Institute of Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Langmuir. 2011 Oct 18;27(20):12458-65. doi: 10.1021/la202616u. Epub 2011 Sep 22.
Charged polymer brushes grafted to surfaces are of great interest for antibacterial, biosensor, nanofluidic, and drug delivery applications. In this paper, chitosans with quaternary ammonium salts, CH-Q, were immobilized on silicon oxide and characterized by in situ quartz-crystal microbalance with dissipation, QCM-D, and in situ spectroscopic ellipsometry, SE. Both methods showed that the hydrated film exhibited a minimum thickness of ~40 nm near pH 5 that increased strongly (up to ~80 nm) at lower and higher pH. This symmetric swelling is surprising because CH-Q is a cationic polymer. The CH-Q grafted layer was stable for pH values from 3 to 8 and exhibited rapid, reversible swelling and contraction upon varying pH. The CH-Q layer also reduced S. aureus colonization by a factor of ~30× compared to bare silicon oxide and an amine terminated silane grafted to silicon oxide. This antibacterial characteristic of CH-Q is attributed to the quaternary ammonium salts and the flexible polymer brush.
带电荷的聚合物刷接枝到表面对于抗菌、生物传感器、纳流控和药物输送等应用具有重要意义。在本文中，季铵盐化壳聚糖（CH-Q）被固定在氧化硅表面，并通过原位石英晶体微天平（QCM-D）和原位椭圆光谱法（SE）进行了表征。这两种方法都表明，在 pH 值约为 5 时，水合膜的最小厚度约为 40nm，在较低和较高的 pH 值下，水合膜的厚度会强烈增加（高达约 80nm）。这种对称的溶胀是令人惊讶的，因为 CH-Q 是一种阳离子聚合物。CH-Q 接枝层在 pH 值为 3 到 8 之间稳定，并在 pH 值变化时表现出快速、可逆的溶胀和收缩。与裸氧化硅和接枝到氧化硅上的胺基封端硅烷相比，CH-Q 层还将金黄色葡萄球菌的定植减少了约 30 倍。CH-Q 的这种抗菌特性归因于季铵盐和柔性聚合物刷。
