Yttrium-encapsulated fullerene (Y@C80) mono-doping with As, Bi, Sb, and P for the enhanced sensing of methylmalonic acid (MMA) as a biomarker for vitamin B12 deficiency: A DFT study

The development of new approaches or approaches for the detection of methylmalonic acid from biological samples is now necessary for early diagnosis of vitamin B₁₂ deficiency and appropriate treatment. In this study, Yttrium-encapsulated fullerene (Y@C₈₀) doped with arsenic (As), bismuth (Bi), phosphorous (P), and antimony (Sb) was investigated for its ability to sense methylmalonic acid (MMA) as a biomarker using M06-2X/GenECP/def2svp/LanL2DZ method. The nanostructural analysis showed a marginal deviation in the bond lengths between atoms of the structure upon optimization of the structures interacting with the MMA biomarker, which demonstrated the stability of the system for sensing. The HOMO-LUMO reactivity descriptor revealed that the compound was reactive toward the sensing of the MMA biomarker, as the various systems MMA_As_Y@C₈₀, MMA_Bi_Y@C₈₀, MMA_P_Y@C₈₀, and MMA_Sb_Y@C₈₀ demonstrated relatively short energy gaps of 2.039 eV, 2.025 eV, 2.135 eV, and 2.023 eV, respectively. The nanomaterial strongly adsorbed the biomarker, as indicated by the negative adsorption energies of −0.47075 eV, −0.70478 eV, 0.9034 eV, and −0.5388 eV corresponding to MMA_As_Y@C₈₀, MMA_Bi_Y@C₈₀, MMA_P_Y@C₈₀, and MMA_Sb_Y@C₈₀, respectively; however, MMA-P-Y@C₈₀ showed a weaker ability to sense the biomarker. Additionally, the recovery time after the detection of the biomarker was relatively short, comparable to the increase in the adsorption strength, with MMA-Bi-Y@C₈₀ having the shortest recovery time (3.829 × 10⁻³⁷). This is significant for the development of a highly sensitive and efficient technique for methylmalonic acid (MMA) biomarker sensing.