In a recent cell-labelling study, which was published in the journal Nanotechnology, the authors reported a simple strategy via a complex formation with peptide to overcome these obstacles. In their paper, the researchers studied a complex formation between negatively charged fluorescent mono-disperse SPION and a positively charged peptide systematically and theoretically, and used the complex formation to improve the MR properties of labelled stem cells.

The team demonstrated that the theoretical approach of SPION-peptide complexes could provide guidelines for cell labelling and possibly predicting NMR relaxation properties of labelled cells in vitro. Magnetic labelling of cells with fluorescent mono-disperse SPION-peptide complexes provided greater changes in signal intensity on T2* weighted images of magnetically labelled cells compared with other SPION-peptide complexes.

The finding that human mesenchymal stem cells (hMSCs) stay intact in flank tumours after seven days holds promise for the detection of stem cells in tissue. The group believes that the developed FL SPION-peptide complex will have a great impact on monitoring stem-cell migration for cell therapy in the future.