Creating multi-antibiofilm therapeutics with cellulase based carbon dots

Pseudomonas aeruginosa biofilms can cause chronic and serious wound infections. Treatment of wound biofilms is difficult, and often requires multiple rounds of antimicrobial therapy and debridement. There is a need to create topical therapeutic treatments with multiple antibiofilm effects. In this work, we explore the potential of cellulase based carbon dots as a potential therapeutic. Cellulase is a glycoside hydrolase that has already been shown to be effective in causing biofilm dispersal as well as reduction in biofilm stiffness and elasticity. By synthesizing the cellulase into a carbon dot, we hypothesize that the molecule can retain some of those capabilities, because carbon dots are known to retain some of the effects of their precursor proteins and increase the bactericidal effect and penetration of the cellulase.

Carbon dots are synthesized from both cellulase and citric acid using a one-step hydrothermal carbonization method, and then characterized for surface properties, size, roughness, compositions, and emission spectra. P. aeruginosa biofilms were grown in a microfluidic environment for 24 hours and then treated with these carbon dots at a range of concentrations. Using microrheology, it was seen that biofilms treated with the cellulase based carbon dots were more viscous and less stiff compared to those treated with citric acid-based carbon dots. This appears to be because the cellulase carbon dots impact PSL within the biofilm based on microrheology studies examining bacteria strains with specific EPS component removed. This is consistent with the impact of molecular cellulase on biofilms. The penetration of the carbon dots into the biofilms is being examined via confocal microscopy. In general, initial studies suggest that the cellulase based carbon dots have the potential to act as an excellent multi-antibiofilm therapeutic in the future.