Multicomponent zirconium-based metal-organic frameworks for impedimetric aptasensing of living cancer cells

Abstract

We have synthesized a series of zirconium-based metal-organic frameworks (Zr-MOFs) using 1,4-dicarbxybenzene (DB), 2-aminoterephthalic acid (AA), and the mixture of AA and 2,5-diaminoterephthalic acid (DA) as ligands (represented by UiO-66, UiO-66-NH2, and UiO-66-2NH2, respectively) and developed them as platforms to anchor phosphate group-modified aptamer (PO4-Apt) and sensitively detect living Michigan cancer foundation-7 (MCF-7) cancer cells. The diversity, complexity, and amino-functionality of UiO-66-2NH2 were increased, but retained the nature of the pristine UiO-66. Compared with UiO-66 and UiO-66-NH2, the multicomponent UiO-66-2NH2 exhibited significant electrochemical activity and stronger bio-affinity toward PO4-Apt via the π−π∗ stacking, electrostatic interaction, and covalently bonds of Zr-O-P. These merits of UiO-66-2NH2 endowed the corresponding aptasensor with high ability to stabilize the formed aptamer-cells complex in aqueous solution. Meanwhile, compared with the label-free immobilized aptamer, PO4-Apt can form strong covalent bond with Zr-atom centers, thus promoting aptamer immobilization and boosting the sensing performance. The developed UiO-66-2NH2-based aptasensor displayed highly significant biosensing to detect MCF-7 cells and showed extremely low detection limit of 31 cell mL−1 in a wide linear range from 100 to 100,000 cell mL−1, as well as high specificity, good stability, and outstanding reproducibility. The present work studied the modulated sensing ability of the multicomponent MOFs for living cancer cells and provided alternative approach for the early diagnosis of cancer.