An international team of chemists from Russia and Switzerland developed a new way to map out tumors and blood vessels damaged by serious cardiac events like a heart attack or stroke.

These novel nanoparticles are made of hafnium oxide and doped with ions of rare earth metals like europium and terbium. They can emit a visible light under ultraviolet and blue spectrums so physicians can use them as a contrast agent when taking pictures of internal tissues.

The rare earth ions produced the high luminescent properties, whereas the oxide component serves as a transparent matrix that maintains the shining properties and protects its biosafety.

“We could not cover nanoparticles with a stabilizer, because it would reduce the quantum yield,” said ITMO University research fellow and first author of this study Aleksandra Furasova, in a statement.

“That is why we doped hafnium oxide with rare earth metal ions. Firstly, they charged surface of the particles that stabilized the latter in biological fluids. Secondly, introducing different rare earths, we learned to shift the luminescence spectrum. For example, particles with terbium emit the green region, but particles with europium – in red. Such adjusting will be useful for solving specific tasks,” continued Furasova.

Tests of this compound revealed that it remained stable in blood plasma and did not change its consistently.

Furthermore, because the rare earth ions are strongly bounded in oxide, they prevent toxicity, keeping the cells safe.

The hope is that these nanoparticles could eventually serve as a replacement to quantum dots, the toxic semiconductor nanoparticles that can only be used in vitro.

The research was published in the journal Colloids and Surfaces B: Biointerfaces.