1. School of Life Science, Changchun Normal University, Changchun 130032, China
2. Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
3. Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, Department of Biomedical Engineering, School of Medicine, Shenzhen University, Shenzhen 518060, China
4. Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health, Bethesda, Maryland 20892, United States
5. Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22903, United States