Promising photodynamic antimicrobial activity of polyimine substituted zinc phthalocyanine and its polycationic derivative when conjugated to nitrogen, sulfur, co-doped graphene quantum dots against Staphylococcus aureus

Evaluation of the effects of different photosensitizers used in antimicrobial photodynamic therapy on tooth discoloration: spectrophotometric analysis

BACKGROUND

Tooth discoloration is a common concern in antimicrobial photodynamic therapy (aPDT) using various photosensitizers (PS). Toluidine Blue (TB), Methylene Blue (MB), Phthalocyanine (Pc), and 2-mercaptopyridine-substituted zinc phthalocyanine (TM-ZnPc) are among those studied, but their relative impacts on tooth discoloration remain unclear.

AIM

This study aimed to compare the effects of TB, MB, Pc, and TM-ZnPc in aPDT on tooth discoloration, utilizing a controlled experimental setup.

MATERIALS AND METHODS

The study comprised seventy-five single-rooted incisors with root canals. Following meticulous preparation, a standardized area on the crown surface was designated for examination, and precise measurements of the initial tooth colors were recorded. Samples were randomly divided into five groups: Negative control, MB, TM, Pc, and TM-ZnPc. Photoactivation was performed using LED light, and color measurements were taken at multiple time points up to 90 days. Data were converted to Lab* color values of the CIE Lab* color system (International Commission on Illumination, Vienna, Austria), and ΔE values were calculated. Statistical analysis was performed using Two-way ANOVA and Post-Hoc Tukey tests (p < 0.05).

RESULTS

At day 7 and 30, TM-ZnPc and Pc caused less discoloration compared to MB and TB. TM-ZnPc caused more tooth discoloration compared to Pc (p < 0.05). Compared to baseline, MB and TM-ZnPc caused more tooth discoloration at 30 days and TB caused more tooth discoloration at 90 days (p < 0.05). No significant difference was observed in terms of tooth discoloration at all periods evaluated after Pc application (p > 0.05). All photosensitizers tested in the study caused tooth coloration.

CONCLUSION

All PS induced clinically detectable tooth discoloration, with TB and MB causing more significant discoloration compared to Pc and TM-ZnPc at certain time points. TM-ZnPc and Pc demonstrated more stable coloration levels over time, suggesting their potential reliability in aPDT applications. This study highlights the importance of selecting appropriate PS to minimize tooth discoloration in aPDT, with Pc showing promise in this regard.

Biological Performance of Hexadeca-Substituted Metal Phthalocyanine/Reduced Graphene Oxide Nanobioagents

This study presents a tetra-substituted phthalonitrile derivative, namely, diethyl 2-(3,4-dicyano-2,5-bis(hexyloxy)-6-(4-(trifluoromethoxy)phenoxy)phenyl)malonate (a), cyclotetramerizing in the presence of some metal salts. The resultant hexadeca-substituted metal phthalocyanines [M= Co, Zn, InCl)] (b-d) were used for the modification of reduced graphene oxide for the first time. The effect of the phthalonitrile/metal phthalocyanines on biological features of reduced graphene oxide (rGO) was extensively examined by the investigation of antioxidant, antimicrobial, DNA cleavage, cell viability, and antibiofilm activities of nanobioagents (1-4). The results were compared with those of unmodified rGO (nanobioagent 5), as well. Modification of reduced graphene oxide with the synthesized compounds improved its antioxidant activity. The antioxidant activities of all the tested nanobioagents also enhanced as the concentration increased. The antibacterial activities of all the nanobioagents improved by applying the photodynamic therapeutic (PDT) method. All the phthalonitrile/phthalocyanine-based nanobioagents (especially phthalocyanine-based nanocomposites) exhibited DNA cleavage activities, and complete DNA fragmentation was observed for nanobioagents (1-4) at 200 mg/L. They can be used as potent antimicrobial and antimicrobial photodynamic therapy agents as well as Escherichia coli microbial cell inhibitors. As a result, the prepared nanocomposites can be considered promising candidates for biomedicine.

