Search

Patterned slippery surfaces based on the technique of slippery liquid-infused porous surface (SLIPS) have broad technological applications in biofouling, liquid handling, biomolecule collection, and droplet microarrays. However, methods to generate patterned SLIPS with flexibility and practical potential remain a technical roadblock. Here, we report an approach for generating patterned SLIPS, and by utilizing which, as a proof-of-technique application, the droplet microarrays have been presented. Our approach is based on a photocross-linkable polyelectrolyte poly(ethyleneimine)/azide-poly(acrylic acid) (PEI/PAA-N3) film, whose surface structures can be dynamically controlled. We have prepared the surface-patterned PEI/PAA-N3 film containing microstructured and flat regions. We then demonstrate that, because of much higher lubricant retaining capability of the microstructured regions, a patterned SLIPS can be simply generated through infusing the lubricant onto the surface and applying a shear spinning pro...

Spatially controlling the evolution of surface structures may provide an effective strategy for patterning surface roughness and facilitating the construction of various functional surfaces. In this study, we report a photo-cross-linkable polymeric film with dynamic surface micro/nanostructures. The surface structures of the un-cross-linked regions can be eliminated under saturated humidity, which can be utilized to create patterned roughness on the film. One potential application of this patternable platform is as a "smart" label material for graphical symbols. Various graphical symbols can be programmed onto this film by partially erasing its surface roughness, enabling visibility due to the difference in light scattering between different areas of the film. When a thus-prepared label was blurred by mechanical scratches, it could be healed under saturated humidity, and its original readability could be fully restored. Furthermore, the patterned rough surface created using our approach can also be very useful in many other research fields, such as surface wettability and cell behavior manipulation.

Cationic antibacterial coating based on quaternary ammonium compounds, with an efficient and broad spectrum bactericidal property, has been widely used in various fields. However, the high density of positive charges tends to induce weak hemocompatibility, which hinders the application of the cationic antibacterial coating in blood-contacting devices and implants. It has been reported that a negatively charged surface can reduce blood coagulation, showing improved hemocompatibility. Here, we describe a strategy to combine the cationic and anionic groups by using mixed-charged copolymers. The copolymers of poly (quaternized vinyl pyridine- co- n-butyl methacrylate- co-methacrylate acid) [P(QVP- co- nBMA- co-MAA)] were synthesized through free radical copolymerization. The cationic group of QVP, the anionic group of MAA, and the hydrophobic group of nBMA were designed to provide bactericidal capability, hemocompatibility, and coating stability, respectively. Our findings show that the hydrophilicity of the copolymer coating increased, and its zeta potential decreased from positive charge to negative charge with the increase of the anionic/cationic ratio. Meanwhile, the bactericidal property of the copolymer coating was kept around a similar level compared with the pure quaternary ammonium copolymer coating. Furthermore, the coagulation time, platelet adhesion, and hemolysis tests revealed that the hemocompatibility of the copolymer coating improved with the addition of the anionic group. The mixed-charged copolymer combined both bactericidal property and hemocompatibility and has a promising potential in blood-contacting antibacterial devices and implants.

Introducing a lubricant layer onto surfaces has emerged as a novel strategy to address a wide range of interface-related challenges. Recent studies of lubricant-infused surfaces have extended beyond repelling liquids to manipulating the mobility of fluids. In this study, we report a design of slippery surfaces based on infusing lubricant onto a polyelectrolyte multilayer film whose surface microstructures can be erased rapidly under mild condition. Unlike other lubricant-infused surfaces, the liquid movements (e.g., moving resistance and direction) on such surfaces can be manipulated via programming the surface microstructures beforehand. The work reported here offers a versatile design concept of lubricant-infused surfaces and may turn on new applications of this emerging class of bioinspired materials.

Optimized ratio in the codelivery of therapeutics is of crucial importance to promote the synergism rather than the antagonistic effects. In this study, a self-healing spongy coating was described to facilitate the surface-mediated delivery of drug "cocktails" proportionally. The formation of spongy structures within the coating was achieved by acidic treatment and freeze-drying. Various drug combinations can be readily integrated through wicking method and subsequent micropore self-healing. The ratio of drug loading can be precisely regulated by the composition of loading solution and the embedded drugs were released in proportion according to the initial ratio of drug combination.