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A hybrid film of chitosan/poly(vinyl alcohol)/cationic Fe(III)-porphyrin (Cht/PVA-FeTMPyP) was synthesized to act as a Fenton-like catalyst to decolorize methyl orange and methyl red azo dyes. The Cht/PVA-FeTMPyP film was characterized by different analytical and microscopy techniques, which indicated that the metalloporphyrin affects different properties of the hybrid film. Batch experiments revealed that the hybrid film exhibits enhanced catalytic activity towards dyes decolorization in the presence of H 2 O 2 as compared to the "free" FeTMPyP. Fast decolorization rates as high as 90 min were observed for both azo dyes under mild conditions (pH 7 and room temperature), even at low concentrations of the catalyst in H 2 O 2. After the decolorization, FTIR analysis showed that simple molecules are released as by-products. Moreover, the hybrid film performed well in cyclic runs without leaching out iron ions or losing its catalytic activity. All these features associated with its ease handling ranks the Cht/PVA-FeTMPyP hybrid film as a promising heterogeneous Fenton-like catalyst for the decomposition of azo dyes in water. [ABSTRACT FROM AUTHOR]

This manuscript reports, at the first time, the photoinactivation evaluation of tetra-cationic and anionic porphyrins as photosensitizers (PS) for the photodynamic inactivation (PDI) of rapidly growing mycobacteria strains. Two different charged porphyrin groups were obtained commercially. PDI experiments in the strains Mycobacterium massiliense e Mycobacterium fortuitum conducted with adequate concentration (without aggregation) of photosensitizer under white light at a fluence rate of 50 mW/cm2 over 90 min showed that the most effective PS caused a 100 times reduction in the concentration of viable mycobacteria. The present results show that porphyrin with positively charge are more efficient PS than anionic porphyrin (negatively charged) against M. massiliense e M. fortuitum. It is also clear that the effectiveness of the molecule as PS for PDI studies with mycobacteria is strongly related with the porphyrin peripheral charge, and consequently their solubility in physiological media. Cationic PSs might be promising anti-mycobacteria PDI agents with potential applications in medical clinical cases and bioremediation. Image 1 [ABSTRACT FROM AUTHOR]

• The tetra-cationic porphyrins with peripheral Pt(II) - and Pd(II) - polypyridyl complexes using PDT displayed a promising alternative for cutaneous leishmaniasis treatment. • The isomeric tetra-cationic porphyrins were found in cytosol and co-localized in the mitochondria and acidic compartments of leishmania parasites. • The isomeric tetra-cationic porphyrins induced the cell death of leishmania amazonensis mainly by a necrotic process in the presence of light. Leishmaniasis is a neglected disease that impacts more than one billion people in endemic areas of the globe. Several drawbacks are associated with the currently existing drugs for treatment such as low effectiveness, toxicity, and the emergence of resistant strains that demonstrate the importance of looking for novel therapeutic alternatives. Photodynamic therapy (PDT) is a promising novel alternative for cutaneous leishmaniasis treatment because its topical application avoids potential side effects generally associated with oral/parenteral application. A light-sensitive compound known as photosensitizer (PS) interacts with light and molecular oxygen to generate reactive oxygen species (ROS), which promote cell death by oxidative stress through PDT approaches. Here, for the first time, we demonstrate the antileishmanial effect of tetra-cationic porphyrins with peripheral Pt(II)- and Pd(II)-polypyridyl complexes using PDT. The isomeric tetra-cationic porphyrins in the meta positions, 3-PtTPyP, and 3-PdTPyP, exhibited the highest antiparasitic activity against promastigote (IC 50-pro = 41.8 nM and 46.1 nM, respectively) and intracellular amastigote forms (IC 50-ama = 27.6 nM and 38.8 nM, respectively) of L. amazonensis under white light irradiation (72 J cm–2) with high selectivity (SI > 50) for both forms of parasites regarding mammalian cells. In addition, these PS induced the cell death of parasites principally by a necrotic process in the presence of white light by mitochondrial and acidic compartments accumulation. This study showed that porphyrins 3-PtTPyP and 3-PdTPyP displayed a promising antileishmanial-PDT activity with potential application for cutaneous leishmaniasis treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

