A Highly Sensitive Capillary-Based Immunosensor by Combining with Peroxidase Nanocomplex-Mediated Signal Amplification for Detection of Procalcitonin in Human Serum

Abstract

While signal amplification is a promising approach for improving the detection sensitivity, it has never been applied in immunoassays with capillary-based sensors. In this study, we construct a sensitive short-capillary immunosensor for determination of procalcitonin (PCT) in human serum by introducing a robust signal amplification system based on a biotin–streptavidin-mediated peroxidase nanocomplex. We show that the proposed sensor combines essential advantages for immunoassays, including less sample consumption, high detection sensitivity, and high specificity. The proposed immunosensor for detection of PCT provides a large linear response range from 2.5 to 8.0 × 104 pg/mL with a low limit of detection of 0.5 pg/mL. The method is successfully applied for PCT determination in human serum samples, and the results are satisfactory with the clinical method. By combining with a signal amplification system that enhances immunoassay sensitivity significantly, the proposed peroxidase nanocomplex-mediated capil...