Chitosan/benzyloxy-benzaldehyde modified ZnO nano template having optimized and distinct antiviral potency to human cytomegalovirus.

Utilization of biomolecules encapsulated nano particles is currently originating ample attention to generate unconventional nanomedicines in antiviral research. Zinc oxide nanoparticle has been extensively studied for antimicrobial, antifungal and antifouling properties due to high surface to volume ratios and distinctive chemical as well as physical properties. Nevertheless, still minute information is available on their response on viruses. Here, in situ nanostructured and polysaccharide encapsulated ZnO NPs are fabricated with having antiviral potency and low cytotoxicity (%viability ~ 90%) by simply controlling the formation within interspatial 3D networks of hydrogels through perfect locking mechanism. The two composites ChH@ZnO and ChB@ZnO shows exceedingly effective antiviral activity toward Human cytomegalovirus (HCMV) having cell viability 93.6% and 92.4% up to 400 µg mL-1 concentration. This study brings significant insights regarding the role of ZnO NPs surface coatings on their nanotoxicity and antiviral action and could potentially guide to the development of better antiviral drug.

Stimuli-Responsive Nanocapsules for the Spatiotemporal Release of Melatonin: Protection against Gastric Inflammation.

Melatonin is a secretory product of the pineal gland that regulates circadian rhythm. It is also well-known for its anti-inflammatory and antioxidant properties against the damaging influences of reactive oxygen species. To improve its therapeutic efficacy, a new formulation with melatonin loaded in a stimuli-responsive polymeric nanocapsule has been prepared following an inverse mini-emulsion technique. The colloidal stability of the melatonin-loaded nanocapsules (MNCs) is studied using dynamic light scattering, while the morphology of these MNCs is characterized using various electron microscopies. These MNCs have an inner diameter of 80-120 nm with a cell wall thickness of 29 ± 11 nm. The emission band maximum for melatonin appears at 350 nm following excitation at 305 nm (quantum yield, Φ350 = 0.13). The self-quenching nature of the entrapped melatonin molecules inside the nanocapsules attributes to a lower Φ350 value for the MNCs. The controlled release of melatonin from MNCs in an in vitro condition is achieved by inducing a rupture of the polymeric backbone through maintaining a certain media pH (∼2.0-4.0) as an external stimulus, and this accounts for a significant enhancement in its characteristic luminescence. The H,K-ATPase, an integral membrane protein, maintains this specific pH range in the interior of the gastrointestinal tract. This methodology is adopted for developing an efficient drug delivery process in the gastric environment. A significant improvement in the AGS cell survival under oxidative stress conditions is observed during preincubation with MNCs compared to free melatonin. In a murine model of the stress-induced gastric ulcer, MNCs outperformed free melatonin in terms of drug efficacy. The value for the gastric ulcer index is reduced from ∼30 to ∼15 by free melatonin and from ∼30 to ∼8 by MNCs treatments, respectively. Such formulation could be a step forward for developing more efficient melatonin-based gastroprotective supplements.

Two photon excitable graphene quantum dots for structured illumination microscopy and imaging applications: lysosome specificity and tissue-dependent imaging.

Biocompatible graphene quantum dots (GQDs), obtained from extracts of neem root, are found to be suitable for structured illumination microscopy and two-photon microscopy (TPM). Results of TPM and confocal luminescence microscopy ensure lysosome specificity in live cells and tissue-dependent localization in zebrafish, respectively, of GQDs.

Fluorescent chemodosimeter for quantification of cystathionine-γ-synthase activity in plant extracts and imaging of endogenous biothiols.

A new reagent for quantification of CgS in plant extracts using a generalized methodology suitable for recognition of homocysteine (Hcy) with luminescence ON response.