Abstract: tBackground: Antimicrobial photodynamic therapy (aPDT) has been used as an adjuvant treatment forperiodontitis. It combines a photosensitizer with a light source to induce reactive oxygen species and killmicrobial cells. PpNetNI is a protoporphyrin derivative, and it has a chemical binding site at biofilm andgreat affinity to microbial cells. The aim of this study was to investigate the effects of aPDT as an adjuvanttreatment for periodontitis.Methods: Thirty healthy male rats Wistar (Rattus norvegicus) were used in this study (Approved by UNI-NOVE Ethical committee AN0029/2015). Periodontitis was induced by placing a cotton ligature aroundthe first mandibular molar in a subgengival position. The contralateral mandibular first molar receivedneither a ligature nor any treatment, and was used as a control. After 7 days, the ligature was removedand all animals received scaling and root planing (SRP) and were divided according to the following treat-ments: SRP group (received SRP and irrigation with PpNetNI, 10 M) and aPDT group (PpNetNI 10 Mfollowed by LED irradiation). aPDT was performed with a LED (630 nm) with an output power of 400 mW(fluence-rate 200 mW/cm2; fluence 18 J/cm2). Rats were euthanized at 24 h, 48 h and 7 days postopera-tively. The area of bone loss in vestibular region of the first molar was evaluated by Optical CoherenceTomography (OCT, THORLABS LTD., Ely, UK). Data were analyzed statistically (ANOVA and Tukey tests,p < 0.05).Results: The animals treated by aPDT showed bone gain of approximately 30% compared to the SRP groupfollowing 7 days from the treatment.Conclusion: aPDT promoted bone recovery 7 days after periodontal intervention.

Palavras-Chave: experimental data; antimicrobial agents; photosensitivity; dentistry; porphyrins; light emitting diodes; tomography; coherent radiation

BELINELLO-SOUZA, ESTEFANI L.; ALVARENGA, LETICIA H.; LIMA-LEAL, CINTIA; ALMEIDA, PATRICIA; LEITE, CAROLINA G.; LIMA, TAIRINE R.; GODOY-MIRANDA, BIANCA; PREVIATI-OLIVEIRA, JHOSEPHER; PRETTO, LUCAS de; FREITAS, ANDERSON Z. de; FERNANDES, ADJACI U.; MARCOS, RODRIGO L.; PRATES, RENATO A. Antimicrobial photodynamic therapy combined to periodontal treatment: experimental model. Photodiagnosis and Photodynamic Therapy, v. 18, p. 275-278, 2017. DOI: 10.1016/j.pdpdt.2017.03.008. Disponível em: http://repositorio.ipen.br/handle/123456789/27755. Acesso em: $DATA.

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Abstract: Meat quality is normally defined by a combination of factors such as visual appearance, smell, firmness, succulence, tenderness, and flavor. Contamination of poultry meat with pathogens remains an important public health issue since it can cause illnesses due to negligence in handling, cooking or post-cooking storage. Conventionally, meat quality tests are based on visual evaluation or chemical analysis, which have the disadvantages of being subjective and time-consuming. To improve the biological contamination detection accuracy and productivity, the evaluation of porphyrin contents in meat by fluorescence spectroscopy is proposed, considering that most microorganisms and animal cells excrete porphyrins. For this purpose, chicken meat was cut into small pieces and separated in three groups: a control group where the meat was conserved under refrigeration, and two experimental groups in which the pieces were kept for 24 and 30 h at room temperature. Porphyrin was extracted from the meat samples and the fluorescence was measured in the range 550-750 nm, under excitation around 400 nm. The fluorescence lifetime was also studied. To ensure porphyrin synthesis, a concentration of 9.3 mM of delta-Aminolevulinic acid (ALA) was added to each sample, 2 h before porphyrin extraction. The results show that, in meat kept at room temperature and incubated with ALA, the porphyrin fluorescence increased, and a short-lived component was enhanced due to the action of microorganisms, indicating a potential new method to test meat quality.

Palavras-Chave: animal cells; chemical analysis; animals; chickens; contamination; meat; fluorescence spectroscopy; porphyrins; food; emission spectroscopy; organic compounds

COURROL, LILIA C.; SAMAD, RICARDO E. Determination of chicken meat contamination by porphyrin fluorescence. Journal of Luminescence, v. 199, p. 67-70, 2018. DOI: 10.1016/j.jlumin.2018.03.006. Disponível em: http://repositorio.ipen.br/handle/123456789/28888. Acesso em: $DATA.

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Abstract: Candida albicans is the main cause of superficial candidiasis. While the antifungals available are defied by biofilm formation and resistance emergence, antimicrobial photodynamic inactivation (aPDI) arises as an alternative antifungal therapy. The tetracationic metalloporphyrin Zn(II) meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin (ZnTnHex-2-PyP4+) has high photoefficiency and improved cellular interactions. We investigated the ZnTnHex-2-PyP4+ as a photosensitizer (PS) to photoinactivate yeasts and biofilms of C. albicans strains (ATCC 10231 and ATCC 90028) using a blue light-emitting diode. The photoinactivation of yeasts was evaluated by quantifying the colony forming units. The aPDI of ATCC 90028 biofilms was assessed by the MTT assay, propidium iodide (PI) labeling, and scanning electron microscopy. Mammalian cytotoxicity was investigated in Vero cells using MTT assay. The aPDI (4.3 J/cm2) promoted eradication of yeasts at 0.8 and 1.5 µM of PS for ATCC 10231 and ATCC 90028, respectively. At 0.8 µM and same light dose, aPDI-treated biofilms showed intense PI labeling, about 89% decrease in the cell viability, and structural alterations with reduced hyphae. No considerable toxicity was observed in mammalian cells. Our results introduce the ZnTnHex-2-PyP4+ as a promising PS to photoinactivate both yeasts and biofilms of C. albicans, stimulating studies with other Candida species and resistant isolates.

