Methods: Development started with buffer and reagent selection tests for a two-antibody sandwich assay with electrochemical detection on a sensor array. Antibody concentrations were then optimized to saliva protein levels based on linearity (R2) of standard curve, limit of detection (blank+2×StdDev), and coefficient of variation. After optimization, both electrochemical immunoassays were tested with protein standards and protein standard in saliva-spiked buffer. Finally, 11 oral cancer and 11 control clinical samples were selected to compare quantification to Luminex assay data.
Results: The protein electrochemical assays were able to discriminate between diseased and control groups with t-test p-value < 0.001. Data from the immunoassays showed strong correlation (R2=.92) with Luminex data.
Conclusion: Our data provided proof of concept data that the electrochemical protein detection platform can discriminate clinical saliva samples from oral cancer and healthy subjects. Our electrochemical immunoassays are inexpensive, fast and only needs 0.6 µl of saliva sample per reading. It puts us one important step closer to an innovative saliva based point-of-care detection of oral cancer.
Supported by PHS grant 5U01DE017790.