Enzymatical biomineralization of DNA nanoflowers mediated by manganese ions for tumor site activated magnetic resonance imaging

DNA nanoflower has been demonstrated as a promising DNA nanostructure for therapeutics and bioimaging primarily because of the programmable DNA sequence and unique structure. Herein, we report manganese ions mediated enzymatic biomineralization to prepare DNA-Mn hybrid nanoflower (DMNF). Paramagnetic Mn2+ was explored as the co-factor of DNA polymerase for the extension of long strand DNA. The biomimetic synthesis of DMNF was performed using the long strand DNA as template via nucleation and growth of Mn2PPi. The morphology and size of DMNF were controllable by tuning reaction time and Mn2+ concentration. The aptamer sequence was encoded into circle template to achieve tumor-targeted DMNF, and cellular uptake assay demonstrated obvious aptamer-mediated internalization. DMNF showed enhanced T1-weighted magnetic resonance (MR) imaging effect in acid environment for high tumor-specific MR imaging, and high spatial resolution imaging of kidneys and liver. Our work provides a facile enzymatically biomineral strategy to integrate multifunctional modules into one DNA structure and promotes the development of DNA nanostructure for precision medicine.