Benefits and Limitations of Porous Substrates as Biosensors for Protein Adsorption
Benefits and Limitations of Porous Substrates as Biosensors for Protein Adsorption
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DOI：
10.1021/ac200725y
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发表时间：
2011-07-15
影响因子：
7.4
通讯作者：
Janshoff, Andreas
中科院分区：
文献类型：
--
作者：
Lazzara, Thomas D.;Mey, Ingo;Janshoff, Andreas
多孔基底在基于分子识别的生物传感器应用中获得了广泛的关注。因此，有一个很大的需求，系统地调查的参数，限制运输的分子朝向和内的多孔基质作为一个功能的孔几何形状。利用有限元模拟和时间分辨光波导光谱实验系统地研究了分子在多孔材料内表面的输运和结合过程。OWS使我们能够测量多孔阳极氧化铝膜内的蛋白质吸附的动力学组成的平行排列，孔半径为10-40 nm和孔深度为0.8-9.6 μ m的圆柱形孔。FES表明，在多孔基质的内表面上的蛋白质吸附几乎完全取决于进入孔的通量。孔内表面几乎充当大分子的完美汇。孔内扩散和表面吸附都不是速率限制步骤，除了非常低的吸附速率常数。虽然孔壁上的吸附主要由进入孔的固定通量决定，但从孔壁内解吸涉及解吸和吸附的速率常数，基本上代表蛋白质表面相互作用势。FES捕获OWS实验的基本特征，如吸附动力学的初始线性斜率，其与孔深度成反比，与蛋白质浓度成线性比例。我们表明，蛋白质吸附动力学允许蛋白质浓度的准确测定，而解吸动力学可用于捕获的大分子与孔壁的相互作用潜力。
Porous substrates have gained widespread interest for biosensor applications based on molecular recognition. Thus, there is a great demand to systematically investigate the parameters that limit the transport of molecules toward and within the porous matrix as a function of pore geometry. Finite element simulations (FES) and time-resolved optical waveguide spectroscopy (OWS) experiments were used to systematically study the transport of molecules and their binding on ism the inner surface of a porous material. OWS allowed us to measure the kinetics of protein adsorption within porous anodic aluminum oxide membranes composed of parallel-aligned, cylindrical pores with pore radii of 10-40 nm and pore depths of 0.8-9.6 mu m. FES showed that protein adsorption on the inner surface of a porous matrix is almost exclusively governed by the flux into the pores. The pore-interior surface nearly acts as a perfect sink for the macromolecules. Neither diffusion within the pores nor adsorption on the surface are rate limiting steps, except for very low rate constants of adsorption. While adsorption on the pore walls is mainly governed by the stationary flux into the pores, desorption from the inner pore walls involves the rate constants of desorption and adsorption, essentially representing the protein surface interaction potential. FES captured the essential features of the OWS experiments such as the initial linear slopes of the adsorption kinetics, which are inversely proportional to the pore depth and linearly proportional to protein concentration. We show that protein adsorption kinetics allows for an accurate determination of protein concentration, while desorption kinetics could be used to capture the interaction potential of the macromolecules with the pore walls.