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In the current work, user-friendly, biodegradable, Zirconium-Lanthanum (ZLPC) and Zirconium-Cerium (ZCPC) complexed Polyvinyl alcohol (PVA) films were solvent casted for effective defluoridation of water. The films were characterised using SEM coupled EDS, XPS, TGA, XRD and FT-IR. These films adsorbed 95−97% fluoride from water at pH 7, with 85% removal by ZLPC and 93% removal by ZCPC within the first 45 minutes of the adsorption process. A maximum adsorption capacity of 11.57 mg/g and 12.88 mg/g, corresponding to ZLPC and ZCPC respectively, was obtained using Langmuir adsorption isotherm. The films followed pseudo-second-order kinetics (R2≤0.99) in both the cases, which was further established by low values of chi-square and root mean square error (RMSE). The ICP-AES analysis confirmed no leaching of the metal ions from the polymer films into the treated water. The films were found to be stable in both acidic and basic medium. No interference to fluoride adsorption was detected even at 100 mg/L of Cl−, NO3− and SO42− while some interference was observed in the presence of PO43− and HCO3−. The change in Gibbs free energy for fluoride adsorption using the ab-initio method was found to be −330.05 kJ/mol, which indicated spontaneity of the process. This was further reinforced by the thermodynamic data obtained from adsorption studies. The films were reusable and showed ∼85% removal of fluoride even after the fifth regeneration cycle. Thus, these handy films have a scope to be developed into a prototype for defluoridation of ground water.

Nanoparticle based sensors are good alternatives for non-enzymatic sensing applications due to their high stability, superior photoluminescence, biocompatibility and ease of fabrication, with the only disadvantage being the cost of the synthesis process (owing to the expensive precursors and infrastructure). For the first time, we report the design of an immunosensor employing streptavidin conjugated copper nanocluster, developed at a much lower cost compared to other nanomaterials like noble metal nanoparticles and quantum dots. Using in silico tools, we have tried to establish the dynamics of conjugation of nanocluster to the streptavidin protein, based on EDC-NHS coupling. The computational simulations have successfully explained the crucial role played by the components of the immunosensor leading to an efficient design capable of high sensitivity. In order to demonstrate the functioning of the Copper Nanocluster ImmunoSensor (CuNIS), HIV-1 p24 biomarker test was chosen as the model assay. The immunosensor was able to achieve an analytical limit of detection of 23.8 pg mL−1 for HIV-1 p24 with a linear dynamic range of 27–1000 pg mL−1. When tested with clinical plasma samples, CuNIS based p24 assay showed 100% specificity towards HIV-1 p24. With the capability of multiplexed detection and a cost of fabrication 100 times lower than that of the conventional metal nanoclusters, CuNIS has the potential to be an essential low-cost diagnostic tool in resource-limited settings.

BCZT (Ba0.85Ca0.15Zr0.1Ti0.9O3) is a recent class of lead-free ferroelectric material associated with high piezoelectric coefficient, making it suitable to inspire hydroxyapatite (HA)-BCZT ceramics for bone materials. Nano-crystalline hydroxyapatite (HA) synthesized using the hydrothermal route was characterized via FT-IR, Raman spectroscopy, X-ray powder diffraction (XRD), and Scanning Electron Microscopy (SEM). We also rationalized its formation as a function of operating conditions such as dwell time and temperature in this route. The nano-crystalline BCZT powder was synthesized via a sol-gel technique and its structural and morphological characterization were carried out using Raman Spectroscopy, XRD and Transmission Electron Microscopy (TEM). These investigations facilitated the optimization of HA-BCZT compositions and their electrical poling conditions to achieve enhanced piezoelectric effect. The composites (HA-BCZT) sintered at 1350∘C exhibited promising piezoelectric properties. We report the enhanced piezoelectric coefficient (d33) of 7±1 pC/N for 50% HA-BCZT which is significant as compared to that reported in the literature for ~98% BT (barium titanate) -HA composites. We highlight the role of Simulated Body Fluid (SBF) on the intriguing phase-change of Tricalcium Phosphate (TCP) obtained at this sintering temperature, to hydroxyapatite for its essential contribution to promote bone growth. We theoretically support the confirmed in vitro biocompatibility of these composites. Graphical abstract: Novel lead-free biocompatible piezoelectric HA-BCZT nanocrystal composites for accelerated Bone regeneration

Given widespread fluoride in the ground water, there is a need for effective defluoridation in several geographical areas. In this regard, we explored heavily doped cationic nano-composites of hydroxyapatite (HA) given its surface chemistry for adsorption of the specific anion. We synthesized and extensively characterized HA nano-rods (HA-NR), Al/Mg-HA nanocomposites and amorphous aluminum hydroxide, and optimized their efficient defluoridation. The kinetics and thermodynamics of adsorption were further evaluated to establish the mechanistic rationale and its spontaneity. We report the optimized ideal adsorbents for the near-total removal of fluoride that demonstrated 99.99% and 99.98% efficiency with adsorption capacities of 83.3 and 81.3mg/g respectively. The adsorbent composites were (Mg-HA)-Al(OH)3 and (HA-NR)-Al(OH)3 in 1:1 ratio. The optimal conditions for defluoridation were 25mg of adsorbent in 25ml (10mg/L) fluoride solution at room temperature agitated for 10h in the pH range of 4.88–7.20.

We report the use of silver decorated plant proteins as spacer material for augmented surface plasmon-coupled emission (120-fold enhancement) and plasmon-enhanced Raman scattering. We extracted several proteins from different plant sources [ Triticum aestivum (TA), Aegle marmelos (AM), Ricinus communis (RC), Jatropha curcas (JC) and Simarouba glauca (SG)] followed by evaluation of their optical properties and simulations to rationalize observed surface plasmon resonance. Since the properties exhibited by protein thin films is currently gaining research interest, we have also carried out simulation studies with Ag-protein biocomposites as spacer materials in metal-dielectric-metal planar microcavity architecture for guided emission of Fabry-Perot mode-coupled fluorescence.