title: Small Molecule Detection in Saliva Facilitates Portable Tests of Marijuana Abuse.
abstract: As medical and recreational use of cannabis, or marijuana, becomes more prevalent, law enforcement needs a tool to evaluate whether drivers are operating vehicles under the influence of cannabis, specifically the psychoactive substance, tetrahydrocannabinol (THC). However, the cutoff concentration of THC that causes impairment is still controversial, and current on-site screening tools are not sensitive enough to detect trace amounts of THC in oral fluids. Here we present a novel sensing platform that employs giant magnetoresistive (GMR) biosensors integrated with a portable reader system and smartphone to detect THC in saliva using competitive assays. With a simple saliva collection scheme, we have optimized the assay to measure THC in the range from 0 to 50 ng/mL, covering most cutoff values proposed in previous studies. This work facilitates on-site screening for THC and shows potential for testing of other small molecule drugs and analytes in point-of-care (POC) settings.
authors.affiliation: Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Jung-Rok
authors.initials: JR
authors.lastname: Lee
authors.affiliation: Department of Electrical Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Joohong
authors.initials: J
authors.lastname: Choi
authors.affiliation: Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Tyler O
authors.initials: TO
authors.lastname: Shultz
authors.affiliation: Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States.|Department of Electrical Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Shan X
authors.initials: SX
authors.lastname: Wang
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D015374:Biosensing Techniques / Q000379:methods; D002417:Cattle; D013759:Dronabinol / Q000032:analysis* / Q000276:immunology; D006801:Humans; D007118:Immunoassay / Q000379:methods; D060328:Magnetic Phenomena; D002189:Marijuana Abuse / Q000175:diagnosis*; D053758:Nanoparticles / Q000737:chemistry; D012463:Saliva / Q000737:chemistry*; D012710:Serum Albumin, Bovine; D000068997:Smartphone; D015813:Substance Abuse Detection / Q000379:methods*
chemical_list: D000906:Antibodies; D012710:Serum Albumin, Bovine; D013759:Dronabinol