The Enhancement of Antimicrobial Photodynamic Therapy of Escherichia Coli by a Functionalized Combination of Photosensitizers: In Vitro Examination of Single Cells by Quantitative Phase Imaging

• Published in: International journal of molecular sciences Vol. 23; no. 11; p. 6137
• Main Authors: Pietrowska, Aleksandra, Hołowacz, Iwona, Ulatowska-Jarża, Agnieszka, Guźniczak, Mateusz, Matczuk, Anna K, Wieliczko, Alina, Wolf-Baca, Mirela, Buzalewicz, Igor
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 30-05-2022; MDPI
• Subjects: Accumulation; Acids; Antibiotics; Antiinfectives and antibacterials; Antimicrobial agents; antimicrobial photodynamic therapy; Bacteria; Bacterial infections; Biofilms; Chlorin e6; digital holotomography; Digital imaging; DNA damage; E coli; Efficiency; Efflux; Escherichia coli; Gram-negative bacteria; Gram-positive bacteria; Immobilization; Infections; Medical imaging; Microscopy; Patients; Pheophorbide a; photodynamic inactivation; Photodynamic therapy; quantitative phase imaging; Refractivity; digital holotomography; Pheophorbide a; photodynamic inactivation; quantitative phase imaging; Chlorin e6; E. coli; antimicrobial photodynamic therapy
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms23116137

The prevention of biofilm formation is crucial for the limitation of bacterial infections typically associated with postoperative infections, complications in bedridden patients, and a short-term prognosis in affected cancer patients or mechanically ventilated patients. Antimicrobial photodynamic therapy (aPDT) emerges as a promising alternative for the prevention of infections due to the inability of bacteria to become resistant to aPDT inactivation processes. The aim of this study was to demonstrate the use of a functionalized combination of Chlorin e6 and Pheophorbide as a new approach to more effective aPDT by increasing the accumulation of photosensitizers (PSs) within
cells. The accumulation of PSs and changes in the dry mass density of single-cell bacteria before and after aPDT treatment were investigated by digital holotomography (DHT) using the refractive index as an imaging contrast for 3D label-free live bacteria cell imaging. The results confirmed that DHT can be used in complex examination of the cell-photosensitizer interaction and characterization of the efficiency of aPDT. Furthermore, the use of Pheophorbide a as an efflux pomp inhibitor in combination with Chlorin e6 increases photosensitizers accumulation within
and overcomes the limited penetration of Gram-negative cells by anionic and neutral photosensitizers.