Drug-Checking with Molecularly Imprinted Polymers: Addressing Xylazine-Contaminated Fentanyl.

Area of Science:

• Analytical Chemistry
• Materials Science
• Forensic Science

Background:

• Xylazine adulteration of fentanyl poses a significant public health threat due to its high toxicity and prevalence in illicit drug supplies.
• Current methods for detecting xylazine in drug-checking settings are insufficient, leading to numerous overdose deaths.
• The complexity of street drug formulations complicates accurate xylazine identification.

Purpose of the Study:

• To develop and validate novel sensor platforms for the accurate detection of xylazine in drug-checking applications.
• To provide rapid and reliable screening tools for harm reduction initiatives.
• To address the challenge of xylazine adulteration in fentanyl samples.

Main Methods:

• Development of two sensor platforms based on molecularly imprinted polymers (MIPs) utilizing vinyl phosphonic acid.
• Integration of MIPs with thermometric (heat-transfer method, HTM) and colorimetric (dye displacement assay) readouts.
• Testing sensor performance with varying xylazine concentrations, interferents, and complex street-like fentanyl samples.

Main Results:

• The heat-transfer method achieved xylazine detection at low concentrations (LoD 16.5 ng/mL) within 15 minutes.
• The colorimetric sensor provided rapid (<5 min) visible detection (LoD > 76 μg/mL) and identified xylazine analogues.
• The colorimetric sensor successfully detected xylazine in a complex fentanyl sample with multiple interferents.

Conclusions:

• The developed MIP-based sensors offer a promising solution for xylazine detection in harm reduction settings.
• The combination of thermometric and colorimetric approaches provides versatile screening capabilities for xylazine and its analogues.
• These sensors can significantly enhance drug-checking services and contribute to mitigating overdose risks.