Europe’s most powerful supercomputer helps researchers to develop biosensors from gold nanoclusters

The researchers at the Nanoscience Center (NSC) of the University of Jyväskylä, Finland, are investigating how to design biosensors from gold nanoclusters. The research involves large-scale atomistic simulations in Europe’s most powerful supercomputer LUMI.

Gold nanoclusters are atomically precise nanostructures of a few nanometers in diameter. They have a nucleus composed of gold atoms and a surface layer of organic ligand molecules. The chemical nature of the surface layer defines the clusters’ solubility and functionality when they interact with the environment. As an example, the surface layer could be modified to contain drug molecules and peptides that recognize cancer-cell-specific receptors which would make the cluster a highly specific nanosized drug carrier system (1). The clusters can also be attached to large biomolecules such as proteins and nanoparticles made from proteins such as viruses, to help increase contrast when these particles are imaged by electron microscopes.

The research team from left: Sami Malola, María Francisca Matus, Hannu Häkkinen and Antti Pihlajamäki. Photo: Kevin Stamplecoskie

Biosensors can detect molecules that are markers for diseases

The organic surface of the gold nanoclusters can be tuned to interact with surrounding biomolecules in a specific way, utilizing its chiral properties. Chirality is a common property of many biomolecules with a common example of the spiral double-stranded DNA molecule (or a more every-day example of the spiral structure of a staircase in an apartment building).

– Depending on the direction of the spiral, called handedness, gold clusters can be expected to react in a different way with right-handed or left-handed form of small biomolecules such as amino acids. These small differences can be detected using optical spectroscopy designed to measure chiral properties, says the lead researcher María Francisca Matus of the University of Jyväskylä.

– One can use this phenomenon to design extremely sensitive biosensors that would detect the “wrong” (non-natural) chirality of a molecule which can be a marker of a disease, she continues.

Hundreds of simulations in the supercomputer

During the project, researchers will screen hundreds of atomistic interfaces that will form between gold nanoclusters of various sizes and a test set of chiral biomolecules with both natural and non-natural handedness. These simulations involve large scale molecular dynamics simulations in aqueous environment. The chiral optical properties will be studied using the electronic structure theory, and the project also tests various machine learning methods to predict the cluster – biomolecule interactions. The simulations will lead to predictions on the most promising nanoclusters for biosensors, which then will be realized in collaboration with experiments in Singapore, Austria, and Switzerland.

– Without the power of LUMI supercomputer we could not run these simulations, says Matus.

– We believe that in collaboration with our partners abroad, we can develop very sensitive biosensors that can detect tiny amounts of chiral molecules in blood samples that may be indicators of certain diseases, which gives this work a huge potential impact.

– We are very excited about this project, which marks a new direction in our long-standing work on understanding properties of gold nanoclusters and is also the first large-scale research project in the University of Jyväskylä utilizing the LUMI supercomputer, comments the team leader, professor Hannu Häkkinen.

Other researchers in the project are Sami Malola and Antti Pihlajamäki from Häkkinen’s group.

(1) M.F. Matus and H. Häkkinen, Understanding ligand-protected noble metal nanoclusters at work, Nature Reviews Materials 2023, https://doi.org/10.1038/s41578-023-00537-1

This article was originally published on the University of Jyväskylä’s website.