Protein Coating of DNA Origami

DNA origami has emerged as a common technique to create custom two- (2D) and three-dimensional (3D) structures at the nanoscale. These DNA nanostructures have already proven useful in development of many biotechnological tools; however, there are still challenges that cast a shadow over the otherwise bright future of biomedical uses of these DNA objects. The rather obvious obstacles in harnessing DNA origami as drug-delivery vehicles and/or smart biodevices are related to their debatable stability in biologically relevant media, especially in physiological low-cation and endonuclease-rich conditions, relatively poor transfection rates, and, although biocompatible by nature, their unpredictable compatibility with the immune system. Here we demonstrate a technique for coating DNA origami with albumin proteins for enhancing their pharmacokinetic properties. To facilitate protective coating, a synthesized positively charged dendron was linked to bovine serum albumin (BSA) through a covalent maleimide-cysteine bonding, and then the purified dendron-protein conjugates were let to assemble on the negatively charged surface of DNA origami via electrostatic interaction. The resulted BSA-dendron conjugate-coated DNA origami showed improved transfection, high resistance against endonuclease digestion, and significantly enhanced immunocompatibility compared to bare DNA origami. Furthermore, our proposed coating strategy can be considered highly versatile as a maleimide-modified dendron serving as a synthetic DNA-binding domain can be linked to any protein with an available cysteine site.