hotodynamic inactivation of Streptococcus pneumoniae with external illumination at 808 nm through the ex vivo porcine thoracic cag

Author(s)

Diaz Tovar, Johan Sebastian ^[1] ; Kassab, Giulia ^[1] ; Buzza, Hilde Harb ^[1] ; Bagnato, Vanderlei Salvador ^{[2, 1]} ; Kurachi, Cristina ^[1]

Affiliation

^[1] Univ Sao Paulo, Sao Carlos Inst Phys, Phys & Mat Sci Dept, Sao Carlos, SP - Brazil

^[2] Texas A&M Univ, College Stn, TX 77843 - USA

• Document type: Journal article
• Source: Journal of Biophotonics; v. 15, n. 2 DEC 2021.
• Web of Science Citations: 0

Abstract

Pneumonia is responsible for high mortality rates around the world, and its major treatment is based on antibiotic treatment. Antimicrobial resistance has been increasing in the last years, resulting in relevant public health concern. A promising alternative for pneumonia is antimicrobial photodynamic therapy. The purpose of this study was to investigate whether 808 nm wavelength is able to be transmitted through the biological tissues of the thoracic wall and be delivered in enough energy inside the cage to activate indocyanine green and promote photodynamic response. A light source panel was developed composed of 200 lasers centered at 808 nm with an irradiance of 77.8 +/- 10.0 mW/cm(2) and tested in an ex vivo thoracic cage model. Monte Carlo simulations were used to understand the photon migration through all the tissues at the thoracic wall. It was observed that tissues responsible for the major absorption of photons are the skin and subcutaneous fat. Experimental measurement of the irradiance was obtained after the light pass-through ex vivo pig thoracic cage, obtaining 3% to 5% of the emitted irradiance. Finally, it was observed that even with 3% of the initial irradiance, a 99.9% reduction of the Streptococcus pneumoniae was successfully achieved after 42.6 minutes of irradiation. (AU)

• FAPESP's process: 13/07276-1 - CEPOF - Optics and Photonic Research Center
• Grantee: Vanderlei Salvador Bagnato
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 16/14033-6 - Basic studies of the combination of photothermal and photodynamic effects in application of a new modality for the Cancer treatment
• Grantee: Hilde Harb Buzzá
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 14/50857-8 - National Institute in Basic Optics and Applied to Life Sciences
• Grantee: Vanderlei Salvador Bagnato
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 18/18188-0 - Photodynamic inactivation of Bacterial Pneumonia with nebulization of the photosensitizer and extracorporeal illumination
• Grantee: Giulia Kassab
• Support Opportunities: Scholarships in Brazil - Doctorate