提出一种基于氧化石墨烯包裹金纳米壳(EGO-AuNS)修饰长周期光纤光栅(LPFG)的新型免疫传感器,并将其应用于禽流感病毒(AIV)检测。利用静电结合原理将石墨烯(GO)包裹在金纳米壳(AuNS)表面形成EGO-AuNS复合材料;采用硅烷偶联剂以共价键结合方式将其固定在LPFG表面;再以AIV单克隆抗体(AIV-MAbs)为特异性生物分子识别单元,固定于光栅表面构成EGO-AuNS-LPFG免疫传感器。结果表明:在折射率(RI)1.333--1.411范围内,EGO-AuNS-LPFG传感器RI灵敏度高达-66.60 nm/RIU,约为普通LPFG传感器的6倍。通过对不同浓度等级AIV抗原溶液的检测,表明该免疫传感器的检测极限约为8 ng/mL,饱和点约为50 μg/mL,在其线性响应区域的检测灵敏度约为2946.25 pm/(μg·mL -1),约为基于GO涂覆包层腐蚀型普通LPFG的AIV免疫传感器灵敏度的7.3倍;此外,其对AIV分子的解离系数约为3.49×10 -9 mol/L。通过对几种尿囊液的对照检测实验,表明该免疫传感器且具有良好的特异性和临床性有效性,因此它在生物医学领域有较大应用潜力。

In this study, a novel immunosensor based on graphene-oxide (GO)-encapsulated Au-nanoshell (EGO-AuNS)-coated long-period fiber grating (LPFG) is presented for avian influenza virus (AIV) detection. The EGO-AuNS composites were obtained by coating GO on the surface of AuNS via electrostatic bonding, and immobilized on the surface of LPFG via covalent bonding using a silane coupling agent. Then, AIV monoclonal antibodies (AIV-MAbs), which serve as specific biomolecule recognition units, were fixed on the grating surface to realize the EGO-AuNS-LPFG immunosensor. The experimental results indicate that the refractive index (RI) sensitivity of the EGO-AuNS-LPFG immunosensor is -66.60 nm/RIU when RI is from 1.333 to 1.411, which is six times greater than that of the LPFG-based sensor. Based on the detection of AIV antigen solutions with different concentrations, the limit of detection of the immunosensor is observed to be approximately 8 ng/mL. Further, the immunosensor becomes saturated at approximately 50 μg/mL and exhibits a linearity sensitivity of approximately 2946.25 pm/(μg·mL ^-1), which is 7.3 times greater than that of the GO-coated cladding-etched LPFG immunosensor. Based on the detection results of several allantoic fluids, the proposed immunosensor exhibits good specificity and clinical effectiveness. Furthermore, it exhibits considerable promise for application in the biomedical field.