A sensitive and quantitative prognosis of C-reactive protein at picogram level using mesoporous silica encapsulated core-shell up-conversion nanoparticle based lateral flow strip assay.

Abstract

C- reactive protein (CRP) is a sensitive indicator for infectious or inflammatory diseases in human which can reflect the body s inflammation latency and early pathophysiological changes. The most common detection method of serum CRP is ELISA that has been proved to be expensive and time-consuming, restricting its use in point-of-care application. In this paper, we demonstrated a lateral flow system for CRP quantification by using mesoporous silica (mSiO2) coated up-converting nanoparticles (UCNPs) (denoted as UCNPs@mSiO2) as fluorescent labels. The up-converting core can emit strong green fluorescence signals under NIR excitation light (980\xa0nm) with excellent photostability, high signal-to-noise ratio and low background fluorescence. By wrapping ultrathin mSiO2 outside, the core-shell structured UCNPs@mSiO2 exhibits good dispersity and stability meanwhile maintains strong fluorescence emission. Besides, the mSiO2 shell provides further functionalities for antibody linkage. By using a portable fluorescence sensor, we reached a CRP detection limit of 0.05\xa0ng/mL and a linear range from 0.1 ng/mL-50\xa0ng/mL, and the detection time was no more than 8\xa0min. The lateral flow test strips exhibit great stability in CRP quantification (CV%<5) and have a life time of more than 1 week at ambient temperature. Furthermore, the proposed system can work with a cloud-enabled smartphone through Bluetooth for Internet of Medical Things application. This CRP detection method proves to be rapid and easy-operated, which has great potential in early inflammatory disease perception in the point-of-care tests and future s 5G-enabled remote healthcare management.