Surface-enhanced Raman scattering (SERS) substrates with multiwavelength rainbow-trapping properties hold the potential for a one-size-fits-all platform for rapid and multiplexed disease detection. We present the first report on the utilization of rainbow-trapping width-graded nano-gratings, a new class of chirped metamaterials, to detect protein biomarkers. Using cytochrome c (Cc), a charged analyte with inherent difficulty in adsorbing onto sputtered silver films, we investigated methods of binding Cc on the silver nano-grating in order to improve the SERS signal strength at both 532 and 638 nm excitation. Cc was not detectable on the Ag nano-gratings without surface functionalization at 1 μM concentration. Upon charge reversal functionalization of the Ag nano-gratings, 1 μM Cc was detectable albeit not reliably. By further crosslinking 1 μM Cc to the functionalized Ag nano-gratings, the analyte-capture detection scheme greatly improved the SERS signal strength and reliability at both excitation wavelengths and allowed for quantification of their coefficients of variation with values down to 27%.

具有多波长彩虹诱捕特性的表面增强拉曼散射 (SERS) 基板具有成为快速和多重疾病检测的通用平台的潜力。我们提出了第一份关于利用彩虹捕获宽度分级纳米光栅（一类新的啁啾超材料）检测蛋白质生物标志物的报告。使用细胞色素 c (Cc)，一种带电分析物，其固有的难以吸附到溅射银膜上，我们研究了将 Cc 结合在银纳米光栅上的方法，以提高 532 和 638 nm 激发下的 SERS 信号强度。在 1 μ M 浓度下，在没有表面功能化的 Ag 纳米光栅上检测不到 Cc 。在 Ag 纳米光栅的电荷反转功能化后，1 μM Cc 是可检测的，尽管不可靠。通过将 1 μ M Cc进一步交联到功能化的 Ag 纳米光栅，分析物捕获检测方案大大提高了两个激发波长下的 SERS 信号强度和可靠性，并允许量化它们的变异系数，值低至 27%。