Title
Cationic Polyelectrolyte Modified Fluorescent DNA-Silver Nanoclusters for Rapid Bioimaging with Enhanced Emission and Higher Stability
Author
Danya Lyu, Jing Li, Xiaowen Wang, Weiwei Guo, Erkang Wang
Year
2018
Journal
analytical chemistry
Abstract
DNA templated silver nanoclusters (DNA-Ag NCs) have shown great potential in various bioanalysis and bioimaging applica-tions, owing to the facile synthesis, ultra-small sizes, and especially the programmable fluorescence emission depending on the sequences of DNA templates. However, the bioimaging applications of DNA-Ag NCs are severely limited by the poor stability in physiological environments and the poor cell permeability of the Ag NCs resulted from highly negatively charged DNA backbones. In this paper, cationic polyelectrolytes were used to modify fluorescent DNA-Ag NCs via electrostatic interaction between the positive polymer backbones and the negatively charged phosphate groups of DNA strands. The fluorescence property of a typical single-stranded DNA (ssDNA) templated Ag NCs changed dramatically after incorporating with the cati-onic polyelectrolyte caused by the conformation changes of DNA, with a three-fold fluorescence emission enhancement of Ag NCs observed after incorporated with a typical cationic polyelectrolyte, poly(diallyldimethylammonium chloride) (PDDA), while the fluorescence of double-stranded DNA (dsDNA) templated Ag NCs changed a little after incorporating. Moreover, the modification of PDDA greatly prolong the stability of both ssDNA and dsDNA stabilized Ag NCs against nuclease digestion and enhanced the cell uptake of the DNA-Ag NCs. Ultrafast cell imaging was demonstrated using NIH/3T3 cell as a model system.
Instrument
J-715
Keywords
Circular dichroism, DNA structure, Chemical stability, Nanostructures, Materials, Biochemistry