Indrani Gupta

Background/Objectives: The widespread use of sulfamethoxazole (SMX) has led to increasing antibiotic resistance, and there is a need for improved formulations to enhance its therapeutic effectiveness. In this study, we investigated the biocidal potential of SMX composite crystals incorporated with functionalized poly(lactic-co-glycolic acid) (nfPLGA) and nano-graphene oxide (nGO). Methods: The composites, namely SMX-nfPLGA and SMX-nGO, were synthesized via antisolvent precipitation and evaluated using Kirby–Bauer disk diffusion assays. Results: Incorporation of nfPLGA and nGO significantly improved SMX solubility, increasing it from 0.029 mg/mL to 0.058 mg/mL and 0.063 mg/mL, respectively. Additionally, the log partition coefficient (log P or K_w) also improved from 1.4 to 0.86 for nGO and 0.92 for nfPLGA composites. Both formulations exhibited improved antibacterial activity with distinct time-dependent bactericidal effects. Compared to pure SMX, the SMX-nfPLGA showed 60% and 53% greater bacterial inhibition at concentrations of 50 mg/mL and 100 mg/mL, respectively. Although SMX-nGO was slightly less potent, it still surpassed pure SMX, with 50% and 33% higher inhibition at the same concentrations. Conclusions: Importantly, neither nfPLGA nor nGO showed any biocidal effects, confirming that the observed enhancement was due to improved SMX solubility caused by their incorporation. These findings suggest that embedding solubility-enhancing nanoparticles into the existing crystal structure of the antibiotic is a promising strategy for enhancing the effectiveness.

This study reports an innovative approach for producing nanoplastics (NP) from various types of domestic waste plastics without the use of chemicals. The plastic materials used included water bottles, styrofoam plates, milk bottles, centrifuge tubes, to-go food boxes, and plastic bags, comprising polyethylene terephthalate (PET), polystyrene (PS), polypropylene (PP), high-density polyethylene (HDPE), and Poly (Ethylene-co-Methacrylic Acid) (PEMA). The chemical composition of these plastics was confirmed using Raman and FTIR spectroscopy, and they were found to have irregular shapes. The resulting NP particles ranged from 50 to 400 nm in size and demonstrated relative stability when suspended in water. To assess their impact, the study investigated the effects of these NP particulates on cell viability and the expression of genes involved in inflammation and oxidative stress using a macrophage cell line. The findings revealed that all types of NP reduced cell viability in a concentration-dependent manner. Notably, PS, HDPE, and PP induced significant reductions in cell viability at lower concentrations, compared to PEMA and PET. Moreover, exposure to NP led to differential alterations in the expression of inflammatory genes in the macrophage cell line. Overall, this study presents a viable method for producing NP from waste materials that closely resemble real-world NP. Furthermore, the toxicity studies demonstrated distinct cellular responses based on the composition of the NP, shedding light on the potential environmental and health impacts of these particles.

The energy crisis in the world is increasing rapidly owing to the shortage of fossil fuel reserves. Climate change and an increase in global warming necessitates a change in focus from petroleum-based fuels to renewable fuels such as biofuels. The remodeling of existing separation processes using various nanomaterials is of a growing interest to industrial separation methods. Recently, the design of membrane technologies has been the most focused research area concerning fermentation broth to enhance performance efficiency, while recovering those byproducts to be used as value added fuels. Specifically, the use of novel nano material membranes, which brings about a selective permeation of the byproducts, such as organic solvent, from the fermentation broth, positively affects the fermentation kinetics by eliminating the issue of product inhibition. In this review, which and how membrane-based technologies using novel materials can improve the separation performance of organic solvents is considered. In particular, technical approaches suggested in previous studies are discussed with the goal of emphasizing benefits and problems faced in order to direct research towards an optimized membrane separation performance for renewable fuel production on a commercial scale.

In this research, the synergistic antiviral effects of carbon nanotubes (CNTs) and metal oxides (MO) in the form of novel hybrid structures (MO-CNTs) are presented. Raw CNTs, Ni(OH)₂, Fe₂O₃ and MnO₂, as well as Ni(OH)₂-CNT, Fe₂O₃-CNT and MnO₂-CNT were explored in this study against Escherichia. coli MS2 bacteriophage, which was used as a virus surrogate. The nano particles were synthesized and characterized using field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), particle size analysis, Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Kinetic parameters such as the LD₅₀ (lethal dose to kill 50% of the population), T₅₀ and T₈₀ (time taken to kill 50% and 80% of the population), SGR (specific growth rate) and IRD (initial rate of deactivation of the population) were also studied to examine the antiviral efficacy of these nanomaterials. Among all the nanomaterials, Ni(OH)₂-CNT was the most effective antiviral agent followed by Fe₂O₃-CNT, MnO₂-CNT, raw CNTs, Ni(OH)₂, Fe₂O₃ and MnO₂. When comparing the metal oxide-CNTs to the raw CNTs, the average enhancement was 20.2%. The average antiviral activity enhancement of the MO-CNTs were between 50 and 54% higher than the MO itself. When compared to the raw CNTs, the average enhancement over all the MO-CNTs was 20.2%. The kinetic studies showed that the LD₅₀ of Ni(OH)₂-CNT was the lowest (16µg/mL), which implies that it was the most toxic of all the compounds studied. The LD₅₀ of Ni(OH)₂, Fe₂O₃ and MnO₂ were 17.3×, 14.5× and 10.8× times greater than their corresponding hybrids with the CNTs. The synergistic mechanism involved the entrapment of phage viruses by the nano structured CNTs leading to structural damage along with toxicity to phage from the release of MO ions. The metal oxide-CNT nano hybrids developed in this project are promising candidates in applications such as antiviral coatings, nanocomposites, adsorbents and as components of personal protection gears.