提出了一种基于微纳光纤耦合器的高灵敏度、便携式生物传感器,并对该传感器用于无标生物检测的灵敏度和重复性进行了研究。通过熔融拉锥法拉制出腰椎直径为3 μm的光纤耦合器, 并进行折射率检测实验。实验测得折射率灵敏度为1402.3 nm/RIU, 对检测结果进行拟合, 得到拟合曲线的相关系数为0.99459。微纳光纤耦合器的弱耦合模型的计算结果和实验结果相符。将此微纳光纤耦合器用于检测羊免疫球蛋白(IgG)抗原, 得到了2 pg/mL的检出限; 10次解离再生实验验证了该传感器的重复性, 表明了微纳光纤耦合器在无标生物传感中具有高检测灵敏度的潜力和较好的实用价值。

A portable biosensor with high sensitivity is proposed, and the biosensor is based on a micro/nano-fiber coupler. When the biosensor is used in label-free biodetection, its sensitivity and reusability are studied. A fiber coupler with the waist diameter of 3 μm is fabricated by the fused biconical taper method, and then the coupler is used in refractive index detection experiment. A refractive index sensitivity of 1402.3 nm/RIU is measured in experiment. The detection results are fitted, and the correlation coefficient of the fitted curve is 0.99459.The calculated results of the weak coupling model of the micro/nano-fiber coupler are in good agreement with the experimental results. The detection limit of 2 pg/mL is obtained when the micro/nano-fiber coupler is used to detect goat immune globulin (IgG) antigen. The reusability of the biosensor is verified by 10 dissociation experiments. These experiments demonstrate that the micro/nano-fiber coupler can obtain a high detection sensitivity in the label-free biosensing and has good practical value.