A CdSe/ZnS quantum dot (QD) based electrochemical immunoassay of phosphorylated bovine serum albumin as a protein biomarker is presented. The QDs were used as labels and were conjugated with the secondary anti-phosphoserine antibody in a heterogeneous sandwich immunoassay. First, the primary BSA antibody was immobilized on polystyrene microwells, followed by the addition of BSA-OP. After that, the QD-labeled anti-phosphoserine antibody was added into microwells for immunorecognition. Finally, the bound QD was dissolved in an acid-dissolution step and was detected by electrochemical stripping analysis. The measured current responses were proportional to the concentration of BSA-OP. Under optimal conditions, the voltammetric response was linear over the range of 0.5 - 500 ng mL-1 of BSA-OP, with a detection limit of 0.5 ng mL-1 at a deposition potential of -1.2 V for 120 s. It also shows good reproducibility with a relative standard deviation of 8.6% of six times determination of 25 ng mL-1 of BSA-OP. This QD-based electrochemical immunoassay offers great promise for simple and cost-effective analysis of protein biomarkers.
Revised: December 3, 2010 |
Published: November 15, 2010
Citation
Pinwattana K., J. Wang, C.T. Lin, H. Wu, D. Du, Y. Lin, and O. Chailapakul. 2010.CdSe/ZnS quantum dots based electrochemical immunoassay for the detection of phosphorylated bovine serum albumin.Biosensors and Bioelectronics 26, no. 3:1109-1113.PNNL-SA-76397.doi:10.1016/j.bios.2010.08.021