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This work demonstrates different stimulus-based antibacterial treatment strategies for both resistant bacteria and biofilms. Moreover, a future perspective has been illustrated for making these modalities clinically feasible.

Among several forms of water pollutants, common pesticides, herbicides, organic dyes and heavy metals present serious and persistent threats to human health due to their severe toxicity. Recently, piezocatalysis based removal of pollutants has become a promising field of research to combat such pollutions by virtue of the piezoelectric effect. In reality, piezoelectric materials can produce electron-hole separation upon external vibration, which greatly enhances the production of various reactive oxygen species (ROS) and further increases the pollutant degradation rate. Piezocatalysis does not alter the quality or composition of water, like several other conventional techniques (adsorption and photocatalysis), which makes this technique non-invasive. The simplicity and tremendously high efficacy of piezocatalysis have attracted researchers worldwide and thus various functional materials are employed for piezocatalytic wastewater remediation. In this frontier, we highlight and demonstrate recent developments on polymer based piezocatalytic nanocomposites to treat industrial wastewater in a facile manner that holds strong potential to be translated into a clean and green technology.

Piezocatalytic bismuth ferrite nanoparticles (BFO) were used for the degradation of organic dye (RhB) and pathogenic bacteria (E. coli), then extracted using external magnetic stimulation after the successful operation.

The present study describes the variation of grain size of natural hematite (α-Fe2O3) from bulk to nano-scale, owing to fractionation by ball milling and also the change in vital electrical properties of the products with respect to their bulk counterpart. Hematite, an important iron ore, is present in abundance in the deposits of most parts of the world. This fact was the rationale behind the selection of this mineral for the study. A gradual decrease in size via top-down synthesis technique was confirmed and the morphological parameters of the materials were analyzed using field emission scanning electron microscopy (FESEM) and corresponding pore diameter and surface area were determined by BET-BJH analysis. The studies were performed on three size fractions, namely, S1 (bulk mineral), S2 (bulk mineral, ball milled for 3 h) and S3 (bulk mineral, ball milled for 12 h). The purities of the natural mineral and its fractionated end products were estimated by using x-ray diffraction (XRD) and x-ray fluorescence (XRF) techniques. Increase in purity with decline in the particle size, especially in the nano-domain, was observed. The changes in dielectric properties of the materials with varying temperature were studied. Temperature dependence of the dielectric constant and ac conductivity were recorded, which indicated a remarkable augmentation in dielectric permittivity with reduction in size of the material. High dielectric constants of the smaller sized materials (S2 and S3) at low frequency signified their potential use in energy storage devices. Thus, using an easily available natural mineral as the starting material, an efficient energy storage appliance can be devised with a low-cost substance, synthesized by the simple approach of fractionation without employing any chemicals.

The large scale amplification of industrial discharge in the modern era is resulting in widespread water pollution, especially from various industrial effluents and wastewater containing heavy metals, posing a severe threat to our environment. In order to combat such problems, this work aims on Multifunctional Fluorescent Nano-Sensor (MFNS) mediated simultaneous detection and removal of hexavalent chromium from real life wastewater which further converts it into an energy harvesting material, namely, “Waste capacitor”. This smart material can detect the presence of the targeted heavy metal (Cr(VI)) in the wastewater and can entrap it by using a facile adsorption process. Thereafter, it will change its microstructure which further enhances its dielectric properties. Morphology, microstructure and optical properties of the synthesized material have been studied thoroughly and a turn-off based fluorescence sensing has been reported herein. Photoinduced electron transfer (PET) based fluorescence quenching is mainly responsible for this sensing mechanism. The selectivity and sensitivity of the material during fluorescence sensing have also been studied by using standard Stern-Volmer method showing that the synthesized material is tremendously selective and sensitive towards the specific target ion. High surface area with slit-like porous structure enhances the adsorption based removal of the contaminant. Nearly 76% of contaminants have been removed by using this smart material. After adsorbing specified target, this MFNS changes its microstructure and results in superior dielectric constant with a minimal tangent loss. Tremendous sensitivity (in nM range), selectivity towards the specific contaminant and adsorption of toxic heavy metal and converting it into a green energy harvesting material (waste capacitor) makes this smart multifunctional material a real waste to wealth converter.

