Precisely controlled polydopamine-mediated antibacterial system: mathematical model of polymerization, prediction of antibacterial capacity, and promotion of wound healing

In this work, the polydopamine (PDA)-mediated antibacterial system is synthesized for in vitro and in vivo antimicrobial activities. To precisely control the surface modification of nanodiamonds (NDs), a mathematical kinetics model of PDA deposition is established, and the conditions of synthesis reaction are discussed including the concentrations of dopamine, the reaction time, and the kinetic constant k (1), which is a function of several variables associated with the reaction temperature, light irradiance, pH value and concentration of dissolved O-2 in the solution. A simulation reveals that the deposition of PDA is positively correlated with these factors and will be terminated if dissolved O-2 levels are inadequate. Then, the precisely controlled thickness of PDA layers can regulate the formation of AgNPs, resulting in a rise in the intensity of Raman peaks and a predicted antibacterial activity against E. coli in vitro. An optimized antibacterial hydrogel incorporating NDs-PDA/Ag is prepared and characterized by the Fourier transform infrared spectroscopy and field emission scanning electron microscopy. Finally, the antibacterial tests are performed to promote in vivo wound healing, as confirmed by pathological and immunohistochemical-stained tissue sections. This work provides a theoretical foundation for predicting the PDA-assisted surface modification of NDs, resulting in a divinable antibacterial effect and promoting in vivo wound healing.

Automated summary

In this study, a polydopamine (PDA)-mediated antibacterial system was synthesized to achieve in vitro and in vivo antimicrobial activities. The surface modification of nanodiamonds (NDs) was precisely controlled using a mathematical model of PDA deposition. The synthesis conditions, including dopamine concentration, reaction time, and kinetic constant k (1), were discussed. Simulation results showed that PDA deposition was positively correlated with various factors and would be terminated if dissolved O-2 levels were inadequate. The controlled thickness of PDA layers regulated the formation of silver nanoparticles (AgNPs), resulting in enhanced Raman peaks and predicted antibacterial activity against E. coli in vitro. An optimized antibacterial hydrogel incorporating NDs-PDA/Ag was prepared and characterized. Antibacterial tests were performed to promote in vivo wound healing, and the results were confirmed by pathological and immunohistochemical-stained tissue sections. This work provides a theoretical foundation for predicting the PDA-assisted surface modification of NDs, leading to a predictable antibacterial effect and promoting in vivo wound healing.