Smart Multiplex Point-of-Care Platform for Simultaneous Drug Monitoring

Recently, illicit drug use has become more widespreadand is linkedto problems with crime and public health. These drugs disrupt consciousness,affecting perceptions and feelings. Combining stimulants and depressantsto suppress the effect of drugs has become the most common reasonfor drug overdose deaths. On-site platforms for illicit-drug detectionhave gained an important role in dealing, without any excess equipment,long process, and training, with drug abuse and drug trafficking.Consequently, the development of rapid, sensitive, noninvasive, andreliable multiplex drug-detecting platforms has become a major necessity.In this study, a multiplex laser-scribed graphene (LSG) sensing platformwith one counter, one reference, and three working electrodes wasdeveloped for rapid and sensitive electrochemical detection of amphetamine(AMP), cocaine (COC), and benzodiazepine (BZD) simultaneously in salivasamples. The multidetection sensing system was combined with a custom-madepotentiostat to achieve a complete point-of-care (POC) platform. Smartphoneintegration was achieved by a customized application to operate, display,and send data. To the best of our knowledge, this is the first multiplexLSG-based electrochemical platform designed for illicit-drug detectionwith a custom-made potentiostat device to build a complete POC platform.Each working electrode was optimized with standard solutions of AMP,COC, and BZD in the concentration range of 1.0 pg/mL-500 ng/mL.The detection limit of each illicit drug was calculated as 4.3 ng/mLfor AMP, 9.7 ng/mL for BZD, and 9.0 ng/mL for COC. Healthy and MET(methamphetamine) patient saliva samples were used for the clinicalstudy. The multiplex LSG sensor was able to detect target analytesin real saliva samples successfully. This multiplex detection deviceserves the role of a practical and affordable alternative to conventionaldrug-detection methods by combining multiple drug detections in oneportable platform.