Sandwich structure composite wound dressing fabrication

One side of CSNWF/AgNPs was sprayed with 10 ml of water and then frozen at −80°C for 0.5 h. Afterward, the homogeneous CS/COL mixture (10 ml) was immediately sprayed on the side of CSNWF/AgNPs which was sprayed with water and then frozen 1 h under −80°C. After lyophilization, the CS/COL sponge combined CSNWF/AgNPs matrix was obtained. Finally, the sandwich structure composite wound dressing was prepared by adhering to the CSNWF/AgNPs-CS/COL matrix to a medical PU membrane.