Enzymatic photochemical sensing using luciferase-immobilized polymer nanoparticles covered with artificial cell membrane

We prepared phospholipid polymer nanoparticles immobilized with luciferase, and the nanoparticles were applied as photochemical sensing nanoparticles. An amphiphilic water-soluble polymer having a phosphorylcholine group was used as an emulsifier and a surface modifier to prepare the nanoparticles. The polymer was composed of three kinds of monomer units, that is, 2-methacryloyloxyethyl phosphorylcholine (MPC) as a hydrophilic and bioinert unit, n-butyl methacrylate as a hydrophobic unit and p-nitrophenyl ester having methacrylate as an enzyme-immobilizing unit. The p-nitrophenyl ester groups to immobilize the proteins were located on the surface of the nanoparticles. Luciferase was immobilized by the reaction between the p-nitrophenyl ester groups and the amino group. The enzymatic reaction on the nanoparticles was followed using a microdialysis system with an optical fiber having a 800 microm diameter in the probe. The nanoparticles conjugated with luciferase reacted with ATP, luciferin and oxygen. It is concluded that the nanoparticles are a promising tool for a photochemical sensing microdiagnostic system.