Recent advances on G-quadruplex for biosensing, bioimaging and cancer therapy

G-quadruplex is a three-dimensional secondary structure of nucleic acids formed by the Hoogsteen hydrogen pairing of four guanines. Diverse topologies of G-quadruplex could be employed in biosensing and bioimaging. By intercalating fluorescence dyes into G-quadruplex or forming a horseradish peroxidase (HRP)-mimicking G-quadruplex/hemin DNAzyme, G-quadruplexes based biosensors realized the sensitive and selective detection of nucleic acids, protein, enzyme activity, ions, small molecules, exosomes, cells, and microorganisms. The vital role that cellular G-quadruplexes played in genome further facilitated the application of G-quadruplex stabilizing on cancer therapy. Combined with G-quadruplex aptamer, which is an efficient therapeutic tool, a current landscape of the application potential of this fascinate nucleic acids structure from clinical diagnosis to cancer therapy is summarized here.