在基于荧光编码微球的液相芯片技术中,非特异性吸附会降低检测灵敏度,影响多元检测能力.为了抑制非特异性吸附现象,以聚乙二醇(PEG)接枝苯乙烯马来酸共聚物(PEG-g-PSMA)为基体材料,采用膜乳化-乳液溶剂挥发法制备铜铟硫/硫化锌量子点复合PEG-g-PSMA荧光微球,通过调节甲氧基聚乙二醇的投料量和相对分子质量控制PEG接枝率和链长,并将复合微球应用于糖类抗原CA199的免疫检测.微球形貌和荧光性能表征结果显示,复合微球呈规则球形且单分散性良好,平均粒径约5 μm,内部量子点及其荧光分布均匀.免疫检测发现微球具有显著抑制非特异性吸附的能力,当PEG接枝率为30、相对分子质量为 1000 时,检测限为0.9 kU/L (1 U=1 μmol/min).该方法适用于复合微球的大量制备,在肿瘤标志物等多元免疫检测方面具有实际应用前景.

In the quantum dot-encoded microspheres based on the suspension array technology, the nonspecific biofouling will decrease the detection sensitivity and the multiplex detection ability. In order to inhibit the nonspecific biofouling, the polyethylene glycol grafted styrene maleic acid copolymer (PEG-g-PSMA) was used as substrate, and the CuInS₂/ZnS quantum dot-encoded PEG-g-PSMA fluorescent microspheres were fabricated via the Shirasu porous glass (SPG) membrane emulsification-emulsion solvent evaporation technique. The grafting ratio and the chain length of PEG in PEG-g-PSMA were controlled by adjusting the feed mass and relative molecular mass of methoxy polyethylene glycol (mPEG), respectively. The microspheres were further applied to the immunoassay of CA199. The results of morphology and fluorescence properties show that the prepared microspheres are spherical and monodisperse, with an average particle size of 5 μm, and the internal quantum dots and fluorescence distribution are uniform. Immunoassay shows that the microspheres can significantly inhibit the nonspecific adsorption. When the optimal grafting ratio of PEG is 30 and the relative molecular mass of PEG is 1000, the limit of detection (LOD) to CA199 reaches up to 0.9 kU/L (1 U=1 μmol/min). The PEG-g-PSMA fluorescent microspheres can be prepared in large quantites by this method and have a promising application in multiplex immunoassay.