Theranostic Infection-Responsive Coating to In Situ Detect and Prevent Urinary Catheter Blockage

Biofilm formation induced by urease-producing species can cause the increase of urine pH, and eventually lead to the blockage of catheters. In this study, a novel theranostic multilayer coating which combines both early visual warning of catheter blockage and antibacterial efficacy is described. The proposed coating comprised multilayered polymeric architecture using electrostatic self-assembly (ESA) technique. In such a system, an inner layer of hydrogel PAA (poly (acrylic acid)) and middle layer of CS (chitosan) are employed to encapsulate an antibiotic delivery system that has sensitive colorimetric transition response upon pH elevation. The two layers are sealed and capped by a pH-response layer of EUDRAGITS 100. The proposed coating sensor hydrogel exhibits chromatic color transitions (blue–purple–red) upon bacterial infection and provides an indication for both initial bacterial infection and subsequent blockage. Meanwhile, encapsulation of antimicrobials increases the amount of antibiotic resident in the vicinity of bacteria in residual urine solution and thus inhibiting bacterial growth.