# Single-layer biosensor for urinary prostate-cancer biomarkers through transition-metal-doped graphene: a DFT study

## TL;DR

This study explores using metal-doped graphene as a biosensor to detect prostate cancer biomarkers in urine, finding silver-doped graphene to be most effective for one key compound.

## Contribution

The novel contribution is identifying Ag-doped graphene as a promising room-temperature biosensor for sarcosine detection in prostate cancer screening.

## Key findings

- Ag-doped graphene shows optimal sensing for sarcosine with strong adsorption and band-gap tuning.
- Pristine and Au/Pd-doped graphenes fail to effectively detect both target biomarkers.
- Furan-3-methanol detection requires alternative chemistries or device designs.

## Abstract

Early, non-invasive detection of prostate cancer (PCa) remains a major clinical challenge, as current screening methods carry significant drawbacks. Biosensors targeting urinary PCa biomarkers offer a promising alternative. Motivated by the recurrent appearance of sarcosine and furan-3-methanol in urinary volatilomics, and by the growing application of 2D nanomaterials in metabolite detection, we employed first-principles calculations to investigate pristine graphene and gold-, palladium-, and silver-doped graphenes as potential single-layer biosensors. We compared atomic optimizations, adsorption energies, band-gap shifts, charge-density differences, recovery times, conductivity changes, and theoretical sensing responses to identify the most effective sensor. Our results revealed that pristine graphene fails to adsorb either molecule; Au-doping binds sarcosine strongly but inadequately retains furan-3-methanol; Pd-doping leads to insufficient retention for both analytes; and Ag-doping enables rapid desorption of furan-3-methanol yet provides optimal sensing for sarcosine. Overall, Ag-doped graphene demonstrates strong potential as a room-temperature sensor for sarcosine, while detecting furan-3-methanol will require alternative chemistries or device architectures.

Ag-doped graphene is identified by DFT as the most responsive single-layer sensor for urinary sarcosine, combining strong adsorption, clear band-gap tuning, and viable room-temperature recovery.