phytochlorin and Staphylococcal-Skin-Infections

Antibacterial photodynamic therapy (PDT) has attracted extremely attention due to not inducing bacteria to generate resistance. However, the poor utilization and low reactive oxygen species (ROS) field of photosensitizers hinder their further application for antibacterial. Here, we designed ultra-thin hollow silica nanoparticles (UHSN), followed by pore-engineering including covalent anchoring of chitosan (UHSN@CS) for enhanced loading and photodynamic property of photosensitizer. The UHSN@CS exhibit high loading efficiency (80.6%, pH = 6.0) and controllable pH-responsive release for Ce6. Additionally, UHSN@CS can enhance the ROS yield of photosensitizers and effectively adhere to S. aureus, thus enormously enhancing antibacterial performance toward bacteria. Moreover, UHSN@CS-Ce6 can obliterate mature S. aureus biofilm and cause an 81% decrease in the biomass, showing a better therapeutic effect than Ce6 (59.2%) under laser irradiation. In vivo results confirm that UHSN@CS-Ce6 is effective to promote infectious wound regeneration. As photodynamic-based nanoplatforms, UHSN@CS-Ce6 are potential antibacterial agents for skin infection therapy.

Topics: Animals; Anti-Bacterial Agents; Biofilms; Chitosan; Chlorophyllides; Cricetinae; Delayed-Action Preparations; Drug Carriers; Drug Compounding; Hydrogen-Ion Concentration; Models, Animal; Nanoparticles; Nanotechnology; Photochemotherapy; Photosensitizing Agents; Reactive Oxygen Species; Staphylococcal Skin Infections; Staphylococcus aureus; Wound Healing; Wound Infection

Methicillin-resistant Staphylococcus aureus (MRSA) skin infections are now known to be a common and important problem in the Unites States. The objective of this study was to investigate the efficacy of photodynamic therapy (PDT) for the treatment of MRSA infection in skin abrasion wounds using a mouse model.. A mouse model of skin abrasion wound infected with MRSA was developed. Bioluminescent strain of MRSA, a derivative of ATCC 33591, was used to allow the real-time monitoring of the extent of infection in mouse wounds. PDT was performed with the combination of a polyethylenimine (PEI)-ce6 photosensitizer (PS) and non-coherent red light. In vivo fluorescence imaging was carried out to evaluate the effect of photobleaching of PS during PDT.. In vivo fluorescence imaging of conjugate PEI-ce6 applied in mice indicated the photobleaching effect of the PS during PDT. PDT induced on average 2.7 log(10) of inactivation of MRSA as judged by loss of bioluminescence in mouse skin abrasion wounds and accelerated the wound healing on average by 8.6 days in comparison to the untreated infected wounds. Photobleaching of PS in the wound was overcome by adding the PS solution in aliquots.. PDT may represent an alternative approach for the treatment of MRSA skin infections.

Topics: Administration, Cutaneous; Animals; Chlorophyllides; Disease Models, Animal; Female; Methicillin-Resistant Staphylococcus aureus; Mice; Mice, Inbred BALB C; Photobleaching; Photochemotherapy; Polyethyleneimine; Porphyrins; Radiation-Sensitizing Agents; Staphylococcal Skin Infections; Wound Infection