Cannabinoid sensing
in biofluids provides great insight into the
effects of medicinal cannabis on the body. The prevalence of cannabis
for pain management and illicit drug use necessitates knowledge translation
in cannabinoids. In this Review, we provide an overview of the current
detection methods of cannabinoids in bodily fluids emphasizing electrochemical
sensing. First, we introduce cannabinoids and discuss the structure
and metabolism of Δ9-THC and its metabolites in relation
to blood, urine, saliva, sweat, and breath. Next, we briefly discuss
lab based techniques for cannabinoids in biofluids. While these techniques
are highly sensitive and specific, roadside safety requires a quick,
portable, and cost-effective sensing method. These needs motivated
a comprehensive review of advantages, disadvantages, and future directions
for electrochemical sensing of cannabinoids. The literature shows
the lowest limit of detection to be 3.3 pg of Δ9-THC/mL
using electrochemical immunosensors, while electrodes fabricated with
low cost methods such as screen-printing and carbon paste can detect
as little as 25 and 1.26 ng of Δ9-THC/mL, respectively.
Future research will include nanomaterial modified working electrodes,
for simultaneous sensing of multiple cannabinoids. Additionally, there
should be an emphasis on selectivity for cannabinoids in the presence
of interfering compounds. Sensors should be fully integrated on biocompatible
substrates with control electronics and intelligent components for
wearable diagnostics. We hope this Review will prove to be the seminal
work in the electrochemical sensing of cannabinoids.