Immuno-nanogold Resonance Scattering Spectral Assay Of Penicillin G

PartⅠIntrodctionThe preparation and identification of gold nanoparticles, the application of gold-labeled technology in biochemical analysis and the application of resonance scattering technology in analytical chemistry were introduced. The analytical progress of penicillin G was also reviewed.PartⅡCombination nanogold resonance scattering effect with immunoreaction for assay of trace penicillin GA new immunonanogold resonance scattering spectral assay was developed for the sensitive determination of penicillin G in milk sample, based on resonance scattering (RS) effect of the nanogold at 580 nm and the nanoglold labeled immunoreactions in the presence of pH 5.4 phosphate citric acid buffer solutions and the polythylene glycol (PEG). The resonance scattering intensity at 580 nm (I580 nm) enhanced greatly with penicillin G. The enhanced RS intensity△I580 nm was linear to the penicillin G concentration in the range of 7.5-1.7×103 ng.mL-1, with a detection limit of 0.78 ng.mL-1. The results indicate that the immunonanogold labeled RS spectral assay has a high specificity and good sensitivity for quantitative determination of penicillin G in raw milk sample.PartⅢImmunonanogold Probe as Catalyst for HAuCl4-NH2OH Particle Reaction and Its Application to Resonance Scattering Assay of Trace Penicillin GBoth nanogold and nanosilver exhibit catalytic activity toward the HAuCl4-NH2OH particle reaction. Based on the catalytic effect of nanogold on the redox reaction and the gold particle resonance scattering (RS) effect at 580 nm, RS can be used to monitor the nanocatalytic reaction and utilized in bioanalytical assay. As a model, we used nanogold in size of 9 nm to label goat anti-rabbit penicillin G to obtain an immunonanogold probe for penicillin G. The immunoreactions between rabbit anti-penicillin G antibody labeled nanogold and penicillin G took place in pH 5.4 phosphate-citric acid buffer solutions, and after centrifugation, the supernatant of the nanogold-labeled immunoreaction was used as nanocatalyst for the redox reaction. After the immunonanogold catalytic reaction, the resonance scattering intensity enhanced at 580 nm (I580 nm). With the addition of penicillin G, the concentration of immunonanogold in the supernatant reduced linearly, which leaded the I580 nm to decrease accordingly. Under the optimal conditions, the decreased intensity ?I580 nm was inversely proportional to the penicillin G concentration in the range of 0.15-225 ng.mL-1, with a detection limit of 0.05 ng.mL-1 penicillin G. These results indicate that the immunonanogold-catalytic resonance scattering spectral assay offers good results for quantitative determination of penicillin G in raw milk sample, with the recovery between 101.6% and 120.3%.PartⅣAs the seeds, small size nanogold can initiate the particle reaction between Cu (II) and glucose. Based on the (Au) nucleus (Cu2O) shell complex nanoparticles resonance scattering (RS) effect at 608 nm, RS can be used to monitor the particle reaction and utilized in bioanalytical assay. As a model, we used nanogold in size of 9 nm to label rabbit anti-penicillin G (RAPG) to obtain an immunonanogold probe for penicillin G (PG). The immunoreactions between rabbit anti-penicillin G antibody labeled nanogold (AuRAPG) and PG took place in pH 5.2 phosphate-citric acid buffer solutions, and after centrifugation, the supernatant of the immunoreaction products were used as seeds for the reaction between Cu (II) and glucose. Then, the RS intensity enhanced at 608 nm (I608 nm). With the addition of PG, the concentration of AuRAPG in the supernatant reduced linearly, which leaded the I608 nm to decrease accordingly. Under the optimal conditions, the decreased RS intensity was inversely proportional to the PG concentration in the range of 0.09-21.6 ng.mL-1, with a detection limit of 0.01 ng.mL-1 PG. It is shown that the data produced here can be used to determine trace PG in raw milk sample, with the recovery between 100.6% and 109.2%.