Development and validation of a novel leaky surface acoustic wave immunosensor array for label-free and high-sensitive detection of cyclosporin A in whole-blood samples

This manuscript described a novel 2×3 model of leaky surface acoustic wave (LSAW) immunosensor array for label-free and high-sensitive detection of Cyclosporin A (CsA) in whole-blood samples. In this technique, every resonator crystal unit of the LSAW immunosensor array had an individual oscillator circuit to work without mutual interference. The LSAW immunosensor was first immobilized with protein A from Staphylococcus aureus and monoclonal anti-CsA antibody on the gold electrode surface of 100 MHz LiTaO3 piezoelectric crystals, which then captured the CsA. The CsA increased the mass loading of LSAW immunosensor and leaded to phase shifts of LSAW. Consequently, under optimal conditions, the designed LSAW immunosensor exhibited a detection limit of 0.89 ng/mL, quantification limit of 2.96 ng/mL, and wide dynamic linear range from 1 ng/mL to 1000 ng/mL for CsA detection. Application of the LSAW immunosensor array to clinical sample revealed that consistency and comparability between LSAW immunosensor and the enzyme multiplied immunoassay method were good. Moreover, the immunosensor could be regenerated for ten times without appreciable loss of activity. Therefore, the self-designed LSAW immunosensor array provided a rapid, accurate, label-free, easy handling, and dynamic real-time method for the detection of immunosuppressive drugs in clinical laboratory.