Borophosphate glasses as active agents for antimicrobial hydrogels

Herein we report the synthesis of transition-metal-free potassium borophosphate glasses and their application as bactericidal and bacteriostatic material. The antimicrobial activity was achieved through a simple change in the molar ratio of boron and phosphorus atoms, making borophosphate glass soluble in water. The glasses were analyzed by X-ray powder diffraction, Raman spectroscopy, laser-induced breakdown spectroscopy, and water absorption. The addition of a boron compound is required to obtain potassium-based phosphate glasses. Moreover, the change in the phosphorus and boron molar ratio (P/B), 2, 1 or 0.5 affects the glass solubilization in water, which increases with the phosphorus content. The glass materials were submitted to tests of biological activity against the bacteria Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. These water-soluble borophosphate glasses were employed in the development of hydrogel formulations using Carbopol®. Phosphorous-rich samples at a concentration of 15 % (w/w) in hydrogel showed better antimicrobial activity against S. aureus and E. coli, when compared to other samples, including commercial alcohol hand sanitizer gel, with an average size of the inhibition halo of 24.02±1.43 and 19.24±1.63mm, respectively.

l-Hypaphorine and d-hypaphorine: Specific antiacetylcholinesterase activity in rat brain tissue

Acetylcholinesterase (AChEis) inhibitors are used to treat neurodegenerative diseases like Alzheimer's disease (AD). l-Hypaphorine (l-HYP) is a natural indole alkaloid that has been shown to have effects on the central nervous system (CNS). The goal of this research was to synthesize l-HYP and d-HYP and test their anticholinesterasic properties in rat brain regions. l-HYP suppressed acetylcholinesterase (AChE) activity only in the cerebellum, whereas d-HYP inhibited AChE activity in all CNS regions studied. No cytotoxic effect on normal human cells (HaCaT) was observed in the case of l-HYP and d-HYP although an increase in cell proliferation. Molecular modeling studies revealed that d-HYP and l-HYP have significant differences in their binding mode positions and interact stereospecifically with AChE's amino acid residues.

S-(4-Methoxyphenyl)-4-methoxybenzenesulfonothioate as a Promising Lead Compound for the Development of a Renal Carcinoma Agent

Organosulfur compounds show cytotoxic potential towards many tumor cell lines. Disulfides and thiosulfonates act through apoptotic processes, inducing proteins associated with apoptosis, endoplasmic reticulum stress, and the unfolded protein response. Three p-substituted symmetric diaryl disulfides and three diaryl thiosulfonates were synthesized and analyzed for inhibition of tubulin polymerization and for human cancer cell cytotoxic activity against seven tumor cell lines and a non-tumor cell line. S-(4-methoxyphenyl)-4-methoxybenzenesulfonothioate (6) exhibited inhibition of tubulin polymerization and showed the best antiproliferative potential, especially against the 786-0 cell line, being six times more selective as compared with the non-tumor cell line. In addition, compound 6 was able to activate caspase-3 after 24 and 48 h treatments of the 786-0 cell line and induced cell-cycle arrest in the G2/M stage at the highest concentration evaluated at 24 and 48 h. Compound 6 was able to cause complete inhibition of proliferation, inducing the death of 786-0 cells, by increasing the number of cells at G2/M and greater activation of caspase-3.

Conversion of "Waste Plastic" into Photocatalytic Nanofoams for Environmental Remediation

Plastic debris is a major environmental concern, and to find effective ways to reuse polystyrene (PS) presents major challenges. Here, it is demonstrated that polystyrene foams impregnated with SnO₂ are easily generated from plastic debris and can be applied to photocatalytic degradation of dyes. SnO₂ nanoparticles were synthesized by a polymeric precursor method, yielding specific surface areas of 15 m²/g after heat treatment to 700 °C. Crystallinity, size, and shape of the SnO₂ particles were assessed by X-ray diffraction (XRD) and transmission electron microscopy (TEM), demonstrating the preparation of crystalline spherical nanoparticles with sizes around 20 nm. When incorporated into PS foams, which were generated using a thermally induced phase separation (TIPS) process, the specific surface area increased to 48 m²/g. These PS/SnO₂ nanofoams showed very good efficiency for photodegradation of rhodamine B, under UV irradiation, achieving up to 98.2% removal. In addition the PS/SnO₂ nanofoams are shown to retain photocatalytic activity for up to five reuse cycles.

Photoreactive surfactants: a facile and clean route to oxide and metal nanoparticles in reverse micelles

A new class of photoreactive surfactants (PRSs) is presented here, consisting of amphiphiles that can also act as reagents in photochemical reactions. An example PRS is cobalt 2-ethylhexanoate (Co(EH)(2)), which forms reverse micelles (RMs) in a hydrocarbon solvent, as well as mixed reversed micelles with the standard surfactant Aerosol-OT (AOT). Small-angle neutron scattering (SANS) data show that mixed AOT/PRS RMs have a spherical structure and size similar to that of pure AOT micelles. Excitation of the ligand-to-metal charge transfer (LMCT) band in the PRSs promotes electron transfer from PRS to associated metal counterions, leading to the generation of metal and metal-oxide nanoparticles inside the RMs. This work presents proof of concept for employing PRSs as precursors to obtain nearly monodisperse inorganic nanoparticles: here both Co(3)O(4) and Bi nanoparticles have been synthesized at high metal concentration (10(-2) M) by simply irradiating the RMs. These results point toward a new approach of photoreactive self-assembly, which represents a clean and straightforward route to the generation of nanomaterials.