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The cover image depicts two modes of functionalized nanoparticle delivery for single-cell studies using a versatile nanofountain probe (NFP). NFPs are scanning probes with integrated microfluidics, enabling both direct-write nanopatterning and direct/in vitro/injection of functional nanoparticles. The NFP is used to pattern dot arrays of chemotherapy-drug-conjugated nanodiamonds with sub-100-nm resolution on glass substrates for subsequent cell culture and precise drug-dosing studies. The same NFP is also used to inject nanodiamond conjugates directly into live cells for further interrogation. For more information, please read the Full Paper “Nanofountain-Probe-Based High-Resolution Patterning and Single-Cell Injection of Functionalized Nanodiamonds” by D. Ho, H. D. Espinosa, et al., beginning on page 1667.

The cover image shows strain-engineered microtubes traveling as self-propelled catalytic microjet engines along various trajectories with speeds up to ≈ 2 mm s⁻¹ (approximately 50 body lengths per second). The motion of the microjets is generated by gas bubbles thrust out of one opening of the tube. The trajectories of various geometries can be traced by long microbubble tails. A magnetic layer is integrated into the wall of the microjet engine, which allows easy control over the direction of motion by applying external magnetic fields. For more information, please read the Full Paper “Catalytic Microtubular Jet Engines Self-Propelled by Accumulated Gas Bubbles” by Y. Mei et al., beginning on page 1688.

This Review provides a critical examination of the various interparticle forces (van der Waals, electrostatic, magnetic, molecular, and entropic) that can be used in nanoscale self-assembly. The magnitudes and length scales of each force (see image) are discussed, with emphasis on characteristics unique to the nanoscale. Recent experimental systems, in which specific interaction types were used to drive nanoscopic self-assembly, accompany the theoretical discussion.

A bilayer nanoimprint lithography method is presented for the fabrication of nanorods (see image) with precisely controllable dimensions. The uniqueness of this method stems from the bilayer polymer design and development of low-cost, large-area nanoporous Si molds.

A surface-engineering approach to produce monodisperse nanoparticles functionalized for conjugations of various biomolecules is described. The oleic acid-capped nanoparticles are modified with triethoxysilylpropylsuccinic anhydride followed by reaction with aminated poly(ethylene glycol) (PEG) to render the nanoparticles hydrophilic and display amine groups at the free termini of PEG chains (see image).

Textured network devices are proposed as a solution to the fundamental problems of nanotube/nanowire network-based devices (see image). Significantly, both experiment and simulation show that “textured” network channels have enhanced mobility and conductivity with reduced channel width, which makes this strategy ideal for nanoscale device applications.

Colored diamonds: Despite concerns that photostable luminescent nitrogen-vacancy (NV) centers do not exist in 5-nm diamonds, time-resolved luminescence experiments on weakly bound clusters of such diamonds show that NV centers can be embedded (see picture). The efficiency of NV formation scales as the fifth power of the crystal radius.

Nanopores in various metallic thin films are defined using self-assembled templates from a sphere-forming block copolymer (see image). This method is versatile and can be used to form antidot arrays in a variety of metals including Ti, Pt, W, Ta, Co, and Ni, and silica, as well as Ni dot arrays.

The frontispiece shows that by dragging a phospholipid solution on microstructured silicon surfaces, phospholipid molecules are selectively deposited inside the microstructures to obtain regular phospholipid multilayer patterns of controlled thickness over a large scale (≈ cm²). The generated patterns are used for the preparation of giant liposomes of controlled size with a narrow size distribution, and can be of great interest for the development of novel biosensors or cell-screening procedures. The method also promises to be applicable for high-fidelity patterning of various synthetic or biological molecules, such as proteins, drugs, conductive polymers, or antibodies. For more information, please read the Full Paper “Preparation of Phospholipid Multilayer Patterns of Controlled Size and Thickness by Capillary Assembly on a Microstructured Substrate” by D. Baigl et al., beginning on page 1661.

By dragging a phospholipid solution on microstructured silicon surfaces, phospholipid molecules are selectively deposited inside the microstructures to yield regular phospholipid multilayer patterns of controlled thickness (from 28 to 100 nm) over a large scale (∼cm²). Electroswelling of phospholipid multilayer patterns leads to the formation of giant liposomes of controlled size and narrow size distributions (see image).

Two modes of functionalized nanoparticle delivery for single-cell studies are demonstrated using a versatile nanofountain probe: direct-write nanopatterning of drug-coated nanoparticles with sub-100-nm resolution, and direct in vitro injection of fluorescently labeled nanoparticles (see image).

Photoluminescence in PbSe colloidal quantum dots (see image) appears as an abrupt change of the exciton emission strength and its decay time upon increasing the temperature. Acoustic phonon coupling activates a dark exciton at 1.4–7 K, and a dark–bright exciton transition occurs at 100–200 K.

Time-resolved photoconductivity of graphene films is detected (see image). The graphene films are prepared through the reduction of graphene oxide. Under different incident light intensities, external electric fields, photon energies, and preparation methods of the films, photocurrent generation efficiency and decay time of these graphene-based films are compared and discussed.

Strain-engineered microtubes with an inner catalytic surface serve as self-propelled catalytic microjet engines, with speeds of up to ≈2 mm s⁻¹ (approximately 50 body lengths per second), and travel along various trajectories that are well-visualized by long microbubble tails (see image).