N,N-DMT is a potent psychoactive compound with relevance in medical, forensic, and public health settings. Established detection methods, such as gas chromatography-mass spectrometry and immunoassays, can be effective but often require expensive equipment and specialist training. That has prompted interest in nanomaterial-based alternatives that could be faster, simpler, and easier to deploy.
Among the materials under investigation is C20 fullerene, a tiny cage-like carbon structure valued for its high surface area, electron-transfer capability and stability. Researchers have previously explored fullerene-based materials for gas and organic molecule detection, but the potential of aluminum- and zinc-doped C20 fullerenes for N,N-DMT detection had not been examined in detail.
Doping alters the fullerene’s electronic structure and chemical reactivity by introducing a metal atom into the system. In principle, that can strengthen binding to a target molecule or improve the electrical and optical responses needed for sensing.
A Computational Investigation
The study was entirely computational. The researchers used density functional theory (DFT), with the B3LYP functional and the 6-311G(d,p) basis set, to optimise molecular geometries and calculate electronic and energetic properties. They also used time-dependent DFT (TD-DFT) to assess the optical absorption associated with possible colorimetric sensing.
To investigate how the materials interacted with N,N-DMT, the team carried out Natural Bond Orbital (NBO), Non-Covalent Interaction (NCI), Reduced Density Gradient (RDG) and Electrostatic Potential (ESP) analyses.
The researchers compared adsorption energies, recovery times, calculated conductivity changes, and UV-visible spectral shifts to assess whether the doped fullerenes would be better suited to sensing, capture, or both.
The Impact of Fullerene Doping
The calculations showed that doping changed both the structure and stability of the fullerene cage. Zinc doping increased structural stability, while aluminum doping made the system slightly less stable than pristine C20. Both doped systems also showed larger HOMO-LUMO energy gaps than the undoped fullerene, with ZnC19 recording the largest value at 3.04 eV.
The strongest binding was observed in AlC19, with an adsorption energy of -49.57 kcal/mol. That points to a very strong interaction with N,N-DMT and suggests the material may be better suited to capture or removal.
ZnC19 showed a more moderate adsorption energy of -22.6 kcal/mol, a profile that is generally more attractive for sensing because the interaction is strong enough to produce a signal without being as difficult to reverse.
ZnC19 also produced the clearest electronic response. Its calculated conductivity fell from 2.67×109 to 1.67×109 S/m after N,N-DMT adsorption. By comparison, pristine C20 and AlC19 showed much smaller changes, suggesting they would be less effective for this type of electrochemical sensing.
Recovery time estimates added an important qualification. For AlC19, adsorption appeared effectively irreversible, with an extremely long calculated recovery time indicating very limited sensor reusability.
ZnC19 showed a more moderate calculated recovery time of around 3.70×104 seconds, or roughly 10 hours. That would still be slow for rapid, high-throughput sensing, but it may be workable in slower or non-continuous detection settings.
The optical data again favoured ZnC19. According to the TD-DFT analysis, its absorption wavelength shifted from 455 nm to 523 nm after binding N,N-DMT. That redshift corresponds to a visible colour change from blue to green, making ZnC19 the strongest candidate in the study for colorimetric sensing. AlC19 and pristine C20 showed smaller shifts and weaker optical sensitivity.
Further analysis supported that pattern. NBO and NCI results indicated substantial charge transfer in the ZnC19 complex, with lone-pair-to-antibonding-orbital donation contributing to a strong binding that altered both electrical and optical properties, while remaining computationally inferred to be more reversible than in the aluminum-doped system.
Taken together, the findings suggest the two doped fullerenes may be suited to different roles. ZnC19 appears to offer the more balanced theoretical sensing profile, while AlC19 appears better suited to irreversible sequestration of N,N-DMT.
A Theoretically Improved Candidate for N,N-DMT Detection
Overall, the study points to zinc-doped C20 fullerene as the more promising theoretical candidate for detecting N,N-DMT, particularly because it combines a meaningful calculated conductivity response with a pronounced optical shift. Aluminum-doped C20, meanwhile, binds the compound more strongly and appears better suited to capture or removal than to reusable sensing.
The findings are still theoretical, and experimental validation will be needed before either material can be considered for practical use. Even so, the work provides a detailed computational basis for future efforts to synthesise ZnC19 and test whether its predicted electrochemical and colorimetric behaviour can be reproduced in the lab.
Journal Reference
Alshahrani, S.M. (2026). Computational evaluation of aluminum and zinc doped C20 fullerenes as advanced sensors for the detection of the narcotic dimethyltryptamine. Scientific Reports. DOI: 10.1038/s41598-026-41537-9