# Detection of Lung Cancer Biomarkers C3H6O, CH2O, and C5H8 through Pd‑, Pt‑, and Ag-Doped BC6N Monolayers: A Density Functional Theory Study

## TL;DR

This paper explores using metal-doped BC6N monolayers to detect lung cancer biomarkers in breath, offering a noninvasive diagnostic approach.

## Contribution

The study introduces Ag-doped BC6N as a superior sensor material for detecting specific VOCs linked to lung cancer.

## Key findings

- Ag-doped BC6N shows stronger adsorption and faster recovery times for VOCs compared to Pd- and Pt-doped variants.
- Electronic modulation and orbital hybridization upon VOC adsorption enhance sensing performance.
- Ag-doped BC6N is identified as a promising candidate for reusable and sensitive lung cancer detection via breath analysis.

## Abstract

Early detection of lung cancer remains a major clinical
challenge,
limited by the high cost, invasiveness, and insufficient sensitivity
of current diagnostic methods. Exhaled volatile organic compounds
(VOCs), such as acetone (C3H6O), formaldehyde
(CH2O), and isoprene (C5H8), have
emerged as promising noninvasive biomarkers, with elevated concentrations
observed in the breath of lung cancer patients. In this study, we
employ density functional theory (DFT) to evaluate the sensing performance
of pristine and transition-metal (TM)-doped (Pd, Pt, and Ag) BC6N monolayers toward these VOCs. TM doping was found to significantly
enhance adsorption strength and sensing response compared to the pristine
surface, with Pd-, Pt-, and Ag-doped BC6N exhibiting notably
greater adsorption energies (−0.295 to −2.211 eV) than
the pure monolayer (0.001 to −0.086 eV). Among the dopants,
Ag–BC6N displays the most favorable sensing properties,
including moderate adsorption energies (−0.295 to −0.535
eV), short adsorption distances (2.23–2.31 Å), and rapid
recovery times (9.74 × 10–4 to 9.84 ×
10–8 s), indicating superior reversibility relative
to Pd and Pt. Band structure, charge transfer, and projected density
of states (PDOS) analyses further reveal strong orbital hybridization
and electronic modulation upon VOC adsorption. These findings establish
Ag–BC6N, in particular, as a highly promising sensor
for sensitive, scalable, and reusable detection of lung cancer biomarkers
via breath analysis.