ArticleLasers in surgery and medicine2012
Type I and Type II mechanisms of antimicrobial photodynamic therapy: an in vitro study on gram-negative and gram-positive bacteria.
Article in Lasers in surgery and medicine, 2012. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 119 papers, 2 of them syntheses that pooled it.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
119 citing papers in PubMed, 2 syntheses or guidelines pooled it, 372 citations in OpenAlex.
- Photodithazine-Mediated Antimicrobial Photodynamic Therapy: A Systematic Review of Efficacy and Applications.International journal of molecular sciences · 2025Pooled it
- Efficacy of laser in re-osseointegration of dental implants-a systematic review.Lasers in medical science · 2023Pooled it
- Treatment of dental plaque biofilms using photodynamic therapy: a randomised controlled study.European archives of paediatric dentistry : official journal of the European Academy of Paediatric Dentistry · 2021Trial
- Trial
- Antimicrobial photodynamic therapy suppresses dental plaque formation in healthy adults: a randomized controlled clinical trial.BMC oral health · 2014Trial
- Function-preserving photooxidation of AS1411 aptamer by a G-quadruplex-guided photosensitizer.Chemical science · 2026Article
- Recent Advances in Zinc(II)-Complexes for Antibacterial Photodynamic Therapy.Chemistry, an Asian journal · 2026Review
- A Critical Synthesis of Natural Photosensitizers in Photodynamic Food Preservation Covering Mechanisms, Matrix-Specific Applications, and Translational Barriers.Comprehensive reviews in food science and food safety · 2026Review
- Antimicrobial Photodynamic Inactivation Using Riboflavin 5'-Phosphate and a 450 nm Diode Laser: An In Vitro Dose-Optimisation Study.Pharmaceutics · 2026Article
- An Ion-Based Strategy Toward Synergistic Surface Functionalization Combining the Osteogenic Properties and NIR-Mediated Antibacterial Activity of PEEK.Advanced materials (Deerfield Beach, Fla.) · 2026Article
- Overcoming Tumor Hypoxia in Photodynamic Therapy: A Comprehensive Review of Oxygen-Delivery Carriers and Type I Photosensitizers.International journal of molecular sciences · 2026Review
- Photodynamic therapy: A paradigm shift in overcoming drug‑resistant tuberculosis (Review).Molecular medicine reports · 2026Review
- Core-Shell Structures of Bioactive Glass Nanoparticles and MIL-100 Framework: Properties and Biomedical Applications.ACS biomaterials science & engineering · 2026Article
- Lectin-Rose Bengal Conjugates for Targeted Photodynamic Inactivation of Pathogenic Bacteria.International journal of molecular sciences · 2026Article
- Empowering photodynamic therapy with artificial intelligence: current trends and future directions.Frontiers in oncology · 2026Review
- Beyond Conventional Disinfectants: A Comparative Review of Cold Atmospheric Plasma and Photodynamic Therapy against Oral Pathogens.Journal of lasers in medical sciences · 2026Review
- Inhalable nanoparticle-based delivery systems for the treatment of pulmonary infections:Drug delivery · 2025Review
- Antimicrobial Photodynamic Activity of the Zn(II) Phthalocyanine RLP068/Cl Versus Antimicrobial-Resistant Priority Pathogens.International journal of molecular sciences · 2025Article
- Pathogen-specific kinetics of oxidative burst in camel leukocytes: Influence of serum opsonization on reactive oxygen species production.Veterinary world · 2025Article
- Iron Oxide-Doped Carbon Nanoparticles Stabilised with Functionally Modified Hyperbranched Polyglycerol for CdJournal of fluorescence · 2025Article
59 more citing papers are in PubMed but not listed here.
Corrections and comments
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Authors and funding
6 authors at 6 institutions in 3 countries.
Funding
Abstract
BACKGROUND AND
objectivesAntimicrobial photodynamic therapy (APDT) employs a non-toxic photosensitizer (PS) and visible light, which in the presence of oxygen produce reactive oxygen species (ROS), such as singlet oxygen ((1) O(2), produced via Type II mechanism) and hydroxyl radical (HO(.), produced via Type I mechanism). This study examined the relative contributions of (1) O(2) and HO(.) to APDT killing of Gram-positive and Gram-negative bacteria. STUDY DESIGN/MATERIALS AND
methodsFluorescence probes, 3'-(p-hydroxyphenyl)-fluorescein (HPF) and singlet oxygen sensor green reagent (SOSG) were used to determine HO(.) and (1) O(2) produced by illumination of two PS: tris-cationic-buckminsterfullerene (BB6) and a conjugate between polyethylenimine and chlorin(e6) (PEI-ce6). Dimethylthiourea is a HO(.) scavenger, while sodium azide (NaN(3)) is a quencher of (1) O(2). Both APDT and killing by Fenton reaction (chemical generation of HO(.)) were carried out on Gram-positive bacteria (Staphylococcus aureus and Enterococcus faecalis) and Gram-negative bacteria (Escherichia coli, Proteus mirabilis, and Pseudomonas aeruginosa).
resultsConjugate PEI-ce6 mainly produced (1) O(2) (quenched by NaN(3)), while BB6 produced HO(.) in addition to (1) O(2) when NaN(3) potentiated probe activation. NaN(3) also potentiated HPF activation by Fenton reagent. All bacteria were killed by Fenton reagent but Gram-positive bacteria needed a higher concentration than Gram-negatives. NaN(3) potentiated Fenton-mediated killing of all bacteria. The ratio of APDT killing between Gram-positive and Gram-negative bacteria was 2 or 4:1 for BB6 and 25:1 for conjugate PEI-ce6. There was a NaN(3) dose-dependent inhibition of APDT killing using both PEI-ce6 and BB6 against Gram-negative bacteria while NaN(3) almost failed to inhibit killing of Gram-positive bacteria.
conclusionAzidyl radicals may be formed from NaN(3) and HO(.). It may be that Gram-negative bacteria are more susceptible to HO(.) while Gram-positive bacteria are more susceptible to (1) O(2). The differences in NaN(3) inhibition may reflect differences in the extent of PS binding to bacteria (microenvironment) or differences in penetration of NaN(3) into cell walls of bacteria.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.