Self-generated single-drop microextraction enhanced aggregation-induced emission strategy based on magnetic...

Lung cancer is one of the most common malignancies with low prevention efficiency and high mortality, so prevention and early detection are very important. In this work, we propose a magnetic metal-organic skeleton nanomaterial bound to biological nucleic acid chains in a spatially confined magnetic single-drop microextraction (SDME) system to enhance the aggregation-induced emission (AIE) effect for fluorescence detection of miRNA-21 associated with lung cancer. DNA/MOF network structure was formed, and loaded with an AIE material, 4',4''',4''''',4'''''''-(ethene-1,1,2,2-tetrayl) tetrakis-([1,1-biphenyl]-3-carboxylic acid) (H₄ETTC), by DNA amplification reaction. From a serum sample, the structure was then spontaneously collected, forming a single drop at the end of a magnetic rod in less than 10 s by utilizing a magnetic SDME process. In this self-generated single drop, the structure was aggregated and the fluorescence signal of H₄ETTC was enhanced. Direct detection by fluorescence spectrophotometry was enabled. The limit of detection of miRNA-21 was 0.194 fM, and the linear range of miRNA-21 was 1 fM to 100 nM, respectively. The method was applied to the fluorescence detection of miRNA in human serum samples. The relative recoveries were 98.4 %-104.5 %.