Fabrication of bioprints self-coated with thermally sensitive lactobacilli for CAUTI applications

Catheter-associated urinary tract infections (CAUTI) represent a large healthcare burden, accounting for a substantial portion of hospital-acquired infections in the United States. Solutions such as intermittent catheterization and catheter surface coatings with antibiotics or silver nanoparticles have offered limited success in preventing uropathogen biofilm formation on the catheter or in promoting a healthy urinary tract. This study explores a novel self-coating biomaterial approach for CAUTI applications, with the goal to promote antibacterial interference. A new fabrication technique is developed to incorporate thermally sensitive Lactobacillus bacteria into a silicone-based polymer. These species are known for their probiotic capabilities and were selected as a means for the material to self-coat with them. Using 3D-printed CAD-designed molds and bio-injection molding, "living probiotic carrier" catheter segments were formed with the probiotic-containing bioink. Lactobacillus-containing segments immersed in artificial urine media (AUM) increased in mass up to 7 days and remained stable at physiological conditions. Increased absorbance via crystal-violet staining indicated biomass accumulation while SEM imaging revealed a visibly large probiotic presence on the segment intraluminal surface over 7-day submersion in AUM. Mechanical integrity testing yielded Shore A hardness values within clinically acceptable ranges. TGA and DSC thermal stability analyses suggested that probiotic presence could affect silicone crosslinking, highlighting the need to fine-tune loading amount and composition of bacterial species to achieve desired polymeric degradation. Overall, the results demonstrate promising biomaterial properties along with lactobacilli biofilm formation, highlighting the potential for silicone catheters self-coated by thermally sensitive lactobacilli to offer a bacterial interference strategy against CAUTI.