Nanoscience and nanotechnology hold the future for Africa’s achievement of some of the United Nations’ Sustainable Development Goals (SDGs), including health, clean water, food security, energy, and climate change, according to Professor Malik Maaza, a senior fellow of the African Academy of Sciences and the UNESCO-UNISA Africa chair in nanoscience and nanotechnology.

Presenting the first African Academy of Sciences (AAS) presidential lecture during a webinar on 27 March 2025, Maaza said Africa could overcome some of its pressing development challenges through emerging nanotechnology.

Nanoscience refers to the study, manipulation and engineering of matter, particles and structures on the nanometric scale. Scientists use this to measure atoms and molecules. A nanometre is equivalent to one-billionth of a metre, for example. Similarly, nanotechnology is the application of nanoscience, which has created new nanomaterials and nanoscale components that are valuable products.

In his address, ‘Nanosciences and nanotechnologies towards SDGs and science with social impact’, Maaza highlighted how different teams of AAS fellows have been conducting cutting-edge nanoscience research that could have social impacts on various SDG challenges in Africa.

Cosmetic applications

The initial study two years ago on ultraviolet radiation reflection based on the Khoi-San indigenous knowledge was headed by Dr Ntombi Ditlopo, the head of human resources and strategic partnerships at NuMeRI in Pretoria, South Africa. Ditlopo and her team have been working on nanocrystals that can block the sun’s ultraviolet radiation, which can lead to sunburn and skin cancer, especially in Sub-Saharan Africa where temperatures are high.

According to Maaza, Ditlopo’s efforts to develop sunscreen cosmetics are based on the indigenous knowledge of the Khoi-San communities in Botswana, Namibia and South Africa. These communities use Hoodia gordonii, a succulent plant also known as ‘bushman’s hat’, to suppress appetite and thirst.

In a 2022 study, Ditlopo’s team noted that, whereas the plant may have some medicinal value in combating obesity, its natural extract contains cerium oxide, a compound that can be used to develop nanocrystals that can reflect the sun’s ultraviolet rays.

So far, Ditlopo’s team has successfully bioengineered cerium oxide nanocrystals from Hoodia, and what remains is the insertion of the compounds in a standard formulation for real-life cosmetic applications. “This particular research has the potential to contribute to good health and well-being, Goal 3 of the SDGs that aims to ensure healthy lifestyles and promote well-being for people of all ages,” Maaza said.

Improved insulation Mabakachaba

Similarly, Maaza highlighted research targeting SDG 7, affordable and clean energy, in which Boitumelo Mabakachaba, a PhD fellow from Botswana, is working alongside six other AAS fellows from Cameroon, Malawi, Senegal, South Africa, and Sudan to develop smart windows to improve insulation and lower costs for air-conditioning facilities.

He noted that the global stock of air conditioners in buildings and vehicles is expected to grow from 1.6 billion to 5.6 billion by 2050. The International Energy Agency estimates that global energy demand from air conditioners will triple by 2050, equivalent to adding 10 new units per second.

Considering Africa’s rising urban population, Maaza said there is an emerging expansion in air-conditioning ownership and use across the continent due to increasing temperatures.

Mabakachaba's team’s end game, according to Maaza, is to develop a window coating laced with nanoparticles of thermochromic materials that will reflect solar radiation during warmer periods and absorb more of it during cooler periods, potentially reducing buildings' heating and cooling needs.

The issue is that thermochromic materials, often in nanoscale amounts, can contribute to green energy utilisation by adapting to seasonal temperature changes. Subsequently, they can reduce the need for air-conditioning in the hot season by reflecting sunlight and helping to retain heat in cold weather.

Maaza did not explain the physics theory behind the development of the intelligent smart window coating, but said the study was inspired by gemsbok or the South African oryx, a large antelope that inhabits the Kalahari and Namib deserts.

According to Maaza, the gemsbok’s skin regulates body temperature in hot desert environments by stopping heat from entering when it is hot and allowing heat in when it is cold. “What these research fellows have done is to biomimic these animals,” Maaza said.

Tackling food crises

Amid efforts to address zero hunger, Goal 2 of the SDGs, and the driver of food production, Maaza introduced five researchers who aim to develop nanofertilisers for sustainable farming. Dr Nandipha Botha, a postdoctoral research fellow from South Africa, leads the team that includes researchers from Botswana, the Democratic Republic of the Congo, Egypt and South Africa.

Their study is based on the production of complex genetically modified nanofertilisers, which are not organic but chemical fertilisers for plants and not nutrients for the soil.

Quoting the Global Report on Food Crises 2024, Maaza said conflict impacts have disrupted food security, while weather extremes and economic shocks have driven food crises throughout the continent. “About 73 million people in 36 African countries are currently facing acute food shortages.”

In their research, Botha and her colleagues have developed a nanofertiliser based on calcium carbonate nanoparticles. This fertiliser has been tested successfully on tomatoes, and researchers are now trying to duplicate their results in different parts of the continent and with other crops.

According to Maaza, this fertiliser offers several advantages, including increased calcium absorption by plants, efficient nutrient delivery, and potential for pest and disease resistance. “You also don’t need a kilogramme of fertilisers for a hectare, but only 10g, because they are nano.”

Solving clean water challenges

Another set of AAS research fellows has been working on imitating titanium dioxide as a photocatalyst for water purification when exposed to ultraviolet radiation. Explaining the process, Maaza said that titanium dioxide can degrade organic pollutants and disinfect water by generating oxygen-containing molecules that can break down harmful bacteria, viruses, and other contaminants.

However, considering that ultraviolet lamps are costly, Dr Adama Fall, a postdoctoral research fellow at the University of South Africa (UNISA) and his research associates from Egypt, Senegal, South Africa and Sudan, have devised a cost-effective solution for Africa.

Maaza explained that the team has developed a computational algorithm that helped them produce an experimental material in the form of powder that, in nanoscale amounts, can decompose dyes and kill bacteria in contaminated water in the agricultural sector and in flush water.

Converting carbon dioxide

Regarding addressing climate action, Goal 13 of the SDGs, Fall and Botha have teamed up with colleagues from Botswana, the Democratic Republic of the Congo, Egypt and Sudan to reduce Africa’s carbon footprint and pave the way forward for the continent’s entry into the carbon market by 2028.

According to Maaza, whereas Africa’s output of global carbon emissions is small, there are indicators that emissions are rising, especially in South Africa, Nigeria, Egypt, Algeria, Angola, Morocco and Libya.

However, he highlighted that the team has developed a cost-effective technology for converting carbon dioxide into carbonate instead of capturing it and storing it in mines or under the sea. “The harmless whitish powder has applications in agriculture as a fertiliser, supplement compound in the cement industry, filling material in dentistry, and powder component for drug delivery.”

In his final remarks, Maaza expressed optimism that nanoscience and nanotechnology are increasingly becoming powerful tools for achieving social impacts in Africa. Their ability to help AAS fellows unlock new possibilities in various fields, including the development of cosmetics against skin cancer, smart window coating for energy efficiency, new plant fertilisers and cost-effective carbon capture strategies spells the future of applications of nanomaterials on the continent.

Despite hope of success, most of those achievements are in their experimental and exploratory stages, and much will depend on whether there will be sufficient funds to propel the products and innovations from the scientific investigation phases to the market.

Original article written by Wachira Kigotho and published in University World News.