Nonlinear Optical Detection of Proteins Based on Localized Surface Plasmons in Surface Immobilized Gold Nanospheres

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• 作者：Shin-ya Fukuba ; Kazuma Tsuboi ; Shinya Abe ; Kotaro Kajikawa
• 刊名：Langmuir
• 出版年：2008
• 出版时间：August 5, 2008
• 年：2008
• 卷：24
• 期：15
• 页码：8367-8372
• 全文大小：387K
• 年卷期：v.24,no.15(August 5, 2008)
• ISSN：1520-5827

文摘

A new nonlinear optical method is presented to detect proteins binding to a gold surface without using fluorescent-dye labeling. After exposure of the protein-binding surface to a gold nanosphere solution, the nanospheres are immobilized above a gold surface with a nanogap supported by the protein. The gold nanospheres immobilized on the gold surface show strong localized surface plasmon (LSP) resonance, and the formation of this structure results in a marked increase in the optical second harmonic (SH) activity of the gold surface arising from a large enhancement of the electric field localized adjacent to the nanospheres on the LSP resonance. The SH image, therefore, gives a high contrast ratio, 7.0:1, of protein-binding spots to control spots. The contrast ratio is much greater than those obtained by linear reflectivity imaging.