Nanoparticle-Decorated Micropillars As Integrated Raman Spectroscopy and Mass Spectrometry Substrates for Quantitative and High-Throughput Toxicology Drug Analysis

The overarching goal of this research is to develop a nanoparticle (NP)-decorated microneedle array for orthogonal high-throughput analysis of toxicology samples using surface-enhanced Raman spectroscopy (SERS) and substrate-supported electrospray ionization-mass spectrometry (ssESI-MS) “multimodal” techniques. Strikingly, in 2022 DEA has seized enough fentanyl that can kill the entire US population. Furthermore, CDC data from January 2022 to September 2022 reveal the second largest number of drug related death (80,000) for a 9-month period ever recorded, including 1150 adolescents. The epidemic has accelerated during the COVID-19 pandemic with a reported 38-50% increase in opioid overdoses in 28 states. Such dismal statistics impose ever greater challenges for criminal justice and drug analysis in forensic toxicology.  LC-MS is the gold standard for analysis, but this technique is labor and time intensive and has proven too complex to implement in most local tox labs. Consequently, serious backlogs have emerged nationally across jurisdictions. This project will utilize uniquely shaped gold NPs in the fabrication of a new NP-decorated microneedle array which functions as both a highly sensitive SERS substrate for Raman analysis as well as an efficient sample preparation and ionization device for ssESI-MS. SERS analysis provides a unique spectroscopic fingerprint for each drug, with signal strength correlated to concentration. ssESI-MS is faster and less labor-intensive than LC-MS, with near equivalent specificity and selectivity. Together, SERS and ssESI-MS are orthogonal and complementary techniques that will be highly specific and able to unambiguously identify relevant concentrations of a large majority of potent drugs (pg/mL). The array will enable high-throughput toxicology drug analysis with minimal sample prep. SERS-ssESI-MS has demonstrated efficacy on a small number of drugs in preliminary studies, but important questions need to be addressed: (1) Do the structural properties of NP-decorated microneedle arrays enable ultrasensitive and highly specific toxicology drug analysis without a purification step? (2) Can this technology provide reliable information for practitioners and courts? (3) How does multimodal analysis-based specificity and selectivity compare with LC-MS in forensic applications? (4) Is this method suitable for implementation for high-throughput drug analysis in local forensic laboratories nationwide? SERS-MS will be used to analyze ~600 whole blood and plasma biospecimens from IU Health and the Indiana State Toxicology Laboratory to assess system feasibility in comparison with LC-MS. Findings will be shared with the Society of Forensic Toxicologists, in workshops, and elsewhere for ultimate use by forensic, healthcare, and law enforcement to battle the drug overdose epidemic. CA/NCF