Combined nano-hypericin antimicrobial photodynamic therapy and postbiotic on Streptococcus mutans.
4 affiliations
- 1Faculty of Dentistry, Tehran Medical Science, Islamic Azad University, Tehran, Iran.
- 2Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran. [email protected].
- 3Department of Oral and Maxillofacial Medicine, TeMS.C., Islamic Azad University, Tehran, Iran. [email protected].
- 4Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Abstract
Dental caries is a prevalent microbial disease, with Streptococcus mutans as a major pathogen. Increasing antibiotic resistance highlights the need for alternative, non-antibiotic strategies. This study evaluated the antimicrobial and anti-virulence potential of nano-hypericin (nHyp)-mediated antimicrobial photodynamic therapy (aPDT) combined with Lactobacillus casei-derived postbiotic (PSLC). nHyp was synthesized and characterized by transmission electron microscopy, UV-Vis spectroscopy, and dynamic light scattering, confirming quasi-spherical nanoparticles (~ 47 nm). PSLC was purified via acid precipitation and chemically profiled by gas chromatography-mass spectrometry, revealing diketopiperazines, fatty acids, hydrocarbons, and phenolic compounds. Planktonic S. mutans were treated with nHyp (1.9-1000 µg/mL) ± blue laser irradiation (450 ± 5 nm, 1-5 min), alone or combined with PSLC at 1/2 × MIC (32 µg/mL). Bacterial viability was measured by colony forming unit (CFU)/mL, and gtfB expression quantified by qRT-PCR. nHyp-mediated aPDT induced dose- and time-dependent reductions in bacterial viability (up to 81%), further enhanced by PSLC (up to 90.5%). Sub-lethal aPDT (15.6 µg/mL + 2 min) downregulated gtfB 4.25-fold, whereas combination with PSLC achieved 7.86-fold suppression, indicating inhibition of glucan synthesis relevant to biofilm formation. These findings demonstrate that nHyp-mediated aPDT combined with PSLC enhances antimicrobial and anti-virulence effects under in vitro conditions, representing a promising dual-mechanism, antibiotic-free approach to modulate cariogenic bacterial pathogenicity.
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BibTeX
@article{ghasemi2026combined,
title = {{Combined nano-hypericin antimicrobial photodynamic therapy and postbiotic on Streptococcus mutans.}},
author = {Narges Ghasemi and Maryam Pourhajibagher and Arash Azizi and Abbas Bahador},
journal = {AMB Express},
year = {2026},
month = jul,
doi = {10.1186/s13568-026-02097-3},
url = {https://europepmc.org/article/MED/42955588},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Combined nano-hypericin antimicrobial photodynamic therapy and postbiotic on Streptococcus mutans.
AU - Narges Ghasemi
AU - Maryam Pourhajibagher
AU - Arash Azizi
AU - Abbas Bahador
PY - 2026
DA - 2026/07/01
JO - AMB Express
DO - 10.1186/s13568-026-02097-3
UR - https://europepmc.org/article/MED/42955588
AB - Dental caries is a prevalent microbial disease, with Streptococcus mutans as a major pathogen. Increasing antibiotic resistance highlights the need for alternative, non-antibiotic strategies. This study evaluated the antimicrobial and anti-virulence potential of nano-hypericin (nHyp)-mediated antimicrobial photodynamic therapy (aPDT) combined with Lactobacillus casei-derived postbiotic (PSLC). nHyp was synthesized and characterized by transmission electron microscopy, UV-Vis spectroscopy, and dynamic light scattering, confirming quasi-spherical nanoparticles (~ 47 nm). PSLC was purified via acid precipitation and chemically profiled by gas chromatography-mass spectrometry, revealing diketopiperazines, fatty acids, hydrocarbons, and phenolic compounds. Planktonic S. mutans were treated with nHyp (1.9-1000 µg/mL) ± blue laser irradiation (450 ± 5 nm, 1-5 min), alone or combined with PSLC at 1/2 × MIC (32 µg/mL). Bacterial viability was measured by colony forming unit (CFU)/mL, and gtfB expression quantified by qRT-PCR. nHyp-mediated aPDT induced dose- and time-dependent reductions in bacterial viability (up to 81%), further enhanced by PSLC (up to 90.5%). Sub-lethal aPDT (15.6 µg/mL + 2 min) downregulated gtfB 4.25-fold, whereas combination with PSLC achieved 7.86-fold suppression, indicating inhibition of glucan synthesis relevant to biofilm formation. These findings demonstrate that nHyp-mediated aPDT combined with PSLC enhances antimicrobial and anti-virulence effects under in vitro conditions, representing a promising dual-mechanism, antibiotic-free approach to modulate cariogenic bacterial pathogenicity.
SN - 2191-0855
ER -