Synopsis: We demonstrate the capability of unique ‘cargo internalization receptors’ (CIR) for specific cell tracking. A nanobody for green fluorescent protein (GFP) was used to engineer surface receptors which undergo rapid internalization after GFP binding. For 19F MR visibility, the GFP carrier was equipped with perfluorocarbon (PFC) contrast cargo. PFC cargo uptake after CIR transfection was verified by flow cytometry, confocal microscopy, and 1H/19F MRI. The results show that this approach can be successfully used for targeted contrast agent internalization, which can be extended to an cell-specific CIR expression in transgenic mice for in vivo cell tracking by 19F MRI.