Single-Walled Carbon Nanotube and its Copper/Nitrogen dual-modified Derivatives as Biosensors for Liver Cancer Biomarkers: Insight from Computational Approach

This study explores the modification of Single-Walled Carbon Nanotubes (SWCNTs) with nitrogen and copper for its application in the sensing of liver cancer biomarkers; hexanal (HXN), limonene (LMN), methanol (MTN), octenol (OTN) and pentanal (PTN). The study employed the M06-2X/D3/Def2svp level of theory for the optimization of the studied interactions, utilizing density functional theory (DFT) calculations. Natural bond orbital (NBO) analysis gave insight to the transfer of charges between the orbitals of the adsorbate and adsorbent, highlighting that adsorption took place. Adsorption energies ranged from − 0.81 eV to − 2.72 eV, indicating chemisorption across the studied complexes, with the more negative values suggesting stronger, more stable adsorbate–adsorbent interactions. Non-covalent interaction (NCI) analysis showed a mixture of interaction types within each complex: weak van der Waals forces were predominant in most systems, while steric repulsion dominated in MTN-@CuNCNT. Regions of strong, covalent-like interaction (denoted by blue in the NCI iso-surfaces) were also identified, indicating localized strong bonding contributing to the overall adsorption strength. The findings in this study suggest that modification of SWCNTs improved its performance, with promising results showing the potential of the modified surfaces to be used as sensors for liver cancer biomarkers.