1. Institute of Biomedical Studies, Baylor University, Waco, Texas 76798, United States
2. Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
3. Department of Chemistry, Howard University, Washington, District of Columbia 20059, United States
4. Department of Chemistry, University of Maryland, College Park, Maryland 20742, United States
5. Center for Microscopy and Imaging, Baylor University, Waco, Texas 76798, United States