Bio-based matrix photocatalysts for photodegradation of antibiotics.

Antibiotics development during the last century permitted unprecedent medical advances. However, it is undeniable that there has been an abuse and misuse of antimicrobials in medicine and cosmetics, food production and food processing, in the last decades. The pay toll for human development and consumism is the emergence of extended antimicrobial resistance and omnipresent contamination of the biosphere. The One Health concept recognizes the interconnection of human, environmental and animal health, being impossible alter one without affecting the others. In this context, antibiotic decontamination from water-sources is of upmost importance, with new and more efficient strategies needed. In this framework, light-driven antibiotic degradation has gained interest in the last few years, strongly relying in semiconductor photocatalysts. To improve the semiconductor properties (i.e., efficiency, recovery, bandgap width, dispersibility, wavelength excitation, etc.), bio-based supporting material as photocatalysts matrices have been thoroughly studied, exploring synergetic effects as operating parameters that could improve the photodegradation of antibiotics. The present work describes some of the most relevant advances of the last 5 years on photodegradation of antibiotics and other antimicrobial molecules. It presents the conjugation of semiconductor photocatalysts to different organic scaffolds (biochar and biopolymers), then to describe hybrid systems based on g-C3N4 and finally addressing the emerging use of organic photocatalysts. These systems were developed for the degradation of several antibiotics and antimicrobials, and tested under different conditions, which are analyzed and thoroughly discussed along the work.

Degradation of Pesticides Using Semiconducting and Tetrapyrrolic Macrocyclic Photocatalysts-A Concise Review.

Exposure to pesticides is inevitable in modern times, and their environmental presence is strongly associated to the development of various malignancies. This challenge has prompted an increased interest in finding more sustainable ways of degrading pesticides. Advanced oxidation processes in particular appear as highly advantageous, due to their ability of selectively removing chemical entities form wastewaters. This review provides a concise introduction to the mechanisms of photochemical advanced oxidation processes with an objective perspective, followed by a succinct literature review on the photodegradation of pesticides utilizing metal oxide-based semiconductors as photosensitizing catalysts. The selection of reports discussed here is based on relevance and impact, which are recognized globally, ensuring rigorous scrutiny. Finally, this literature review explores the use of tetrapyrrolic macrocyclic photosensitizers in pesticide photodegradation, analyzing their benefits and limitations and providing insights into future directions.

Photoantibacterial Poly(vinyl)chloride Films Applying Curcumin Derivatives as Bio-Based Plasticizers and Photosensitizers.

Herein we describe the design of natural curcumin ester and ether derivatives and their application as potential bioplasticizers, to prepare photosensitive phthalate-free PVC-based materials. The preparation of PVC-based films incorporating several loadings of newly synthesized curcumin derivatives along with their standard solid-state characterization is also described. Remarkably, the plasticizing effect of the curcumin derivatives in the PVC material was found to be similar to that observed in previous PVC-phthalate materials. Finally, studies applying these new materials in the photoinactivation of S. aureus planktonic cultures revealed a strong structure/activity correlation, with the photosensitive materials reaching up to 6 log CFU reduction at low irradiation intensities.

Trimethoprim-Based multicomponent solid Systems: Mechanochemical Screening, characterization and antibacterial activity assessment.

In this work, multicomponent trimethoprim-based pharmaceutical solid systems were developed by mechanochemistry, using coformers from the GRAS list and other active pharmaceutical ingredients. The choice of coformers took into account their potential to increase the aqueous solubility/dissolution rate of TMP or its antibacterial activity. All the binary systems were characterized by thermal analysis, powder X-ray diffraction and infrared spectroscopy, and 3 equimolar systems with FTIR pointing to salts, and 4 eutectic mixtures were identified. The intrinsic dissolution rate of TMP in combination with nicotinic acid (a salt) and with paracetamol (eutectic mixture) were 25% and 5% higher than for pure TMP, respectively. For both Gram-positive and -negative strains, the antibacterial activity of TMP with some of the coformers was improved, since the dosage used was lower than the TMP control. A significant increase in antibacterial activity against E. coli was found for the eutectic mixture with curcumin, with the best results being obtained for the eutectic and equimolar mixtures with ciprofloxacin. Combining trimethoprim with coformers offers an interesting alternative to using trimethoprim alone: multicomponent forms with enhanced TMP dissolution rates were identified, as well as combinations showing enhanced antibacterial activity relatively to the pure drug.

Synthesis of Photosensitizers Based on Tetrapyrrolic Macrocycles for Combination with Antibiotics: Dual Inactivation of Bacteria.

The combination of photodynamic therapy with antibiotics or antimicrobial peptides for inactivation of bacteria is an area of growing interest due to the synergistic effect already observed by many authors. It has been shown that the efficiency of this dual antimicrobial therapy is highly dependent on the structure of the photosensitizer, being tetrapyrrolic macrocycles the ones with most promising results. There are a few review articles in the recent literature describing the main microbiological results concerning this dual inactivation of bacteria, but none of them focus on the synthetic processes of these photosensitizers and their remarkable chemical versatility. Therefore, herein we present an overview on synthetic methodologies for preparation of tetrapyrrolic macrocycles and their conjugates with antibiotics or antimicrobial peptides, for use in dual inactivation of bacteria. This review will be divided in two sections concerning the physical or covalent combinations of PS with antibiotic/cationic peptides, followed by brief critical analysis on their corresponding antimicrobial outcomes.