Encapsulation of GFP in Complex Coacervate Core Micelles.

Protein encapsulation with polymershas a high potential for drugdelivery, enzyme protection and stabilization. Formation of such structurescan be achieved by the use of polyelectrolytes to generate so-calledcomplex coacervate core micelles (C3Ms). Here, encapsulation of enhancedgreen fluorescent protein (EGFP) was investigated using a cationic-neutraldiblock copolymer of two different sizes: poly(2-methyl-vinyl-pyridinium)41-b-poly(ethylene-oxide)205andpoly(2-methyl-vinyl-pyridinium)128-b-poly(ethylene-oxide)477. Dynamic light scattering and fluorescence correlationspectroscopy (FCS) revealed a preferred micellar composition (PMC)with a positive charge composition of 0.65 for both diblock copolymersand micellar hydrodynamic radii of approximately 34 nm. FCS data showthat at the PMC, C3Ms are formed above 100 nM EGFP, independent ofpolymer length. Mixtures of EGFP and nonfluorescent GFP were usedto quantify the amount of GFP molecules per C3M, resulting in approximately450 GFPs encapsulated per micelle. This study shows that FCS can besuccessfully applied for the characterization of protein-containingC3Ms. [ABSTRACT FROM AUTHOR]