1. Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Science, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa;
2. Department of Molecular and Cell Biology, Faculty of Science, University of Cape Town, Cape Town, South Africa;
3. Department of Biotechnology, Faculty of Natural Sciences, University of the Western Cape, Bellville, South Africa;
4. Department of Science and Innovation/Mintek Nanotechnology Innovation Centre, Biolabels Node, Department of Biotechnology, Faculty of Natural Sciences, University of the Western Cape, Bellville, South Africa