An application of a plasmonic chip with enhanced fluorescence to a simple biosensor with extended dynamic range
An application of a plasmonic chip with enhanced fluorescence to a simple biosensor with extended dynamic range
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具有增强荧光的等离子体芯片在具有扩展动态范围的简单生物传感器中的应用
DOI：
10.1016/j.snb.2011.04.086
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
TakahikoNakaoki
中科院分区：
文献类型：
--
作者：
Keiko Tawa*;YoshikiYokota;KenjiKintaka;JunjiNishii;TakahikoNakaoki
将等离子体激元芯片涂敷薄的银和SiO2层，制成一种简单的宽动态范围的生物传感器，该传感器具有灵敏度高、表面选择性好等优点，但荧光检测系统简单，不需要复杂的光学材料。测量由来自芯片后面板的照射光激发的荧光标记的标记蛋白cy5-链霉亲和素（SA）的增强荧光。为了通过在由来自后照射的光栅耦合的表面等离子体共振增强的电场下的激发获得最大荧光增强，研究了最佳银厚度，发现其为30 - 35 nm。在等离子体芯片上还观察到了由于荧光与等离子体激元之间的再耦合而产生的定向荧光，并且与载玻片上的荧光相比增强了90倍，这是上级的。与载玻片上的方法相比，孵育10 min后，检测限提高到50 pM，动态范围也扩大了2个数量级。来自后板的照射在100 nM浓度的cy5-SA的表面选择性检测中表现出优势。该等离子体芯片具有检测速度快、操作简单、灵敏度高（动态范围宽）、表面选择性好、抑制非特异性吸附等优点，在生物传感领域具有广阔的应用前景。
Plasmonic chips coated with thin silver and SiO2layers were applied to a simple biosensor with wide dynamic range, which has some advantages in the points of sensitivity and surface selectivity in spite of a simple fluorescence detection system without complex optical stuffs. The enhanced fluorescence of fluorescent labeled-marker proteins, cy5-streptavidin (SA), excited by irradiation light from the rear panel of the chip was measured. To obtain the maximum fluorescence enhancement by excitation under an electric field enhanced by grating-coupled surface plasmon resonance from the rear irradiation, the optimal silver thickness was studied and found to be 30–35 nm. A directional fluorescence due to re-coupling between fluorescence and plasmon polaritons was also observed on the plasmonic chips and enhanced fluorescence 90 times compared with that on glass slides was superior to the others reported. The limit of detection (LOD) studied here was improved up to 50 pM after 10-min incubation and dynamic range was also extended by 2 order, compared with that on glass slides. The irradiation from the rear panel demonstrated advantage in the surface-selective detection of cy5-SA at 100 nM concentration. Our plasmonic chip has great potential in biosensing application due to its advantages of rapid detection, simple operation, high sensitivity (wide dynamic range), surface selectivity, and suppression of non-specific adsorption.