Abstract
Carcinoembryonic antigen (CEA) is an important broad-spectrum tumor marker. For CEA detection, a novel type of metal–organic framework (MOF) was prepared by grafting CEA aptamer-incorporated DNA tetrahedral (TDN) nanostructures into PCN-222 (Fe)-based MOF (referred as CEAapt-TDN-MOF colloid nanorods). The synthesized CEAapt-TDN-MOF is a very stable detection system due to the vertex phosphorylated TDN structure at the interface, possessing a one-year shelf-life. Moreover, it exhibits a significant horseradish peroxidase mimicking activity due to the iron porphyrin ring, which leads to a colorimetric reaction upon binding toward antibody-captured CEA. Using this method, we successfully achieved the highly specific and ultra-sensitive detection of CEA with a limit of detection as low as 3.3 pg/mL. In addition, this method can detect and analyze the target proteins in clinical serum samples, effectively identify the difference between normal individuals and patients with colon cancer, and provide a new method for the clinical diagnosis of tumors, demonstrating a great application potential.
Highlights
Zeta potential of PCN-222 (Fe) as well as the synthesized representation of molecular recognition event that occurred between DNA-AuNPs and the Schematic representation of molecular recognition event that occurred between DNA-AuNPs newly prepared tetrahedron nanostructure (TDN)’-metal–organic framework (MOF), with a transmission electron microscope (TEM) image
DNA tetrahedron was successfully the surface of PCN-222 (Fe), that is,indithe cating a strong molecular recognition. These results fully demonstrate that a tetraCEAapt -TDN-MOF was successfully prepared
The results show that the signal response value of CEAapt-TDN-MOF was higher than that of CEAapt -MOF under the same conditions (CEA concentration is 20 ng/mL), which was probably because the rigid structure of TDN could effectively promote the molecular recognition between the aptamer sequence and target protein, while the flexible single-strand structure might adhere to the surface of the MOF material and reduce the than that of carcinoembryonic antigen (CEA)
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. The nano-MOFs crystals can be dispersed in various chemical solvents in the form of colloids [19] Based on this strategy, they fabricated functional complexes of DNA-MOF that exhibited very great application potential in drug and protein delivery [20,21]. We designed and prepared DNA tetrahedron nanostructure (TDN)functionalized MOF colloid nanorods as a colorimetric biosensor for the sensitive detection of the tumor marker carcinoembryonic antigen (CEA) (Scheme 1, referred as CEAapt -TDNMOF). In order to achieve a good molecular recognition and interface assembly process, zirconium metal ions were used as ligands so as to realize high-efficiency coordination assembly with vertex phosphorylation-modified DNA tetrahedron, as well as the successful integration of a CEA aptamer sequence in a TDN structure for capturing targets. 3,30 ,5,50 -tetramethylbenzidine (TMB) was used as the substrate
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