Wrapping DNA-gated mesoporous silica nanoparticles for quantitative monitoring of telomerase activity with glucometer readout

Abstract

This work reports a simple and sensitive sensing protocol for the quantitative monitoring of telomerase activity based on target-responsive release of cargo from wrapping DNA-capped mesoporous silica nanoparticles (MSNs) by coupling with a portable personal glucometer (PGM). To construct such an assay system, glucose molecules are initially loaded into the pores of the aminated MSN, and the pores are then sealed with a specially designed wrapping DNA. Upon the addition of telomerase and dNTPs, the assembled wrapping DNA strands are prolonged with the assistance of telomerase on the aminated MSN. Accompanying the progression of telomerase, the extended DNA strands detach from the MSN, owing to the formation of rigid, hairpin-like DNA structures. The “molecular gates” are then opened, resulting in the release of glucose from MSN. The released glucose molecules can be quantitatively monitored using an external PGM. The PGM signal increases with the increment of telomerase activity. Under optimal conditions, the PGM-based sensing platform exhibits good analytical properties for the determination of telomerase activity and allows for the detection of telomerase activity in the HeLa extract at concentrations as low as 80 cells mL⁻¹. Using somatic and tumor cell lines, the generality of the assay is evaluated with satisfactory results. The inhibition effect of 3′-azido-3′-deoxythymidine also receives a good performance in the telomerase-inhibitor screening research. The methodology affords good reproducibility and simple operations, thus providing a useful scheme for practical use in a quantitative telomerase activity assay for clinical application.