Fabrication of PVA-Silver nanoparticle composite film for elimination of microbial contaminant from effluent

The effluent contains many harmful microbes which should be eliminated before it is discharged into a water body. Silver nanoparticles (AgNPs) being high-quality significance and have a great impact on this research field as it inhibits microbial proliferation and infection. Therefore, it may use for Bioremediation purposes, our laboratory is fascinated by the production of polymer matrix entrapment silver nanoparticles for in situ bio-remediation purposes. The AgNPs was prepared from sawdust by decoction method. The yellowish solution turns into dark brown colour indicating the formation of AgNPs. A sharp SPR (Surface Plasmon Resonance) band formation in UV-vis spectroscopy scan establishes the formation and stability of silver nanoparticles in an aqueous solution. SEM microphotograph indicated roughly spheroidal structure with (63±3) nm average diameters of newly synthesized AgNp. Polyvinyl alcohol (PVA) is eco-friendly and non-toxic to the environment was chosen for the preparation of polymeric matrix. The non-toxic concentration (1 μg/mL) of AgNp was dispersed into PVA solution followed by cross-linked with maleic acid. PVA- maleic acid is cross-linked by the formation of an ester bond, whereas silver nanoparticles physically entrap into the cross-linked matrix. The silver nanoparticles were released from the matrix nearly after 10 min of swelling of the composite film. In a microbial assay using E. coli agar medium, PVA-AgNp composite film shows the significant killing of microorganisms. Microbial elimination is measured indirectly by pH measurement and dissolved oxygen concentration measurement of the effluent in situ against RO- water, taken as control. The dissolved oxygen concentration from RO water and effluent water was measured on Day “0” followed by treatment and incubation at the BOD chamber. The treatment with PVA-AgNp composite film reduced the BOD Level and increase dissolved oxygen level simultaneously increasing the quality of water

Continuous flow production of bioactive ceria quantum dots: New paradigms to the effect of process parameters on surface oxygen vacancy tuning

Precisely monitored nucleation-growth kinetics for governing the size, surface chemistry, and sought-after attributes of quantum dots (QDs) for large-scale manufacturing remains a formidable challenge. This study evinces the importance of ultrafast mixing and high heating rates for rapid nucleation, particularly in synthesizing monodispersed QDs with enriched surface defects. Recently, cerium oxide (CeO2) nanostructures have gained prominence in antioxidant therapy owing to the co-existence of Ce3+ and Ce4+. However, current batch processes lack scalability, reproducibility, and control over the reaction kinetics, key for fine-tuning the surface defect-driven properties of CeO2 nanostructures. Addressing this knowledge gap, we demonstrate a unique, sustainable, continuous flow platform that allows simultaneous engineering of surface oxygen vacancies (VO●) and regulates the size of L arginine functionalized CeO2 QDs (VO●-rich L-arg-CeO2 QDs). Introduction of the helical coil reactor regulated by dean vortices yields monodispersed QDs with enhanced Ce3+/Ce4+ ratio and VO● at the surface. Through various experimental methodologies, we showed how adjusting temperature, flowrate, and pH enables achieving the desirable size (3 nm), thereby bestowing an optimal surface Ce3+ and VO● fractions, pivotal for size-dictated photo-response, physiochemical properties, and biofunctionality of the QDs. The abundant surface VO● (72%) entails narrowing of the band gap (~ 2.5 eV), resulting in unprecedented photothermal response (ΔT = 19.7±0.6°C) and photoluminescence, features not typically found in defect-free conventional CeO2 nanostructures. With a strategic combination of process parameters, the defect-rich material system displayed excellent biocompatibility (95.6%), and antioxidant efficacy on human keratinocyte (HaCaT) cells, and long-term stability (ζ = -29±1.5 mV) in suspensions, even after 120 days. This economical, high throughput continuous flow platform for fabricating biofunctionalized VO●-rich L-arg-CeO2 QDs outperforms conventional batch processes, opening numerous possibilities for lab-to-clinic translation in the fight against oxidative stress-related disorders

Rationalizing Defective Biomimetic Ceria: In vitro Demonstration of a Potential “Trojan horse” Nanozyme Based-Platform Leveraging Photo-Redox Activities for Minimally Invasive Therapy

Metal oxide nanostructures with surface-defect mediated chemistry have garnered pronounced interest due to the influence of these defects in tuning the photo-induced intracellular bio-catalytic (enzyme-mimicking) responses. However, designing defective nanozymes with pH-responsive multi-bio-catalytic functions without any dopants is challenging. Herein, oxygen-deficient “trojan horse-like” folate-functionalized, L-arginine-coated ceria (FA-L-arg-CeO2) nanozymes with synergistic multi-enzyme-mimicking and anti-cancer potential are introduced. The nanozymes possessed enhanced surface oxygen vacancies (VO●), strategically created under kinetically favourable synthesis conditions. Increased surface VO● promoted band structure reconstruction and amplified photochemical-response efficacy under single laser irradiation (808 nm), outperforming the defect-free commercial nano-CeO2 in rapid anti-tumorigenic activities. Through folate receptor-mediated endocytosis, these biostable nanozymes localized in MDA-MB-231 cells (84% in 48 h) and demonstrated NIR-accelerated enzymatic functions depending on the pH of the biological milieu. The reduced band gap energy facilitated effective electron-hole separation, up-regulating in vitro photo-redox reactions that impart exceptional therapeutic potential and inhibit 62% cell metastasis within only 12 h. By perturbing intratumoural redox homeostasis, VO●-rich FA-L-arg-CeO2 nanozymes unanimously killed 86% of MDA-MB-231 cancer cells while preferentially shielding benign L929 cells. Unlike conventional drug-loaded or dopant-incorporated CeO2 nanoplatforms, these defective multi-modal nanozymes unravel a new avenue for developing smart, low-cost, bio-active agents with enhanced efficacy and bio-safety

Acidic pH-Triggered Release of Doxorubicin from Ligand-Decorated Polymeric Micelles Potentiates Efficacy against Cancer Cells

Current chemotherapeutic strategies against various intractable cancers are futile due to inefficient delivery, poor bioavailability, and inadequate accumulation of anticancer drugs in the diseased site with toxicity caused to the healthy neighboring cells. Drug delivery systems aiming to deliver effective therapeutic concentrations to the site of action have emerged as a promising approach to address the above-mentioned issues. Thus, as several receptors have been identified as being overexpressed on cancer cells including folate receptor (FR), where up to 100–300 times higher overexpression is shown in cancer cells compared to healthy cells, approximately 1–10 million receptor copies per cancer cell can be targeted by a folic acid (FA) ligand. Herein, we developed FA-decorated and doxorubicin-conjugated polymeric micelles of 30 nm size. The hydrophilic block comprises poly(ethylene glycol) units, and the hydrophobic block contains aspartic acid. Decoration of FA on the micelle surface induces ligand–receptor interaction, resulting in enhanced internalization into the cancer cell and inside the endolysosomal compartment. Under acidic pH, the micelle structure is disrupted and the hydrazone bond is cleaved, which covalently binds the doxorubicin with the hydrophobic backbone of the polymer and release the drug. We observed that the cellular uptake and nuclear colocalization of the targeted micelle are 2–4 fold higher than the control micelle at various incubation times in FR-overexpressed various cancer cell lines (KB, HeLa, and C6). These results indicate significant prospects for anticancer therapy as an effective and translational treatment strategy