• Application of tetra-cationic porphyrins against Gram-positive bacteria. • Tetra-cationic porphyrins 3PtPyP are highly effective in the photo-inactivation of Enterococcus faecium and MRSA clinical isolate in vitro. • Combination of porphyrins and commercial antimicrobials presented synergic activity. This manuscript presents the first report on antimicrobial photo-inactivation in vitro using tetra-cationic porphyrins with peripheral platinum(II) bipyridyl complexes against Gram-positive bacteria. Two isomeric tetra-cationic porphyrins (3TPyP and 4TPyP) were tested against clinically important bacterial species. The antimicrobial activity assays were performed at specific photosensitizer (PS) concentrations under dark and white-light LED irradiation conditions for 120 min. The porphyrin 3-PtTPyP was the most efficient PS against the bacteria tested, inhibiting bacterial growth in just 15 min and 30 min at low concentrations (3.75 and 0.45 µM). The minimal inhibitory concentration of the porphyrin increased in the presence of reactive oxygen species scavengers, indicating that singlet oxygen and radical species likely participated in the photo-oxidation mechanism. In addition, the checkerboard assay that tests the association of compounds, showed a synergistic effect, suggesting a potentiation of the antibacterial effect when porphyrin was tested in combination with ciprofloxacin and vancomycin. Thus, tetra-cationic porphyrins containing platinum(II) complexes are promising agents for microbial photo-inactivation as an alternative therapy against infections. [Display omitted] [ABSTRACT FROM AUTHOR]

• The tetra-cationic porphyrins totally inactivated and killed Candida spp. • The cationic porphyrins interfered with Candida spp. biofilm formation. • 3-H 2 TMeP+ decreased the adhesion force of Candida parapsilosis. Background: Candida spp. is the main fungal genus related to infections in humans, and its treatment has become a challenge due to the production of biofilm and its resistance/multi-resistance profile to conventional antifungals. Antimicrobial photodynamic therapy stands out as a treatment characterized by a broad spectrum of antimicrobial action, being able to induce oxidative stress in pathogens, and porphyrins are photosensitizers with high selectivity to pathogens. Thus, this work aimed to analyze the photoinactivation of different species of Candida by two cationic (4-H 2 TMeP+ and 3-H 2 TMeP+) and one anionic (4-H 2 TPSP‒) porphyrins. Materials and Methods: Microdilution assays were performed to determine the MIC 100 , with subsequent determination of MFC 100. Determination of oxidative species was done through the use of scavengers, while biofilm morphological features were investigated using the atomic force microscopy. Results: Cationic porphyrins were significantly efficient in inactivating Candida albicans and non- albicans species with 100% growth inhibition and fungicidal activity (MFC 100 /MIC 100 ≤ 4.0). The cationic porphyrins were also able to interfere in Candida spp biofilm formation. The photo-oxidative mechanism activated by 3-H 2 TMeP+ in Candida spp. is concurrent with the production of singlet oxygen and oxygen radical species. In the AFM analysis, 3-H 2 TMeP+ was able to reduce yeast adhesion to the surface. Conclusions: Cationic porphyrins can photo-inactivate different species of Candida in both planktonic and biofilm-associated forms, and reduce the adhesion of these fungi to the surface. [Display omitted] [ABSTRACT FROM AUTHOR]

