Determination of VEGF165 using impedimetric aptasensor based on cyclohexanehexone-melem covalent-organic framework

Mikrochim Acta. 2021 May 28;188(6):211. doi: 10.1007/s00604-021-04843-9.

Abstract

A porous nanostructured covalent-organic framework (COF) has been prepared via condensation polymerization between the two building blocks of melem and hexaketocyclohexane octahydrate (represented as M-HO-COF). Basic characterizations revealed that the M-HO-COF network was composed of C=N and highly conjugated aromatic moieties, along with a high surface area, large pore size, remarkable electrochemical activity, and strong bioaffinity toward aptamer strands. Given that the vascular endothelial growth factor 165 (VEGF165)-targeted aptamer was stably anchored over M-HO-COF via weak intermolecular forces, the prepared M-HO-COF network exhibited great potential as a sensitive and selective platform for the impedimetric VEGF165 aptasensor. Consequently, the M-HO-COF-based aptasensor displayed an ultralow limit of detection of 0.18 fg mL-1 within a wide range of VEGF165 concentrations from 1 fg mL-1 to 10 ng mL-1. Considering its strong fluorescence performance, excellent biocompatibility, and small nanosheet-like structure, the obtained COF-based aptasensor showed a superior sensing performance and regeneration capability after 7 regeneration cycles for the detection of osteosarcoma cells (K7M2 cells), which overexpressed with VEGF165, with a low limit of detection of 49 cells mL-1. For real f human serum samples, the obtained COF-based aptasensor exhibits acceptable mean apparent recoveries of 97.41% with a relative standard deviation of 4.60%. Furthermore, the proposed bifunctional aptasensor for the detection VEGF165 and K7M2 cells exhibited good stability, appropriate selectivity toward other biomarkers or normal cells, acceptable reproducibility, and applicability. A bifunctional sensing system was constructed for detecting osteosarcoma cells (K7M2 cells) and VEGF165 based on the a porous nanostructured covalent-organic framework (M-HO-COF) via condensation polymerization between melem and hexaketocyclohexane octahydrate. The M-HO-COF-based aptasensor displayed ultralow detection limit of 0.18 fg mL-1 toward VEGF165 and 49 cell mL-1 for K7M2 cells with high selectivity, acceptable reproducibility, and good stability.

Keywords: Cancer biomarkers; Covalent-organic framework; Early diagnosis; Impedimetric aptasensor; Melem and hexaketocyclohexane octahydrate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aptamers, Nucleotide / chemistry*
  • Aptamers, Nucleotide / metabolism
  • Biomarkers, Tumor / blood
  • Cell Line, Tumor
  • Cyclohexanes / chemistry
  • Electrochemical Techniques / methods*
  • Heterocyclic Compounds, 3-Ring / chemistry
  • Humans
  • Limit of Detection
  • Metal-Organic Frameworks / chemistry*
  • Triazines / chemistry
  • Vascular Endothelial Growth Factor A / analysis*
  • Vascular Endothelial Growth Factor A / blood

Substances

  • Aptamers, Nucleotide
  • Biomarkers, Tumor
  • Cyclohexanes
  • Heterocyclic Compounds, 3-Ring
  • Metal-Organic Frameworks
  • Triazines
  • Vascular Endothelial Growth Factor A
  • melem