Adhesion to cells of enzyme conjugated phospholipid polymer nanoparticles

We investigated the bioconjugation of proteins on polymer nanoparticles covered with bio-inert phosphorylcholine groups. Poly[2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate-co-p-nitrophenyloxycarbonyl polyethyleneglycol methacrylate] was used as an emulsifier and a surface modifier to prepare the poly (L-lactic acid) nanoparticles by a solvent evaporation technique. The diameter and surface potential of the nanoparticles were approximately 260 nm and -5 mV, respectively. We considered that the polymer chain that transformed the conformation by change in pH may be used as a method of controlling the bio-reaction. The enzyme activity in a different pH under the coexistence of poly (glutamic acid) (PGA) and the enzyme was measured. Therefore, the enzyme activity increased in pH 6 in PGA/enzyme mixture system compared with that in pH 7 while the activity was constant in the enzyme single conjugation regardless of the pH change.