Fig. 1: Spectroscopic characterization and rheological behavior of Andro–Cu²⁺ coordination hydrogels.

A Raman spectra of Andro (black), Andro + NaCl (red), and Andro + CuCl₂ (blue). The Andro + CuCl₂ trace exhibits a new Cu–O coordination band at ~585 cm^-1 and attenuation of the 1725 cm^-1 (C=O) and 1675 cm^-1 (C=C) features; Andro + NaCl overlaps with pure Andro, confirming the specificity of Cu²⁺ coordination. B FTIR spectra of Matrix, ASFH-L, and ASFH-H hydrogels showing coordination-induced shifts. C–E Angular frequency scanning curves of matrix, ASFH-L, and ASFH-H hydrogels at 25 °C, showing storage modulus G’ and loss modulus G” as functions of angular frequency. F–H Temperature scanning curves of matrix, ASFH-L, and ASFH-H hydrogels.