• Use of water-soluble tetra-cationic porphyrins against Gram-negative bacteria. • Antimicrobial and a preliminary antibiofilm activity against Pseudomonas aeruginosa. • The water-soluble tetra-cationic porphyrin 4-H 2 TMePor is highly effective in photoinactivating PA01. • 4-H 2 TMePor was not cytotoxic against human keratinocytes and fibroblasts. This manuscript presents the cytotoxicity, antimicrobial activity, antibiofilm preliminary properties, and associated therapy with commercial drugs using water-soluble tetra-cationic porphyrins against Pseudomonas aeruginosa. Two commercial tetra-cationic porphyrins were tested against a standard strain of P. aeruginosa 01 (PA01) in antibacterial activity assays under dark conditions and irradiated with white light for 120 min. Porphyrin 4-H 2 TMePor showed better antimicrobial activity and was chosen for further tests. Increased minimum inhibitory concentration was observed in the presence of reactive oxygen species, suggesting that photooxidation was mediated by the singlet oxygen production. In the time-kill curve assay, 4-H 2 TMePor inhibited bacterial growth in 90 min of irradiation. The checkerboard assay revealed synergistic interactions. Biofilms of the standard PA01 strain and three clinical isolates were formed. The biofilm destruction assay was more efficient for PA01, significantly reducing the biofilm biomass formed compared to the positive control. The associated treatment to destroy the biofilm potentiated a significant decrease in the biofilm biomass compared to the positive control. The photosensitizer did not damage human keratinocytes or mouse fibroblasts in the cytotoxicity assays, demonstrating the safety of using 4-H 2 TMePor. Atomic force microscopy indicated lower adhesion force, higher cell wall deformation, and higher dissipation energy in the treated control compared to untreated PA01. Given our findings, it is evident that water-soluble tetra-cationic porphyrins have excellent antimicrobial and a preliminary antibiofilm activity against Gram-negative bacteria, proving to be a potential photosensitizer for clinical use. [ABSTRACT FROM AUTHOR]

• 4-H 2 TMeP porphyrin is effective to inactivate MDR bacteria after aPDT. • aPDT using 4-H 2 TMeP porphyrin can inactivate Gram-positive and -negative bacteria in mono and in polycultures. • Gram-positive bacteria are inactivated by aPDT using 4-H 2 TMeP porphyrin faster than Gram-negative. • AFM analysis demonstrate different damages at the bacteria membranes after aPDT. Multidrug-resistant (MDR) organisms have been frequently isolated from integumentary lesions of animals, and these lesions are usually infected by more than one pathogen. This study evaluated an in vitro antimicrobial photodynamic therapy (aPDT) using two water-soluble tetra-cationic porphyrins (3 - H 2 TMeP and 4 - H 2 TMeP) against mono and polyculture of MDR bacteria isolated from dogs, cats, and horses. Ten isolates of MDR bacteria (two of each species: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Serratia marcescens , and Staphylococcus pseudointermedius) were used to evaluate aPDT against the monoculture using a non-cytotoxic concentration of 3 - H 2 TMeP and 4-H 2 TMeP porphyrins (40 µM), with 30 min of light irradiation in Gram-positive and 90 min for Gram-negative bacteria. The aPDT using the 4 - H 2 TMeP porphyrin was also tested against five different polycultures (Coagulase positive Staphylococcus (CPS) and Pseudomonas sp.; E. coli and Proteus sp.; Pseudomonas sp. and Proteus sp.; CPS and E. coli ; and CPS and Proteus sp.) for 90 min. The efficacy of both treatments was evaluated by plating the solution exposed to light or kept in the dark and counting the colonies forming units after 24 h of incubation at 37 °C. Atomic force microscope analysis was used to map bacteria morphological changes and extract adhesion force parameters from the bacteria membranes. Only the 4 - H 2 TMeP porphyrin had antibacterial activity against MDR bacteria in monoculture, especially S. pseudointermedius and P. aeruginosa. In polyculture, the 4 - H 2 TMeP porphyrin reduced bacterial concentrations (p < 0.05) in the associations of E. coli and S. pseudointermedius, P. aeruginosa and S. pseudointermedius , and P. aeruginosa and P. mirabilis. These results showed that aPDT using 4 - H 2 TMeP is a good option for future associations of aPDT and other therapies or in vivo research. [Display omitted] [ABSTRACT FROM AUTHOR]

