Sanjay Mehra

Nitric oxide (˙NO) plays a crucial role in various biological processes, but its reactive nature and short half-life make its precise detection challenging. Developing sensitive and selective probes for ˙NO detection is essential for advancing biological and biomedical research. Here, we report the design of a hydrolytically stable and highly luminous amine-functionalized cobalt-based metal–organic framework (MOF), PUC-9, as a novel ˙NO sensor. PUC-9 exhibits a distinct fluorescence “turn-off” response to ˙NO via a deamination-based quenching mechanism, effectively differentiating it from other reactive oxygen and nitrogen species (ROS and RNS). It demonstrates a low detection limit (LOD) of 0.019 μM and a notable Stern–Volmer constant (K_sv) of 0.13 × 10⁵ M⁻¹. With minimal cytotoxicity, PUC-9 enables ˙NO detection comparable to standard assays through absorbance, fluorescence, and imaging-based methods, showing its reliability and versatility across different detection platforms. These findings establish PUC-9 as a highly sensitive and selective tool for ˙NO detection in aqueous media and biological environments.

Metal–organic frameworks (MOFs) are emerging as a key solution for detecting and adsorbing hazardous nitroaromatic compounds, driven by environmental and security concerns. In this paper, a high pH and water-stable fluorescent MOF (PUC-10) with distorted pentagonal bipyramidal geometry and interesting hcb topology was prepared by a solvothermal method. Furthermore, a PUC-10 NP based composite (PUC-10@HNT) was fabricated and applied for the sensitive detection of hydroxyl group-containing nitroaromatic compounds (NACs). In particular, trinitrophenol (TNP), dinitrophenol (DNP) and para-nitrophenol (4-NP) rapidly quench the fluorescence of PUC-10@HNT, with a detection limit of 0.027 μM, 0.031 μM and 0.036 μM, respectively. The sensing ability of PUC-10 and PUC-10@HNT was compared to signify the composite formation. This method effectively analyzes the respective NACs in natural water and a Whatman-paper-strip sensing element was also developed for efficient visual detection of analytes. Moreover, PUC-10@HNT showed excellent recyclability over four cycles. Based on the DFT calculations, zeta-potential, absorption and photoluminescence spectra of the analytes and probe, the fluorescence quenching mechanism was analyzed and found to be due to a combination of PET, FRET, and competitive light absorption between the analytes and PUC-10@HNT.

A MOF based eutectogel with antibacterial and antioxidant attributes, along with hemocompatibility, is used for the encapsulation and sustained release of curcumin.

Spirocyclic carbonates: A simple and efficient organocatalytic approach for the chemical fixation of CO ₂ with spiroepoxy oxindoles has been demonstrated. The catalytic protocol may provide additional possibilities to new applications.

Lignin is an amorphous, heterogeneous, aromatic biopolymer that is obtained from nature.