Synthesis of aptamer-functionalized Ag nanoclusters for MCF-7 breast cancer cells imaging

Aptamer-functionalized silver nanoclusters(Ag NCs) have been attracting a lot of interest as label-free probes which have been successfully applied to both cell imaging and molecular detection.MUCl aptamer is an ssDNA aptamer that specifically binds to MUCl mucin which is a large transmembrane glycoprotein whose expression level increases at least 10-fold in primary and metastatic breast cancers.Using C4A4C3-linker-MUCl as template,the Ag NCs were synthesized through one-pot process.The fluorescence intensity of Ag NCs was found to be closely related to the length and type(poly adenine or thymine) of the linker,the optimum linker being-AAAAA-.Using the C4A4C3-A5-MUC1 as the scaffold,the synthesized Ag NCs emitted fluorescence with high quantum yield(QY) of 66.5%.Based on the specific interaction between the MUCl aptamer and MUCl mucin,the C4A4C3-A5-MUC1-stabilized Ag NCs could recognize and differentiate the MCF-7 breast cancer cells from MDA-MB-231 breast cancer and A549 human lung cancer cells.