An amphiphilic dansyl based multianalyte sensor for the detection of Hg2+, PPi, and TNP: A three-in-one chemical sensor.

A fluorescent dansyl-based amphiphilic probe, 5-(dimethylamino)-N-hexadecylnaphthalene-1-sulfonamide (DLC), was synthesized and characterized to detect multiple analytes at different sensing environments. In acetonitrile, DLC detects nitro explosives such as trinitrophenol (TNP) and 2,4-dinitrophenol (2,4-DNP) by an emission "on-off" response method, and the detection limits (LOD) were estimated to be as low as 4.3 µM and 17.4 µM, respectively. Amphiphilic long chains of the probe were embedded into lipid bilayers to form nanoscale vesicles DLC.Ves. Nanovesicular probe DLC.Ves was found to be highly selective for Hg2+ among other metal ions and for pyrophosphate (PPi) ions among various anions. DLC.Ves could detect Hg2+ with a turn "on-off" emission and PPi with ratiometric change in emission at 525 nm. It is proposed that DLC.Ves could detect Hg2+ via the Hg2+-induced aggregation quenching mechanism and PPi through the Hydrogen bonding. The LODs are estimated as 6.41 µM and 70.9 µM for Hg2+ and PPi, respectively. 1H NMR, SEM, and fluorescence lifetime measurements confirmed the binding mechanism. Thus, it is believed that the simple fluorescent probe DLC could be a prominent sensor to detect multiple analytes depending on the sensing medium.

Multifunctionality exploration of NiCo2O4-rGO nanocomposites: photochemical water oxidation, methanol electro-oxidation and asymmetric supercapacitor applications.

Different weight percentages of NiCo2O4-rGO nanocomposites were prepared via a facile hydrothermal method. The prepared nanocomposites were structurally and morphologically characterized by X-ray diffraction, Raman spectroscopy, and electron microscopy. The structural studies show the formation of rGO-NiCo2O4 nanocomposites by embedment of porous NiCo2O4 rods on rGO sheets. The effect of the NiCo2O4 content on photochemical water oxidation was investigated. It revealed that the catalysts NiCo2O4-rGO with 1 : 26 ratio (NCO26) and 1 : 13 ratio (NCO13) are efficient in generating oxygen under light illumination. It proves that NCO26 works far more effectively as a photocatalyst compared to NCO13. Methanol electro-oxidation of the NCO26 nanocomposite shows a current density of 24 mA cm-2 at a potential of 0.45 V in cyclic voltammetry and maintains the current for 3600 s at 0.45 V in chronoamperometry. An onset potential of 0.344 V was observed for 0.5 M methanol oxidation. The specific capacitance values were found to be 354.75 F g-1 and 375.32 F g-1 at 1 mV s-1 and 1 A g-1, respectively, for NCO26 in supercapacitor studies. The charge stored via capacitive and diffusion-controlled processes was determined using Power's law and Trasatti plot. An asymmetric supercapacitor device shows a specific capacitance of 122.2 F g-1 at a current density of 1 A g-1 and exhibits a retention of 74.3% after 5000 cycles. An energy density of 67.89 W h kg-1 and a power density of 1 kW kg-1 at a current density of 1 A g-1 are observed.

Lipid-encapsulated upconversion nanoparticle for near-infrared light-mediated carbon monoxide release for cancer gas therapy.

Cancer gas therapy is just in an early stage of research and development. Several important gasotransmitters have proven their therapeutic potentials, but handling, delivery and controlled release of these gases remain very challenging for therapeutic purposes. This research develops a versatile nanosystem that is capable of delivering carbon monoxide (CO) gasotransmitter in the form of photo-responsive carbon monoxide-releasing molecule (CORM) for targeted cancer therapy. The core-shell upconversion nanoparticles (UCNPs) were designed to transfer bio-friendly low energy near infrared (NIR) light to ultraviolet (UV) light and trigger CO release from the loaded CORM. The synthesized delivery system demonstrated its ability to mediate the sustained release of CO upon 808 or 980 nm NIR light excitation. The optimized nanoformulation was efficiently taken up by HCT116 cancer cells and showed dose-dependent cytotoxicity to HCT116 and other cancer cells. Intracellular CO release and subsequent therapeutic action involving ROS production were found to significantly contribute to cell apoptosis. Therefore, the current research demonstrates the potency and efficiency of an NIR-mediated UCNP-based CORM prodrug delivery system for targeted cancer gas therapy.

Fluorescent nanoprobes for the sensing of gasotransmitters hydrogen sulfide (H2S), nitric oxide (NO) and carbon monoxide (CO).

Fluorescent nanomaterials as sensing probes have experienced immense growth in recent years due to the intrinsic optical and physicochemical properties, high sensitivity, specificity, targeting ability, and suitability for medicinal applications. The fluorescent detection of gaseous signaling molecules, such as Hydrogen sulfide (H2S), nitric oxide (NO) and carbon monoxide (CO) are very important due to their potential therapeutic application. This review intends to provide the recent progress in the detection of H2S, CO and NO via fluorescent based nano probes. These probes work based on different mechanisms such as fluorescence enhancement and quenching, also defined as "turn-on" and "turn-off" responses respectively. It could be achieved through PET, FRET or ratiometric methods. In this article, we have discussed about a variety of fluorescent nanoprobes of QDS, CDs, AuNPs and UCNPS, working on the fluorescent sensing mechanisms and applicable for the detection of H2S, CO and NO in biological and environmental samples. Methods used for the detection, structural features of nanomaterials, type of fluorescence response observed, fluorescence sensing mechanism and their sensitivity are highlighted.