MRI-detectable pH nanosensors incorporated into hydrogels for in vivo sensing of transplanted cell viability

1] The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA [2] Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
Nature Material (Impact Factor: 36.5). 01/2013; 12(3). DOI: 10.1038/nmat3525
Source: PubMed


Biocompatible nanomaterials and hydrogels have become an important tool for improving cell-based therapies by promoting cell survival and protecting cell transplants from immune rejection. Although their potential benefit has been widely evaluated, at present it is not possible to determine, in vivo, if and how long cells remain viable following their administration without the use of a reporter gene. Here, we report a pH-nanosensor-based magnetic resonance imaging (MRI) technique that can monitor cell death in vivo non-invasively. We demonstrate that specific MRI parameters that change on cell death of microencapsulated hepatocytes are associated with the measured bioluminescence imaging radiance. Moreover, the readout from this pH-sensitive nanosensor can be directly co-registered with high-resolution anatomical images. All of the components of these nanosensors are clinical grade and hence this approach should be a translatable and universal modification of hydrogels.

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Available from: Michael T Mcmahon, Oct 03, 2015
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    • "Due to an exchange process between the mobile (saturated) gelatin protons and the water protons, from which the MRI signal is derived, the water MRI signal is reduced; hence these exchangeable protons are detected indirectly. CEST imaging is now being recognized as an emerging technique for molecular and cellular MR imaging: it can be used to detect MRI reporter genes [15e17], enzyme activity [18], pH changes associated with cell death [14], and the occurrence of an immune response against foreign body materials [19]. "
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