Controlling bio-reaction on the interface of the nanoparticles by pH response polymer chain

We investigated the bioconjugation of membrane protein on polymer nanoparticles covered with bioinert phosphorylcholine groups. Poly [2-methacryloyloxyethyl phosphorylcholine (MPC) -co- n-butyl methacrylate-co- p-nitrophenyloxycarbonyl polyethyleneglycol methacrylate (MEONP) (PMBN)] was used as an emulsifier and a surface modifier to prepare the poly (L-lactic acid) nanoparticles by a solvent evaporation technique in aqueous medium. The diameter and surface potential of the nanoparticles were approximately 260 nm and -5∼0 mV, respectively. It thought the polymer chain that changed the structure by the pH change was used as a method of controlling the bio-reaction. Poly glutamic acid (PGA) that changed from the random coil to α-helix the polymer chain structure changing the pH was used. The enzyme activity in a pH different under the coexistence of PGA and the enzyme was measured. Therefore the activity rate rose in pH 6 in PGA/enzyme mixture system while the activity rate was constant in the enzyme single conjugation regardless of the pH change.