痕量甲胎蛋白的免疫纳米金催化-氧化亚铜微粒共振散射光谱分析

Immunonanogold Catalytic-Cu_2O Particle Resonance Scattering Spectral Determination of Trace α-Fetoprotein

用粒径15 nm的纳米金标记单克隆羊抗人甲胎蛋白(GAFP),制备了甲胎蛋白(AFP)的免疫纳米金探针(AuGAFP).纳米金及AuGAFP均对葡萄糖还原铜(Ⅱ)生成Cu2O微粒这一慢反应具有较强的催化作用,Cu2O微粒在620 nm处产生1个较强的共振散射峰.将AFP-AuGAFP免疫反应与离心分离技术结合,建立了超痕量AFP的免疫纳米金催化-Cu2O微粒共振散射光谱新方法.随着AFP浓度的增大,AFP-AuGAFP免疫复合物微粒增多,离心液中AuGAFP浓度降低,620 nm处的共振散射光强度I620 nm线性降低,其降低值ΔIRS与AFP质量浓度ρ(AFP)在0.10～16.0 ng/mL范围内呈现良好的线性关系,其回归方程为ΔIRS=4.27ρ(AFP)+1.28,检出限为0.05 ng/mL.本方法所用试剂易得,反应易控制,灵敏度高,选择性好,用于定量分析人血清中的AFP,结果令人满意.

15 nm-nanogold was used to label monoclone goat antihuman α-fetoprotein antibody（GAFP） to obtain immunonanogold probe（AuGAFP） for α-fetoprotein （AFP）. Both nanogold and the probe have catalytic effect on the slow Cu20 particle reaction between Fehling reagent and glucose that exhibit a resonance scattering peak at 620 nm. Combining AFP-AuGAFP immunoreaction with centrifugation technique, a highly sensitive immunonanogold catalytic-Cu20 particle resonance scattering spectral assay for AFP was proposed. With addition of AFP, the AFP-AuGAFP immunocomplex increased, the excess probe in the supematant decreased, and the resonance scattering intensity at 620 nm decreased linearly. The decreased intensity AIRs was linear to AFP eoneentration[p（AFP）] in the range of 0. 10-16. 0 ng/mL, with a regression equation of AIRs = 4. 27p（AFP） ＋ 1.28, and a detection limit of O. 05 ng/mL. This method was applied to the detection of AFP in sera, with high sensitivity and good selectivity, in addition to low-cost reagents and easy controlling reaction.