. [65] These were shown to be able to capture and release microbes from the colloid surface in as timuli-responsive manner. Finally, there have been efforts at generating extended tissue-like hybrid materials by using 3D printing of synthetic tissues composed of lipid-membrane-coated synthetic cell chassis. These constructs contained embedded mammalian cells,a n approach that allows high-solution patterning of cells within ap rinted material and has potential applications in regenerative medicine. [66] Angewandte Chemie Minireviews 5608 www.angewandte.org

Conclusions
Thefield of living/synthetic hybrid cellular systems is still very much in anascent stage,with most studies relying on the development of underpinning technologies and proof-ofconcept experiments.The field is probably 15 years or so from reaching the maturity needed for true applications to be realised. What is already clear, however,i st hat combining synthetic cells with living cells could be strategically important to the fields of cellular and molecular bioengineering.It will drive innovation and widen synthetic biologysa pplication base,a llowing cells to be coupled with artificial microsystems that include electronic, mechanical, and chemical components.
Potential biotechnological and biomedical applications are wide and diverse:f rom cell therapies shielded by an artificial membrane delivery chassis,t oc hemical microsystems powered by photosynthesis,t os elf-healing materials that use biosynthetic pathways to regenerate building blocks, to hybrid chemo/bioreactors.H owever,b efore such applications can be realised, the engineering routes to interlink biological and synthetic cells need to be devised, which is the current focus of activities in this area. Moreover,for the field to realise its potential, the creation of hybrid living/synthetic systems need be not only possible,b ut also affordable, scalable,a nd adaptable for different applications.T here are also some structural issues which have stymied progress in this area. Research in top-down and bottom-up synthetic biology typically belong to different scientific domains,a nd are housed in different university departments:t he former tend to lie in life sciences and bioengineering (molecular biology, metabolic engineering,c ell biology) and the latter in the physical sciences (soft matter,b iophysics,m icrofluidics, chemical biology,chemical engineering).
At this point, it should be noted that there are limitations to this hybridisation approach. Most importantly,w hile combining the different advantages associated with living and synthetic systems,o ne would also be in danger of accumulating the disadvantages.F or this reason, hybrid cellular systems will be more suited for particular applications than others.A st he field advances,m itigation strategies to minimise the downsides are expected to be developed.
There is atimeliness to this research challenge,given the unique opportunities derived from the proliferation of physical science innovations related to this area. These include microfluidic devices for the high-throughput manufacture of cell-sized vesicles and other compartmentalised structures [24,67] as well as new methods for the efficient encapsulation of biological macromolecules in membrane capsules. [49] New optical trapping technologies have allowed the manipulation of cell-sized objects and assembly of userdefined biomimetic architectures. [68] Laser-based approaches for the spatial patterning of tissue-like materials with fine spatio-temporal resolution have also been elegantly demonstrated, [69] and there are growing synergies between electronic and living cellular systems. [70] Moreover,r apid developments in DNAn anotechnology [71] and protein engineering [72] will further expand the repertoire of building blocks which can be used to interface synthetic and living cells.
From the bio-science sector,t he rise of commercial cellfree expression kits,cheap and portable DNAs equencing, [73] online repositories of DNA" biobrick" genetic components, and gene synthesis services will no doubt continue to drive the development of hybrid cellular systems.M oreover,m any of the processes involved have been effectively "deskilled" with the evolution of biohackspaces and the growing ubiquity of 3D printers and bio-printers. [74] There are also an everexpanding array of commercial ready-to-use biochemical systems for enzymatic assays,cell-free protein expression, and synthetic biology education. [75] All this means that technology development and applications are no longer restricted to specialised microfluidics groups,a nd biochemical functionalisation of synthetic constructs is not confined to life-science labs,w hich aids this inherently multidisciplinary endeavour.
In conclusion, given the pace of change in this area, it is expected that hybrid living/synthetic cellular bionic systems will rapidly increase in number and complexity over the coming years.T here will no doubt be unexpected hurdles along the way,but there are already indications that this will emerge as ad istinctive and disruptive research area that bridges the life,p hysical, and engineering sciences.N ot only will it lead to diverse applications,b ut it also has fascinating philosophical implications:b lurring the boundary between living and non-living matter will change our perception of what it means for something to be alive.