Label-Free Detection of Single Protein Using a Nanoplasmonic-Photonic Hybrid Microcavity
Label-Free Detection of Single Protein Using a Nanoplasmonic-Photonic Hybrid Microcavity
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DOI：
10.1021/nl401633y
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发表时间：
2013-07-01
期刊：
影响因子：
10.8
通讯作者：
Arnold, Stephen
中科院分区：
文献类型：
--
作者：
Dantham, Venkata R.;Holler, Stephen;Arnold, Stephen
最近，我们报道了最小的RNA病毒MS 2的检测和大小的质量为6 ag的回音壁模式纳米壳混合谐振器（WGM-h）的共振频率偏移吸附在纳米壳上，并预计，单一的蛋白质以上0.4 ag应该是可检测的，但具有相当小的信号。在这里，我们报告检测单个甲状腺癌标志物（甲状腺球蛋白，Tg）和牛血清白蛋白（BSA）蛋白质的质量只有1 ag和0.11 ag（66 kDa），分别。然而，波长偏移增强超出了我们早期工作中预期的Tg和BSA分别为240%和1500%。这种令人惊讶的灵敏度被追踪到我们的Au纳米壳受体表面附近的短程反应场，这是由于蛋白质大小的内在随机凸起，导致对单个蛋白质的灵敏度意外增加，随着蛋白质大小的减小，单个蛋白质变得更大。由于我们的BSA实验中最大的信噪比（S/N近似为13），我们保守地估计我们的WGM-h的新蛋白质检测限为5 kDa。
Recently we reported the detection and sizing of the smallest RNA virus MS2 with a mass of 6 ag from the resonance frequency shift of a whispering gallery mode-nanoshell hybrid resonator (WGM-h) upon adsorption on the nanoshell and anticipated that single protein above 0.4 ag should be detectable but with considerably smaller signals. Here, we report the detection of single thyroid cancer marker (Thyroglobulin, Tg) and bovine serum albumin (BSA) proteins with masses of only 1 ag and 0.11 ag (66 kDa), respectively. However, the wavelength shifts are enhanced beyond those anticipated in our earlier work by 240% for Tg and 1500% for BSA. This surprising sensitivity is traced to a short-range reactive field near the surface of our Au nanoshell receptor due to intrinsic random bumps of protein size, leading to an unanticipated increase in sensitivity to single protein, which grows larger as the protein diminishes in size. As a consequence of the largest signal-to-noise ratio in our BSA experiments (S/N approximate to 13), we conservatively estimated a new protein limit of detection for our WGM-h of 5 kDa.