In modern society, massive industrialization escalates environmental degradation by liberating various contaminants into the environment. Hexavalent chromium is a heavy metal that is being discharged from tannery and other industries, resulting in various carcinogenic diseases. This study reports a carbon dot (cdot)-based fluorometric probe for detecting hexavalent chromium in water. This is the very first time that cdots are tailored over the boehmite nanoparticle's surface using an in situ approach. Validation of formation of the nanocomposite has been discussed in detail employing the Rietveld refinement-based X-ray crystallography method. Vibrational spectroscopy and electron microscopy of the sample authenticate the nucleation process and the growth mechanism. The Stern-Volmer approach and time-resolved fluorescence measurements justify the sensitivity of the sensor (∼58 nM), and selectivity is analyzed by exposing the material to different ionic environments. Density functional theory (DFT) is applied herein to analyze the origin of fluorescence and the sensing mechanism of the probe, which shows that photoinduced electron transfer is responsible for the turn-off-based sensing of Cr(VI). The molecular docking simulation is carried out to ensure the binding of cdots to the binding pocket of the glutathione enzyme, which is responsible for treating reactive oxygen species-mediated DNA damage due to elements such as hexavalent chromium. Time-dependent density functional calculations show that the fluorometric probe is capable of detecting Cr(VI) in living cells making it an early stage chromium-mediated carcinogen detector.

This article reports the fluorometric detection of toxic hexavalent chromium Cr (VI)) in wastewater and Cr (VI) contaminated living cells using in-situ grown carbon quantum dots into the goethite (α-FeOOH) nano-matrix. The synthesized nano-hybrid shows enormous potential in determining the chromium contamination levels in various types of water samples. This selective fluorometric probe is enormously sensitive (LOD 81nM) towards hexavalent chromium, which makes it a dedicated chromium sensor. Moreover, the sensing mechanism has been assessed using Stern-Volmer’s equation and fluorescence lifetime experiments showing the simultaneous occurrence of photoinduced electron transfer and inner filter effect. This chromium sensor has also been employed to assess the contamination level in real-life industrial wastewater. The performance of this probe in real-life wastewater sample is quite commendable. Further, this biocompatible fluorometric probe has been used to demonstrate the in-vitro sensing of Cr (VI) in HeLa cells. The rapid detection mechanism of hexavalent chromium in living cells has been validated using theoretical docking simulations. Henceforth, this fluorometric sensor material could open new avenues not only in wastewater monitoring but also in biomedical applications.

In the modern era, the escalation of heavy metal discharges, especially from the industrial sector, is causing an enormous threat to nature. This article explores the dual sensing of heavy metals (Cr6+ and Fe3+) using a naturally formed microcline based sensor. A nano-sized microcline (M) was obtained via a facile top-down synthesis. In order to enhance the fluorescence property of the material, nitrogenous carbon-dots were loaded into the porous structure of the microcline (MCD) causing a bright blue fluorescence with remarkable stability. Detailed analysis of the composition and structure of the natural nano-sensor was carried out using X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and BET analysis. This sensor material is highly selective towards Cr6+ and Fe3+, demonstrating a “turn-off” response in aqueous Fe3+ and a radical red shift of the fluorescence maxima for aqueous Cr6+. Density functional studies suggest that photoinduced electron transfer (PET) based quenching of fluorescence is responsible for these types of fluorescence alteration mechanisms. Efficient sensing of both Cr6+ and Fe3+ in various real-life water samples along with a real wastewater sample is also reported herein. A few studies have previously reported on efficient, natural material-based sensors, but they lack real-life applications due to their complicated synthesis and restricted functionalities. This work manages to overcome those drawbacks in its own fashion, providing a tremendously selective and sensitive (4 μM for Cr6+ and 19 μM for Fe3+) dual fluorescent probe.

This article reports a copper doped boehmite (CBH) based nano-material which is capable of detecting and removing hexavalent chromium simultaneously. Basic characterization has been performed to determine its phase purity, particle size (∼20 nm), morphology and surface properties (surface area 15.29 m2 g−1 and pore diameter 3.9 nm) by using some basic characterization tools. The Rietveld refinement method has been adopted to analyze the microstructural details of the synthesized nanostructure. Photoinduced electron transfer (PET) based quenching of fluorescence is mainly responsible for chromium sensing in this case. This nanosensor is exceptionally sensitive (limit of detection ∼ 6.24 μM) and merely selective towards hexavalent chromium ions. Industrial wastewater samples have also been used here to demonstrate the real life applicability of this material, which shows the same trend. This fluoro-sensor gains its multi-functionality when it comes to the adsorption based removal of Cr(VI) from wastewater. The synthesized material shows a remarkably high adsorption rate (∼85% in just 5 minutes) due to its sponge-like porous structure. Adsorption of hexavalent chromium from wastewater enhances the dielectric constant of this material significantly (∼7.93 times). Ionic polarization-dependent enhancement of the dielectric constant resulting from industrial wastewater treatment is a quite unmarked approach. Very low tangent loss with augmented dielectric permittivity makes this nano-material desirable for energy harvesting applications. Previously many articles have reported the sensing and removal of various industrial effluents. Keeping this in mind, this work has been designed and, apart from sensing and removal, it provides a new insight into energy harvesting from wastewater.

