Sensitive detection of protein and miRNA cancer biomarkers using silicon-based photonic crystals and a resonance coupling laser scanning platform.
Sensitive detection of protein and miRNA cancer biomarkers using silicon-based photonic crystals and a resonance coupling laser scanning platform.
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DOI：
10.1039/c3lc50579k
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发表时间：
2013-10-21
期刊：
影响因子：
6.1
通讯作者：
Cunningham BT
中科院分区：
文献类型：
--
作者：
George S;Chaudhery V;Lu M;Takagi M;Amro N;Pokhriyal A;Tan Y;Ferreira P;Cunningham BT
通过在纳米结构光子晶体 (PC) 表面上进行基于表面的荧光测定来增强荧光输出已被证明可以将信号强度增加 >8000 倍。利用与 PC 的光学共振耦合的乘法效应来增加荧光标记所经历的电场强度（“增强激发”）以及通过与 PC 共振耦合而产生的荧光团发射的空间偏置漏斗（“增强提取”），PC 增强荧光（PCEF）可用于降低疾病生物标志物测定的检测限，并减少高灵敏度检测仪器的尺寸和成本。在这项工作中，我们展示了第一个用于多重生物标志物测定的硅基 PCEF 检测平台。该平台中的传感器是硅基PC结构，由覆盖有高折射率TiO2薄膜的SiO2光栅组成，并在半导体铸造厂中生产，以实现低成本、均匀且可重复的制造。构成该平台的紧凑型检测仪器旨在有效地将半导体激光器的荧光激发耦合到 PC 的谐振光学模式，从而提高电场强度，该电场强度高度集中在距离 PC 表面 <100 nm 的区域内。该仪器利用圆柱形聚焦线在 1 分钟内扫描微阵列。为了证明该传感器-检测器平台的功能，使用 Cy5 标记的二抗对两种癌症生物标志物（TNF-α 和 IL-3）进行了微点荧光夹心免疫测定。检测到的生物标志物浓度低至 0.1 pM。在用于检测乳腺癌 miRNA 生物标志物 miR-21 的荧光微阵列中，可检测浓度为 0.6 pM 的 miRNA。
Enhancement of the fluorescent output of surface-based fluorescence assays by performing them upon nanostructured photonic crystal (PC) surfaces has been demonstrated to increase signal intensities by >8000×. Using the multiplicative effects of optical resonant coupling to the PC in increasing the electric field intensity experienced by fluorescent labels (“enhanced excitation”) and the spatially biased funneling of fluorophore emissions through coupling to PC resonances (“enhanced extraction”), PC enhanced fluorescence (PCEF) can be adapted to reduce the limits of detection of disease biomarker assays, and to reduce the size and cost of high sensitivity detection instrumentation. In this work, we demonstrate the first silicon-based PCEF detection platform for multiplexed biomarker assay. The sensor in this platform is a silicon-based PC structure, comprised of a SiO2 grating that is overcoated with a thin film of high refractive index TiO2 and is produced in a semiconductor foundry for low cost, uniform, and reproducible manufacturing. The compact detection instrument that completes this platform was designed to efficiently couples fluorescence excitation from a semiconductor laser to the resonant optical modes of the PC, resulting in elevated electric field strength that is highly concentrated within the region <100 nm from the PC surface. This instrument utilizes a cylindrically focused line to scan a microarray in <1 minute. To demonstrate the capabilities of this sensor-detector platform, microspot fluorescent sandwich immunoassays using secondary antibodies labeled with Cy5 for two cancer biomarkers (TNF-α and IL-3) were performed. Biomarkers were detected at concentrations as low as 0.1 pM. In a fluorescent microarray for detection of a breast cancer miRNA biomarker miR-21, the miRNA was detectable at a concentration of 0.6 pM.