Interdisciplinary Program of Integrated Biotechnology, Sogang University, Seoul, Republic of Korea.
PLoS One. 2011 Feb 24;6(2):e15836. doi: 10.1371/journal.pone.0015836.
Near-infrared surface-enhanced Raman spectroscopy (SERS) is a powerful technique for analyzing the chemical composition within a single living cell at unprecedented resolution. However, current SERS methods employing uncontrollable colloidal metal particles or non-uniformly distributed metal particles on a substrate as SERS-active sites show relatively low reliability and reproducibility. Here, we report a highly-ordered SERS-active surface that is provided by a gold nano-dots array based on thermal evaporation of gold onto an ITO surface through a nanoporous alumina mask. This new combined technique showed a broader distribution of hot spots and a higher signal-to-noise ratio than current SERS techniques due to the highly reproducible and uniform geometrical structures over a large area. This SERS-active surface was applied as cell culture system to study living cells in situ within their culture environment without any external preparation processes. We applied this newly developed method to cell-based research to differentiate cell lines, cells at different cell cycle stages, and live/dead cells. The enhanced Raman signals achieved from each cell, which represent the changes in biochemical compositions, enabled differentiation of each state and the conditions of the cells. This SERS technique employing a tightly controlled nanostructure array can potentially be applied to single cell analysis, early cancer diagnosis and cell physiology research.
近红外表面增强拉曼光谱（SERS）是一种强大的技术，可以以前所未有的分辨率分析单个活细胞内的化学成分。然而，目前采用不可控胶体金属颗粒或在基底上不均匀分布的金属颗粒作为 SERS 活性位点的 SERS 方法，显示出相对较低的可靠性和重现性。在这里，我们报告了一种高度有序的 SERS 活性表面，它是通过在 ITO 表面上通过纳米多孔氧化铝掩模热蒸发金而提供的基于金纳米点阵列的。由于在大面积上具有高度可重复且均匀的几何结构，这种新的组合技术显示出更广泛的热点分布和更高的信噪比，优于当前的 SERS 技术。这种 SERS 活性表面被用作细胞培养系统，用于在其培养环境中对活细胞进行原位研究，而无需任何外部制备过程。我们将这种新开发的方法应用于基于细胞的研究，以区分细胞系、不同细胞周期阶段的细胞以及活/死细胞。从每个细胞获得的增强拉曼信号代表了生化成分的变化，从而能够区分每个状态和细胞的条件。这种采用紧密控制的纳米结构阵列的 SERS 技术可能适用于单细胞分析、早期癌症诊断和细胞生理学研究。
