Infusing Lubricant onto Erasable Microstructured Surfaces toward Guided Sliding of Liquid Droplets

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

Self-Healing Spongy Coating for Drug “Cocktail” Delivery

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

Bactericidal and Hemocompatible Coating via the Mixed-Charged Copolymer

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-<i>co</i>-<i>n</i>-butyl methacrylate-<i>co</i>-methacrylate acid) [P­(QVP-<i>co</i>-<i>n</i>BMA-<i>co</i>-MAA)] were synthesized through free radical copolymerization. The cationic group of QVP, the anionic group of MAA, and the hydrophobic group of <i>n</i>BMA 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