Construction And Application Of Functionalized Cell Membrane Vesicles Based On DNA Nanostructures

Cell-derived cell membrane vesicles have good biocompatibility and low immunogenicity,and can be used as a biomimetic carrier with excellent properties for drug delivery.However,cell membrane vesicles themselves do not have a targeted recognition effect.Therefore,how to improve the specific recognition ability of cell membrane vesicles has become an urgent problem to be solved in the development of cell membrane vesicles as biomimetic carriers.Based on the advantages of DNA molecules such as designability and good programmability,DNA as a natural biological material has been widely used in the field of biomedicine.Among them,nucleic acid aptamers with recognition ability can specifically bind various targets from ions to proteins.Based on the principle of base complementation,combining nucleic acid aptamers with DNA nanostructures c an construct DNA functional modules with recognition capabilities and flexibly control the recognition performance of DNA functional modules.Based on the unique advantages of DNA nanotechnology,in this paper,we constructed DNA nanostructures modified by nucleic acid aptamers and modified them on the surface of cell membrane vesicles,thereby improving the ability of cell membrane vesicles to recognize target cells.Using this cell membrane vesicle as a carrier,we load gold carbon dots（GCDs）into cell m embrane vesicles and use them to m o n i t o r r e d o x c h a n g e s i n t a r g e t c e l l s.T h e s p e c i f i c w o r k i s a s f o l l o w s :（1）We designed two DNA nanostructures with targeting effects,and anchored the nanostructures on the surface of cell membrane vesicles,thereby giving the cell membrane vesicles specific recognition of target cells.We first constructed a DNA logic gate structure composed of DNA tetrahedrons,I-motif sequences and nucleic acid aptamer Sgc8.This combined DNA nanostructure is responsive to the slightly acidic environment of tumors.When exposed to an acidic p H environment,I-motif is released from the logic gate structure and at the same time restored the targeting ability of the Sgc8 aptamer.The DNA hybrid strand displacement reaction（HCR）can generate repeating unit structures.Based on this DNA nanostructure,we integrate the nucleic acid aptamer Sgc8 with it to obtain DNA functional units with multivalent recognition capabilities,which can be achieved by increasing the surface of the vesicles.Connect the number of aptamers to increase their ability to bind to target cells.This functional modification method based on DNA nanotechnology provides a new idea for the functional modification of cell membrane vesicles and expands the biomedical applications of cell membrane vesicles.（2）We loaded gold carbon dots（GCDs）into cell membrane vesicles,and modified the cell membrane vesicles using the above-mentioned DNA logic gate nanostructure to obtain cell membrane vesicles that can monitor the redox stat e of target cells.On the one hand,DNA logic gates modified on the surface of cell membrane vesicles can respond logically to environmental stimuli and biomarkers.On the other hand,after GCDs enter the target cells,the fluorescence characteristics of GCDs can be used to monitor the changes in the redox state of the cells in real time,providing a new way for real-time monitoring of the effects of drugs on tumor cells.