Recent advances in stimuli-responsive antibacterial coatings: Bacteria-killing and releasing mechanism, design strategies, and potential applications

A variety of smart antibacterial antifouling strategies have been developed to prevent bacterial contamination of biological surfaces which function by reducing bacterial attachment and killing adherent bacteria. Recently, many smart coatings have been developed that respond to external environmental stimuli to release bacteria. The release of killed bacteria mostly involves a conformational change in the responsive polymer due to changes in external conditions such as pH, temperature, and light, which in turn affects the wettability and other properties of the smart surface. However, whether the functional surface can be repeatedly regenerated after the bacteria release is an important determinant of the practical applicability of smart antimicrobial surfaces. Thus, a regenerative smart antimicrobial strategy that combines bacteria-killing and releasing functions can be an effective strategy against multidrug-resistant (MDR) bacterial infections. Here, we introduce several stimulus responses such as pH, temperature, salt solution, light, sugar, or combination that can trigger the antibacterial function, further explain the killing/release mechanism and potential applications with examples, and finally, briefly describe other methods of bacterial release in addition to the stimulus-response. This work provides a brief outlook on the development of such smart antimicrobial strategies.