Multi-Modal Spectroscopic and Biochemical Approaches for Fentanyl Detection: Integrating Raman, ATR-FTIR, and Enzyme Kinetics Analysis

When drugs enter the body, they cause molecular changes in biological tissues that can be detected using spectroscopic methods. Fentanyl binds to specific receptors in the nervous system, but this creates biochemical effects throughout the body that alter protein structure in various tissues, including growing nails. This research combines spectroscopic analysis of human nails with enzyme studies to understand both how to detect fentanyl exposure and why these detection methods work at the molecular level.
Human nail samples from clinically validated subjects were analyzed using Raman and ATR-FTIR spectroscopy combined with machine learning classification algorithms. To understand the molecular mechanisms behind the observed spectroscopic changes, we used butyrylcholinesterase as a model protein system, investigating how fentanyl analogues affect enzyme function through kinetic studies and comparing Raman spectra of active versus inhibited enzyme states.
Both nail-based spectroscopic methods achieved excellent donor-level accuracy. Enzyme kinetics revealed mixed inhibition with preference for binding to enzyme-substrate complexes. Importantly, Raman spectroscopy of enzyme samples showed clear structural differences between active and inhibited states, demonstrating that fentanyl analogues cause detectable protein changes.
Although fentanyl receptors are concentrated in nervous tissue, systemic fentanyl exposure appears to alter the molecular composition of nail matrix during growth, as evidenced by spectroscopic changes in keratin-associated signatures. The enzyme studies provide direct evidence that fentanyl can alter protein structure beyond its primary receptor targets, explaining why spectroscopic signatures appear in nails. This multi-technique approach establishes both effective detection methods and the scientific foundation for understanding how drug exposure creates detectable molecular changes in biological matrices.