A kind of modified bovine serum albumin with great potential for applying in gene delivery

Bovine serum albumin (BSA) was modified through a facile synthesis method to increase its isoelectric point (pI) from 4.8 to 6.0. When pH is higher than 6.0, the protein shows a negative surface charge, on the contrary, the protein is positively charged. In this study, the charge-reversal modified BSA (crBSA) was utilized to assemble with the binary complexes of pDNA/poly(vinylpyrrolidone)-graft-poly(2-dimethylaminoethyl methacrylate) (pDNA/PVP-g-PDMAEMA) to shield the excess positive charges of complexes at physiological pH (pH 7.4). When the complex coated with crBSA located in the environment at endosomal pH (pH 5.0), the charge-reversal of crBSA led to the deviation of crBSA from polyplex by electrostatic repulsion, which would benefit the transfection of the target gene. The crBSA shows great potential for improving the transfection efficiency of pDNA/PVP-g-PDMAEMA.