Electrochemical bioplatforms for the simultaneous determination of interleukin (IL)-8 mRNA and IL-8 protein oral cancer biomarkers in raw saliva.

The development of electrochemical magnetobiosensors for the simultaneous determination of two biomarkers associated with salivary oral cancer, protein IL-8 and its messenger RNA (IL-8 mRNA) associated, in undiluted human saliva samples is reported in this work. The implemented methodology involves the use of functionalized magnetic beads, specific antibodies against IL-8 protein, a specific hairpin DNA sequence for IL-8 mRNA and amperometric detection at disposable dual screen printed carbon electrodes. This methodology exhibits high sensitivity and selectivity for the target analytes providing detection limits of 0.21 nM for IL-8 mRNA and 72.4 pgmL(-1) (far below the clinical established cut-off of 600 pgmL(-1)) for IL-8 protein in undiluted saliva samples. The dual amperometric magnetobiosensor was applied to the direct determination of both biomarkers in spiked raw saliva samples and to determine the endogenous content of IL-8 protein in saliva samples from 7 healthy individuals. The obtained results were statistically in agreement with those provided by a commercial ELISA kit.