An Electrochemical Sensor Based on Amino Magnetic Nanoparticle-Decorated Graphene for Detection of Cannabidiol

MXene-poly(propylene carbonate) nanofiber network-based modification of SPE interfaces for electrochemical immuno-sensing of synthetic cannabinoid

The decriminalization and legalization of cannabis have increased its consumption and the need for effective monitoring methods. Synthetic cannabinoids, while chemically distinct from natural cannabinoids like THC, can be more potent and cause severe adverse effects, often evading detection by traditional drug tests. Thus, there is a critical need for new biosensors that offer rapid, sensitive, and reliable detection of these compounds in biological samples. This study presents a novel electrochemical immunosensor based on aminated MXene integrated with poly(propylene carbonate) (PPC) nanofibers and monoclonal antibodies designed to enhance the detection of synthetic cannabinoids. The PPC/MXene-NH₂ nanofibers, electrospun onto screen-printed electrodes (SPEs), provide increased surface area and high sensitivity, stability, and selectivity. The biosensor achieved a wide detection range of 0.6-2000 ng/mL in saliva, a low limit of detection (LOD) of 0.66 ng/mL, and demonstrated excellent specificity. It showed high repeatability and reproducibility with minimal signal degradation, with vacuum-sealed storage proving to significantly extend sensor stability over time. These results highlight the potential of MXene-enhanced PPC nanofiber immunosensors as sensitive, selective, and portable tools for rapid detection of synthetic cannabinoids in clinical and forensic settings.

Copper-Cobalt Nanozyme Mimicking Laccase for Sensitive Colorimetric Determination of Cannabidiol in Food and Cosmetics

In colorimetric analysis, nanozymes are invaluable tools due to their simple production, long-lasting stability, and adaptable enzymatic activity, which enable them to induce changes in substrate color. In this study, a simple nanozyme-based colorimetric sensor was developed to detect cannabidiol (CBD) by using the laccase activity of the self-made MOF with copper and cobalt loading (Cu/Co@MOF) nanozyme, which was synthesized using a one-pot microwave method. The Cu/Co@MOF has the ability to catalyze the coupling reaction between 4-AP and various phenolic substrates, thereby converting colorless phenolic substrates into red substances. Notably, 16 ng/mL was the limit of detection. Based on Y = 0.137X + 0.003 equation, absorbance and CAN concentrations (0.067 to 10 μg/mL with a correlation value [R2] of 0.993) had a significant correlation. The developed colorimetric method was subsequently employed to determine CBD in facial masks and essential oil samples, resulting in relative standard deviations (RSDs) ranging from 1.4% to 4.3%. Therefore, this sensitive, cost-effective, and rapid method ensures an effective determination of CBD in food and cosmetics.

Nanomaterials-Based Electrochemical Δ9-THC and CBD Sensors for Chronic Pain

Chronic pain is now included in the designation of chronic diseases, such as cancer, diabetes, and cardiovascular disease, which can impair quality of life and are major causes of death and disability worldwide. Pain can be treated using cannabinoids such as Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD) due to their wide range of therapeutic benefits, particularly as sedatives, analgesics, neuroprotective agents, or anti-cancer medicines. While little is known about the pharmacokinetics of these compounds, there is increasing interest in the scientific understanding of the benefits and clinical applications of cannabinoids. In this review, we study the use of nanomaterial-based electrochemical sensing for detecting Δ9-THC and CBD. We investigate how nanomaterials can be functionalized to obtain highly sensitive and selective electrochemical sensors for detecting Δ9-THC and CBD. Additionally, we discuss the impacts of sensor pretreatment at fixed potentials and physiochemical parameters of the sensing medium, such as pH, on the electrochemical performance of Δ9-THC and CBD sensors. We believe this review will serve as a guideline for developing Δ9-THC and CBD electrochemical sensors for point-of-care applications.