The size-dependent antibacterial activities of three minerals namely; alkali feldspar, calcite and stibnite are reported as examined individually against Escherichia coli and Staphylococcus aureus by evaluating minimum inhibitory concentration (MIC) with colony counting method, along with cell survivability assay (MTT). Each of these minerals were grinded into fine-size fractions—S1 (bulk), S2 (ball milled) and S3 (nanosized) and spectroscopically characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and ultraviolet-visible (UV-Vis) spectroscopy. Antibacterial activity was found to be highest in the nanosized (S3) minerals. Interaction between bacteria and nanosized mineral samples produce intracellular reactive oxygen species (ROS), which might cause higher bacterial mortality. The penetration due to nano-dimension is another significant observation as evidenced by bacterial FESEM micrographs. The current findings thus provide a pathway for future research on antibacterial products retrievable from widely available geological materials. The size dependant antibacterial activity of naturally formed minerals is a new insight to reduce bacterial contamination in living systems.

Among the different types of polymeric vehicles, (PLGA) is biodegradable and has emerged as promising tool for the delivery of cancer therapeutics. The salient features of PLGA micro carriers include prolonged circulation time, increased tumor localization and biodegradability and effectiveness of the therapeutics. We have synthesized PLGA microspheres where curcumin can be loaded and thereby increases its bioavailability. The cytotoxicity of curcumin (PLGA@CCM) microspheres was evaluated on triple negative breast cancer (TNBC) cell lines. They were found to induce apoptosis by perturbing the mitochondrial membrane potential. PLGA@CCM@FA induces apoptosis in human triple negative breast cancer cells by up-regulating Cleaved caspase-3 and down regutes p-AKT. The in-vivo study in BALB/C mice model exhibited more tumor regression in case of PLGA@CCM@FA microspheres. Our results suggests that these microspheres can be an effective vehicle for delivery of hydrophobic drugs to the folate over expressed cancer cells.

The present article reports the crystal defect-mediated changes in electrical characteristics, especially, dielectric properties, of naturally formed microcline and kyanite in two different size fr...

A flexible nano-engineered natural mineral (carbon dot doped natural microcline) based membrane (MCPV) has been developed, which can efficiently detect the presence of hexavalent chromium (Cr6+) and trivalent iron (Fe3+) ions in water by altering its fluorescence emission. Detailed characterization of the membrane was carried out using XRD, FT-IR spectroscopy, FESEM, TEM, and UV-Vis spectroscopy. Mechanical and temperature stabilities were also investigated. This new-generation sensor membrane is designed in such a way that it does not dissolve in water, keeping the water quality unaffected. The fluorescence studies were conducted at 414 nm and “turn-off” response was observed specifically for Fe3+ at 489 nm. A prominent red shift (530 nm) of the fluorescence maxima takes place when it comes to Cr6+. Figures of merit, such as LOD (8.7 μM for Cr6+ and 18.4 μM for Fe3+) and LOQ (29.1 μM for Cr6+ and 61.6 μM for Fe3+), were evaluated from the linear range (0–60 μM for Cr6+ and 0–30 μM for Fe3+) of the calibration curve (Stern-Volmer plots) showing high sensitivity of this sensing probe toward Cr6+ and Fe3+. Recovery and RSD calculations were done in various real-life water samples on intraday-interday basis to determine the accuracy of the sensor. This work validates the fact that the synthesized sensor membrane is capable of detecting these heavy metals in glutathione environment as well, which could be beneficial for early-stage carcinogen detection in living cells.

