Enhancing Antimicrobial Performance of Gauze via Modification by Ag-Loaded Polydopamine Submicron Particles.

Silver nanoparticles (AgNPs) are known for their antibacterial properties and their ability to promote wound healing. By incorporating silver nanoparticles into medical gauze, the resulting composite material shows promise as an advanced wound dressing. However, clinical applications are hindered by challenges related to the stability of silver nanoparticle loading on the gauze as nanoparticle leaching can compromise antibacterial efficacy. In this study, silver nanoparticles were immobilized onto polydopamine (PDA) submicron particles, which were then used to modify medical gauze. Energy dispersive spectroscopy (EDS) was employed to analyze the elemental distribution on the modified gauze, confirming successful surface modification. The antibacterial properties of the modified gauze were assessed using a laser scanning confocal microscope (CLSM). The results demonstrated a significant reduction in the adhesion rates of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) by 99.1% and 63%, respectively, on the PDA-Ag-modified gauze. Optical density (OD) measurements at 590 nm indicated that the modified gauze effectively inhibited biofilm formation, underscoring its potent antimicrobial capabilities. Further antibacterial efficacy was evaluated by diluting and plating co-cultured bacterial solutions with the modified dressing, followed by 24 h incubation and colony counting. The gauze exhibited an antibacterial efficiency of 99.99% against E. coli and 99.8% against S. aureus. Additionally, cell compatibility tests, involving the co-culture of PDA-Ag composites with human cells, demonstrated excellent biocompatibility. These findings suggest that PDA-Ag-modified medical gauze holds significant potential for the treatment of infected wounds, offering a promising solution to improve wound care through enhanced antimicrobial activity and biocompatibility.

In vitro enzymatic hydrolysis of amylopectins from rice starches.

The effects of the molecular structures of amylopectins on the enzymatic hydrolysis of waxy-rice amylopectin (WRA) and normal-rice amylopectin (NRA) were investigated. The results indicated that compared to NRA, WRA possessed larger chain length, number of chains, internal chain length, degree of polymerisation, interblock chain length, and lower degree of branching and short:long B-chains, which caused WRA was much less susceptible to enzymatic hydrolysis than NRA. The digestibility curves for WRA and NRA were well fitted by the first-order kinetic equation. WRA and NRA were hydrolyzed in two separates phases in the LOS plots. Whether using α-amylase alone, or together with amyloglucosidase, WRA and NRA exhibited different digestibility rates due to different chain structure of amylopectin. The low C1∞ values predicted that WRA and NRA would have little impact on blood glucose concentrations in the early digestion stage. HPLC results showed that G1∼G5 from WRA using α-amylase were lower than that from NRA, whereas from WRA were higher than that from NRA. There was the synergism between α-amylase and amyloglucosidase in glucose released from WRA and NRA.