1. Department of Chemical and Biomolecular EngineeringNational University of Singapore 4 Engineering Drive 4 Singapore 117585 Singapore
2. CAS Key Laboratory of Health InformaticsResearch Laboratory for Biomedical Optics and Molecular ImagingInstitute of Biomedical and Health EngineeringShenzhen Institute of Advanced TechnologyChinese Academy of Sciences Shenzhen 518055 P. R. China
3. Shenzhen College of Advanced TechnologyUniversity of Chinese Academy of Science Shenzhen 518055 China