Simultaneous detection of salivary Δ9-tetrahydrocannabinol and alcohol using a Wearable Electrochemical Ring Sensor

Driving under the influence of cannabis and alcohol represents a major safety concern due to the synergistic or additive effect of these substances of abuse. Hence, rapid road-site testing of these substances is highly desired to reduce risks of fatal accidents. Here we describe a wearable electrochemical sensing device for the simultaneous direct, decentralized, detection of salivary THC and alcohol. The new ring-based sensing platform contains a voltammetric THC sensor and an amperometric alcohol biosensor on the ring cap, along with the wireless electronics embedded within the ring case. Rapid replacement of the disposable sensingelectrode ring cap following each saliva assay is accomplished by aligning spring-loaded pins, mounted on the electronic board (PCB), with the current collectors of the sensing electrodes. The printed dual-analyte sensor ring cover is based on a MWCNT/carbon electrode for the THC detection along with a Prussian-blue transducer, coated with alcohol oxidase/chitosan reagent layer, for the biosensing of alcohol. THC and alcohol can thus be detected simultaneously in the same diluted saliva sample within 3 min, with no cross talk and no interferences from the saliva matrix. The new wearable ring sensor platform should enable law enforcement personnel to screen drivers in a single traffic stop and offers considerable promise for addressing growing concerns of drug-impaired driving.