Dual-mode colorimetric/fluorescent chemosensor for Cu2+/Zn2+ and fingerprint imaging based on rhodamine ethylenediamine bis(triazolyl silsesquioxane).

A novel dual functional and visual rhodamine ethylenediamine bis(triazolyl silsesquioxane) (RBS) chemosensor was successfully synthesized using "click" chemistry. The results have unambiguously demonstrated that RBS can act in fluorescent and colorimetric sensing of Cu2+ and Zn2+ by their respective coordination with triazole structures and, more importantly, it has also been found that triazole-amide of RBS could turn on chelation-enhanced fluorescence (CHEF) of Cu2+. Remarkably, the addition of Cu2+ triggered an enhanced fluorescent emission by 63.3-fold (ϕF = 0.41), while Zn2+ enhanced it 48.3-fold (ϕF = 0.29) relative to the original RBS (ϕF = 0.006) in acetonitrile (MeCN) solvent. The fluorescent limit of detection for Cu2+ and Zn2+ is similar and fall within 3.0 nM, while under colorimetric sensing the responses were 2.14 × 10-8 and 4.0 × 10-8 mol L-1, respectively. Moreover, the effective sensing profile of RBS and extended applications of RBS-Cu2+ and RBS-Zn2+ for fingerprinting detection and imaging were observed with adequate sensitivity, stability and legibility under the dual visual responses.

Fluorescent-Labeled Octasilsesquioxane Nanohybrids as Potential Materials for Latent Fingerprinting Detection.

The recent demand for fluorescent-labeled materials (FLMs) in forensic security concepts such as latent fingerprints (LFs) that encode information for anti-counterfeiting and encryption of confidential data makes necessary the development of building new and innovative materials. Here, novel FLMs based on polyhedral oligomeric silsesquioxanes (POSS) functionalized with fluorophores via "click" reactions have been successfully synthesized and fully characterized. A comprehensive study of their photophysical properties has displayed large Stokes's shift together with good photostability in all cases, fulfilling the fundamental requisites for any legible LF detection on various surfaces. The excellent performance of the hetero-bifunctional FLM in the visualization of LF is emphasized by their legibility, selectivity, sensitivity and temporal photostability. In this study, development mechanisms have been proposed and the overall concept constitute a novel approach for vis-à-vis forensic investigations to trace an individual's identity.

Protective role of diosgenin against hyperglycaemia-mediated cerebral ischemic brain injury in zebrafish model of type II diabetes mellitus.

Impairment in glucose regulation is an indicatory effect capable of mediating multiple dysfunction such as cerebrovascular disorder with ischemia and brain damage inclusive. This study aims at investigating the glucose-lowering and neuroprotective capability of Diosgenin (DG) towards hyperglycemia-induced cerebral injury in a developed type 2 diabetes mellitus (T2DM) Zebrafish (ZF) model. T2DM was developed in ZF with 20 mg/kg body weight (b.w) multiple-low dose (MLD) Streptozotocin (STZ) for 28 days. Different doses of 20 mg/kg b.w (DG1) and 40 mg/kg b.w (DG2) DG was intraperitoneally administered twice in 7 days for a period of 28 days after T2DM was completely developed. Weight and behavioral changes were monitored and the catalytic activity including the plasma glucose level of diseased and treated ZF was spectrometrically estimated. Histopathological studies were employed to image the brain pathological condition during disease and treatment. SPSS was used as the statistical tool for result analysis and comparison of data obtained. STZ significantly (###p < 0.001) induced hyperglycemia when compared to control as plasma glucose increases from 101.56 ± 4.52 mgdL-1 to 175.87 ± 6.00 mg/dL. Our results have indicated a marked reduction in glucose concentration from a mean average of 175.87 ± 6.00 mgdL-1 to 105.68 ± 4.48 mgdL-1 and 82.06 ± 7.27 mgdL-1 in DG 1 and DG 2 respectively. Catalytic activity significantly decreases (p < 0.05) from 206.42 ± 30.77 unit/mL to 123.85 ± 29.99 unit/mL at a minimum and maximum value of 103.21 and 275.23 in diseased ZF respectively. On DG treatment, catalytic activity significantly (p < 0.01) rise from 101.58 ± 11.29 and 130.73 ± 27.52 to 130.98 ± 17.13 and 255.96 ± 30.34 with DG1 and DG2 treatment respectively. Studies on the behavioral pattern of STZ-induced anxiolytic effect on ZF confirmed changes in the number of transitions and time spent in both Novel tank test (NTT) and Dark/light test (LDT). Histopathological analysis confirmed the cerebral cortex with inflammatory brain cells in the diseased condition and an attenuation of damage posed revealed in diseased state was largely reversed with DG. As compared to the normal control, a significant ( # p < 0.05 and ### p < 0.001) changes in weight of fishes were recorded and DG1 and DG2 significantly promotes (***p < 0.001) body weight and improves the irregularities in weight of ZF during disease progression. Our study confirms that the potential of DG towards the management of hyperglycemia and hyperglycemia-mediated cerebral ischemic injury is through its blood glucose-lowering properties, anti-inflammatory activity, antioxidant effect, and anxiolytic capabilities.

A dual-purpose silver nanoparticles biosynthesized using aqueous leaf extract of Detarium microcarpum: An under-utilized species.

The need for green synthesis of emerging industrial materials has led to the biosynthesis of nanoparticles from plants to circumvent the adverse by-products of chemical synthesis. In this study, the leaf extract of Detarium mirocarpum Guill & Perr, a small tree belonging to the family Fabaceae (Legume), was used to synthesize silver nanoparticles (DAgNPs). DAgNPs were characterized using spectroscopic techniques (Ultraviolet-Visible spectroscopy and Fourier Transform Infrared spectroscopy) which showed hydroxyl and carbonyl functional groups to be responsible for their synthesis. DAgNPs were observed to be crystalline and spherical. The average size, determined by transmission electron microscopy (TEM) was 17.05nm. The antioxidant activity of DAgNPs ranked from moderate to good. The ability of DAgNPs to sense Hg(2+) and Fe(3+) ions in aqueous medium was also investigated. The quenching of the SPR peak at 430nm was used to monitor the toxic and heavy metal ions with linear ranges of 20-70µgmL(-1) and 10-40µgmL(-1) for Hg(2+) and Fe(3+), respectively. The limit of detection (LOD) and limit of quantification (LOQ) obtained for Hg(2+) was 2.05µgmL(-1) and 6.21µgmL(-1), respectively and for Fe(3+) was 5.01µgmL(-1) and 15.21µgmL(-1), respectively. The intra- and inter-day assessments of accuracy and repeatability gave relative errors less than 1% in all instances. DAgNPs can therefore provide a convenient method of sensing the toxic metals easily.

Modified procedure for improved synthesis of some octameric silsesquioxanes via hydrolytic polycondenzation in the presence of Amberlite ion-exchange resins.

Practical alternative procedures are described for the syntheses of octavinylsilsesquioxane 1, octaphenylsilesquioxane and octabenzylsilsesquioxane. The hydrolytic polycondensation of RSiX3 (R = CH2=CH-, C6H5- or C6H5CH2-; X = Cl, OCH3, or OC2H5) in the presence of solid acid or base Amberlite ion-exchange resin gave improved yields of the corresponding octameric oligosilsesquioxanes. Repetitive usage of the Amberlite resin as the hydrolysis reagent was tested during synthesis of 1. The results indicate that it could be used many times in the same solvent making the procedure a more economically viable technique.