Researchers show off a pen-like instrument in ACS’ Analytical Chemistry that can swiftly and non-invasively gather molecules from the skin’s surface for mass spectrometry-based opioid screening.
A pen-like tool collects molecules from the skin that can be screened for opioids. Image Credit: William Clarke, Johns Hopkins University School of Medicine
Opioids such as fentanyl, morphine, and oxycodone are the drugs most associated with overdoses in the United States. Blood, saliva, or urine samples are commonly collected as part of drug testing.
Liquid chromatography mass spectrometry (LCMS) is a typical analytical method for detecting opioids in blood, saliva, and urine. Clinic-based LCMS screening has great detection and sensitivity, but sample collection and preparation are complex and time-consuming.
Opioids are found in the skin as well as body fluids. So William Clarke, Livia Eberlin, and colleagues collaborated to transform their handheld MasSpec Pen into a modular tool that rapidly captures molecules from the skin's surface to be tested for opioids, avoiding the need for additional sample preparation.
The new MasSpec Pen delivers a small droplet of water and ethanol to the skin's surface. While sitting there, the liquid removes molecules that could indicate previous drug usage. After 3 seconds, the pen draws the liquid droplet into a collection vial. The material can be evaluated immediately using electrospray ionization mass spectrometry or kept for later analysis.
Following successful proof-of-concept demonstrations on human skin patches, the MasSpec Pen was tested on the arm or hand of eight participants who had previously been exposed to fentanyl and hydromorphone. When the researchers compared the novel collecting tool’s skin sample data with previously gathered urine and saliva data, they discovered:
- Fentanyl in seven of the MasSpec Pen skin samples, but no hydromorphone
- Fentanyl and hydromorphone in all eight urine samples
- Fentanyl in five saliva samples (one sample could not be tested) and hydromorphone in four saliva samples
Although the samples obtained by the MasSpec Pen did not have the same degree of detection as the urine and saliva samples, the device’s ease of use and portability indicate potential for future improvement.
The researchers point out inconsistencies may be due to the timing of medication consumption vs testing. Future research by the researchers may look at the effect of skin type, skin cleanliness, and drug exposure on the MasSpec Pen’s detection and analysis of opioids.
The authors gratefully acknowledge support from the Eli Lilly Young Investigator Award, a Welch Research Grant, and Thermo Fisher Scientific. The Cooperative Human Tissue Network Institutional Review Board authorized the methodology for collecting the human skin samples utilized in this study. The clinical investigation followed the authorized protocol from the Johns Hopkins University School of Medicine.
Some writers are affiliated with MS Pen Technologies, Inc., a company commercializing the MasSpec Pen, and they own patents on the device.
Journal Reference:
Gatmaitan, A. N., et al. (2025) Development and Application of the Modular MasSpec Pen System for Clinical Opioid Screening. Analytical Chemistry. doi.org/10.1021/acs.analchem.5c00558.