Immuno-nanogold Resonance Scattering Spectral Assay Of Immunoglobulin M And Human Chorionic Gonadotrophin

PartⅠIntroductionThe preparation and identification of colloid gold and the application of gold-labeled technology in biochemical analysis were summarized. The application of resonance scattering technology in analytical chemistry in resent years was introduced. The analytical progress of immunoglobulin M and human chorionic gonadotrophin was also reviewed.PartⅡImmuno-nanogold Resonance Scattering Spectral Assay of Trance Immunoglobulin MGold nanoparticles of 8 nm, which were prepared by the improved method of trisodium citrate, were used to label goat anti-human immunoglobulin M (anti-IgM). In KH2PO4-Na2HPO4 buffer of suitable pH, the immune reaction between gold-labeled anti-IgM and IgM took place and the intensity of resonance scattering peak at 580 nm enhanced greatly. The intensityΔI580 nm is proportional to the concentration of IgM in the range of 0.0015-2.00μg/mL. The regression equation isΔI580nm= 39.91c+1.95 (n =7, R=0.9989), with the detection limits of 0.98 ng/mL (3σ). Owing to its simplicity, sensitivity and better selectivity, the method has been applied to the determination of IgM in serum of healthy human, with satisfactory results.PartⅢResonance Scattering Effect of Silver-gold Composite Nanoparticles and Its Application to Immunoassay of Trace Immunoglobulin MGold nanoparticles in the size of 8 nm were used to label goat anti-human immunoglobulin M (anti-IgM). In pH4.49 KH2PO4-Na2HPO4 buffer, the gold-labeled anti-IgM interacted with IgM, immunogold complex formed and its upper solution reacted with silver-enhanced reagents after centrifuging. The decreased intensity at 350 nm was recorded. Under the optimum condition, the decreased intensityΔI350nm was proportional to the concentration of IgM in the range of 0.13-333.3 ng/mL. The regression equation wasΔI350 nm=0.1857cIgM +2.10 (n =7, R=0.9982), with the detection limits of 0.08 ng/mL (3σ). The method has been also applied to the determination of IgM in serum of healthy human, with satisfactory results.PartⅣImmuno-nanogold Resonance Scattering Spectral Assay of Trance Human Chorionic GonadotrophinGold nanoparticles of 8-50 nm are used to label the polyclonal antibody of rabbit anti-human chorionic gonadotrophin(anti-hCG) . In citric acid-NaH2PO4 buffer of suitable pH, the immune reaction between gold-labeled rabbit anti-hCG and hCG took place and the intensity of resonance scattering peak at 580 nm decreased. The changed intensityΔI580 nm is proportional to the certain concentration of hCG .To the systems of gold nanoparticles of 8, 10 and 15 nm, the concentration of hCG in the range of 40-10000, 40-10000 and 40-8000 mIU/mL was proportional to the intensity with the detection limits of 19.4, 15.1 and 13.6 mIU/mL respectively. Owing to its simplicity, sensitivity and better selectivity, the method has been applied for the determination of hCG in urine of pregnant women, with satisfactory results.PartⅤA Silver-enhanced nanogold Labeling Immunoresonance Scattering Assay for Trace Human Chorionic GonadotrophinGold nanoparticles of 8 nm was used to label rabbit anti-human chorionic gonadotrophin(hCG). In pH5.0 citric acid-Na2HPO4 buffer, gold-labeled rabbit anti-hCG interacted with hCG, immunogold complex formed and its upper solution after centrifugation reacted with silver-enhanced reagents in pH3.4 citric acid-trisodium citrate buffer, while there was the strongest resonance scattering peak of gold-silver composite nanoparticles at 423 nm. Under the optimum condition, the decreased intensityΔI423nm was proportional to the concentration of hCG in the range of 7.5-625.0 mIU/mL. The regression equation wasΔI423 nm=0.2262c+0.17(n =7, R=0.9979), with the detection limits of 2.7 mIU/mL(3σ). The method has been also applied to the determination of hCG in urine samples of pregnant women, while immunospectrophotometry was used to compare, with satisfactory results.