# Lifetime positron annihilation spectroscopy and photo-inactivated bacteria

## TL;DR

This paper explores the use of lifetime positron annihilation spectroscopy to monitor photodamage in bacteria during photodynamical therapy, aiming to improve the control of bacterial inactivation.

## Contribution

It introduces a novel application of lifetime positron annihilation spectroscopy for assessing bacterial damage in PDT, supported by literature survey and experimental examples.

## Key findings

- Positron annihilation spectroscopy can detect structural changes in bacteria during PDT.
- The method provides potential real-time monitoring of bacterial cell damage.
- Application to gram-positive and gram-negative bacteria demonstrates versatility.

## Abstract

Combined positron and visible light irradiations in the photodynamical therapy (PDT) applications are analyzed. Objectives and goals of PDT are killing or irreversible oxidative damage of pathogenic cells, or rather their cell walls, cell membranes, peptides, and nucleic acids by photo-activated oxygen of photosentizer injected into the target cell during light irradiation. In this paper, the arguments for involving of lifetime positron annihilation spectroscopy to control of photodamaging cells in the course of the PDT procedure are given on the examples of gram-positive and gram-negative bacteria basing on a brief survey of the literature.