WPI-Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
Sci Rep. 2011;1:112. doi: 10.1038/srep00112. Epub 2011 Oct 10.
Detecting and identifying single molecules are the ultimate goal of analytic sensitivity. Single molecule detection by surface-enhanced Raman scattering (SM-SERS) depends predominantly on SERS-active metal substrates that are usually colloidal silver fractal clusters. However, the high chemical reactivity of silver and the low reproducibility of its complicated synthesis with fractal clusters have been serious obstacles to practical applications of SERS, particularly for probing single biomolecules in extensive physiological environments. Here we report a large-scale, free standing and chemically stable SERS substrate for both resonant and nonresonant single molecule detection. Our robust substrate is made from wrinkled nanoporous Au₇₉Ag₂₁ films that contain a high number of electromagnetic "hot spots" with a local SERS enhancement larger than 10⁹. This biocompatible gold-based SERS substrate with superior reproducibility, excellent chemical stability and facile synthesis promises to be an ideal candidate for a wide range of applications in life science and environment protection.
检测和识别单分子是分析灵敏度的最终目标。通过表面增强拉曼散射（SM-SERS）进行单分子检测主要依赖于 SERS 活性金属衬底，通常是胶体银分形簇。然而，银的高化学反应性和其与分形簇复杂合成的低重现性一直是 SERS 实际应用的严重障碍，特别是在广泛的生理环境中探测单生物分子。在这里，我们报告了一种用于共振和非共振单分子检测的大规模、独立和化学稳定的 SERS 衬底。我们的坚固衬底由褶皱纳米多孔 Au₇₉Ag₂₁薄膜制成，其中包含大量电磁“热点”，局部 SERS 增强大于 10⁹。这种基于金的 SERS 衬底具有出色的重现性、优异的化学稳定性和简便的合成，有望成为生命科学和环境保护领域各种应用的理想候选材料。
