1. Center for Biomaterials, The University of Connecticut Health Center, Farmington, Connecticut 06030, Department of Physiology and Center for Biomedical Imaging Technology, The University of Connecticut Health Center, Farmington, Connecticut 06030, Department of Chemistry, The University of Connecticut, Storrs, Connecticut 06269, and Department of Physiology and Center for Biomaterials, The University of Connecticut Health Center, Farmington, Connecticut 06030