Paper-based chemiluminescence enzyme-linked immunosorbent assay enhanced by biotin-streptavidin system for high-sensitivity C-reactive protein detection

High-sensitivity C-reactive protein (hs-CRP) has been regarded as a risk predictor of cardiovascular disease (CVD). Despite there are many methods to detect hs-CRP, quantitative, rapid, convenient, multiplex and highly sensitive measurement of it is still a challenge for point-of-care applications. In this study, we developed a paper-based ELISA to detect hs-CRP and the sensitive chemiluminescence was applied as detection signal. In this developed assay method, CRP concentration and chemiluminescence intensity were linearly correlated (r = 0.999) with a limit of detection (LOD) as low as 0.49 ng mL(-1), which was comparable to that of conventional ELISA and superior to most of the current reported POCT methods for detection of hs-CRP. The precision of the assay was confirmed for low coefficient of variations, less than 7% for infra-assay and less than 10% for inter-assay. In clinical sample analysis, the results of hs-CRP detected by this assay were in good accordance with which obtained by commercial high sensitivity ELISA kit for in vitro diagnosis (r = 0.975). This assay required only 4 mu L of sample and could be finished in less than 30 min. It may therefore be employed as a rapid pre-screening tool to identify patients with elevated risk of CVD.