Nanomaterial-based drug-delivery system as an aid to antimicrobial photodynamic therapy in treating oral biofilm

Diverse microorganisms live as biofilm in the mouth accounts for oral diseases and treatment failure. For decades, the prevention and treatment of oral biofilm is a global challenge. Antimicrobial photodynamic therapy (aPDT) holds promise for oral biofilm elimination due to its several traits, including broad-spectrum antimicrobial capacity, lower possibility of resistance and low cytotoxicity. However, the physicochemical properties of photosensitizers and the biological barrier of oral biofilm have limited the efficiency of aPDT. Nanomaterials has been used to fabricate nanocarriers to improve photosensitizer properties and thus enhance antimicrobial effect. In this review, we have discussed the challenges of aPDT used in dentistry, categorized the nanomaterial-delivery system and listed the possible mechanisms involved in nanomaterials when enhancing aPDT effect.

Carbon quantum dots (CQDs)-modified polymers: a review of non-optical applications

Carbon quantum dots (CQDs) are a promising candidate to replace metal-based additives for polymer reinforcement and functionalization. Specifically, vast interest in CQDs for polymer functionalization stems from their cost effectiveness, sustainable organic precursors, and their non-toxicity. Although several reviews of optical devices based on CQDs have been reported, this mini-review covers the non-optical aspects of CQD-polymer composites. Applications of CQD-modified polymers for smart devices, mechanical reinforcement, textile surface-modification methods, membranes, protective coatings, and thermal resistance are summarized. The synthesis method of CQDs, their dispersion in a polymer matrix and the underlying mechanisms related to the enhanced performance of composites are outlined. Unlike nano-reinforcements, CQDs are self-stabilized and offer an extremely high surface area, which significantly alters the polymer properties at a 1-2% concentration. Finally, a comparative analysis of recent advances in CQD-polymer composites, their problems, and future directions are discussed.

The synthesis of novel water-soluble zinc (II) phthalocyanine based photosensitizers and exploring of photodynamic therapy activities on the PC3 cancer cell line

In this study, Schiff base substituted phthalocyanine complexes (Zn1c, Zn2c) and their quaternized derivatives (Q-Zn1c, Q-Zn2c) were synthesized for the first time. Their structures have been characterized by FT-IR, 1H-NMR, UV-Vis, mass spectrometry and elemental analysis as well as. The photophysicochemical properties (fluorescence, singlet oxygen and photodegradation quantum yield) of these novel complexes were investigated in dimethylsulfoxide (DMSO) for both non-ionic and quaternized cationic phthalocyanine complexes and in aqueous solution for quaternized cationic phthalocyanine complexes. Water soluble cationic phthalocyanine compounds gave good singlet oxygen quantum yield (0.65 for Q-Zn1c, 0.66 for Q-Zn2c in DMSO; 0.65 for Q-Zn2c in aqueous solution). The binding of Q-Zn1c and Q-Zn2c to BSA/DNA was studied by using UV-Vis and fluorescence spectroscopy and these. Studies indicate that the mechanism of BSA quenching by quaternized zinc(II) phthalocyanines was static quenching. Quaternized zinc(II) phthalocyanines interacted with ct-DNA by intercalation. Quaternized zinc(II) phthalocyanines caused a decrease in cell viability and triggered apoptotic cell death after PDT was applied at a concentration that did not have a toxic effect on their own. Q-Zn1c and Q-Zn2c mediated PDT reduced the activity of SOD, CAT, GSH while increased MDA level in the prostate cancer cells. Furthermore, expression of apoptotic proteins after PDT was examined. The results revealed that the synthesized water soluble quaternized zinc(II) phthalocyanine complexes (Q-Zn1c and Q-Zn2c) are promising potential photosensitizers for PDT.

