Garcia-Sacristan Clara, Garcia Ricardo
Instituto de Ciencia de Materiales de Madrid, CSIC, c/ Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain.
Nanoscale. 2025 Jul 10;17(27):16476-16483. doi: 10.1039/d5nr01313e.
Collagen is the most abundant structural protein in mammals. Collagen in tissues is exposed to cross-linking processes such as glycation which might cause progressive tissue stiffening. Tissue stiffening might be considered a landmark of aging. Yet a quantitative characterization of the elastic modulus of collagen nanofibers under different cross-linking processes and stages is not available. Bimodal AFM was applied to generate time-lapsed maps of Young's modulus of type I collagen nanoribbons under two cross-linking processes associated, respectively, with the presence of ribose and glutaraldehyde in the solution. Elastic modulus maps were acquired for different incubation times (0, 30 min, 12 h, 24 h and 1 week). The experiments were performed in liquid. The Young's modulus showed an initial sharp increase after an incubation time of 30 min, from a few MPa (native) to 100 MPa. From then onwards we measured a monotonic increase until a saturation value of about 2 GPa was reached after one week. We did not observe a dependence on the elastic modulus evolution using ribose glutaraldehyde. The saturation value was very similar to that measured on dry collagen nanoribbons.
胶原蛋白是哺乳动物中含量最丰富的结构蛋白。组织中的胶原蛋白会经历诸如糖基化等交联过程，这可能导致组织逐渐硬化。组织硬化可被视为衰老的一个标志。然而，目前尚无关于不同交联过程和阶段下胶原纳米纤维弹性模量的定量表征。采用双峰原子力显微镜（Bimodal AFM）生成了I型胶原纳米带在两种交联过程下的杨氏模量的时间推移图，这两种交联过程分别与溶液中核糖和戊二醛的存在有关。针对不同的孵育时间（0、30分钟、12小时、24小时和1周）获取了弹性模量图。实验在液体中进行。孵育30分钟后，杨氏模量最初急剧增加，从几兆帕（天然状态）增加到100兆帕。从那时起，我们测量到其单调增加，直到一周后达到约2吉帕的饱和值。我们没有观察到弹性模量的演变对使用核糖或戊二醛有依赖性。该饱和值与在干燥胶原纳米带上测得的值非常相似。
