Rapid and sensitive detection of protein biomarker using a portable fluorescence biosensor based on quantum dots and a lateral flow test strip.

A portable fluorescence biosensor with rapid and ultrasensitive response for protein biomarker has been built up with quantum dots and a lateral flow test strip. The superior signal brightness and high photostability of quantum dots are combined with the promising advantages of a lateral flow test strip and result in high sensitivity and selectivity and speed for protein detection. Nitrated ceruloplasmin, a significant biomarker for cardiovascular disease, lung cancer, and stress response to smoking, was used as model protein biomarker to demonstrate the good performances of this proposed quantum dot-based lateral flow test strip. Quantitative detection of nitrated ceruloplasmin was realized by recording the fluorescence intensity of quantum dots captured on the test line. Under optimal conditions, this portable fluorescence biosensor displays rapid responses for nitrated ceruloplasmin with the concentration as low as 1 ng/mL. Furthermore, the biosensor was successfully utilized for spiked human plasma sample detection in a wide dynamic range with a detection limit of 8 ng/mL (S/N = 3). The results demonstrate that the quantum dot-based lateral flow test strip is capable of rapid, sensitive, and quantitative detection of nitrated ceruloplasmin and hold a great promise for point-of-care and in field analysis of other protein biomarkers.