Bardin Fabrice, Bellemain Alain, Roger Gisèle, Canva Michael
Laboratoire Charles Fabry de l'Institut d'Optique, Institut d'Optique Graduate School, Univ Paris Sud, CNRS, Campus Polytechnique RD128 91127 Palaiseau cedex, France.
Biosens Bioelectron. 2009 Mar 15;24(7):2100-5. doi: 10.1016/j.bios.2008.10.023. Epub 2008 Nov 6.
Surface plasmon resonance (SPR) techniques have become, over the last ten years, powerful tools to study biomolecular surface interaction kinetics in real-time without any use of labels. The highest resolution is currently obtained using spectroscopic SPR systems through the measurement of the complete surface plasmon resonance curve in angular or spectral configuration. But, these systems are limited to a few independent channels (<10). In order to expand their capability to an array format, SPR sensors have also been developed in an imaging mode, allowing parallel monitoring of hundreds of sensing spots onto a camera. However, such sensors rely on the intensity variation measurement at a single position of the resonance spectrum, hence resulting in smaller resolution. We present in this work a SPR spectro-imaging system which aims at keeping the advantage of a mono-channel SPR sensor based on the full resonance curve measurement while introducing an additional spatial dimension (linear multi-spot array). The system is based on the illumination of a biochip through a vertical slit (y-dimension) by a white light source. The reflected light spectrum obtained through a diffracting grating is then imaged on the x-dimension of the camera. The complete spectral resonance curve of a full column of sensing spots can be monitored in parallel and in real-time. We demonstrate that data processing is key to reduce the noise and to improve the resolution. We report on the detection of signals with resolution comparable to the one obtained with a classical SPR mono-channel spectroscopic sensor (3.5 x 10(-7) Refractive Index Unit), gaining an order of magnitude compared to SPR imaging sensors. Eventually, we show that short base DNA-DNA hybridizations with concentrations as low as 100 pM can be detected and discriminated in a few tens of minutes following injection by the SPR spectro-imaging system.
在过去十年中，表面等离子体共振（SPR）技术已成为研究生物分子表面相互作用动力学的强大工具，无需使用任何标记即可实时进行。目前，通过在角度或光谱配置下测量完整的表面等离子体共振曲线，使用光谱SPR系统可获得最高分辨率。但是，这些系统仅限于少数几个独立通道（<10个）。为了将其功能扩展到阵列形式，还开发了成像模式的SPR传感器，可在相机上并行监测数百个传感点。然而，此类传感器依赖于共振光谱单个位置处的强度变化测量，因此分辨率较低。在这项工作中，我们展示了一种SPR光谱成像系统，该系统旨在保留基于全共振曲线测量的单通道SPR传感器的优势，同时引入额外的空间维度（线性多点阵列）。该系统基于白光源通过垂直狭缝（y维度）照射生物芯片。然后，通过衍射光栅获得的反射光谱成像在相机的x维度上。可以并行且实时地监测一整列传感点的完整光谱共振曲线。我们证明数据处理是降低噪声和提高分辨率的关键。我们报告了所检测信号的分辨率与经典SPR单通道光谱传感器获得的分辨率相当（3.5×10^(-7) 折射率单位），与SPR成像传感器相比提高了一个数量级。最终，我们表明SPR光谱成像系统在注入后几十分钟内可以检测和区分浓度低至100 pM的短链碱基DNA - DNA杂交。
