离子强度对胶原与4-硫酸软骨素间相互作用的影响

胶原与硫酸较骨素(CS)间相互作用力的研究具有重要的生理意义和病理意义,采用差示扫描量热法(DSC)和二维红外分析(2DIR)研究离子强度对胶原与4-硫酸软骨素(CSA)间相互作用力的影响。DSC结果表明:相同胶原/CSA质量比下,共混物热稳定性随着离子强度的增加而降低;相同离子强度下,共混物热稳定性随着CSA量的增加而增强。2DIR结果表明:CSA含量小于50%时,离子强度影响胶原与CSA间相互作用的强度和种类;离子强度为0.2mol/kg时,胶原分子与CSA间存在氢键作用和静电相互作用;进一步增加离子强度,胶原分子带正电荷的基团与CSA离子化的硫酸根基团和竣酸根基团间的静电作用消失,仅存在胶原分子与CSA间的氢键作用。CSA含量大于50%时,离子强度仅影响胶原分子与CSA间相互作用的强度;离子强度增至0.3-0.4mol/kg时,胶原分子与CSA间均存在静电作用及氢键作用。随着溶液离子强度的增加,胶原与CSA间相互作用的强度均随之减弱。

Effect of ionic strength on molecular interactions between collagen and 4-chondroitin sulfate

The nature of interactions occurring between collagen and chondroitin sulfate (CS) bears great physiologic and pathologic importance.Differential scanning calorimeter (DSC) and two-dimensional infrared correlation analysis (2D IR) were applied to study the influence of ionic strength on the molecular interactions between collagen and 4-chondroitin sulfate (CSA) and the thermal stability of composite biomaterials.DSC results show that the thermal stability of composite biomaterials decreases with the increase of ionic strength at the same collagen/CSA weight ratio,however,the thermal stability under the same ionic strength is improved obviously as a result of blending with CSA and the in crease degree is dose dependent.2D IR results show that when CSA content is less than 50 wt%,the kinds and intensity of the interactions between collagen and CSA are influenced by ionic strength.When ionic strength falls to 0.2 mol/kg,the electrostatic interactions between ionized carboxyl group or sulfate group of CSA and e-amino group of lysine or guanidine group of arginine of collagen appears.With the increase of ionic strength,this kinds of e? lectrostatic interaction disappears and only hydroxyl group of CSA interact with C =0 group of collagen.When CSA content is more than 50 wt%,only the intensity of interactions between collagen and CSA is influenced by ionic strength.When ionic strength ranges from 0.3~ 0.4 mol/kg,both electrostatic interaction and hydrogen bond exists with the increase of ionic strength.With the increase of ionic strength,the intensity of interactions between collagen and CSA is weakened.