1. Department of Chemistry, University of Fort Hare, Alice, South Africa
2. Polymer and Composites, CSIR Materials Science and Manufacturing, Pretoria, South Africa
3. 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
4. DST/CSIR National Centre for Nanostructured Materials, Council for Scientific and Industrial Research, Pretoria, South Africa