There is an emerging quest for fabrication of water-soluble fluorescent silver nanoclusters (AgNCs) with long-lasting fluorescent properties and dimensional stability while being sustainable and functional. Thus, a well-known seed-mediated growth strategy has been developed to manufacture AgNCs supported onto carboxyl and aldehyde modified cellulose nanofiber (DATCNF) with ultra-small and intense fluorescence. The DATCNF acts as a reductant, template, and stabilizer while the protective ligand, 2-Mercaptonicotinic Acid (2-H 2 MA), provides AgNCs with luminous characteristic and constrained size of 4.47 nm. The structural feature of 2-H 2 MA also governs the formation and stability of AgNCs, imparting them with hydrophobic nature and steady fluorescence emission in water. This aqueous colloidal suspension (DATCNF-AgNCs) is highly dispersed, photobleaching resistant, and hardly agglomerates. Even after two months of exposure to the sun, the fluorescence intensity had only fallen by 20 %. Furthermore, the aqueous colloidal suspension exhibits outstanding antibacterial property and UV shielding capability, making it suitable as an additive for the production of TCNF films with high UV blocking capacity and high tensile strength. This strategy opens the door to design and fabricate mechanically robust DATCNF-AgNCs composites for luminescent, antimicrobial, and UV protection applications.
Yu Chen,Huan Chen,Haihua Wang,Xia Xin,Wenbing Kang
Silver nanoclusters (NCs) possess precise and tunable structures characterized by their unique properties, yet a single component often underperforms in practical applications. In this work, a series of stable and highly effective antibacterial gels were prepared by incorporating fluoropolymer (perfluoro-2, 5-dimethyl-3, 6-dioxactyl glycol acrylate-co-acrylic acid, FAA) into aqueous solutions of (NH 4 ) 6 [Ag 6 (mna) 6 ] (Ag 6 -NCs). It can be quickly gelated within a few seconds to achieve the rapid transformation of one-dimensional into three-dimensional structures. These gels are formed through the layering of nanowires, and their mechanical properties can be tailored by adjusting the FAA concentration. The assembly process of Ag 6 -NCs/FAA hydrogels was investigated by comparing it with various poly carboxylic acids, neutralized FAA, and aqueous AgNO 3 solutions under identical experimental conditions. This assembly results from various interactions, including hydrophobic interactions, van der Waals forces and hydrogen bonds. Furthermore, the hydrogel system demonstrated improved antibacterial activity due to the presence of Ag ions and fluorine atoms. The functional composite of materials, achieved through heterogeneous assembly, promoted the design of metal NC materials and furthered the development of macro manufacturing technology.
Abstract This study was mainly aimed to evaluate the potential use of a novel ocular drug delivery system, organic–inorganic hybrid nanocomposites based on chitosan derivatives and layered double hydroxides (LDH). Organic polymers of chitosan–glutathione (CG) and pre-activated chitosan–glutathione (CG-2MNA) were successfully synthesized and characterized. LDH with intercalated phacolysin (PCL), including larger hexagonal LDH–PCL (Lh-LDH–PCL), larger spherical LDH–PCL (Ls-LDH–PCL), smaller hexagonal LDH–PCL (Sh-LDH–PCL), CG hybrid LDH–PCL (LDH–PCL-CG), and CG-2MNA hybrid LDH–PCL (LDH–PCL-CG-2MNA), were prepared. The nanocomposites with particle size of 107.2–274.9 nm were characterized by powder X-ray diffraction, Fourier transform infrared, transmission electron micrographs, etc. In vivo precorneal retention studies showed that the detectable time of all nanocomposites was prolonged from 2 to 6 h in comparison to PCL saline. Accordingly, the AUC 0–6h values of Lh-LDH–PCL, Ls-LDH–PCL, Sh-LDH–PCL, LDH–PCL-CG, and LDH–PCL-CG-2MNA nanocomposites were increased by 2.27-, 2.08-, 3.08-, 4.67-, and 3.36-fold, respectively. The Draize test and hematoxylin and eosin staining demonstrated that modified LDH had no eye irritation after single and repeated administration. These results indicated that chitosan derivatives-LDH hybrid nanocomposite dispersion could be a promising ocular drug delivery system to improve precorneal retention time of drugs. Graphical Abstract Thiolated chitosan-LDH hybrid nanocomposite dispersion could be a promising ocular drug delivery system to improve precorneal retention time of drugs and may facilitate penetration of drugs into tissues of the eyes.
危险品化学品经营许可证（带存储）