pH-Responsive DNA nanoassembly for detection and combined therapy of tumor.

We have developed a novel cancer theragnostic nanoassembly with high biocompatibility, stability and low toxicity which are activated rapidly by tumor microenvironment to realize selective fluorescence imaging, chemotherapy as well as chemoenzymatic therapy. The nanoprobes are synthesized by hybridization of fluorophore labeled hairpin DNAs containing a 5-aza-dC at hemimethylated CpG sites and pH-sensitive DNA sequence covalently conjugated with PEGylated GO. The aptamer, which is also covalently conjugated on PEGylated GO, enables to target the tumor site and the weak acid environment of tumor triggers the release of drug loaded by nanoprobes including functionalized DNA and DOXs, effectively activating fluorescence signals and selectively killing the tumor cells. The results revealed that the nanoprobe enables sensitive detection of pH changes within subcellular environment, selectively imaging and great synergy of multicombination therapeutic including chemotherapy and chemoenzymatic therapy, implying that developed pH activatable probe has considerable potential for diagnosis and efficient therapy of cancer.