Multi-targets of antimicrobial photodynamic therapy mediated by erythrosine against Staphylococcus aureus identified by proteomic approach.

Staphylococcus aureus is a global challenge to the clinical field and food industry. Therefore, the development of antimicrobial photodynamic therapy (aPDT) has become one of the valuable methods to control this pathogen. The antibacterial activity of photoinactivation by erythrosine (Ery) against S. aureus has been reported, but its modes of action are unclear. This study aimed to employ a proteomic approach to analyze modes of action of Ery-aPDT against S. aureus. We determined the antibacterial effect by Ery-aPDT assays, quantified reactive oxygen species (ROS) and injury to the cell membrane, and determined protein expression using a proteomic approach combined with bioinformatic tools. Ery-aPDT was effective in reducing S. aureus to undetectable levels. In addition, the increment of ROS accompanied the increase in the reduction of cell viability, and damage to cellular membranes was shown by sublethal injury. In proteomic analysis, we found 17 differentially expressed proteins. These proteins revealed changes mainly associated with defense to oxidative stress, energy metabolism, translation, and protein biosynthesis. Thus, these results suggest that the effectiveness of Ery-aPDT is due to multi-targets in the bacterial cell that cause the death of S. aureus.

Promising onychomycosis treatment with hypericin-mediated photodynamic therapy: Case reports.

BACKGROUND: Onychomycosis (OM) is a common nail plate disorder caused by dermatophyte molds, yeasts, and non-dermatophyte molds, which use keratin in the nail plate as an energy source. OM is characterized by dyschromia, increased nail thickness, subungual hyperkeratosis, and onychodystrophy, and is typically treated with conventional antifungals despite frequent reports of toxicity, fungal resistance, and OM recurrence. Photodynamic therapy (PDT) with hypericin (Hyp) as a photosensitizer (PS) stands out as a promising therapeutic modality. When excited by a specific wavelength of light and in the presence of oxygen, to lead to photochemical and photobiological reactions on the selected targets. METHODS: OM diagnosis was made in three suspected cases, and the causative agents were identified by classical and molecular methods, and confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). Susceptibility of planktonic cells of the clinical isolates to conventional antifungals and PDT-Hyp was evaluated, and photoacoustic spectroscopy (PAS) of Hyp permeation in nail fragments ex vivo was analyzed. Furthermore, the patients opted to undergo PDT-Hyp treatment and were subsequently followed up. The protocol was approved by the human ethics committee (CAAE, number 14107419.4.0000.0104). RESULTS: The etiological agents of OM in patients ID 01 and ID 02 belonged to the Fusarium solani species complex, being identified as Fusarium keratoplasticum (CMRP 5514) and Fusarium solani (CMRP 5515), respectively. For patient ID 03, the OM agent was identified as Trichophyton rubrum (CMRP 5516). PDT-Hyp demonstrated a fungicidal effect in vitro, with reductions of p3 log10 (p < 0.0051 and p < 0.0001), and the PAS analyses indicated that Hyp could completely permeate through both healthy and OM-affected nails. After four sessions of PDT-Hyp, mycological cure was observed in all three cases, and after seven months, clinical cure was confirmed. CONCLUSION: PDT-Hyp showed satisfactory results in terms of efficacy and safety, and thus can be considered a promising therapy for the clinical treatment of OM.

4th Generation Biomaterials Based on PVDF-Hydroxyapatite Composites Produced by Electrospinning: Processing and Characterization.

Biomaterials that effectively act in biological systems, as in treatment and healing of damaged or lost tissues, must be able to mimic the properties of the body's natural tissues in its various aspects (chemical, physical, mechanical and surface). These characteristics influence cell adhesion and proliferation and are crucial for the success of the treatment for which a biomaterial will be required. In this context, the electrospinning process has gained prominence in obtaining fibers of micro- and nanometric sizes from polymeric solutions aiming to produce scaffolds for tissue engineering. In this manuscript, poly(vinylidene fluoride) (PVDF) was used as a polymeric matrix for the manufacture of piezoelectric scaffolds, exploring the formation of the ß-PVDF piezoelectric phase. Micro- and nanometric hydroxyapatite (HA) particles were incorporated as a dispersed phase in this matrix, aiming to produce multifunctional composite membranes also with bioactive properties. The results show that it is possible to produce membranes containing micro- and nanofibers of the composite by the electrospinning process. The HA particles show good dispersion in the polymer matrix and predominance of ß-PVDF phase. Also, the composite showed apatite growth on its surface after 21 days of immersion in simulated body fluid (SBF). Tests performed on human fibroblasts culture revealed that the electrospun membranes have low cytotoxicity attesting that the composite shows great potential to be used in biomedical applications as bone substitutions and wound healing.