This article reports a facile strategy to detect hexavalent chromium (Cr (VI)) using a naturally formed mineral (kyanite) based fluorometric sensor. Nitrogenous carbon dots have been incorporated into natural kyanite (KYCD) nanoparticles causing a stable bright blue fluorescence compared to its pristine counterpart. This sensing probe structurally stabilizes and resists the agglomeration of carbon dots, thus retaining fluorescence quality for a longer period. The promising bright blue fluorescence has been utilized further to detect Cr (VI) in wastewater and living cells. Ease of synthesis, low cost, and stability of the system offers the benefit for large-scale production, which is convenient for industrial production the sensing probe. The sensor shows high selectivity and sensitivity (LOD and LOQ of 0.11 µM and 0.36 µM respectively in case of linear fitting, whereas 0.26 µM and 0.88 µM respectively for full range plot) towards hexavalent chromium in presence of other interfering elements. A detailed study of photoinduced electron transfer (PET) mediated rapid 'turn off' sensing mechanism was carried out using Time-Dependent Density functional (TDDFT) calculations. The sensing efficacy of the probe remains unaltered under a wide range of pH and can be effective in various water types. Onsite sampling and probing of Cr (VI) in tannery wastewater has been performed to validate its real-life efficiency that yields excellent results. The sensor can effectively detect chromium at a cellular level (HeLa cells) in a similar way as the bright blue fluorescence diminishes in presence of the quenching ion. Experimental in vitro studies along with theoretical docking analysis has been conducted to substantiate such issues and a higher possibility of fluorophore binding was found for Isoleucine (2.9 Å), Serine (2.96 Å), and Glycine (3.16 Å). This biocompatible sensor rapidly senses hexavalent chromium in living cells, which makes this efficient probe a true heavy metal-induced carcinogen sensor.

In the modern era, the escalation of heavy metal discharges, especially from the industrial sector, is causing an enormous threat to nature. This article explores the dual sensing of heavy metals (Cr6+ and Fe3+) using a naturally formed microcline based sensor. A nano-sized microcline (M) was obtained via a facile top-down synthesis. In order to enhance the fluorescence property of the material, nitrogenous carbon-dots were loaded into the porous structure of the microcline (MCD) causing a bright blue fluorescence with remarkable stability. Detailed analysis of the composition and structure of the natural nano-sensor was carried out using X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and BET analysis. This sensor material is highly selective towards Cr6+ and Fe3+, demonstrating a "turn-off" response in aqueous Fe3+ and a radical red shift of the fluorescence maxima for aqueous Cr6+. Density functional studies suggest that photoinduced electron transfer (PET) based quenching of fluorescence is responsible for these types of fluorescence alteration mechanisms. Efficient sensing of both Cr6+ and Fe3+ in various real-life water samples along with a real wastewater sample is also reported herein. A few studies have previously reported on efficient, natural material-based sensors, but they lack real-life applications due to their complicated synthesis and restricted functionalities. This work manages to overcome those drawbacks in its own fashion, providing a tremendously selective and sensitive (4 μM for Cr6+ and 19 μM for Fe3+) dual fluorescent probe.

In this article, nanostructures of boehmite (γ-AlOOH) have been successfully synthesized in a time varied, facile and cost effective hydrothermal route. The samples have been characterized by using X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM) and Fourier Transform Infrared (FTIR) spectroscopy. Our samples exhibit remarkably high photoluminescence emission intensity and dielectric constant (3.71 × 106 for BH12 sample) with a nominal dielectric tangent loss. A detailed growth mechanism including the nucleation and self assembly of our nanomaterial has been discussed. Moreover, we are the first to report here the electrical properties of the boehmite nanoparticles. Present investigation also explores temperature dependent dielectric property and ac conductivity of these samples. The role of crystallinity in the optical and electrical enhancement of our samples has been illustrated with proper analytical details. Not only high emission intensity in the blue and green region of the spectrum makes our sample a strong candidate for bio-imaging and bio-sensing applications, but also high dielectric constant makes them desirable for cost-effective energy storing devices, such as supercapacitors and solar cells.

This work reports a handheld fluorometric probe, namely ‘Kavach’ for monitoring hexavalent chromium in industrial wastewater and living systems. Kavach is capable to detect chromium contamination in a rapid and facile way. The device is made of a thin layer (~1 mm) of carbon dot decorated boehmite nanostructure (BH@CD) incorporated in a layer of poly vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) membrane. The doped membrane has an excellent blue fluorescence upon UV excitation (355 nm) and alters its fluorescence level when exposed to Cr(VI). In reality, tiny carbon dots leach out from the nano-matrices to produce secondary contamination. Incorporation of the BH@CD into the polymeric matrix of PVDF-HFP significantly reduces such contamination and makes this material a potential sensing probe. This photoinduced electron transfer (PET) based sensor is tremendously selective and sensitive (LOD ~66 nM) towards aqueous chromium. The performance of the probe remains unaltered in different pH and water qualities. Additionally, this material can sense chromium in living cells, which has been validated theoretically using molecular docking and observed experimentally using fluorescence microscopy. Kavach is truly a handheld, reusable and non-invasive sensing probe against Cr(VI), which can be employed for on-site low-cost detection.