Palavras-Chave: fungi; yeasts; candida; photodynamic therapy; antimicrobial agents; porphyrins

SOUZA, SUEDEN O.; RAPOSO, BRUNO L.; SARMENTO-NETO, JOSE F.; REBOUCAS, JULIO S.; MACEDO, DANIELLE P.C.; FIGUEIREDO, REGINA C.B.Q.; SANTOS, BEATE S.; FREITAS, ANDERSON Z.; CABRAL FILHO, PAULO E.; RIBEIRO, MARTHA S.; FONTES, ADRIANA. Photoinactivation of yeast and biofilm communities of Candida albicans mediated by ZnTnHex-2-PyP4+ porphyrin. Journal of Fungi, v. 8, n. 6, p. 1-14, 2022. DOI: 10.3390/jof8060556. Disponível em: http://repositorio.ipen.br/handle/123456789/33187. Acesso em: $DATA.

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Abstract: Background: Experimental models of prostate cancer have demonstrated increased levels of protoporphyrin IX (PpIX) in the blood and faeces of mice. Hence, the quantification of these autofluorescent molecules could be hypothesized to be a potential marker for this type of tumour. In this case-control study, the autofluorescence of porphyrins in human faeces from patients with prostate cancer and control subjects was analysed using fluorescence spectroscopy. Methods: First, 3 mL of analytical-grade acetone was added to 0.3 g of faeces, and the mixture was macerated and centrifuged at 4000 rpm for 15 min. The supernatant was analysed spectroscopically. The emission spectra from 550 to 750 nm were obtained by exciting the samples at 405 nm. Results: A significant difference between the samples from control and cancer subjects was established in the spectral region of 670–675 nm (p = 0.000127), which corresponds to a significant increase in faecal porphyrins in patients with cancer. There was no statistically significant correlation between PSA levels and faecal porphyrins. Conclusion: In this preliminary study conducted in humans, the results show a simple and non-invasive method to assess faecal porphyrins, which have the potential to function as a tumour biomarker in patients with prostate cancer. This approach has improved sensitivity and specificity over PSA testing. Additional prospective studies with larger sample sizes are required to validate these findings.

Palavras-Chave: protoporphyrins; neoplasms; prostate; fluorescence spectroscopy; mice; laboratory animals; biological markers; patients; porphyrins

GOTARDELO, DANIEL R.; COURROL, LILIA C.; BELLINI, MARIA H.; SILVA, FLAVIA R. de O.; SOARES, CARLOS R.J. Porphyrins are increased in the faeces of patients with prostate cancer: a casecontrol study. BMC Cancer, v. 18, n. 1090, 2018. DOI: 10.1186/s12885-018-5030-1. Disponível em: http://repositorio.ipen.br/handle/123456789/29403. Acesso em: $DATA.

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Abstract: The unbridled use of antimicrobial drugs over the last decades contributed to the global dissemination of drug-resistant pathogens and increasing rates of life-threatening infections for which limited therapeutic options are available. Currently, the search for safe, fast, and efective therapeutic strategies to combat infectious diseases is a worldwide demand. Antimicrobial photodynamic therapy (APDT) rises as a promising therapeutic approach against a wide range of pathogenic microorganisms. APDT combines light, a photosensitizing drug (PS), and oxygen to kill microorganisms by oxidative stress. Since the APDT feld involves branches of biology and physics, the strengthening of interdisciplinary collaborations under the aegis of biophysics is welcome. Given this scenario, Brazil is one of the global leaders in the production of APDT science. In this review, we provide detailed reports of APDT studies published by the Laboratory of Optical Therapy (IPEN-CNEN), Group of Biomedical Nanotechnology (UFPE), and collaborators over the last 10 years. We present an integrated perspective of APDT from basic research to clinical practice and highlight its promising use, encouraging its adoption as an efective and safe technology to tackle important pathogens. We cover the use of methylene blue (MB) or Zn(II) porphyrins as PSs to kill bacteria, fungi, parasites, and pathogenic algae in laboratory assays. We describe the impact of MB-APDT in Dentistry and Veterinary Medicine to treat diferent infectious diseases. We also point out future directions combining APDT and nanotechnology. We hope this review motivates further APDT studies providing intuitive, vivid, and insightful information for the readers.

Palavras-Chave: antimicrobial agents; methylene blue; inactivation; photodynamic therapy; photosensitivity; porphyrins; zinc

CABRAL, FERNANDA V.; SOUZA, TIAGO H. dos S.; SALLERA, FABIO P.; FONTES, ADRIANA; RIBEIRO, MARTHA S. Strengthening collaborations at the Biology‑Physics interface: trends in antimicrobial photodynamic therapy. Biophysical Reviews, v. 15, n. 4, p. 685-697, 2023. DOI: 10.1007/s12551-023-01066-5. Disponível em: http://repositorio.ipen.br/handle/123456789/34213. Acesso em: $DATA.

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