A Rapid Response Electrochemical Biosensor for Detecting Thc In Saliva

Area of Science:

• Analytical Chemistry
• Biomedical Engineering
• Forensic Science

Background:

• Marijuana's psychoactive compound, tetrahydrocannabinol (THC), is a key indicator of impairment.
• Existing roadside tests for marijuana-impaired driving are limited, creating a need for rapid detection methods.
• Saliva offers a non-invasive medium for THC testing, correlating with blood levels.

Purpose of the Study:

• To develop a novel, rapid, electrochemical biosensor for detecting THC in human saliva.
• To establish a non-invasive, portable roadside test for identifying individuals driving under the influence of marijuana.
• To achieve a low detection limit and wide dynamic range for accurate THC quantification.

Main Methods:

• Utilized affinity biosensing with a specific antibody reaction to target THC.
• Employed impedimetric measurements for signal output related to THC concentration.
• Validated the biosensor using Fourier transform infrared spectroscopy and zeta potential studies.
• Integrated the biosensor with low-power electronics and a portable saliva swab.

Main Results:

• Achieved a low detection limit of 100 pg/ml and a dynamic range of 100 pg/ml - 100 ng/ml in saliva.
• Demonstrated rapid detection time of less than one minute.
• Confirmed successful immobilization and stability of the THC immunoassay across varying salivary pH.
• Employed a binary classification system with high performance (AUC = 0.95) for THC presence prediction.

Conclusions:

• The developed electrochemical biosensor is the first affinity-based impedimetric sensor for rapid THC detection in saliva.
• The biosensor platform shows promise as a portable, hand-held device for roadside identification of marijuana-impaired driving.
• This technology addresses the critical need for effective marijuana DUI testing, enhancing public safety.