Progress in drug delivery and diagnostic applications of carbon dots: a systematic review

Carbon dots (CDs), which have particle size of less than 10 nm, are carbon-based nanomaterials that are used in a wide range of applications in the area of novel drug delivery in cancer, ocular diseases, infectious diseases, and brain disorders. CDs are biocompatible, eco-friendly, easy to synthesize, and less toxic with excellent chemical inertness, which makes them very good nanocarrier system to deliver multi-functional drugs effectively. A huge number of researchers worldwide are working on CDs-based drug delivery systems to evaluate their versatility and efficacy in the field of pharmaceuticals. As a result, there is a tremendous increase in our understanding of the physicochemical properties, diagnostic and drug delivery aspects of CDs, which consequently has led us to design and develop CDs-based theranostic system for the treatment of multiple disorders. In this review, we aim to summarize the advances in application of CDs as nanocarrier including gene delivery, vaccine delivery and antiviral delivery, that has been carried out in the last 5 years.

Efficacy of Antimicrobial Photodynamic Therapy Mediated by Photosensitizers Conjugated with Inorganic Nanoparticles: Systematic Review and Meta-Analysis

Antimicrobial photodynamic therapy (aPDT) is a method that does not seem to promote antimicrobial resistance. Photosensitizers (PS) conjugated with inorganic nanoparticles for the drug-delivery system have the purpose of enhancing the efficacy of aPDT. The present study was to perform a systematic review and meta-analysis of the efficacy of aPDT mediated by PS conjugated with inorganic nanoparticles. The PubMed, Scopus, Web of Science, Science Direct, Cochrane Library, SciELO, and Lilacs databases were searched. OHAT Rob toll was used to assess the risk of bias. A random effect model with an odds ratio (OR) and effect measure was used. Fourteen articles were able to be included in the present review. The most frequent microorganisms evaluated were Staphylococcus aureus and Escherichia coli, and metallic and silica nanoparticles were the most common drug-delivery systems associated with PS. Articles showed biases related to blinding. Significant results were found in aPDT mediated by PS conjugated with inorganic nanoparticles for overall reduction of microorganism cultured in suspension (OR = 0.19 [0.07; 0.67]/p-value = 0.0019), E. coli (OR = 0.08 [0.01; 0.52]/p-value = 0.0081), and for Gram-negative bacteria (OR = 0.12 [0.02; 0.56/p-value = 0.0071). This association approach significantly improved the efficacy in the reduction of microbial cells. However, additional blinding studies evaluating the efficacy of this therapy over microorganisms cultured in biofilm are required.

Graphene quantum dots-porphyrins/phthalocyanines multifunctional hybrid systems: from interfacial dialogue to applications

Engineered well-ordered hybrid nanomaterials are at a symbolically pivotal point, just ahead of a long-anticipated human race transformation. Incorporating newer carbon nanomaterials like graphene quantum dots (GQDs) with tetrapyrrolic porphyrins...

Antibacterial photodynamic activity of hydrophobic carbon quantum dots and polycaprolactone based nanocomposite processed via both electrospinning and solvent casting method

Inhabitation of various types of bacteria on different surfaces causes vital health problems worldwide. In this work, a wound dressing defeating bacterial infection had been fabricated. The antibacterial effect of polycaprolactone and hydrophobic carbon quantum dots (hCQDs) based nanocomposite has been presented. The nanocomposite was fabricated both via solvent casting and electrospinning method. Nanocomposites with and without hCQDs had been investigated. A detailed study on their morphology and surface properties were performed by scanning electron microscopy, atomic force microscopy and Raman spectroscopy. Prepared nanocomposites had been evaluated by the contact angle, UV-Vis spectroscopy, electron paramagnetic resonance spectroscopy, and antibacterial activity. It was found that nanocomposites were able to produce singlet oxygen upon blue light irradiation at 470 nm, and they were effective in the eradication of Gram positive (Staphylococcus aureus, Listeria monocytogenes) and Gram negative (Escherichia coli, Klebsiella pneumoniae) bacteria.