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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.
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http://dx.doi.org/10.3390/ijms23116137 | DOI Listing |
Lasers Med Sci
September 2025
Laser Research Center of Dentistry, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
Microbial contamination of absorbable collagen membranes used in guided bone regeneration (GBR) may compromise healing outcomes. This study aimed to investigate whether the minimum inhibitory concentration (MIC) of hydrogen peroxide (HO) can improve the antibacterial effect of indocyanine green (ICG)-mediated antimicrobial photodynamic therapy (PDT) on absorbable collagen membranes while reducing the need for high HO concentrations. A laboratory-based model was developed using Streptococcus sanguinis and Staphylococcus aureus.
View Article and Find Full Text PDFACS Appl Mater Interfaces
September 2025
Affiliated Hospital of Shandong Second Medical University, Shandong Second Medical University, Weifang, Shandong 261053, P.R. China.
Decades of antibiotic misuse have spurred an antimicrobial resistance crisis, creating an urgent demand for alternative treatment options. Although phototherapy has therapeutic potential, the efficacy of the most advanced photosensitizers (PS) is essentially limited by aggregation-induced quenching, which significantly reduces their therapeutic effect. To address these challenges, we developed a cationic metallocovalent organic framework (CRuP-COF) via a solvent-mediated dual-reaction synthesis strategy.
View Article and Find Full Text PDFJ Mater Chem B
September 2025
School of Materials Science and Engineering, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China.
Antibacterial photodynamic therapy offers a promising approach for combating both susceptible and multidrug-resistant pathogens. However, conventional photosensitizers have limitations in terms of poor binding specificity and weak penetration for pathogens. In this study, we developed synergistic photobactericidal polymers that integrate hydrophilic toluidine blue O (TBO) with the lipophilic penetration enhancer citronellol (CT).
View Article and Find Full Text PDFPhotodiagnosis Photodyn Ther
September 2025
Laboratory of Applied Microbiology Department of Dental Materials and Prosthodontics, Universidade Estadual Paulista "Júlio de Mesquita Filho", Faculdade de Odontologia de Araraquara, Araraquara, SP, Brazil. Electronic address:
Objective: To evaluate whether pretreatment strategies targeting the extracellular matrix (ECM), such as DNase I and low-frequency ultrasound, enhance the efficacy of successive antimicrobial photodynamic therapy (aPDT) against Candida albicans biofilms and to assess the effects on biofilm components.
Methods: Forty-eight-hour C. albicans (ATCC 90028) biofilms were treated under four conditions: (I) aPDT [Photodithazine (PDZ) (25 mg/L) for 20 min + Light-Emitting Diode (LED) (660 nm, 18 J/cm²)], (II) DNase+aPDT [5 min with 20 U/mL DNase I before aPDT], (III) sonication+aPDT [7 W, 170-190 J before aPDT], (IV) Dn+So+aPDT.
Int J Food Microbiol
September 2025
Department of Food Science, Rutgers University, New Brunswick, NJ 08901, United States. Electronic address:
Alternatives to the use of chemical antimicrobials to treat meat and poultry carcasses during processing and food processing environments are of interest to consumers globally. The influence of bacterial cell concentration, membrane permeabilizing agents, and effect on macromolecules of the photosensitizer curcumin (PSC) on Salmonella inactivation in a medium model and on chicken skin and the inactivation of Listeria monocytogenes biofilms on stainless steel were determined. The addition of 30 mg/mL CaCl or higher significantly reduced the level of Salmonella compared to PSC treatment alone in a liquid media system.
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