An electrochemical aptasensor for Δ9-tetrahydrocannabinol detection in saliva on a microfluidic platform

We present a novel "on-off", cost-effective, rapid electrochemical aptasensor combined with a microfluidics cartridge system for the detection of Δ⁹-THC (Δ⁹-tetrahydrocannabinol) in human saliva via differential pulse voltammetry. The assay relied on the competitive binding between the Δ⁹-THC and a soluble redox indicator methylene blue, using an aptamer selected via FRELEX. We found that the aptasensor can detected 1 nM of Δ⁹-THC in PBS in a three-electrode cell system, while the sensitivity and both the dissociation constant (K_d) and association constant (K_b) were dependent on the aptamer density. The aptamer also showed great affinity towards Δ⁹-THC when tested against cannabinol and cannabidiol. The same limit of detection of 1 nM in PBS was achieved in small volume samples (∼60 μL) using the aptamer-modified gold screen-printed electrodes combined with the microfluidic cartridge setup, however, the presence of 10% raw human saliva had a negative effect which manifested in a 10-fold increase in the LOD due to interfering elements. Filtering the saliva, improved the tested volume to 50% and the LOD to 5 nM of Δ⁹-THC which is lower than the concentrations associated with impairment (6.5-32 nM). The aptasensor showed a good storage capability up to 3 days, however, the reusability significantly dropped from 10 cycles (freshly prepared) to 5 cycles. The results clearly demonstrate the feasibility of the aptasensor platform with the microfluidics chamber towards a point-of-care testing application for the detection of Δ⁹-THC in saliva.

Electrochemical Detection of Olivetol Based on Poly(L-Serine) Film Layered Copper Oxide Modified Carbon Paste Electrode (p-L-Serine/CuO/CPE)

Olivetol is an important polyphenol compound and intermediate in the synthesis of cannabinoids possessing many types of biological activities. A facile electrochemical sensor for olivetol was fabricated based on p-L-serine, and copper oxide (CuO) nanoparticles modified carbon paste electrode (p-L-serine/CuO/CPE). The proposed p-L-serine/CuO/CPE was applied to the electrochemical detection of olivetol by cyclic voltammetry (CV) and differential pulse voltammetric (DPV). Through the characterizations of materials and modified electrodes, the p-L-serine/CuO/CPE exhibited enhanced electrochemical signals for olivetol compared to bare CPE and CuO/CPE in both CV and DPV methods. Under the optimized conditions, the proposed p-L-serine/CuO/CPE showed a good quantitative analysis ability and a wide analysis range from 20 to 100 μmol L^-1 of olivetol with a limit of detection of 1.04 μmol L^-1. Based on the reproducibility, repeatability, and stability exhibited by this fabricated sensor and the cheap and accessible raw materials, the p-L-serine/CuO/CPE became a novel determination choice for olivetol in the electrochemical method with the advantages of being cost-effective and convenient.

Portable biosensors for rapid on-site determination of cannabinoids in cannabis, a review

Recent studies highlight the therapeutic virtues of cannabidiol (CBD). Furthermore, due to their molecular enriched profiles, cannabis inflorescences are biologically superior to a single cannabinoid for the treatment of various health conditions. Thus, there is flourishing demand for Cannabis sativa varieties containing high levels of CBD. Additionally, legal regulations around the world restrict the cultivation and consumption of tetrahydrocannabinol (THC)-rich cannabis plants for their psychotropic effects. Therefore, the use of cannabis varieties that are high in CBD is permitted as long as their THC content does not exceed a low threshold of 0.3%-0.5%, depending on the jurisdiction. These chemovars are legally termed 'hemp'. This controlled cannabinoid requirement highlights the need to detect low levels of THC, already in the field. In this review, cannabis profiling and the existing methods used for the detection of cannabinoids are firstly evaluated. Then, selected valuable biosensor technologies are discussed, which suggest portable, rapid, sensitive, reproducible, and reliable methods for on-site identification of cannabinoids levels, mainly THC. Recent cutting-edge techniques of promising potential usage for both cannabis and hemp analysis are identified, as part of the future cultivation and agricultural improvement of this crop.