Laser-Assisted Scalable Manufacturing of Nanoporous Carbon Electrodes for Rapid and Low-Cost Detection of Opioid and Non-Opioid Drugs in Biofluids

Ineffective pain management is becoming a serious health problem in the United States, affecting at least 50 million individuals as of 2020. Fentanyl-based opioid medicines are highly effective at managing severe pain but are the leading source of morbidity and mortality. On the other hand, non-opioid substitutes like lidocaine are nearly very effective but again have systemic toxicity complications from overdosage. As clinicians and medical authorities try to practice multimodal drugs with both opioids and non-opioids to reduce their respective complications, control over such drugs depends upon an individual’s bodily characteristics. Thus, it is necessary to develop systems that could detect the amount of drugs present in the human body for effective drug administration. However, the main obstacle along with the progress toward mass production and commercialization of these sensors is the inability to find a simple and cost-effective manufacturing process.<br/>Laser-carbonization is a potential technology that allows carbonized materials to be used in 2D electronics and high-surface-area applications. Unlike traditional deposition techniques like PVD and CVD, laser carbonization yields a swift synthesis route for manufacturing porous carbon materials directly onto a polymeric substrate without the need for any post-processing and patterning approaches. This manufacturing technique offers a rapid and localized elevation in temperature on the polyimide surface converting it into a nanoporous carbon electrode. Moreover, altering the laser parameters on the polyimide surface could potentially obtain the desired surface characteristics and electrical properties towards the electrochemical detection of target analytes.<br/>Herein, we demonstrate the use of laser-induced hierarchical carbon patterns on polyimide substrates for opioid drug sensing application in human biofluid by exploring square wave voltammetry (SWV) toward rapid, decentralized “in-field” fentanyl and lidocaine detection. The sensor consists of a three-electrode pattern rastererd out using a CO₂ laser (10.6 μm), with carbon working-counter electrode and Ag/AgCl ink modified reference electrode. Forward scan oxidation peak at +0.526 and +0.7 V was observed towards fentanyl and Lidocaine in SQW in 0.1 M of PBS solution. SWV profile reports rapid sensing of the opioid at micromolar level in the occurrence of other co-existing cutting agents frequently found in unlawful drug formulations. This novel sensor elucidates the effective detection of fentanyl and lidocaine in various biofluid environments, thereby elucidating its accuracy in a real-time environment. Such sensors could be envisioned to be an initial step towards the detection of pain relief drugs at various biofluids using scalable and mass-manufacturable electrode strips. Development of such low-cost wearable surfaces would help these sensors to be equipped for first responders and police officers to monitor the civilians under influence.