1. Center for Integrative Nanotechnology Sciences, University of Arkansas at Little Rock, Little Rock, AR, USA;
2. Arkansas Nanomedicine Center, Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, AR, USA;
3. National Institute for Research and Development of Isotopic and Molecular Technologies, Cluj-Napoca, Romania;
4. Department of Chemistry, University of Arkansas at Little Rock, Little Rock, AR, USA