OFET Cannabinoid Sensing for Rapid THC and CBD Quantification

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Solution Overview

Problem

Current methods for detecting cannabinoids are costly, time-consuming, and lack specificity and sensitivity, particularly for on-the-spot analysis of THC and CBD content in cannabis products, posing challenges for law enforcement, quality control, and consumer use.

Innovation Solution

A method using organic field-effect transistors (OFETs) with phthalocyanine derivatives and diazonium salts as probes to detect cannabinoids through electrochemical property changes, allowing for rapid, selective, and quantitative analysis of THC and CBD in liquid or gaseous samples.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high pressure liquid or gas chromatography (HPLC or GC) is used to measure cannabinoids, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvecannabinoid content measurementVSAvoidinstrument complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical chromatography systems (HPLC/GC) with an organic field-effect transistor (OFET) based electrochemical sensor system. The OFET device detects cannabinoids through electrochemical property changes in the semiconductor layer, eliminating the need for complex mechanical separation and detection equipment while achieving comparable or superior measurement precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary substance (such as a probe molecule or functionalized semiconductor material) that specifically interacts with cannabinoids to produce detectable electrochemical signals. This intermediary enables the OFET to selectively detect target cannabinoids without requiring the complex separation mechanisms of chromatography.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If HPLC or GC is used for cannabinoid analysis, then measurement precision is improved, but loss of time increases

Engineering Contradiction:
Improvecannabinoid content measurementVSAvoidanalysis time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The OFET sensor is pre-functionalized with probe molecules or functional materials that are specifically designed to interact with cannabinoids. This preliminary preparation allows for immediate detection upon sample application, eliminating the time-consuming separation and detection steps required by HPLC/GC while maintaining measurement precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces time-consuming mechanical chromatography separation processes with rapid electrochemical detection using OFET. The electronic detection mechanism provides real-time or near-real-time results without the lengthy elution and detection cycles inherent in liquid or gas chromatography.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If conventional detection methods are used, then measurement precision is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvecannabinoid content measurementVSAvoidoperational simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The OFET-based detection system is designed to be self-contained and user-friendly, requiring minimal operational skill. The device automatically performs detection and provides results without requiring the complex sample preparation, instrument operation, and data analysis skills needed for HPLC/GC systems, thereby improving ease of operation while maintaining precision.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent employs disposable OFET sensor elements that can be easily replaced rather than requiring maintenance and calibration of complex instruments. These single-use sensors eliminate the operational complexity of maintaining sophisticated chromatography equipment while providing consistent measurement precision.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Measurement precision

If fee-for-service cannabinoid testing is used, then measurement precision is improved, but loss of time increases

Engineering Contradiction:
Improvecannabinoid content measurementVSAvoidtesting delay
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The OFET device enables users to perform cannabinoid testing independently without needing to send samples to external laboratories. This self-testing capability eliminates shipping delays, laboratory backlogs, and waiting periods while maintaining accurate measurement precision through the integrated sensor system.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces centralized laboratory chromatography systems with decentralized portable OFET devices. This transition from centralized to distributed testing eliminates the time losses associated with sample transport and laboratory scheduling while providing immediate results through on-site electrochemical detection.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method provides enhanced sensitivity and selectivity for cannabinoid detection, enabling rapid, cost-effective, and accurate quantification of THC and CBD, suitable for various applications including law enforcement, quality control, and consumer devices.

Implementation Method 1

interactions between the sensor element and the cannabinoid changes or affects the sensor element's electrochemical properties

Methodology Applied
Scientific EffectElectrochemical property changes:

Data Source

PatentEP3969890B1Methods for selective detection of cannabinoids
Publication Date: 2026.01.28 UNIVERSITY OF OTTAWA
  • EP3969890B1 patent drawingFigure 1A
  • EP3969890B1 patent drawingFigure 1B
  • EP3969890B1 patent drawingFigure 1C

AI summary

Systems, devices, and methods for detecting cannabinoids in liquid or gaseous samples. In one aspect, the present invention uses a sensor element and two electrical circuit elements. When the sensor element is in contact with a sample containing a cannabinoid, interactions between the sensor element and the cannabinoid changes or affects the sensor element's electrochemical properties. Using the two electrical circuit elements, this change can be detected. An analog signal relating to the changed electrochemical properties can be measured using the two electrical circuit elements. In one implementation, there is provided an organic field effect transistor (OFET) whose signal changes when in contact with a cannabinoid containing sample.