Lyon L A, Musick M D, Natan M J
Department of Chemistry, Pennsylvania State University, University Park 16802, USA.
Anal Chem. 1998 Dec 15;70(24):5177-83. doi: 10.1021/ac9809940.
Surface plasmon resonance (SPR) biosensing using colloidal Au enhancement is reported. Immobilization of approximately 11-nm-diameter colloidal Au to an evaporated Au film results in a large shift in plasmon angle, a broadened plasmon resonance, and an increase in minimum reflectance. The incorporation of colloidal Au into SPR biosensing results in increased SPR sensitivity to protein-protein interactions when a Au film-immobilized antibody and an antigen-colloidal Au conjugate comprise the binding pair. A highly specific particle-enhanced analogue of a sandwich immunoassay is also demonstrated by complexing the Au particle to a secondary antibody. A tremendous signal amplification is observed, as addition of the antibody-Au colloid conjugate results in a 25-fold larger signal than that due to addition of a free antibody solution that is 6 orders of magnitude more concentrated. Picomolar detection of human immunoglobulin G has been realized using particle enhancement, with the theoretical limits for the technique being much lower. Finally, a quasi-linear relationship between particle coverage and plasmon angle shift is presented, thereby providing for a direct correlation between plasmon shift and solution antigen concentration. Together, these results represent significant advances in the generality and sensitivity of SPR as it is applied to biosensing.
报道了使用胶体金增强的表面等离子体共振（SPR）生物传感。将直径约11纳米的胶体金固定到蒸发的金膜上会导致等离子体角度发生大的偏移、等离子体共振变宽以及最小反射率增加。当金膜固定抗体和抗原 - 胶体金缀合物组成结合对时，将胶体金纳入SPR生物传感会提高SPR对蛋白质 - 蛋白质相互作用的灵敏度。通过将金颗粒与二抗络合，还展示了一种高度特异性的颗粒增强夹心免疫测定类似物。观察到巨大的信号放大，因为添加抗体 - 金胶体缀合物产生的信号比添加浓度高6个数量级的游离抗体溶液产生的信号大25倍。使用颗粒增强实现了皮摩尔级人免疫球蛋白G的检测，该技术的理论极限要低得多。最后，给出了颗粒覆盖率与等离子体角度偏移之间的准线性关系，从而提供了等离子体偏移与溶液抗原浓度之间的直接相关性。总之，这些结果代表了SPR应用于生物传感时在通用性和灵敏度方面的重大进展。
