Magnetic-bioluminescent-nanoliposomes for ultrasensitive and portable detection of protein biomarkers in blood.

Protein biomarkers play an important role in the diagnosis and treatment of disease. Herein, we report an ultrasensitive magnetic-bioluminescent-nanoliposome based technique using a portable ATP luminometer for the point-of-care testing (POCT) of protein biomarkers in blood. In this study, we use alpha-fetoprotein (AFP, a protein biomarker associated with hepatocellular carcinoma) as a model protein. The bioluminescent nanoliposomes conjugated to magnetic particles (LBM) enabled target protein capture, isolation and detection. In this assay, we use a portable magnetic bead separation pen to simplify the steps. The output RLUs (relative light units) had a linear correlation with AFP concentration between 0.05 and 1000 ng/mL, with a limit of detection of 0.016 ng/mL. Our LBM assay for AFP based on the portable luminometer exhibited high specificity for AFP, with no cross-reactivity with other proteins tested at 25 ng/mL. Forty clinical samples (twenty AFP positive and twenty AFP negative) were tested by the LBM assay, and the results were in good agreement with those determined by electrochemiluminescence, with relative deviations of less than 10%. The successful application of magnetic-bioluminescent-nanoliposomes with a portable ATP luminometer system to detect protein biomarkers in blood has opened a new avenue for biomarker testing. Thus, our LBM assay holds great potential as a POCT assay for use in clinical diagnostics.