Preparation of Vitamin- g -Lignin Nanohybrids with Excellent Biological Activity and Fluorescence Performance.

As a natural renewable biomacromolecule, lignin has some inherently interesting properties such as fluorescence, antioxidation, and antibacterial performance. However, the unsatisfactory fluorescence and biological activities have greatly limited their value-added and large-scale applications. In this work, lignin nanoparticles (LNPs) grafted with vitamin B 1 hybrid nanoparticles (LEVs) were obtained by using ethylenediamine and different contents of vitamin B 1 through a simple hydrothermal method. The chemical structure, fluorescence properties, and bioactivity were characterized to assess the effects of ethylenediamine and vitamin B 1 on the properties of LEVs. It was found that the fluorescence performance of synthesized LEV particles was improved with the increase in the amount of vitamin B 1 . The free radical scavenging rate (RSA, %) increased to 97.8%, while the antibacterial rates reached up to 99.9%. The antibacterial activity of LEV involved multiple combined mechanisms. The introduction of imine, amide groups, and positively charged VB 1 of LEV will make it easier to interact with the negatively charged bacterial phospholipid membranes and cause bacterial lysis and death. Then, the PVA/LEV hydrogel composites were prepared by the freezing-thawing method, and the results showed that PVA/LEV hydrogels had more comprehensive performance such as improved mechanical properties and antioxidant and antibacterial activities, resulting in its great potential to be used as an efficient biomedical material.