Two-dimensional coordination polymer-based nanosensor for sensitive and reliable nucleic acids detection in living cells

Abstract

A reliable and sensitive strategy which can assess nucleic acid levels in living cells would be essential for fundamental research of biomedical applications. Some nanomaterial-based fluorescence biosensors recently developed for detecting nucleic acids, however, are often with expensive, complicated and time-consuming preparation process. Here, by using a facile bottom-up synthesis method, a two-dimensional (2D) coordination polymer (CP) nanosheet, [Cu(tz)] (Htz = 1,2,4-triazole), was successfully prepared after optimizing reaction conditions. These ultrathin CP nanosheets with thickness of 4.7 ± 1.1 nm could readily form nanosensors by assembly with DNA probes, which exhibited a low limit of detection (LOD) for p53 DNA fragment as 144 pmol/L. Furthermore, by integrating [Cu(tz)] nanosheets with hybridization chain reaction (HCR) probes, miR-21, one kind of microRNA upregulated in many cancer cells, can be sensitively detected with a LOD of 100 pmol/L and monitored in living cells, giving consistent results with those obtained by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis. Thus [Cu(tz)] nanosheets, which not only possess much better nucleic acids sensing performance than bulk cystals, but also exhibit nucleic acid delivery functions, could be used as a novel nanoplatform in biomedical imaging and sensing applications.