Electrochemical Sensor for Multiplex Biomarkers Detection

Purpose: Multiplexing assay of biomarkers at the point-of-care is an elusive goal for molecular diagnostics. Experimental Design: Here, we report an electrochemical (EC) sensor for oral cancer detection based on the simultaneous detection of two salivary biomarkers: interleukin (IL)-8 mRNA and IL-8 protein. Results: Under the multiplexing mode, the limit of detection of salivary IL-8 mRNA reaches to 3.9 fM and 7.4 pg/mL for IL-8 protein in saliva. Multiplex assay of these 2 biomarkers directly from 28 cancer and 28 matched control saliva samples shows significant difference between the two groups. From the receiver operating characteristic analysis, the EC sensor yields around 90% sensitivity and specificity for both IL-8 mRNA and IL-8 protein, which are very close to the data measured by traditional assays (ELISA and PCR) with the same group of saliva. Combined IL-8 mRNA and protein show better AUC compared with single biomarker. Conclusions: We show, for the first time, concurrently multiplexing detection of salivary mRNA and protein biomarkers using point-of-care EC sensor.