Influence of the Debye length on the interaction of a small molecule-modified Au nanoparticle with a surface-bound bioreceptor
作者:Natalia Bukar、Sandy Shuo Zhao、David M. Charbonneau、Joelle N. Pelletier、Jean-Francois Masson
DOI:10.1039/c4cc01423e
日期:——
We report that a shorter Debye length and, as a consequence, decreased colloidal stability are required for the molecular interaction of folic acid-modified Au nanoparticles (Au NPs) to occur on a surface-bound receptor, human dihydrofolate reductase (hDHFR). The interaction measured using surface plasmon resonance (SPR) sensing was optimal in a phosphate buffer at pH 6 and ionic strength exceeding 300 mM. Under these conditions, the aggregation constant of the Au NPs was approximately 104 M−1 s−1 and the Debye length was below 1 nm, on the same length scale as the size of the folate anion (approximately 0.8 nm). Longer Debye lengths led to poorer SPR responses, revealing a reduced affinity of the folic acid-modified Au NPs for hDHFR. While high colloidal stability of Au NPs is desired in most applications, these conditions may hinder molecular interactions due to Debye lengths exceeding the size of the ligand and thus preventing close interactions with the surface-bound molecular receptor.
我们报告说,叶酸修饰的金纳米粒子(Au NPs)与表面结合的受体--人二氢叶酸还原酶(hDHFR)发生分子相互作用需要更短的德拜长度,因此胶体稳定性也会降低。在 pH 值为 6、离子强度超过 300 mM 的磷酸盐缓冲液中,利用表面等离子体共振(SPR)传感技术测量到的相互作用效果最佳。在这些条件下,Au NPs 的聚集常数约为 104 M-1 s-1,Debye 长度低于 1 nm,与叶酸阴离子的大小(约 0.8 nm)处于同一长度范围。德拜长度越长,SPR 反应越差,表明叶酸修饰的 Au NPs 对 hDHFR 的亲和力降低。虽然大多数应用都希望 Au NPs 具有较高的胶体稳定性,但由于 Debye 长度超过了配体的大小,这些条件可能会阻碍分子的相互作用,从而妨碍与表面结合的分子受体的密切相互作用。