Breakthrough in metamaterials: How to turn transparent calcite into artificial gold?
Israeli material magicians were able to create an optical metamaterial from vaterite, a nearby calcite mineral, and gold nanoparticles. Similar metamaterials are usually produced from toxic chemicals, which prevents their use in biomedicine. “Golden vaterite” can be used, for example, in photothermal treatment, photoacoustic tomography or bioimaging.
An international research team led by experts from Tel Aviv University in Israel has achieved significant success in the field of nanomaterials. They have developed an innovative nanotechnology that allows the conversion of transparent calcite nanoparticles into glittering particles enriched with gold. In other words, they turned the transparent nanoparticles into particles that are visible. It may sound simple, but it is a significant breakthrough in nanomedicine, which could bring a number of interesting applications in the treatment of cancer and other serious diseases.
Roman Noskov and his collaborators created biocompatible particles of metamaterial that have no parallel in nature. In addition, their approach is promising for much wider use in biomedical systems. It offers the possibility of creating nanoparticles for sensors, photothermal treatment, photoacoustic tomography, bioimaging or targeted drug delivery.
According to Noskov, their research is the result of an interdisciplinary effort in nanomedicine, combining the physics of metamaterials and bioorganic chemistry. Together with colleagues, they created submicron-sized metamaterial from biocompatible components. At the same time, biocompatibility is a typical problem with similar structures today, which prevents the use of similar optical metamaterials in medicine and biology. Their production usually involves the use of toxic chemicals.
The procedure of Nosk’s team involves the controlled infusion of gold nanoparticles into vaterite, a polymorphic mineral formed by calcium carbonate. Upon reaction with water at low temperatures, this mineral changes to calcite. The result of this procedure is the metamaterial “gold vaterite”, whose optical properties can be adjusted by the amount of gold it contains. The gold vaterite particles hold a large amount of “cargo”, which may be a drug and / or a fluorescent substance.
Researchers have already verified the functionality of golden vaterite for photothermal treatment and photoacoustic tomography. In a pilot experiment, they irradiated the new metamaterial with a laser with red and near-infrared light. Golden vaterite has been successfully heated, which is exactly what is desirable for the mentioned biomedical procedures.