Several analytical methods have been employed to elucidate bonding mechanisms between dental hard tissues, luting agents and restorative materials. Atomic Force Microscopy (AFM) imaging that has been extensively used in materials science, but its full capabilities are poorly explored by dental research community. In fact, commonly used to obtain topographic images of different surfaces, it turns out that AFM is an underestimated technique considering that there are dozens of basic and advanced modes that are scarcely used to explain properties of biomaterials. Thus, this paper addresses the use of phase-contrast imaging, force-distance curves, nanomechanical and Kelvin probe force techniques during AFM analysis to explore topological, nanomechanical and electrical properties of Y-TZP samples modified by different surface treatments, which has been widely used to promote adhesive enhancements to such substrate. The AFM methods are capable of access erstwhile inaccessible properties of Y-TZP which allowed us to describe its adhesive properties correctly. Thus, AFM technique emerges as a key tool to investigate the complex nature of biomaterials and highlighting its inherent interdisciplinarity that can be successfully used for bridging fragmented disciplines such as solid-state physics, microbiology and dental sciences. • Many AFM advanced modes were revisited in this work, focusing on dental and biomedical applications. • AFM basic and advanced modes were described with the intention to be useful for new users. • Representative images were carefully chosen in order to exemplify what is worth discussing in AFM imaging. • Fractal analysis and its relations with materials science is deeply discussed and demonstrated. [ABSTRACT FROM AUTHOR]

Several synthetic metallated protoporphyrins (M-PPIX) were tested for their ability to block the cell cycle of the lethal human malaria parasite Plasmodium falciparum . After encapsulating the porphyrin derivatives in micro- and nanocapsules of marine atelocollagen, their effects on cultures of red blood cells infected (RBC) with P. falciparum were verified. RBCs infected with synchronized P. falciparum incubated for 48 h showed a toxic effect over a micromolar range. Strikingly, the IC 50 of encapsulated metalloporphyrins reached nanomolar concentrations, where Zn-PPIX showed the best antimalarial effect, with an IC 50 = 330 nM. This value is an 80-fold increase in the antimalarial activity compared to the antimalarial effect of non-encapsulated Zn-PPIX. These findings reveal that the incubation of P. falciparum infected-RBCs with 20 μM Zn-PPIX reduced the size of hemozoin crystal by 34%, whereas a 28% reduction was noticed with chloroquine, confirming the importance of heme detoxification pathway in drug therapy. From the Clinical Editor In this study, synthetic metalloporphyrins were tested as therapeutics that target Plasmodium falciparum. The IC50 of encapsulated metalloporphyrins was found to be in the nanomolar concentration range, with encapsulated Zn-PPIX showing an 80-fold increase in its antimalarial activity compared to the non-encapsulated form. [ABSTRACT FROM AUTHOR]

• Application of tetra-cationic Ag(II)-porphyrins against mycobacteria; • Use of cationic porphyrins in the treatment of mycobacteriosis; • AgTMeP tetra-cationic porphyrin is very effectiveness in photo-inactivation of mycobacteria; We report the photoinactivation evaluation of Ag(II) porphyrins (cationic AgTMeP and anionic AgTPPS) in the antimicrobial photodynamic therapy (aPDT) of rapidly growing mycobacterial strains. The aPDT assays in the Mycolicibacterium fortuitum, Mycobacteroides abscessus subs. abscessus, Mycobacteroides abscessus subsp. massiliense , and Mycolicibacterium smegmatis strains conducted without aggregating photosensitizers (PS) under irradiation for 90 min (270 J/cm2) showed that the most effective PS (nanomolar range) significantly reduced the concentration of viable mycobacteria. Structural damage on the Mycolicibacterium smegmatis non-pathogenic model was observed using atomic force microscopy, revealing that Ag(II)-porphyrin induced extensive changes in its electrical and adhesive forces, demonstrating changes in topography that may be linked to the action of different fractions of reactive oxygen species. The results presented in this paper provide solid evidence for using cationic porphyrin AgTMeP as an alternative to the conventional treatment of cutaneous mycobacteriosis and the disinfection of prosthetic devices and hospital equipment. [Display omitted] [ABSTRACT FROM AUTHOR]

