As submitted by the applicant: The goal of this project is to develop a more specific method for the presumptive determination of designer drugs in biological fluids based on surface enhanced Raman spectroscopy. Gold nanoparticles in the presence of chloride salts aggregate producing enhanced Raman signals for drugs of abuse in saliva and urine. This permits a quick detection of trace levels of these drugs in situations such as drug overdose, driving under the influence, and workplace testing. The procedure is rapid and unlike immunoassays can quickly detect synthetic analogs of known drugs based on searchable spectra.
Currently toxicological screening is carried out using a set of antibodies with varying specificity and sensitivity toward drug targets. Situations can occur in which antibodies fail or lack specificity towards a target compound. This can be particularly problematic with synthetic cannabinoids (spice) of which new derivatives of each compound are being developed to defeat detection. Instead, we will use Surface Enhanced Raman Spectroscopy (SERS) a technique which can permit detection of ng/mL levels of the drugs and provide spectral identification of unknowns.
The project will involve a collaborative effort between the FIU Department of Chemistry, Thermo Scientific, and Dr. Barry Logan (Center for Forensic Science Research and Education). Testing of blank and spiked saliva and urine from 25 volunteers who will mostly consist of college students will be included. The study will involve the optimization of surface enhanced Raman spectroscopy for drug screening by determining the optimum mixtures of sample extracts and gold nanoparticles to detect trace levels of drugs extracted from saliva and urine. Different aggregating agents will be studied to enhance the interactions between the drug extracts and the particles and achieve high sensitivity. We will then apply this method to detect and screen a variety of synthetic cannabinoids and their metabolites that will be identified by specific and characteristic peaks that are representative of the individual drugs. Once this is completed, rapid extraction techniques using pipette tips coated with solid phase media (Zip-Tips) will be developed. This procedure will be combined with a portable Raman spectrometer for a faster and easier detection of saliva samples. Validation studies will be performed with spiked and adjudicated samples and comparisons made with existing techniques. The results of this study will be a series of peer reviewed publications and protocols for SERS detection.
This project contains a research and/or development component, as defined in applicable law.