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Introduction <p>Silicon and nitrogen co-doped carbon quantum dots (SiN@CQDs) showed the strongest potential as a sensing platform for pathogen mycotoxins. Frontier molecular orbital analysis showed that SiN@CQD had the smallest intrinsic HOMO–LUMO gap (1.51&#xa0;eV) compared to N@CQD and Si@CQD, indicating enhanced chemical softness, charge mobility, and reactivity. Adsorption of aflatoxin (AFT), dothistromin (DTM), and versicolorin (VCR) on SiN@CQD was spontaneous and thermodynamically favorable, with energies of − 2.62, − 2.81, and − 2.95&#xa0;eV, respectively. Natural bond orbital analysis revealed strong bidirectional charge transfer between toxins and the quantum dot surface, with the VCR–SiN@CQD complex exhibiting the highest stabilization energy and smallest donor–acceptor gap. Density of states, atomic charge, and molecular electrostatic potential analyses further demonstrated pronounced charge redistribution near the Fermi level following adsorption. Quantum theory of atoms in molecules (QTAIM) and non-covalent interaction (NCI) results confirmed adsorption via hydrogen bonding, π–π stacking, and electrostatic interactions. Overall, these findings provide molecular-level evidence supporting SiN@CQD as a promising candidate to guide subsequent experimental design of toxin detection systems.</p> Methods <p>All calculations were performed using Gaussian 09 software. Density functional theory (DFT) computations were carried out using the PBE0 hybrid functional with Grimme’s D3 dispersion correction (PBE0-D3) and the Def2-SVP basis set. Natural bond orbital (NBO) analysis was carried out with NBO 3.0 to quantify charge transfer and donor–acceptor interactions. Quantum theory of atoms in molecules, NCI, and density of states (DOS) analyses were conducted using Multiwfn 3.8. Molecular orbitals, topological features, and isosurfaces were visualized using visual molecular dynamics (VMD). Finite CQD surface models were used to represent local adsorption environments.</p>

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Density functional theory investigation of adsorption and charge transfer of fungal polyketide mycotoxins on Si, N Co-doped carbon quantum dots

  • 期刊论文

  • 发表日期：

    2026年6月23日

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  • Temitope Ruth Folorunso,
  • Precious Uchechi Ebereonwu,
  • Adetomiwa Ayomipo Fasanmi,
  • Siddanagouda R. Shivanagoudra,
  • David John

摘要

Introduction

Silicon and nitrogen co-doped carbon quantum dots (SiN@CQDs) showed the strongest potential as a sensing platform for pathogen mycotoxins. Frontier molecular orbital analysis showed that SiN@CQD had the smallest intrinsic HOMO–LUMO gap (1.51 eV) compared to N@CQD and Si@CQD, indicating enhanced chemical softness, charge mobility, and reactivity. Adsorption of aflatoxin (AFT), dothistromin (DTM), and versicolorin (VCR) on SiN@CQD was spontaneous and thermodynamically favorable, with energies of − 2.62, − 2.81, and − 2.95 eV, respectively. Natural bond orbital analysis revealed strong bidirectional charge transfer between toxins and the quantum dot surface, with the VCR–SiN@CQD complex exhibiting the highest stabilization energy and smallest donor–acceptor gap. Density of states, atomic charge, and molecular electrostatic potential analyses further demonstrated pronounced charge redistribution near the Fermi level following adsorption. Quantum theory of atoms in molecules (QTAIM) and non-covalent interaction (NCI) results confirmed adsorption via hydrogen bonding, π–π stacking, and electrostatic interactions. Overall, these findings provide molecular-level evidence supporting SiN@CQD as a promising candidate to guide subsequent experimental design of toxin detection systems.

Methods

All calculations were performed using Gaussian 09 software. Density functional theory (DFT) computations were carried out using the PBE0 hybrid functional with Grimme’s D3 dispersion correction (PBE0-D3) and the Def2-SVP basis set. Natural bond orbital (NBO) analysis was carried out with NBO 3.0 to quantify charge transfer and donor–acceptor interactions. Quantum theory of atoms in molecules, NCI, and density of states (DOS) analyses were conducted using Multiwfn 3.8. Molecular orbitals, topological features, and isosurfaces were visualized using visual molecular dynamics (VMD). Finite CQD surface models were used to represent local adsorption environments.