Department of Biomedical Engineering, Georgia Institute of Technology , 950 Atlantic Drive NW, Atlanta, Georgia 30332, United States.
Anal Chem. 2017 Dec 19;89(24):13596-13602. doi: 10.1021/acs.analchem.7b04105. Epub 2017 Dec 1.
Quantitative analysis of biomolecular adsorption on a substrate is crucial for understanding biomolecular interactions. A quartz crystal microbalance (QCM) is a highly sensitive device to detect such interactions based on mass. However, the physicochemical analysis by the QCM alone often leads to overestimation of the actual adsorbed mass. Here, a combined reflectometric interference spectroscopy (RIfS) and QCM is developed to simultaneously analyze adsorption of biomolecules. RIfS detects the adsorbed mass based on the reflectance and predicts the adsorbed condition by modeling the reflection spectra using the transfer matrix method. In contrast, the QCM detects physicochemical characteristics of the adsorbed molecules along with the adsorbed mass. The combined RIfS-QCM successfully detected the adsorption of proteins with different surface properties and lipid vesicles with different phase transition temperatures. The initial stage of adsorption revealed distinct individual properties of the adsorbates. Moreover, the RIfS-QCM revealed differential adsorption of the vesicles on silicon dioxide, titania, and gold surfaces, and the differences in adsorption were further interrogated by atomic force microscopy. The results demonstrate that the RIfS-QCM serves as a useful tool to quantitatively analyze molecular adsorption on various surfaces.
对生物分子在基底上的吸附进行定量分析对于理解生物分子相互作用至关重要。石英晶体微天平（QCM）是一种基于质量高度灵敏的检测此类相互作用的设备。然而，QCM 的物理化学分析往往导致实际吸附质量的高估。在这里，开发了一种组合反射干涉光谱（RIfS）和 QCM 来同时分析生物分子的吸附。RIfS 基于反射率检测吸附质量，并通过使用转移矩阵方法对反射光谱进行建模来预测吸附状态。相比之下，QCM 检测吸附分子的物理化学特性以及吸附质量。组合的 RIfS-QCM 成功地检测到具有不同表面性质的蛋白质和具有不同相变温度的脂质囊泡的吸附。吸附的初始阶段揭示了吸附物的独特个体特性。此外，RIfS-QCM 揭示了囊泡在二氧化硅、二氧化钛和金表面上的差异吸附，并且通过原子力显微镜进一步探究了吸附的差异。结果表明，RIfS-QCM 可作为一种有用的工具，用于定量分析各种表面上的分子吸附。
