Abstract
Here, we report a novel magnetic resonance imaging (MRI)/fluorescence bimodal amplification platform for the detection of glutathione (GSH) on the basis of redoxable manganese dioxide (MnO2) nanosheets, which can be readily applied as a DNA nanocarrier, fluorescence quencher, and intracellular GSH-activated MRI contrast agent. The binding of aptamers that absorbed on the MnO2 nanosheets to their target can facilitating the endocytosis of target-nanoprobes. Once endocytosed, the MnO2 nanosheets can react with cellular GSH, resulting in the disintegration of nanosheets to generate plenty of Mn2+ ions for MRI and releases the primers which were adsorbed on the MnO2 nanosheets. Then the rolling circle amplification (RCA) reaction was initiated to amplify the fluorescence signal. In addition, after treatment with GSH, the MnO2 nanosheets were reduced and then most of the fluorescence was recovered. Therefore, this MnO2 nanoprobe exhibits excellent selectivity, suggesting a potential detection platform for analyzing the glutathione level in cells.
Highlights
In the presence of target cells, MnO2 nanosheets can react with intracellular GSH, resulting in the disintegration of the nanosheets and complete release of primers which were adsorbed in the MnO2 nanosheets
Under the action of Phi[29] DNA polymerase, the rolling circle amplification (RCA) reaction was initiated by adding circular DNA template (CDT, the circular template used in this study; its sequence is given in Table S1 in supporting information) and deoxynucleotides
The modified hairpin DNA probes were measured with a fluorescence spectrometer
Summary
After treatment with GSH, the MnO2 nanosheets were reduced and most of the fluorescence was recovered This MnO2 nanoprobe exhibits excellent selectivity, suggesting a potential detection platform for analyzing the glutathione level in cells. There are various analytical techniques to use for GSH detection, such as fluorescence spectroscopy[7], colorimetric assay[8], magnetic resonance spectroscopy[9], surface enhanced Raman scattering (SERS)[10], enzyme-linked immunosorbent assay[11], electrochemiluminescence (ECL)[12], and high performance liquid chromatography (HPLC)-based separation followed by electrochemical detection[13] These conventional methods that were developed early still encounter several challenges, such as tedious electrode modifications, high cost, low sensitivity. It provides a convenient to develop a platform with active MRI contrast agents and fluorescence signals
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