Department of Pharmaceutical Technology and Biopharmacy, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
Biotechnol Appl Biochem. 2011 Sep-Oct;58(5):376-89. doi: 10.1002/bab.41. Epub 2011 Sep 20.
Hyaluronic acid (HA) was chemically modified either by oxidation to obtain aldehyde-HA (aHA) or 3,3'-dithiobis(propanoic hydrazide) to obtain thiol-HA (tHA) that was covalently immobilized on model substrata such as amino-terminated surfaces or gold. Knowledge about the effect of modification with HA on physicochemical surface properties of these substrata and estimates of the quantities of immobilized HA were obtained by different physical methods such as contact angle measurements, ellipsometry, and atomic force microscopy. The bioactivity of aHA and tHA toward their natural binding partner aggrecan was studied by comparing surface plasmon resonance to native HA; this shows that binding of aggrecan was achieved in a similar way. Dermal human fibroblasts were used as a model cell to study how chemical modification and immobilization of HA impact adhesion and spreading of cells, which also affects cell growth and differentiation. A lower number and spreading of cells were observed on HA-modified surfaces compared to amino- and vinyl-terminated glass and silicon surfaces. Immunofluorescence microscopy also revealed that adhesion of fibroblast plated on HA-modified surfaces was mediated primarily by HA receptor CD44, indicating that bioactivity of HA was not significantly reduced by chemical modification.
透明质酸（HA）通过化学修饰，要么被氧化得到醛基-HA（aHA），要么与 3,3'-二硫代双（丙酰基）肼反应得到巯基-HA（tHA），然后将其共价固定在模型底物上，如氨基末端表面或金表面。通过接触角测量、椭圆光度法和原子力显微镜等不同物理方法，可以获得关于 HA 修饰对这些底物物理化学表面性质的影响以及固定化 HA 量的估计。通过比较表面等离子体共振与天然 HA，研究了 aHA 和 tHA 对其天然结合伴侣聚集蛋白聚糖的生物活性；这表明聚集蛋白聚糖的结合方式相似。用人真皮成纤维细胞作为模型细胞，研究了 HA 的化学修饰和固定化如何影响细胞的黏附和铺展，这也会影响细胞的生长和分化。与氨基和乙烯基末端玻璃和硅表面相比，在 HA 修饰的表面上观察到细胞数量减少且铺展程度较低。免疫荧光显微镜还揭示了在 HA 修饰表面上培养的成纤维细胞的黏附主要是通过 HA 受体 CD44 介导的，这表明 HA 的生物活性没有因化学修饰而显著降低。
