Recoloured TEM image showing showing silver nanoparticles used in a study to inactivate SOD enzymes from Plasmodium falciparum. Image courtesy of Dr Jacqui Van Marwijk.
The search for drugs which can specifically target infected cells without harming healthy cells drives a multibillion dollar industry globally. Nanotherapy or nanomedicine technologies are rapidly emerging, holding vast potential to transform the field as we know it. This month we take a look at how differences in the way nanomaterials interact with proteins can offer potential new therapeutic approaches for targeting malaria.
Dr Jacqui Van Marwijk has an enduring interest in metal nanoparticles. With a PhD from the University of the Free State her studies in so-called “green synthesis” of nanomaterials has taken her on a journey to Rhodes University where she hopes to help unlock their potential as a future therapy for malaria.
The trick for many scientists working in the area of malaria drug research she says is finding specific differences between human and parasite proteins. It is these very differences between the same or similar proteins which scientists can then use to target the parasite without harming human cells.
She explains further that her specific focus is on targeting the differences in the protein structure between the enzyme superoxide dismutase (or SOD for short), which is present in both human cells and in the malaria parasite’s cells.
SOD works normally in cells to mop up harmful free radicals as part of the cells natural armoury. Her work is based on the theory that if the SOD enzymes in the malaria cell could be inactivated, that it would be robbed of this protective mechanism, leading ultimately to cell death. This is where nanomaterials come in.
Introducing silver nanoparticles (between 8 nm and 20 nm in size) to the SOD enzymes from both human and malaria cells generated some surprising results. The activity of the SOD enzyme from humans was increased (meaning in theory that it could afford greater protection against free radicals) while the activity of the malarial SOD enzyme decreased. It is this decrease in activity of the malarial SOD from the parasite Plasmodium falciparum that has her interest piqued.
Her work forms part of a larger study in Prof Chris Whiteley’s group at Rhodes University probing alternative drug targets for the treatment of a range of illnesses. In ongoing research the team are currently in the process of examining exactly how the nanoparticles are interacting with the SOD enzymes, finding further evidence to confirm their theories, and a possible gateway to treating malaria in the future.
Writers: J van Marwijk and J.L.Limson