Lin Dai

Simple and green fabrication of AgCl/Ag-cellulose paper with antibacterial and photocatalytic activity

A green in situ technique to prepare a kind of multifunctional hybrid paper, AgCl/Ag particles hybrid cellulose-paper (AgCl/Ag-paper), was established. The AgCl/Ag-paper was obtained from a facile ultrasound agitation procedure. Scanning electron microscope observation showed that AgCl/Ag particles were highly dispersed outside surface and inside of the paper matrix. The resultant AgCl/Ag-paper demonstrated satisfactory antibacterial activity and biocompatibility. Moreover, AgCl/Ag-paper showed good photocatalytic activity and stability for decomposing organic pollutants (methyl blue) under the direct sunlight. Overall, this work provided a simple and green approach for the preparation of a new paper-based material with effectively antibacterial, photocatalytic activity, and biocompatibility for various applications and also showed the potential of scale-up production.

Fabrication of high-performance poly(l-lactic acid)/lignin-graft-poly(d-lactic acid) stereocomplex films

The need for green renewable alternatives such as lignin to traditional fillers has driven recent interest in polylactic acid blend materials. Herein, lignin-graft-polylactic acid copolymers (LG-g-PDLA, LG-g-PDLLA, and LG-g-PLLA) have been synthesized via ring-opening polymerization of d-, dl-, and l-lactic acid. Then poly(l-lactic acid)/lignin-graft-polylactic acid (PLLA/LG-g-PDLA, /LG-g-PDLLA, and /LG-g-PLLA) complex films have been prepared. The results showed that, compared with LG-g-PDLA and LG-g-PLLA, a small amount of LG-g-PDLA addition could improve the crystallization rate, reduce the glass transition temperature and cold crystallization temperature of PLLA due to the stereocomplex crystallites. The thermal stability, tensile strength and strain of the stereocomplex films were also enhanced. Moreover, the PLLA/LG-g-PDLA films have good ultraviolet resistance and excellent biocompatibility. This study provides a green approach to design advanced polylactic acid-based blends with renewable natural resources.

Antibacterial and hemostatic hydrogel via nanocomposite from cellulose nanofibers

Bacterial infection and uncontrolled bleeding are the major challenges facing the wound treatment. In order to solve these problems, we have devised a green nanocomposite hydrogel by introducing the aminated silver nanoparticles (Ag-NH2 NPs) and gelatin (G) to carboxylated cellulose nanofibers (CNF). Interpenetrating polymeric network (IPN) was formed by interaction of multicomponent, leading to the non-covalent (dynamic ionic bridges) crosslinked hydrogel CNF/G/Ag. The produced hydrogel dressing with 0.5 mg/mL Ag-NH2 NPs (CNF/G/Ag0.5) demonstrated stronger mechanical, self-recovery, antibacterial properties, satisfactory hemostatic performance, and appropriate balance of fluids on the wound bed (2093.9 g/m2 per day). More importantly, the wound healing model evaluation in vitro and in vivo of CNF/G/Ag0.5 showed an outstanding biocompatibility (∼100% infected cell viability) and wound healing efficacy (∼90% healed and 83.3% survival after 14 days). Our study paved a highly promising approach to improve the performance of cellulose-based hydrogel dressing and would also be useful for developing ideal skin wound dressings by other green materials.