da Silva Rafael L C G, Ando Rômulo Augusto, Petri Denise F S
Fundamental Chemistry Department, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, São Paulo 05508-000, Brazil.
Gels. 2025 Jun 26;11(7):496. doi: 10.3390/gels11070496.
The mechanical properties of cell scaffolds are strongly influenced by their hydration state. In this study, we investigated the effect of the aqueous phase on the elastic modulus of chitosan hydrogel films using two complementary techniques: uniaxial tensile testing and atomic force microscopy (AFM) nanoindentation. Our results demonstrate that hydration markedly reduced the elastic modulus, decreasing from approximately 2 GPa in dry films to 120 kPa in swollen films, primarily due to the plasticizing effect of water. Moreover, hydrogel films in equilibrium with the aqueous phase exhibited a Young's modulus three times lower than that of swollen films not in equilibrium. Raman spectroscopy further reveals a solvent "squeeze-out" phenomenon, as evidenced by an increased signal intensity in the 850-1200 cm region for stretched films that were out of swelling equilibrium, whereas equilibrated films showed stable spectral features. These findings highlight the crucial role of hydration dynamics in determining the mechanical behavior of chitosan hydrogel films, offering valuable insights for tailoring their properties in biomedical scaffold applications.
细胞支架的力学性能受其水化状态的影响很大。在本研究中，我们使用两种互补技术研究了水相对壳聚糖水凝胶膜弹性模量的影响：单轴拉伸试验和原子力显微镜（AFM）纳米压痕。我们的结果表明，水化显著降低了弹性模量，从干膜中的约2 GPa降至溶胀膜中的120 kPa，主要是由于水的增塑作用。此外，与水相处于平衡状态的水凝胶膜的杨氏模量比未处于平衡状态的溶胀膜低三倍。拉曼光谱进一步揭示了溶剂“挤出”现象，对于处于溶胀平衡之外的拉伸膜，在850-1200 cm区域的信号强度增加证明了这一点，而处于平衡状态的膜显示出稳定的光谱特征。这些发现突出了水化动力学在决定壳聚糖水凝胶膜力学行为中的关键作用，为在生物医学支架应用中定制其性能提供了有价值的见解。