The present article reports three different grain morphologies of boehmite nanoparticles: spherical (EBH), needle-shaped (UBH) and flower-like (HBH). EBH possesses the highest surface area, whereas HBH has the lowest. A novel synthesis route for spherical (EBH) boehmite nanostructures using ethylenediamine has been reported here. Moreover, we have compared the growth mechanisms and morphology-dependent changes in the optical and electrical properties of the three samples. The band gap energies were evaluated to be 5.30 eV, 5.44 and 5.87 eV for EBH, UBH and HBH, respectively. Strong photoluminescence (PL) emission for all the nanostructures, the highest for HBH, was noted. The lowest surface area of HBH provides a surface with fewer defects; this seals the possibility of energy loss via non-radiative recombination of electrons and holes, which enhances the PL intensity. The dielectric constants for EBH, UBH and HBH are 1.49 × 106, 1.14 × 105, and 7.14 × 104, respectively. Variations in the dielectric loss tangents and temperature-dependent electrical properties of the three morphologies were evaluated in support. Also, the ac conductivity and impedance analyses are in good accordance with our dielectric analysis. The present investigation may be highly beneficial in developing biosensors, bio-imaging, and fabricating cost-effective energy storage devices.

This article reports the effect of Gd(III) doping on the structure, microstructure, and optical properties of boehmite nanoparticles. The bright-blue fluorescence along with a long lifetime makes our material an efficient candidate for optical applications. Our material particularly targets and eliminates hexavalent chromium ions (Cr(VI)) from aqueous media, which turns it into a multifunctional fluorescent nanosensor (MFNS). The development of an efficient hexavalent chromium ion (Cr(VI)) sensor to detect and quantify Cr(VI) ions is still a serious issue worldwide. Thus, this work will be very beneficial for various environmental applications. No such work has been reported so far which includes cost-effective and biocompatible boehmite nanoparticles in this field. Detailed synthesis and characterization procedures for the MFNS have been incorporated here. The biocompatibility of the MFNS has also been studied rigorously by performing cell survivability assay (MTT) and cellular morphology assessments. Our extensive research confirmed that the "turn-off" sensing mechanism of this sensor material is based on a collisional quenching model which initiates the photoinduced electron transfer (PET) process. High selectivity and sensitivity (∼1.05 × 10-5 M) of the MFNS toward hexavalent chromium ions even in real life wastewater samples have been confirmed, which makes this fluorescent probe a potential candidate for new age imaging and sensing technologies.

Among the different types of polymeric vehicles, (PLGA) is biodegradable and has emerged as promising tool for the delivery of cancer therapeutics. The salient features of PLGA micro carriers include prolonged circulation time, increased tumor localization and biodegradability and effectiveness of the therapeutics. We have synthesized PLGA microspheres where curcumin can be loaded and thereby increases its bioavailability. The cytotoxicity of curcumin (PLGA@CCM) microspheres was evaluated on triple negative breast cancer (TNBC) cell lines. They were found to induce apoptosis by perturbing the mitochondrial membrane potential. PLGA@CCM@FA induces apoptosis in human triple negative breast cancer cells by up-regulating Cleaved caspase-3 and down regutes p-AKT. The

Among the different types of biomaterials, natural excipients gum acacia (GA) is economic and has the potential for controlled drug delivery. We have synthesized GA microspheres by co-precipitation method and characterized them by XRD, FESEM, 1H NMR, FTIR, UV visible spectra and DLS. Despite its potential anti-cancer activity, solubility of curcumin is very low rendering its limit in application. We have used GA microspheres where curcumin can be loaded comfortably and thereby increases its bioavailability. The cytotoxicity of curcumin encapsulated GA microspheres was evaluated on triple negative breast cancer cell lines. They were found to induce apoptosis by perturbing the mitochondrial membrane potential. Folic acid was conjugated to curcumin encapsulated GA microspheres, for delivering it specifically to the cancer cells. The in-vivo study in BALB/C mice model exhibited more tumor regression in case of folic acid targeted curcumin encapsulated GA microsphere. Our results implicates that these microspheres can be an effective therapeutic agent to folate receptors over expressing cancer cells.