Search

Cost-effective and time-efficient synthesis of natural mineral (kyanite) based biocompatible, fluorometric sensor for highly selective and sensitive detection of Cr (VI) in aqueous media, industrial wastewater and living cells. [Display omitted] • Synthesis of carbon dot doped natural kyanite nanostructure has been reported. • Selective detection of Cr (VI) in industrial wastewater and live cells is found. • Limit of detection is found to be ∼ 0.11 µM against hexavalent chromium. • Theoretical and experimental validation of the detection mechanism is reported. 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. [ABSTRACT FROM AUTHOR]

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. [Display omitted] • Synthesis and fabrication of 'Kavach', a handheld and fluorometric sensor of Cr(VI). • Carbon dot leaching from the host nanomaterial is restricted using PVDF-HFP. • Limit of detection is found to be ~66 nM against hexavalent chromium. • Selective detection of Cr (VI) in industrial wastewater and live cells is found. • Sensing mechanism of the device is verified using molecular docking and DFT. [ABSTRACT FROM AUTHOR]