A switchable Gquadruplex device with the potential of a nanomachine for anticancer drug detection

The unique ability of living systems to translate biochemical reactions into mechanical work has inspired the design of synthetic DNA motors which generate nanoscale motion via controllable conformational change. It is believable that G-quadruplex structures in certain regions of the genome may play a role in the poor maintenance of genomic stability, which is a characteristic of many types of cancers. In this regards, formation and stabilization of the quadruplex structures at the telomeric repeats is an effective way to hamper the telomere extension and blocking the elongation step. Here, we report a DNA machine for selective Gquadruplex-binding ligand recognition, based on a conformational change; the forces exerted by the precise DNA machine for Gquadruplex conformational change were probed via an electrical signal transducer electrochemically by differential pulse voltammetry and cyclic voltammetry. The proposed machine was prepared by modifying the screen-printed graphite electrode (SPE) with the synthesized SBA-N-propylpipyrazine-N-(2-mercaptopropane-1-one) (SBA@NPPNSH) mesoporous structures and Au nanoparticles (AuNPs). The thiolated functionalized groups of SBA@NPPNSH structures can help for preconcentration of the synthesize AuNPs on the surface. Then SH-G4DNA was linked to the modified electrode by an AuNPsS bond. The morphology of constructed machine was characterized by the Field emission scanning electron microscope (FESEM).