Stranski-Laboratorium, Department of Chemistry, TU Berlin, Strasse des 17. Juni 124, D-10623, Berlin, Germany.
Phys Chem Chem Phys. 2018 Jul 18;20(28):19082-19086. doi: 10.1039/c8cp02621a.
Atomic force microscopy (AFM) was used to determine the mechanical properties as the indentation modulus of native and crosslinked poly(l-lysine) (PLL)/hyaluronic acid (HA) multilayer films by static force measurements. The influence of the surrounding medium on the mechanical properties of the films after preparation is investigated. The indentation modulus of native and crosslinked film was measured at different pH values, ionic strengths and temperatures. The native HA/PLL films, which behave like a physical gel, show the highest values of the indentation modulus for an intermediate pH value and low ionic strength. Any changes in the pH or an increase in the ionic strength/temperature decreases the measured indentation modulus. In contrast, the crosslinked films show an increase by a factor of 80 in the indentation modulus but no response to changes in the pH, ionic strength or temperature; they behave like a chemical gel. The pH, ionic strength and temperature used in this work are close to the in vivo conditions and thus give a fundamental point of view on the nanomechanical response of the PLL/HA films. Furthermore, information about the mechanical properties can be used for the understanding and manipulation of cell adhesion.
原子力显微镜（AFM）被用于通过静电力测量来确定天然和交联聚（L-赖氨酸）（PLL）/透明质酸（HA）多层膜的机械性能作为压痕弹性模量。研究了制备后周围介质对膜机械性能的影响。在不同的 pH 值、离子强度和温度下测量了天然和交联膜的压痕弹性模量。天然的 HA/PLL 膜表现为物理凝胶，在中间 pH 值和低离子强度下表现出最高的压痕弹性模量值。任何 pH 值的变化或离子强度/温度的增加都会降低测量的压痕弹性模量。相比之下，交联膜的压痕弹性模量增加了 80 倍，但对 pH 值、离子强度或温度的变化没有响应；它们表现为化学凝胶。本工作中使用的 pH 值、离子强度和温度接近体内条件，因此为 PLL/HA 膜的纳米力学响应提供了基本的观点。此外，关于机械性能的信息可用于理解和操纵细胞黏附。
