Surface Modified Superparamagnetic Iron Oxide Nanoparticles for Long Term Stem Cell Tracking

Abstract

In the initial stages of this project, the aim was to develop polymer coated superparamagnetic iron oxide nanoparticles (SPIONs) which would be stable in physiological buffer solutions at 37 °C (body temperature) for cell labelling experiments. Well-defined end functional hydrophilic poly(2-methacryloyloxyethyl phosphorylcholine) (pMPC) homopolymers were prepared by atom transfer radical polymerisation (ATRP) and used to couple onto the surface of functionalised SPIONs using an end grafting-to approach. pMPC was chosen due to its well-known biocompatibility. The pMPC coated SPIONs were investigated as a potential T2 magnetic resonance image (MRI) contrast agent through biocompatibility and colloidal stability screening prior to biological studies of the polymer coated SPIONs with stem cells. In the later stages of this project, silica and gold nanoparticle (NP) surface coatings were individually investigated for their chemical stability and protection of the SPION core to acidic conditions mimicking those found in the lysosome of the stem cell. This was carried out in order to develop and screen a coating that would enable long term stem cell tracking. Again, the nanomaterials prepared were assessed for biocompatibility and their magnetic properties were measured prior to stem cell labelling studies. In the final chapter, the nanomaterials prepared throughout this Thesis were subjected to stem cell labelling and the retention of the nanomaterials inside stem cells was investigated.