Tammy Louise Kalber1,2, Nick J Mitchell3,
Simon Walker-Samuel1, Quentin A. Pankhurst4, Helen C.
Hailes3, Alethea B. Tabor3, Sam M. Janes2, Mark
F. Lythgoe1
1Centre for Advanced
Biomedical Imaging, Division of Medicine & Institute of Child Health,
University College London, London, United Kingdom; 2Centre for
Respiratory Research, Department of Medicine, University College London,
University College London, London, United Kingdom; 3Department of
Chemistry, University College London, London, United Kingdom; 4Davy-Faraday
Research Laboratories, The Royal Institution of Great Britain, London, United
Kingdom
Two formulations of bimodal liposomes, carrying both gadolinium chelates and fluorescent markers with different modifications of the polyethylene glycol (PEG) chain (named ME42 and CH300 liposomes), were used to assess how PEG can affect both liposomal relaxivity and cell uptake. Relaxivity measurements, as well as cell uptake analysis by reduction of T1 on MR images, and fluorescence by both fluorescence microscopy and flow cytometry. ME42 PEG liposomes demonstrated reduced relaxivity, and cellular uptake compared to CH300 PEG liposomes. This therefore indicates that altering PEG synthesis is essential for the optimization of liposomes as both contrast agents and drug delivery systems. microscopy and flow cytometry. ME42 PEG liposomes demonstrated reduced relaxivity, and cellular uptake compared to CH300 PEG liposomes. This therefore indicates that altering PEG synthesis is essential for the optimization of liposomes as both contrast agents and drug delivery systems.