Applications Of DNA-and BSA-based Self-Assemblies On Cells

Self-assembly is an effective method to fabricate materials due to its extraordinary properties.Biomacromolecules based self-assemblies have been applied for living cell imaging,cancer diagnosis and drug delivery system widely because of their good bio-compatibility and bio-degradability.DNA is a high biocompatible biomaterial with good designability.Bovine serum albumin(BSA)is an bovine serum abundant protein which low cost.In this study,we have fabricated biomaterials-based self-assemblies for living cell imaging and drug delivery system using bovine serum albumin(BSA)and DNA.The self-assemblies are used to load doxorubicin,an anticancer drug which are easy to be loaded on DNA double helix and protein due to the hydrophobic interaction and electrostatic interaction.Ethanol,propyl alcohol and isopropyl alcohol have been used as desolvating agent to fabricate BSA nanoparticles.After fully investigating the properties of these BSA nanoparticles,the results indicate that all the desolvating agents can produce uniform BSA nanoparticles with good biocompatibility.In addition,propyl alcohol and isopropyl alcohol show stronger desolvating ability,whilst ethanol can help to achieve size control.Based on the investigation above,biomacromolecular fluorescent nanoparticles,DNA@BSA nanoparticles,were developed through a facile desolvating process using single-stranded DNA segments and BSA molecules.The obtained nanoparticles have a narrow and relatively uniform size distribution with an average size of about 122 nm and the PDI value 0.087.Moreover,the DNA@BSA nanoparticles can be accumulated in MCF-7 cells and achieve living cell imaging.To achieve target drug delivery and fluorescent imaging,we used DNA aptamer as targeting unit to fabricate drug carrier.Firstly,we systematically compared the affinity of S2.2,AS1411 and SYL3 C to MCF-7 cells.These aptamers were heated to break the hydrogen bonds and subsequently treated by annealing,ice bath and room temperature cooling,respectively.Finally,the affinity of these aptamers was evaluated by flow cytometry.The results indicate that AS1411 shows the highest affinity to MCF-7.This work provides more evidence to choose aptamers.Based on the results above,we chose AS1411 to fabricate DNA nanocarriers.Inspired by natural structure of bean sprouts and cockleburs,two kinds of DNA assemblies were designed and constructed.The so-called “DNA bean sprout” and “DNA nano-cocklebur” show high doxorubicin loading ability and effective targeting inhibiting ability to MCF-7 cells.