Kannie Wai Yan Chan1,2, Xiaolei Song1,2, Guanshu Liu1,3, Dian Arifin1,2, Heechul Kim1,2, Chulani Galpoththawela1,2, Ming Yang4, Justin Hanes4,5, Assaf Gilad1,2, Piotr Walczak1,2, Jeff W. M. Bulte1,2, Michael T. McMahon1,3
1Russell H. Morgan Department of Radiology & Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 2Cellular Imaging Section & Vascular Biology Program, Institute for Cell Engineering, Baltimore, MD, USA; 3F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA; 4Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 5Department of Oncology & the Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
Semi-permeable microcapsules have been used previously to immunoprotect and visualize therapeutic cells after transplantation. We have constructed pH-sensitive microcapsules which generate CEST contrast dependent on the local physicochemical microenvironment. These capsules can be tracked and also used as a unique way to monitor cell viability through MRI. In this study, we have tested whether or not our new CEST microcapsules could monitor the viability of hepatocytes expressing luciferase both in vitro and in vivo. We observed a decrease in CEST contrast with decreasing hepatocyte viability upon administration of STS in vitro and also after subcutaneous transplantation into mice, as validated with bioluminescent imaging.