Electrochemical Aptamer-Based Sensor for Rapid Opioid Detection in Seized Substances

Opioids are a class of highly addictive and dangerous drugs that can cause severe health consequences and death. The US is currently facing the worst drug crisis in its history known as the 'opioid epidemic', a national emergency that represents a serious threat to public safety and poses new challenges for law enforcement and forensic labs. This epidemic has been fueled by the ever-increasing availability of heroin and pharmaceutical opioids and the rise of fentanyl and its analogs. The presumptive screening of such opioids in seized samples is important for the enforcement of laws against drug possession, manufacturing, and trafficking, but existing techniques are deeply flawed. Chemical spot tests are rapid, cheap, and simple to use, but suffer from poor specificity. Handheld Raman spectrometers perform well with relatively pure drug samples, but often produce inconclusive results when challenged with street opioid samples. Lateral-flow immunoassays can detect traditional opioids like morphine and codeine, but lack the specificity and cross-reactivity required to detect new fentanyl analogs. Aptamers are excellent candidates for solving such problems associated with existing opioid-screening methods. They are artificial nucleic-acid-based bioreceptors isolated in vitro to bind to specific molecules with high affinity. The PI proposes to develop an electrochemical aptamer-based (E-AB) sensor as a user-friendly presumptive testing tool that can be used to screen for opioids in seized substances. This sensor will provide a yes-or-no answer for the presence of an opioid from either the morphine or fentanyl family within seconds for drug samples such as powders, tars, pastes, counterfeit tablets, or other formulations. This project has three aims. First, a single cross-reactive aptamer will be isolated that binds to seven morphine-related opioids without responding to interferents commonly found in street samples. Second, another aptamer will be isolated that can bind to fentanyl and at least 15 different analogs. Third, these aptamers will be engineered and chemically modified and then used to fabricate a single E-AB sensor that can simultaneously detect multiple such opioids in seized substances. This sensor will be superior to current presumptive tests, as it is more specific than chemical spot tests, more affordable and less prone to inconclusive results than handheld Raman spectrometers, and more cross-reactive to opioids than immunoassays. We believe our sensor will fulfill the need of the forensic community for reliable opioid detection to facilitate the enforcement of drug laws, gathering drug intelligence, and finally bringing the opioid epidemic to a halt. Note: This project contains a research and/or development component, as defined in applicable law, and complies with Part 200 Uniform Requirements - 2 CFR 200.210(a)(14). CA/NCF