• Application of positively charged porphyrins against fungi. • Use of cationic porphyrins to treat dermatophytosis. • 3PtP tetra-cationic porphyrins are highly effective in photoinactivating dermatophyte fungi. [Display omitted] This manuscript reports enhanced antimicrobial photoinactivation using tetra-cationic porphyrins with peripheral platinum(II) and palladium(II) complexes against fungal dermatophyte strains. Six different positively charged porphyrins were used and applied in antimicrobial photodynamic therapy experiments (aPDT) against dermatophyte fungi colonies. The microbiological tests were conducted with an adequate concentration of photosensitizer (PS) under white-light irradiation for 120 min and the most effective PS meta isomer 3PtP significantly reduced the concentration of viable fungal colony. In this way, tetra-cationic porphyrins containing platinum(II)-bipyridyl complexes may be promising fungicidal aPDT agents with potential applications in future clinical cases. [ABSTRACT FROM AUTHOR]

• Application of tetra-cationic Pd(II)-porphyrins against mycobacteria. • Use of porphyrins in the treatment of mycobacteriosis. • 3-PdTPyP tetra-cationic porphyrin meta isomer is very effectiveness in photo-inactivation of mycobacteria. Antimicrobial photodynamic therapy (aPDT) has gained prominence in microbiology, especially in treating non-invasive infections. Diseases such as mycobacteriosis, which causes localized infections and has a slow treatment, tend to be future targets for this type of technology. Therefore, this study aimed to explore the action of two isomeric Pd(II)-porphyrins on fast-growing mycobacterial strains (RGM). Tetra-cationic porphyrins (4-PdTPyP and 3-PdTPyP) were synthesized and applied against standard strains of Mycobacteroides abscessus subsp. abscessus (ATCC 19977), Mycolicibacterium fortuitum (ATCC 6841), Mycolicibacterium smegmatis (ATCC 700084), and Mycobacteroides abscessus subsp. massiliense (ATCC 48898). Reactive oxygen species (ROS) scavengers were used in an attempt to determine possible ROS produced by the photosensitizers (PS) under study. Moreover, the impact of porphyrin on the mycobacterial surface was further evaluated by atomic force microscopy (AFM), and we observed significant damage on cells walls and altered nanomechanical and electrostatic adhesion properties. The results presented herein show that the positively charged porphyrin at the meta position (3-PdTPyP) was the most efficient PS against the RGM strains, and its bactericidal activity was proven in two irradiation sessions, with singlet oxygen species being the main ROS involved in this process. This study demonstrated the therapeutic potential of porphyrins, especially the 3-PdTPyP derivative [Display omitted]. [ABSTRACT FROM AUTHOR]

• Photophysical and photobiological properties for cisplatin-porphyrins were investigated. • Excite triplet states of these cisplatin tetra-cationic porphyrins were investigated. • Antimicrobial photodynamic therapy was explored in the Pt(II)-porphyrin derivatives. In this manuscript, we report, the photophysical study of triplet excited states and antimicrobial photoinactivation of positively charged tetra-cisplatin porphyrin derivatives against Gram + and Gram ‒ bacterial strains. Isomeric cisplatin-porphyrins were used and applied in aPDT assays in the bacilli Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa (Gram negative) and a cocci Staphylococcus aureus (Gram positive) strains. The results show that compound substituted at meta position (3-cis-PtTPyP) is the more efficient photosensitizer against bacteria culture. In this way, tetra-cationic porphyrins containing cisplatin derivatives might be promising aPDT agents with potential applications in clinical infections. [Display omitted] [ABSTRACT FROM AUTHOR]

