The Ch-8Q/PLA mats and their complexes, PLA and Ch/PLA mats were screened for in vitro antibacterial activity against bacteria S. aureus 749 using the viable cell-counting method. Each of the fibrous mats was sterilized by UV irradiation for 30 min and then was added into a suspension of the bacteria (5 mL containing 105 cells/mL). Then the suspension was stirred and incubated at 37 °C. At predetermined time points, 1 mL samples were removed from each tube and serially diluted 10-fold with sterile phosphate-buffered saline (PBS). Finally, the surviving bacteria were counted using the spread-plate method. Triplicate counting was done for each experiment. The number of surviving cells was determined as colony-forming unit (CFU).
The adhesion of bacteria S. aureus 749 on the surface of the Ch-8Q/PLA mats and their complexes, and PLA and Ch/PLA mats was assessed using SEM observation with a Jeol JSM-5510 SEM spectrometer (Jeol Ltd., Tokyo, Japan). Mats were incubated in 3 mL of S. aureus culture (containing about 107 cells/mL) at 37 °C for 24 h. After incubation, the mats were washed with PBS and then immersed in 2.5 vol.% glutaraldehyde solution in PBS at 4 °C for 5 h. Finally, the mats were washed with PBS, freeze-dried, coated with gold with Jeol JFC-1200 fine coater and studied by a Jeol JSM-5510 SEM spectrometer (Tokyo, Japan).
The adhesion of bacteria S. aureus 749 on the surface of the Ch-8Q/PLA mats and their complexes, and PLA and Ch/PLA mats was assessed using SEM observation with a Jeol JSM-5510 SEM spectrometer (Jeol Ltd., Tokyo, Japan). Mats were incubated in 3 mL of S. aureus culture (containing about 107 cells/mL) at 37 °C for 24 h. After incubation, the mats were washed with PBS and then immersed in 2.5 vol.% glutaraldehyde solution in PBS at 4 °C for 5 h. Finally, the mats were washed with PBS, freeze-dried, coated with gold with Jeol JFC-1200 fine coater and studied by a Jeol JSM-5510 SEM spectrometer (Tokyo, Japan).