* Corresponding authors

^a CAS Key Laboratory of Magnetic Materials and Devices, & Key Laboratory of Additive Manufacturing Materials of Zhejiang Province, & Division of Functional Materials and Nanodevices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, 1219 ZhongGuan West Road, Ningbo, Zhejiang 315201, China
E-mail: aiguo@nimte.ac.cn

^b Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892, USA
E-mail: shawn.chen@nih.gov