One-Pot Microwave-Assisted Synthesis of Carbon Dots and in vivo and in vitro Antimicrobial Photodynamic Applications

María Paulina Romero; Fernanda Alves; Mirian Denise Stringasci; Hilde Harb Buzzá; Heloísa Ciol; Natalia Mayumi Inada; Vanderlei Salvador Bagnato

doi:10.3389/fmicb.2021.662149

One-Pot Microwave-Assisted Synthesis of Carbon Dots and in vivo and in vitro Antimicrobial Photodynamic Applications

Front Microbiol. 2021 Jun 21:12:662149. doi: 10.3389/fmicb.2021.662149. eCollection 2021.

Authors

María Paulina Romero^{1

2}, Fernanda Alves¹, Mirian Denise Stringasci¹, Hilde Harb Buzzá¹, Heloísa Ciol¹, Natalia Mayumi Inada¹, Vanderlei Salvador Bagnato^{1

3}

Affiliations

¹ São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil.
² Departamento de Materiales, Facultad de Ingeniería Mecánica, Escuela Politécnica Nacional, Quito, Ecuador.
³ Hagler Fellow, Texas A&M University, College Station, TX, United States.

Abstract

Carbon-based photosensitizers are more attractive than the other ones based on their low cost, high stability, broadband of light absorption, tunable emission spectra, high quantum yield, water solubility, high resistance to metabolic degradation, and selective delivery. These properties allow multiple applications in the field of biology and medicine. The present study evaluated in vitro and in vivo the antimicrobial photodynamic effect of a one-pot microwave produced C-DOTS based on citric acid. The in vitro assays assessed the effectiveness of illuminated C-DOTS (C-DOTS + light) against Staphylococcus aureus suspension and biofilm. The concentrations of 6.9 and 13.8 mg/mL of C-DOTS and light doses of 20 and 40 J/cm² were able to reduce significantly the microorganisms. Based on these parameters and results, the in vivo experiments were conducted in mice, evaluating this treatment on wounds contaminated with S. aureus. The viability test showed that C-DOTS-mediated photodynamic inactivation reduced 10⁴ log of the bacteria present on the skin lesions. These results, altogether, showed that antibacterial photodynamic therapy using C-DOTS is a promising and viable treatment for Gram-positive bacteria-infected wounds.

Keywords: Staphylococcus aureus; antibacterial materials; antibacterial photodynamic therapy (aPDT); carbon dot; carbon-based materials; carbon-based photosensitizer; nanomedicine; photodynamic therapy.