“…The pristine SF exhibited characteristic peaks at 3300 cm⁻ 1 (-NH stretching group), 1636 cm⁻ 1 (amide I), 1556 cm⁻ 1 (amide II), and 1232 cm⁻ 1 (amide III) [42]. SF crosslinked with EDC-NHS (ENSF) showed a strong peak at 1716 cm⁻ 1 , an amide group that confirms chemical crosslinking between the carboxyl group of SF and the amine group of EDC [43]. The 0.3% GG/3.7% SF/CS, 0.5% GG/3.5% SF/CS, 0.75% GG/3.25% SF/CS, and 1% GG/3% SF/CS hydrogels displayed characteristic peaks at 3302 cm⁻ 1 , 3302 cm⁻ 1 , 3306 cm⁻ 1 , and 3303 cm⁻ 1 (-OH and -NH stretching); 1634 cm⁻ 1 , 1634 cm⁻ 1 , 1633 cm⁻ 1 , and 1634 cm⁻ 1 (amide I); 1557 cm⁻ 1 , 1557 cm⁻ 1 , 1563 cm⁻ 1 , and 1563 cm⁻ 1 (amide II); 1221 cm⁻ 1 , 1227 cm⁻ 1 , 1229 cm⁻ 1 , and 1226 cm⁻ 1 (amide III); and 1026 cm⁻ 1 , 1030 cm⁻ 1 , 1029 cm⁻ 1 , and 1029 cm⁻ 1 (-COC stretching).…”