Magnesium Nanoparticles: Earth-Abundant and Biocompatible Thermoplasmonics (MagNanoThermo)

Light is energy. Sunlight can be harnessed by solar cells, for instance, turning light into electricity, which can, in turn, be used to power big and small devices. This is, however, a rather inefficient process and light can be used differently for various applications.

One way to efficiently use light is through a photothermal material, which converts light into heat. Heat is an important user of fossil fuels: industrial processes for instance consume vast quantities of fossil fuels. It has been reported that 4.2% of worldwide delivered energy is consumed manufacturing basic inorganic, organic, and agricultural chemicals. Of this 17 quadrillion Btu, 78% comes from liquid fuels, natural gas, and coal, leading to greenhouse gas emissions. [1] A substantial fraction of these fuels are used to heat up chemical reactions, while free, green, and abundant sunshine could instead provide the required energy via a photothermal material.

Heat also heals: photothermal materials injected near cancer cells can be excited by an otherwise non-interacting infrared light, leading to local temperature rise (of the order of 10s of degrees) sufficient to kill cancer cells without any surgery or chemotherapy.

This proposal targets the development of a new class of biocompatible photothermal material based on the 8th most abundant element in earth's crust, magnesium. We have shown previously that small particles of magnesium are stable in air and interact strongly with light. Magnesium, like gold and silver, is extraordinarily good at absorbing light because its interaction is different than that of simple "black" materials. Indeed, these nanoparticles act like antenna for light and consequently absorb more light than their physical footprint. This phenomenon is truly nanoscale; it involves the light-driven oscillation of electrons in small metallic particles and is called localized surface plasmon resonance.

In the two years of this project, we first aim to develop ways to make large quantities of magnesium nanostructures, suitable for industrial-scale production. We will then demonstrate their ability to efficiently produce heat from light, and will study how to best match the particle size to the specific application, for both sunlight-matched and medical applications. At the end of the project, we will be in a position to approach industrial partners to discuss further development and commercialization of these new green technologies.

[1] Energy Information Administration, Government Publications Office, International Energy Outlook: 2016 with Projections to 2040. U.S. Government Printing Office: 2016.