以柠檬酸三钠作还原剂, 采用微波高压合成法制备了粒径约为20 nm的银纳米微粒。 在pH 9.0条件下, 用银纳米微粒标记羊抗人IgG制备了IgG的免疫纳米银探针(AgGIgG)。 在pH为6.0的磷酸盐缓冲溶液及聚乙二醇(PEG)-6000和KCl存在下, IgG与AgGIgG发生免疫反应, 裸露的银纳米颗粒在KCl和PEG-6000的作用下发生了聚集, 导致体系在485 nm处的共振散射峰增强。 考察了pH值、 AgGIgG、 PEG和KCl浓度, 温育温度和时间及共存物质的影响。 在最佳条件下, IgG浓度cIgG在4.0～480 ng·mL-1范围内与485 nm处的共振散射光强度增加值ΔI485 nm呈线性关系, 回归方程为ΔI485 nm=76.8cIgG+4.7, 方法检出限为2.4 ng·mL-1 IgG 。 该法用于定量分析血清IgG, 简便快速, 本法结果与免疫比浊法结果一致。

Using tri-sodium citrate as reducer, stable silver nanoparticles the size of about 20 nm were prepared by the microwave high pressure procedure with simplicity and rapidity. At pH 9.0, sliver nanoparticle was used to label goat anti-human IgG (GIgG) to obtain an immuno-nanosilver resonance scattering spectral probe (AgGIgG) for IgG. In pH 6.0 buffer solution and in the presence of polythylene glycol (PEG) and KCl, the immune reaction of IgG with AgGIgG took place, the silver nanoparticles released from AgGIgG produced aggregations, and the resonance scattering intensity at 485 nm (I485 nm) was enhanced greatly. The influence factors such as pH value, buffer solution volume, concentration of AgGIgG, KCl, PEG-4000, PEG-6000, PEG-10000 and PEG-20000, incubation temperature and time were considered, respectively. Under the conditions of 0.40 mL of pH 6.0 phosphate buffer solution, 1.20 mL of 9.8 μg·mL-1 AgGIgG, 0.20 mL of 20% PEG-6000, 0.50 mL of 10% KCl, and ultrasonic irradiation for 25 min at room temperature, the increased intensity ΔI485 nm was proportional to the IgG concentration (ｃIgG) from 0.004 to 0.48 μg·mL-1, with a detection limit of 2.4 ng·mL-1. The regress equation was ΔI485 nm=76.8ｃIgG+4.7. The effect of foreign substances such as 20μg·mL-1 Ni2+, Fe2+, Pb2+ and BSA, 60 μg·mL-1 Cu2+, Ca2+ and HSA, 60 μg·mL-1 Mg2+ and Mn2+, 320 μg·mL-1 Zn2+, glucose and urea on the ΔI485 nm was examined, respectively. Results showed that there was no interference. This assay showed high sensitivity and good selectivity for quantitative determination of IgG in human serum with satisfactory results. The analytical results were in agreement with that of the reference results.