A water-soluble highly fluorescent silver cluster on Au(I) surface has been synthesized with green chemistry under sunlight. The evolution of the silver cluster is synergistic, demanding gold and glutathione. The fluorescent Au(I)core-Ag(0)shell particles are huge in size and at the same time they are robust. That is why they become a deliverable fluorescing solid upon drying. Again, the giant particles run into common water miscible solvents. As a result, the fluorescence intensity increases to a great extent without any alteration of emission maxima. In this respect, acetone has been found to be the best-suited solvent. To have a universal applicability of the fluorescent clusters, the particles in the water pool of a reverse micelle have been prepared to transfer the particles into different water immiscible solvents. The comparatively lower fluorescence intensity of the particles has been ascribed to a space confinement effect. Finally, giant-cluster-impregnated yellow-orange fluorescent polymer film and fluorescent cotton wool, as well as paper substrate, have been prepared. The antibacterial activity of the fluorescent particle has also been tested involving modified cotton wool and paper substrate for Gram-negative and -positive Escherichia coli and Staphylococcus aureus, respectively.
Chitin is a linear homo-polymer of N-acetyl-D-glucosamine (GlcNAc) and the second most abundant biopolymer after cellulose. Several industries rely on the bioprocesses for waste chitin recycle and hydrolysis by chitinase (EC 3.2.1.14) for potential healthcare applications through the production of its monomeric subunit, GlcNAc. In the present study, a chitinase-producing fungus (named as MFSRK-S42) was isolated from the marine water sample of North Bay of the Andaman and Nicobar Islands. It was identified as Aspergillus terreus by morphological and molecular characterization methods leveraging the internal transcribed spacer between 18S rRNA and 5.8S rRNA. Chitinase that was isolated from the fermentation broth of marine Aspergillus terreus was used to carry out biotransformation of chitineaceous wastes. Prior to the enzymatic hydrolysis step, chitins from different sources were characterized for the presence of characteristic functional groups, grain size distribution, and surface morphology. Enzymatic hydrolysis of 50 mg/ml substrate with six units of enzyme incubated for 5 days revealed 15, 36.5, 40, and 46 mg/ml GlcNAc production from ground prawn shell, chitin flakes, colloidal prawn shell, and swollen chitin respectively under standardized conditions, as determined by HPLC. In this study, 30, 73, 80, and 92% GlcNAc yields were observed from ground prawn shell, chitin flakes, colloidal prawn shell, and swollen chitin conversion respectively. The HPLC-eluted product was confirmed as GlcNAc by the presence of characteristic functional groups in FTIR and 244 Da molecular weight peak in HRMS analyses.
For decades, 5‐fluorouracil (5FU) has been the only chemotherapeutic agent to demonstrate a strong activity against colorectal cancer. However intravenous administration of 5FU mandates the development of an oral controlled delivery system for improved patient compliances. With this rationale, hydrogels comprising polyvinyl alcohol and sodium alginate were crafted and subjected to cold atmospheric plasma treatment by coating with hexamethyldisiloxane (HMDSO) using three different carrier gases viz Ar, He and N2. Surface hydrophobicity ensuing from HMDSO plasma was evident from contact angle goniometry. FT‐IR analyses were affirmative of the effectual deposition of Si−O−Si and Si−CH3 groups on the hydrogel surfaces. Moreover, plasma treatment rendered the hydrogels stiffer and tougher. The plasma‐modified hydrogels displayed lower water uptake capacity in comparison to the pristine one. Drug release was significantly prolonged from the plasma‐treated hydrogels that conformed to the oral delivery of 5FU to colon. Preliminary kinetics assay revealed drug release was predominantly governed by polymer chain relaxation process post‐plasma modification. The Ar/HMDSO‐plasma modified hydrogel was found to be best of the lot for achieving an oral controlled release for 5FU.
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