Biogenic synthesis of metal nanoparticles is of considerable interest, as it affords clean, biocompatible, nontoxic, and cost-effective fabrication. Driven by their ability to withstand variable extremes of environmental conditions, several microorganisms, notably bacteria and fungi, have been investigated in the never-ending search for optimal nanomaterial production platforms. Here, we present a hitherto unexplored algal platform featuring Chlorella pyrenoidosa, which offers a high degree of consistency in morphology of synthesized silver nanoparticles. Using a suite of characterization methods, we reveal the intrinsic crystallinity of the algae-derived nanoparticles and the functional moieties associated with its surface stabilization. Significantly, we demonstrate the antibacterial and photocatalytic properties of these silver nanoparticles and discuss the potential mechanisms that drive these critical processes. The blend of photocatalytic and antibacterial properties coupled with their intrinsic biocompatibility and eco-friendliness make these nanoparticles particularly attractive for wastewater treatment.

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Electrically conductive polycarbazole−titanium dioxide nanocomposite (PCz/TiO 2 ) have been synthesized for the first time by in situ chemical oxidative polymerization of carbazole (Cz) in the presence of titanium dioxide (TiO 2 ) nanoparticles. FTIR, SEM, TEM, XRD, TGA, and DTA were used to characterize PCz/TiO 2 nanocomposites. The characterization results confirmed that there is a strong interaction between PCz and TiO 2 nanoparticles and the nanocomposites showed higher thermal stability than pure PCz. The composite showed electrical conductivity and isothermal stability in terms of DC electrical conductivity retention under ambient condition below 100 °C. A nanocomposite-based sensor was fabricated for the detection of aqueous ammonia, it was found that the resistivity of the nanocomposites increases on exposure to ammonia at room temperature (25 °C), and it showed a linear relationship between the responses and the concentration of ammonia. The comperative antimicrobial activities of PCz, its PCz/TiO 2 -7 nanocomposite and ciprofloxacin drug with different bacteria have also been studied.

Samarium-doped ZnO nanoparticles (1%, 3%, and 5%) were synthesized by a gel-combustion route and their application as an efficient photocatalyst for the degradation of Malachite green (MG) dye is demonstrated.

Nanoparticle-reinforced polymer-based scaffolding matrices as artificial bone-implant materials are potential suitors for bone regenerative medicine as they simulate the native bone. In the present work, a series of bioinspired, osteoconductive tricomposite scaffolds made up of nanohydroxyapatite (NHA) embedded xanthan gum−chitosan (XAN−CHI) polyelectrolyte complex (PEC) are explored for their bone-regeneration potential. The Fourier transform infrared spectroscopy studies confirmed complex formation between XAN and CHI and showed strong interactions between the NHA and PEC matrix. The X-ray diffraction studies indicated regulation of the nanocomposite (NC) scaffold crystallinity by the physical cues of the PEC matrix. Further results exhibited that the XAN−CHI/NHA5 scaffold, with a 50/50 (polymer/NHA) ratio, has optimized porous structure, appropriate compressive properties, and sufficient swelling ability with slower degradation rates, which are far better than those of CHI/NHA and other XAN−CHI/NHA NC scaffolds. The simulated body fluid studies showed XAN− CHI/NHA5 generated apatite-like surface structures of a Ca/P ratio ∼1.66. Also, the in vitro cell−material interaction studies with MG-63 cells revealed that relative to the CHI/NHA NC scaffold, the cellular viability, attachment, and proliferation were better on XAN−CHI/NHA scaffold surfaces, with XAN−CHI/ NHA5 specimens exhibiting an effective increment in cell spreading capacity compared to XAN−CHI/NHA4 and XAN−CHI/ NHA6 specimens. The presence of an osteo-friendly environment is also indicated by enhanced alkaline phosphatase expression and protein adsorption ability. The higher expression of extracellular matrix proteins, such as osteocalcin and osteopontin, finally validated the induction of differentiation of MG-63 cells by tricomposite scaffolds. In summary, this study demonstrates that the formation of PEC between XAN and CHI and incorporation of NHA in XAN−CHI PEC developed tricomposite scaffolds with robust potential for use in bone regeneration applications.