The Investigation On Uptake Of DNA Origami Nanostructures In Tumor Multicellular Spheroids

Nanostructures can effectively improve the uptake and selective accumulation of drugs in solid tumor tissues,and become a promising means of anti-tumor therapy.What's more,researches have found that the transport and delivery of nanostructures in tumor tissues can be effectively improved by regulating the properties of nanostructures,such as size,shape,surface charge and so on.Due to the interference of complex environments in vivo and the differences between different material systems,these studies have not reached a unified conclusion at this stage.Therefore,with the help of a relatively simple three-dimensional model in vitro,it is imperative to investigate the effects of the physical and chemical properties of nanostructures on their penetration and accumulation in tumor tissues systematically.However,the traditional method of nanostructures preparation is often difficult to use the same material to meet the requirements of shape and surface physical and chemical properties regulate at the same time.Whereas DNA origami has the characteristics of powerful shape designability,excellent addressability and easy functionalization,so it is an ideal solution to deal with these above problems.In this paper,a series of DNA origami nanostructures(DNs),with different shapes,hydrophobicity and charge modification were designed based on DNA origami,and three-dimensional tumor multicellular spheres(MCSs)were constructed by the non-scaffold method.The effects of shape,hydrophobicity and surface charge on the uptake and penetration of nanostructures in MCSs were systematically explored.The main research results are as follows:(1)DNs with five different shapes were constructed based on DNA origami.The results of cell experiments showed that smaller aspect ratio was beneficial to monolayer cell uptake of DNs,however in MCSs,smaller size and larger aspect ratio were beneficial to DNs uptake and penetration.In addition,the DNA origami structure was only internalized by peripheral cells,it was difficult to penetrate into the interior of MCSs.(2)By introducing different numbers of ss DNA-lipid hydrophobic molecules into the surface of DNA origami nanorods(Rod),it was proved that the penetration efficiency of nanostructures in MCSs could be significantly improved by introduced appropriate amount of hydrophobic molecules.Nevertheless,too high proportion of hydrophobic modification would cause the agglomeration of Rod nanostructures,thus reducing the penetration efficiency and penetration depth in MCSs.(3)The c HSA-Tile nanostructure with the overall positive electricity and the C-Tile nanostructure modified by partial regionalized positive charge were constructed by electrostatic adsorption and atom transfer radical polymerization(ATRP),respectively.The experimental results showed that the coated of c HSA could significantly improve the uptake efficiency of DNs in MCSs,while the C-Tile nanostructure not only had higher uptake efficiency,but also could evenly penetrate into MCSs.