表面等离子体-拉曼散射双模式复合生物芯片

本文提出了复合表面等离子体(SPR)无标记检测及表面增强拉曼散射(SERS)的显微成像技术.证明了双模式SPR-SERS生物芯片的可实施性,即在同一芯片上实现了表面等离子共振和表面增强拉曼显微检测.鉴于双模芯片的高保真性,基于显微技术的高精准、多通道无标记检测技术有望在临床医学检测中得以广泛应用.

Surface Plasmon-Raman Scattering Dual-mode Biochip

A microscopy based imaging technology was proposed to provide both surface plasmonic resonance (SPR) detection and surface-enhanced Raman scattering (SERS) spectral of attached molecules on a dual-mode biochip. Experimental studies were conducted to reveal that both SPR and SERS signals can be acquired from the same biochip. SPR excitation and low concentration SERS detection are successfully performed on metallic nanogap grating with periodicities of 400 or 600 nm ensuring the SPR excitation under the illumination of 633 or 785 nm irradiation, respectively. The excited SPR propagates on the metallic surface, efficiently excites dipole moment resonance at the nanogap in the grating trough, leading to extremely high local electric field built up at the nanogap and the metallic surface. Therefore, besides SPR detection, SERS evaluation can be conducted to identify the molecules attached on the biochip. The experimental results show that the SPR bulky sensitivity of the dual-mode biochip is S = 68.8°/RIU, and the surface sensitivity is S = 1.5°/(mol·L^-1). The Raman enhancement factor of the dual-mode biochip reaches up to 10⁶ and the minimum detection concentration of 10^-15 mol/L could be achieved. Due to its high-fidelity measurement of the dual-mode chip and the high precision of microscopy imaging technology, multi-channel label-free detection is expected to be widely used in biological detections. Our future work is to achieve the practical application of SPR-SERS dual-mode biological detection.