Study Of Nano-spherical Polymer Brush And Its Binding With Bovine Serum Albumin

Through photo-emulsion polymerization, this study synthesizes the thermo-sensitive core-shell structured nano-particle--polymer brush. Use polystyrene as the core and linear polymers intensely attached to the core by chemical bonding like brushes. It can absorb metal ions, enzymes and diagnostic groups selectively. This study explored the interactions between the particles with BSA by dynamic light scattering (DLS), turbidity and pH titration and analyze the influence from the surrounding factors like Temperature、Ionic Strength and PH. Due to the stability of its combination with proteins, it has a great potential in biomedicine research.(1) Through the photo-emulsion polymerization, this study synthesizes three kinds of electric neutrality nano-spherical polymer brush-PS-PNIPA、PS-PDEA and PS-PAAm. Use the DLS to study the distribution of diameter and the response to temperature、ionic strength and PH. The results show that the former2have the Lower Critical Solution Temperature(LCST) and it will form the [H] with water below the LCST then show the swelling situation-hydrophilic. When the temperature increases, the system will shrink because of the hydrophobic from Alkyl Group.(2) Through the Turbidity titration, we study the interactions between PS-PNIPA> PS-PDEA and BSA. The results show these systems can make the binding with BSA through [H] when temperature is less than30℃.When the temperature increases, because of the hydrophobic and the [H], it can reduce the denaturation of BSA. The same phenomenon can be seen when the graft density increases. For PS-PDEA, because of its special structure, its LCST will change according to the different amounts of SDS. They have the positive correlation. For PS-PAAm system, although it doesn’t have the thermo-sensitive property, it still can bind with BSA through [H]. With increasing of the graft density, the mutual interaction will increase. Because of the different steric hinerance in these three systems, they have different results when binding with BSA.(3) Add BIS as a cross-linking agent into the three systems, it can make the chain network. With the increasing amount of BIS, the diameter will decrease. When the systems have interaction with BSA, the interaction power is bigger than before and the power will increase with decreasing amount of BIS and increasing amount of monomer.