An efficient direct competitive nano-ELISA for residual BSA determination in vaccines

Abstract

A simple, fast, and highly sensitive direct competitive enzyme-linked immunosorbent assay (ELISA) based on bovine serum albumin (BSA) antigen labeled amine-terminated silicon dioxide (SiO-NH-BSA) nanoparticles was developed to determine residual BSA in vaccines. As nano-ELISA using nanomaterials with a very high surface-to-volume ratio has emerged as a promising strategy, SiO-NH-BSA nanoparticles were prepared in this study by the coupling of BSA to SiO nanoparticles modified with amidogen, followed by the quantification of BSA via a direct competitive binding of BSA-antigen-labeled SiO nanoparticles to anti-BSA antibody conjugated with horseradish peroxidase. The validation study showed that the linear range of this method was from 1 to 90 ng/mL (r = 0.998) and the limit of detection was 0.67 ng/mL. The intra-assay and interassay coefficients of variation were less than 10% at three concentrations (10, 40, and 70 ng/mL), and the recovery was 92.4%, indicating good specificity. As a proof of principle, this new method was applied in the analysis of residual BSA in five different vaccines. Bland-Altman plots revealed that there was no significant difference in the accuracy and precision between our new method and the most commonly used sandwich ELISA. From the results taken together, the new method developed in this study is more sensitive and facile with lower cost and thus demonstrated potential to be applied in the quality control of biological products. Graphical Abstract Illustration of the procedures of the direct competitive enzyme immunoassay.

Label-Free Colorimetric Detection of Urine Glucose Based on Color Fading Using Smartphone Ambient-Light Sensor

“…Horseradish peroxidase-hydrogen peroxide-3,3′5,5′-tetramethylbenzidine (HRP-H2O2-TMB) is a coloring system that is commonly used in enzyme-linked immune-absorbent assay ELISA [20,21]. TMB is oxidized to blue in the presence of HRP and H2O2.…”

Competitive Protein Binding Assay of Naproxen by Human Serum Albumin Functionalized Silicon Dioxide Nanoparticles

“…Some of the binding sites on HSA binding to free naproxen were measured, while others binding to HRP-naproxen. After centrifugal separation of excessive HRP, the catalytic color reactions were investigated on an HRP/TMB/H 2 O 2 system [33,34,35] by the HRP-naproxen/nano-SiO 2 -HSA composite. The free naproxen to be measured and HRP-naproxen added were competitively bound to HSA, thus the higher content of naproxen in the sample, the less HRP-naproxen binding to HSA, resulting in a weaker color of the substrate solution.…”

“…The HSA immobilized nano-SiO 2 nanoparticles (SiO 2 -HSA) were prepared following our similar procedures reported previously [33,34,35]. Briefly, SiO 2 nanoparticles (nano-SiO 2 ) were firstly prepared by the hydrolysis of TEOS according to the typical Stöber process.…”

Optimization of Vortex-Assisted Dispersive Liquid-Liquid Microextraction for the Simultaneous Quantitation of Eleven Non-Anthocyanin Polyphenols in Commercial Blueberry Using the Multi-Objective Response Surface Methodology and Desirability Function Approach

“…Under these conditions, the recoveries of 11 compounds were GA 93.56 ± 1.39%, PC 91.71 ± 1.02%, VA 93.61 ± 1.52%, SA 94.75 ± 0.79%, FA 92.26 ± 1.52%, Que 88.29 ± 1.32%, C 91.13 ± 0.72%, EC 95.76 ± 1.16%, GCG 93.35 ± 0.92% ECG 92.67 ± 1.08% and EGCG 92.71 ± 0.84%. The consistency between the predicted values and experimental values was assessed by Bland-Altman analysis [ 25 ]. Using 95% as the confidence interval, the limits of agreement for measurement difference were [−0.0029, 0.0421].…”