Polymers Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
Langmuir. 2010 Apr 6;26(7):4822-30. doi: 10.1021/la903581w.
The kinetics of nanoparticle (NP) adsorption on a model biological interface (collagen) is measured in microfluidic channels using surface plasmon resonance (SPR) imaging over a range of CdSe/ZnS quantum dot concentrations to investigate the underlying binding process. Spherical CdSe/ZnS core-shell NP, derivatized with 3-mercaptopropionic acid (3-MPA), were considered to be model NPs because of their widespread use in biological applications and their relatively monodisperse size. The kinetic adsorption data suggests that the binding between the NP and the collagen substrate is irreversible at room temperature (pH approximately 7.4), and this type of adsorption process was further characterized in the context of a surface absorption model. Specifically, diffusion-limited adsorption was found to predominate the adsorption process at lower concentrations (<0.4 micromol/L), and NP adsorption was reaction-limited at higher concentration (>0.4 micromol/L). A limited pH study of our system indicates that NPs desorb from collagen under acidic conditions (pH 5.5); no significant desorption was observed under neutral and basic pH conditions. These observations are consistent with electrostatic interactions being the dominant force governing NP desorption from collagen substrates. Our present methodology for characterizing the seemingly irreversible NP adsorption complements our earlier study where NP adsorption onto weakly adsorbing surfaces (self-assembled monolayers) was characterized by Langmuir NP adsorption measurements.
在微流控通道中使用表面等离子体共振（SPR）成像测量纳米粒子（NP）在模型生物界面（胶原蛋白）上的吸附动力学，研究了在一系列 CdSe/ZnS 量子点浓度下的基础结合过程。具有 3-巯基丙酸（3-MPA）官能化的球形 CdSe/ZnS 核壳 NP 因其在生物应用中的广泛使用及其相对单分散的尺寸而被认为是模型 NP。动力学吸附数据表明，NP 与胶原底物之间的结合在室温（pH 约为 7.4）下是不可逆的，这种吸附过程在表面吸收模型的背景下进一步得到了表征。具体来说，在较低浓度（<0.4 μmol/L）下，扩散限制吸附主导吸附过程，而在较高浓度（>0.4 μmol/L）下，NP 吸附受到反应限制。我们系统的有限 pH 研究表明，NP 在酸性条件（pH 5.5）下从胶原蛋白中解吸；在中性和碱性 pH 条件下，没有观察到明显的解吸。这些观察结果与静电相互作用是控制 NP 从胶原蛋白底物解吸的主要力一致。我们目前用于表征看似不可逆的 NP 吸附的方法补充了我们早期的研究，其中 NP 吸附到弱吸附表面（自组装单分子层）的吸附通过 Langmuir NP 吸附测量进行了表征。
