Search

In recent years, mesoporous silica nanoparticles have attracted attention as a promising component of nanomachines [1, 2]. Due to Si-MPs' excellent biocompatibility [3] and multiple functionalization [4], they have been [...], In this paper, an adenosine-5'-triphosphate (ATP) controlled-release strategy to construct a fluorescence sensing platform has been designed. In the sensing platform, because of ATP aptamer and single-stranded DNA (ssDNA)-linked mesoporous silica nanoparticles (Si-MPs) were hybridized, the pores of SiMPs were blocked with Au nanoparticles (AuNPs) modified with ATP aptamer. Carboxy fluorescein was plugged in channels of Si-MPs. In the presence of target molecule ATP, the ATP aptamer combined with ATP and the AuNPs got away from the pore of the surface of Si-MPs modified by ssDNA. 5-Carboxyfluorescein molecule was released to allow the fluorescent detection. By monitoring the fluorescence at 518 nm, ATP could be quantitatively detected with a detection limit of 6 x [10.sup.-8] M. The linear response range was 6 x [10.sup.-8] to 1 x [10.sup.-6] M. This assay was also able to discriminate ATP from its analogs. The controlled-release aptamer-based biosensor could have an effective application in human breast cancer MCF-7 cells. Keywords: adenosine triphosphate, aptamer, mesoporous silica nanoparticles, controlled-release, fluorescence

On the basis of the extension reaction of a telomerase substrate (TS) primer in the presence of the telomerase, the inherent signal-transduction mechanism of the hairpin fluorescence probe, and the strand-displacement property of polymerase, an amplified fluorescence detection of telomerase activity in the cancer cells was described in this manuscript. A hairpin fluorescence probe was used as not only the fluorescence signal carrier but also a template of the telomere elongation reaction. In the presence of the telomerase, the stems of the hairpin probes were opened and the telomerase activity could be determined with the fluorescence enhancement. The telomerase activity in the HeLa extracts equivalent to 40-1000 cells was detected by this method, with the multiple rounds of isothermal strand replication, which led to strand displacement, and constituted consecutive signal amplification for the novel detection paradigm that allowed measurment of telomerase activity in crude cell extracts equivalent to 4 cultured HeLa cells. Using magnetic beads as both the separation tool and the immobilization matrix of the aptamer of Ramps cells (CRL-1596, B-cell, human Burkitt's lymphoma), the detection of the amount of the Ramps cell with the low concentration of 100 cells [mL.sup.-1] confirmed the reliability and practicality of the protocol, which reveal a good prospect of this platform for analysis. 10.1021/ac902818w