Biomedical Materials Group, Institute of Pharmacy, Martin Luther University Halle-Wittenberg , Heinrich-Damerow-Strasse 4, 06120 Halle (Saale), Germany.
Langmuir. 2013 Nov 12;29(45):13853-64. doi: 10.1021/la4028157. Epub 2013 Oct 30.
Here, the layer-by-layer method was applied to assemble films from chitosan paired with either heparin or a semisynthetic cellulose sulfate (CS) that possessed a higher sulfation degree than heparin. Ion pairing was exploited during multilayer formation at pH 4, while hydrogen bonding is likely to occur at pH 9. Effects of polyanions and pH value during layer formation on multilayers properties were studied by surface plasmon resonance ("dry layer mass"), quartz crystal microbalance with dissipation monitoring ("wet layer mass"), water contact angle, and zeta potential measurements. Bioactivity of multilayers was studied regarding fibronectin adsorption and adhesion/proliferation of C2C12 myoblast cells. Layer growth and dry mass were higher for both polyanions at pH 4 when ion pairing occurred, while it decreased significantly with heparin at pH 9. By contrast, CS as polyanion resulted also in high layer growth and mass at pH 9, indicating a much stronger effect of hydrogen bonding between chitosan and CS. Water contact angle and zeta potential measurements indicated a more separated structure of multilayers from chitosan and heparin at pH 4, while CS led to a more fuzzy intermingled structure at both pH values. Cell behavior was highly dependent on pH during multilayer formation with heparin as polyanion and was closely related to fibronectin adsorption. By contrast, CS and chitosan did not show such dependency on pH value, where adhesion and growth of cells was high. Results of this study show that CS is an attractive candidate for multilayer formation that does not depend so strongly on pH during multilayer formation. In addition, such multilayer system also represents a good substrate for cell interactions despite the rather soft structure. As previous studies have shown specific interaction of CS with growth factors, multilayers from chitosan and CS may be of great interest for different biomedical applications.
在这里，采用层层自组装的方法将壳聚糖与肝素或半合成硫酸纤维素（CS）组装成膜，CS 的硫酸化程度比肝素高。在 pH 4 下，利用离子配对进行多层形成，而在 pH 9 下可能发生氢键作用。通过表面等离子体共振（“干层质量”）、石英晶体微天平耗散监测（“湿层质量”）、水接触角和zeta 电位测量研究了在层形成过程中多阴离子和 pH 值对多层性质的影响。研究了多层膜的生物活性，包括纤连蛋白的吸附以及 C2C12 成肌细胞的黏附和增殖。当发生离子配对时，两种多阴离子在 pH 4 下的层生长和干质量都更高，而在 pH 9 下肝素的层生长和干质量则显著降低。相比之下，CS 作为多阴离子，在 pH 9 下也导致了高的层生长和质量，这表明壳聚糖和 CS 之间氢键的作用更强。水接触角和 zeta 电位测量表明，在 pH 4 下，壳聚糖和肝素的多层膜具有更分离的结构，而 CS 则导致在两种 pH 值下都具有更模糊的交织结构。细胞行为在肝素作为多阴离子的多层形成过程中高度依赖 pH 值，并且与纤连蛋白的吸附密切相关。相比之下，CS 和壳聚糖在 pH 值下没有表现出这种依赖性，细胞的黏附和生长都很高。本研究结果表明，CS 是一种有吸引力的候选物，其在多层形成过程中对 pH 值的依赖性不那么强。此外，尽管结构较软，这种多层体系仍然是细胞相互作用的良好基质。由于先前的研究表明 CS 与生长因子具有特异性相互作用，因此壳聚糖和 CS 的多层膜可能在不同的生物医学应用中具有重要意义。
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