van der Mei Henny C, Engels Eefje, de Vries Joop, Dijkstra Rene J B, Busscher Henk J
Department of Biomedical Engineering, University Medical Center Groningen and University of Groningen, 9700 AD Groningen, The Netherlands.
Eur J Oral Sci. 2007 Aug;115(4):303-7. doi: 10.1111/j.1600-0722.2007.00454.x.
The salivary pellicle is a negatively charged protein film, to which oral bacteria readily adhere. Chitosans are cationic biomolecules with known antimicrobial properties that can be modified in different ways to enhance its antimicrobial activity. Here, we determined the changes in surface chemical composition using X-ray photoelectron spectroscopy (XPS), in hydrophobicity by analyzing water contact angles, in charge through measuring streaming potentials, and evaluated morphology using atomic force microscopy (AFM), of salivary pellicles upon adsorption of different chitosans. The adsorption of chitosans to pellicles was chemically evident from altered carbon functionalities and the presence of an N(1s) peak at 401.1 eV as a result of protonated amines in XPS. Chitosan adsorption made the pellicle (zeta potential of untreated pellicles 29 mV) positively charged and more hydrophobic. A chemically modified chitosan (CL) and an unmodified chitosan (UC) caused aggregation of adsorbed salivary proteins, and AFM revealed clumps of protein after treatment with these chitosans, yielding an increase in pellicle surface roughness from 5.1 nm to between 16.3 and 35.6 nm for CL and UC, respectively. In summary, chitosans have a clear tendency to adsorb to salivary pellicles with a profound effect on the surface properties of the pellicle. Therefore, chitosans may provide anchoring molecules to affix antimicrobials to pellicle surfaces.
唾液薄膜是一种带负电荷的蛋白质膜，口腔细菌很容易附着其上。壳聚糖是具有已知抗菌特性的阳离子生物分子，可以通过不同方式进行修饰以增强其抗菌活性。在此，我们使用X射线光电子能谱（XPS）测定了不同壳聚糖吸附后唾液薄膜的表面化学成分变化，通过分析水接触角测定了其疏水性变化，通过测量流动电位测定了其电荷变化，并使用原子力显微镜（AFM）评估了其形态。壳聚糖吸附到薄膜上在化学上表现为碳官能团的改变以及XPS中由于质子化胺导致的401.1 eV处N(1s)峰的出现。壳聚糖的吸附使薄膜（未处理薄膜的ζ电位为29 mV）带正电荷且更疏水。一种化学修饰的壳聚糖（CL）和一种未修饰的壳聚糖（UC）导致吸附的唾液蛋白聚集，AFM显示用这些壳聚糖处理后有蛋白团块，CL和UC处理后薄膜表面粗糙度分别从5.1 nm增加到16.3至35.6 nm之间。总之，壳聚糖具有明显吸附到唾液薄膜上的倾向，对薄膜的表面性质有深远影响。因此，壳聚糖可能提供锚定分子，将抗菌剂固定在薄膜表面。
