Kujda Marta, Adamczyk Zbigniew, Morga Maria, Sofińska Kamila
J Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, Cracow, 30-239 Poland.
J Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, Cracow, 30-239 Poland.
Colloids Surf B Biointerfaces. 2015 Mar 1;127:192-9. doi: 10.1016/j.colsurfb.2015.01.033. Epub 2015 Jan 28.
Recombinant human serum albumin (rHSA) in monomeric state is widely used in pharmaceutical industry as a drug excipient and for preparing coatings for medical devices. In this work the adsorption process of rHSA on model mica surface at pH 3.5 was studied using the atomic force microscopy (AFM) and in situ streaming potential measurements. The kinetics of albumin adsorption was determined by a direct enumeration of single molecules over various substrate areas. These results were consistent with streaming potential measurements carried out for the parallel-plate channel flow and with theoretical predictions derived from the random sequential adsorption (RSA) model. Desorption kinetics of albumin under flow conditions was also evaluated via the streaming potential measurements. In this way, the amount of irreversibly bound albumin was quantitatively evaluated to be 0.64 and 1.2 mg m(-2) for ionic strength of 0.01 and 0.15 M, respectively. This agrees with previous results obtained for HSA and theoretical calculations derived from the RSA model. Additionally, it was demonstrated that there existed a fraction of reversibly bound albumin that can be fully eluted within a few hours. The binding energy of these fraction of molecules was -18 kT that is consistent with the electrostatic controlled adsorption mechanism of albumin at this pH. It was concluded that the rHSA monolayers of well-defined coverage can find applications for quantitatively analyzing ligand binding and for performing efficient biomaterials and immunological tests.
单体状态的重组人血清白蛋白（rHSA）在制药行业中广泛用作药物赋形剂，并用于制备医疗器械涂层。在这项工作中，使用原子力显微镜（AFM）和原位流动电势测量研究了rHSA在pH 3.5的模型云母表面上的吸附过程。白蛋白吸附动力学通过对不同基底区域的单分子进行直接计数来确定。这些结果与平行板通道流动的流动电势测量以及随机顺序吸附（RSA）模型的理论预测一致。还通过流动电势测量评估了流动条件下白蛋白的解吸动力学。通过这种方式，对于离子强度为0.01和0.15 M，不可逆结合的白蛋白量分别定量评估为0.64和1.2 mg m(-2)。这与先前获得的HSA结果以及RSA模型的理论计算结果一致。此外，还证明存在一部分可逆结合的白蛋白，其可以在几小时内完全洗脱。这些分子部分的结合能为-18 kT，这与该pH下白蛋白的静电控制吸附机制一致。得出的结论是，具有明确覆盖率的rHSA单分子层可用于定量分析配体结合以及进行高效的生物材料和免疫测试。