• Inactivation of enveloped and non-enveloped bovine viruses by water-soluble porphyrins; • H 2 TMeP and ZnTMeP porphyrins were able to inactivate enveloped virus; • H 2 TMeP and ZnTMeP porphyrins were able to inactivate non-enveloped virus; • Tetra-cationic porphyrins could be used to inactivate viruses in immunobiological and solutions; Porphyrins are photoactive compounds that can absorb the energy of light and transfer it to oxygen molecules, producing reactive oxygen species (ROS). Once produced, ROS may alter biological molecules and cellular mechanisms, leading to cell apoptosis or inactivation of microorganisms, such as bacteria, fungi, and viruses. Therefore, the objective of this study was to evaluate the in vitro virucidal activity of six tetra-cationic porphyrins against two bovine viruses (Bovine alphaherpesvirus 1 , BoHV-1, enveloped; and Bovine adenovirus , BAV, non-enveloped). For this, viral suspensions were incubated with each porphyrin (H 2 TMeP , ZnTMeP , and CuTMeP at 4.0 μM, NiTMeP at 5.0 μM, and CoClTMeP and MnClTMeP at 1.0 μM) and exposed to white-light irradiation for 0, 60, 120, and 180 min (BAV) or 0, 30, 60, 90, and 120 min (BoHV-1). Then, the remaining viral titers were determined by limiting dilution and compared with the control (virus + porphyrins without light exposition). The porphyrins H 2 TMeP and ZnTMeP showed the highest virucidal activity against both viruses. ZnTMeP inactivated BoHV-1 after 30 min of photoactivation and H 2 TMeP after 60 min. The BAV was photo-inactivated by both porphyrins at 180 min of white-light exposition. CuTMeP , NiTMeP , and CoClTMeP porphyrins had weak virucidal activity against BoHV-1 and MnClTMeP showed no virucidal activity against both viruses. These results indicated that free-base H 2 TMeP and ZnTMeP porphyrins present virucidal activity against non-enveloped and enveloped viruses, opening the possibility for their use to inactivate viruses on surfaces, biological substrates, and solutions. [ABSTRACT FROM AUTHOR]

• Tetra-cationic platinum(II) metalloporphyrins have antitumor action in metastatic melanoma. • Platinum(II) metalloporphyrins improves their interaction with APO B-100. • Zn-4-PtTPyP, Cu-4-PtTPyP and Ni-4-PtTPyP have affinity for ERT-B. • Zn-4-PtTPyP, Cu-4-PtTPyP and Ni-4-PtTPyP have affinity for HSA, have potential as drug delivery. • Zn(II), Cu(II) and Ni(II) platinum(II) porphyrins have affinity for antioxidant enzymes. Tetra-cationic porphyrins with peripheral Pt (II) -bipyridyl complexes demonstrated a potential as photosensitizers to be used in photodynamic therapy (PDT). First-line transition metals, such as zinc (II), copper (II) and nickel (II), can be incorporated into the porphyrin nucleus, making this molecule more selective and more effective for this therapy in combating to tumor cells, such as metastatic melanoma. We characterized these derivatives to verify the improvement in selectivity of platinum (II) 4-PtTPyP porphyrins. Receptors such as LDL and endothelin (ERT-B) were investigated, as well as the binding affinity of two antioxidants: catalase model enzymes and superoxide dismutase. Human serum albumin (SAH) HSA binding properties have been verified. In addition, we evaluated the antitumor action of such metalloporphyrins in an in vitro cell viability. Our results demonstrated that porphyrins have significant antitumor potential when exposed to white light conditions. The affinity for the LDL receptor was better when compared to platinum porphyrin 4-PtTPyP without addition of metals and the affinity for the endothelin receptor was higher than the control used in this study. Still, the interaction with the HSA showed the possibility of this connection taking photosensitizers to places of interest, such as the delivery of medicines. [ABSTRACT FROM AUTHOR]

• Application of tetra-cationic Pd(II)-porphyrins against bacteria. • Use of porphyrins in the treatment of bacteriosis. • 3-PdTPyP tetra-cationic porphyrin meta isomer is very effectiveness in photo-inactivation of bacteria. In this work, we report the antimicrobial photoinactivation using tetra-cationic porphyrins with peripheral palladium(II) complexes against bacterial strains. Two different isomeric Pd(II)-porphyrins were used and applied in PDI experiments in the strains Gram negative bacilli Escherichia coli , Klebsiella pneumoniae and Pseudomonas aeruginosa and a Gram positive cocci Staphylococcus aureus. All experiments are conducted with adequate concentration (without aggregation) of photosensitizer under white-light irradiation over 2 h. We showed that the most effective PS caused a significative reduction in the concentration of viable bacteria. The present results show that porphyrin with positively charge at meta position (3-PtTPyP) are more efficient photosensitizer against bacteria strains. In this way, tetra-cationic porphyrins might be promising antibacterial PDI agents with potential applications in clinical cases. [ABSTRACT FROM AUTHOR]