1. MOE key laboratory for analytical science of food safety and biology Institution College of Chemistry Fuzhou University Fuzhou 350108 P. R. China
2. College of Biological Science and Engineering Fuzhou University Fuzhou 350108 P. R. China
3. Laboratory of Molecular Imaging and Nanomedicine (LOMIN) National Institute of Biomedical Imaging and Bioengineering (NIBIB) National Institutes of Health (NIH) Bethesda MD 20892 USA