Quantitative and sensitive detection of SARS coronavirus nucleocapsid protein using quantum dots‐conjugated RNA aptamer on chip

Abstract BACKGROUND: Globally, severe acute respiratory syndrome coronavirus (SARS‐CoV) is a newly emerging virus that causes SARS with high mortality rate in infected people. The nucleocapsid (N) protein of the severe acute respiratory syndrome (SARS)‐associated coronavirus (SARS‐CoV) is an important antigen for the early diagnosis of SARS and the detection of diseases. Here, a new quantum dots (QDs)‐conjugated RNA aptamer with high sensitivity and rapidity is proposed for the detection of SARS‐CoV N protein using an on chip system. RESULTS: A QDs‐conjugated RNA aptamer can specifically hybridize on the immobilized SARS‐CoV N protein on the surface of a glass chip. Detection is based on the optical signal variation of a QDs‐supported RNA aptamer interacting on an immobilized protein chip. Using an optical QDs‐based RNA aptamer chip, SARS N protein was detected at concentrations as low as 0.1 pg mL −1 . CONCLUSIONS: It was demonstrated that the QDs‐conjugated RNA aptamer could interact on a designed chip specifically and sensitively. This device could form a QDs‐conjugated biosensor prototype chip for SARS‐CoV N protein diagnosis. The proposed visual SARS‐CoV N protein detection technique may avoid the limitations of other reported methods because of its high sensitivity, good specificity, ease of use, and the ability to perform one‐spot monitoring. Copyright © 2011 Society of Chemical Industry