Gao Tingjuan, Lu Jinghui, Rothberg Lewis J
Department of Chemistry, Center for Future Health, University of Rochester, Rochester, New York 14627, USA.
Anal Chem. 2006 Sep 15;78(18):6622-7. doi: 10.1021/ac0609226.
We use reflectivity changes at an interface functionalized with molecular probes to detect label-free biomolecular binding. Attachment of the target molecules to the surface alters the effective thickness of an antireflective coating formed by thermal oxidation of a silicon wafer to remove destructive interference of the reflected waves. The thermal oxide thickness is adjusted for precise interference using electrostatic layer-by-layer self-assembly of polyelectrolytes to which the molecular probes can be bound covalently. Reflectivity increases of over a factor of 100 are observed for binding of 2.5 nm of streptavidin to biotinylated polyelectrolytes, considerably more sensitive than surface plasmon resonance detection. Theoretical modeling is in agreement with the experimentally observed reflectivity increases and suggests the sensitivity is at present limited by the roughness of the oxide.
我们利用在由分子探针功能化的界面处的反射率变化来检测无标记生物分子结合。目标分子附着到表面会改变通过硅晶片热氧化形成的抗反射涂层的有效厚度，以消除反射波的相消干涉。使用分子探针可以共价结合的聚电解质的静电逐层自组装来调节热氧化层厚度以实现精确干涉。对于2.5纳米链霉亲和素与生物素化聚电解质的结合，观察到反射率增加超过100倍，比表面等离子体共振检测灵敏得多。理论建模与实验观察到的反射率增加一致，并表明目前灵敏度受氧化物粗糙度限制。
