Development of Antimicrobial Laser-Induced Photodynamic Therapy Based on Ethylcellulose/Chitosan Nanocomposite with 5,10,15,20-Tetrakis(m-Hydroxyphenyl)porphyrin

Abstract

The development of new antimicrobial strategies that act more efficiently than traditional antibiotics is becoming a necessity to combat multidrug-resistant pathogens. Here we report the efficacy of laser-light-irradiated 5,10,15,20-tetrakis(<i>m</i>-hydroxyphenyl)porphyrin (<i>m</i>THPP) loaded onto an ethylcellulose (EC)/chitosan (Chs) nanocomposite in eradicating multi-drug resistant <i>Pseudomonas aeruginosa</i>, <i>Staphylococcus aureus</i>, and <i>Candida albicans.</i> Surface loading of the ethylcelllose/chitosan composite with <i>m</i>THPP was carried out and the resulting nanocomposite was fully characterized. The results indicate that the prepared nanocomposite incorporates <i>m</i>THPP inside, and that the composite acquired an overall positive charge. The incorporation of <i>m</i>THPP into the nanocomposite enhanced the photo- and thermal stability. Different laser wavelengths (458; 476; 488; 515; 635 nm), powers (5-70 mW), and exposure times (15-45 min) were investigated in the antimicrobial photodynamic therapy (aPDT) experiments, with the best inhibition observed using 635 nm with the <i>m</i>THPP EC/Chs nanocomposite for <i>C. albicans</i> (59 ± 0.21%), <i>P. aeruginosa</i> (71.7 ± 1.72%), and <i>S. aureus</i> (74.2 ± 1.26%) with illumination of only 15 min. Utilization of higher doses (70 mW) for longer periods achieved more eradication of microbial growth.