| Many historical buildings were built of limestone, such as Vienna’s St. Stephen’s Cathedral. Limestone is easy to work with, but does not withstand weathering well. It consists mainly of calcite minerals that are relatively weakly bound to each other, which is why parts of the stone keep crumbling away over the years, often requiring costly restoration and conservation treatments. | |
| However, it is possible to increase the resistance of the stone by treating it with special silicate nanoparticles. The method is already being used, but what exactly happens in the process and which nanoparticles are best suited for this purpose has been unclear until now. | |
| A research team from TU Wien and the University of Oslo has now been able to clarify exactly how this artificial hardening process takes place through elaborate experiments at the DESY synchrotron in Hamburg and with microscopic examinations in Vienna. That way, the team could determine which nanoparticles are best suited for this purpose. |
An aqueous suspension with nanoparticles |
|
| “We use a suspension, a liquid, in which the nanoparticles initially float around freely,” says Prof. Markus Valtiner from the Institute of Applied Physics at TU Wien. “When this suspension gets into the rock, then the aqueous part evaporates, the nanoparticles form stable bridges between the minerals and give the rock additional stability.” | |
| This method is already used in restoration technology, but until now it was not known exactly what physical processes take place. When the water evaporates, a very special kind of crystallisation occurs: Normally, a crystal is a regular arrangement of individual atoms. However, not only atoms, but also entire nanoparticles can arrange themselves in a regular structure – this is then referred to as a “colloidal crystal”. | |
| The silicate nanoparticles come together to form such colloidal crystals when they dry in the rock and thus jointly create new connections between the individual mineral surfaces. This increases the strength of the natural stone. | |
Measurements at the large-scale research facility DESY and in Vienna |
|
| To observe this crystallisation process in detail, the TU Wien research team used the DESY synchrotron facility in Hamburg. Extremely strong X-rays can be generated there, which can be used to analyse the crystallisation during the drying process. | |
| “This was very important to understand exactly what the strength of the bonds that form depends on,” says Joanna Dziadkowiec (University of Oslo and TU Wien), the first author of the publication in which the research results have now been presented (Langmuir, “Cohesion Gain Induced by Nanosilica Consolidants for Monumental Stone Restoration”). “We used nanoparticles of different sizes and concentrations and studied the crystallisation process with X-ray analyses.” It was shown that the size of the particles is decisive for optimal strength gain. | |
| To this end, the TU Vienna also measured the adhesive force created by the colloidal crystals. For this purpose, a special interference microscope was used, which is perfectly suited for measuring tiny forces between two surfaces. | |
Small particles, more force |
|
| “We were able to show: The smaller the nanoparticles, the more can they strengthen the cohesion between the grains of minerals,” says Joanna Dziadkowiec. “If you use smaller particles, more binding sites are created in the colloidal crystal between two grains of minerals, and with the number of particles involved, the force with which they hold the minerals together thus also increases.” | |
| How many particles are present in the emulsion is also important. “Depending on the particle concentration, the crystallisation process proceeds slightly differently, and this has an influence on how the colloidal crystals form in detail,” says Markus Valtiner. The new findings will now be used to make restoration work more durable and more targeted. |
News
Nanomedicine in 2026: Experts Predict the Year Ahead
Progress in nanomedicine is almost as fast as the science is small. Over the last year, we've seen an abundance of headlines covering medical R&D at the nanoscale: polymer-coated nanoparticles targeting ovarian cancer, Albumin recruiting nanoparticles for [...]
Lipid nanoparticles could unlock access for millions of autoimmune patients
Capstan Therapeutics scientists demonstrate that lipid nanoparticles can engineer CAR T cells within the body without laboratory cell manufacturing and ex vivo expansion. The method using targeted lipid nanoparticles (tLNPs) is designed to deliver [...]
The Brain’s Strange Way of Computing Could Explain Consciousness
Consciousness may emerge not from code, but from the way living brains physically compute. Discussions about consciousness often stall between two deeply rooted viewpoints. One is computational functionalism, which holds that cognition can be [...]
First breathing ‘lung-on-chip’ developed using genetically identical cells
Researchers at the Francis Crick Institute and AlveoliX have developed the first human lung-on-chip model using stem cells taken from only one person. These chips simulate breathing motions and lung disease in an individual, [...]
Cell Membranes May Act Like Tiny Power Generators
Living cells may generate electricity through the natural motion of their membranes. These fast electrical signals could play a role in how cells communicate and sense their surroundings. Scientists have proposed a new theoretical [...]
This Viral RNA Structure Could Lead to a Universal Antiviral Drug
Researchers identify a shared RNA-protein interaction that could lead to broad-spectrum antiviral treatments for enteroviruses. A new study from the University of Maryland, Baltimore County (UMBC), published in Nature Communications, explains how enteroviruses begin reproducing [...]
New study suggests a way to rejuvenate the immune system
Stimulating the liver to produce some of the signals of the thymus can reverse age-related declines in T-cell populations and enhance response to vaccination. As people age, their immune system function declines. T cell [...]
Nerve Damage Can Disrupt Immunity Across the Entire Body
A single nerve injury can quietly reshape the immune system across the entire body. Preclinical research from McGill University suggests that nerve injuries may lead to long-lasting changes in the immune system, and these [...]
Fake Science Is Growing Faster Than Legitimate Research, New Study Warns
New research reveals organized networks linking paper mills, intermediaries, and compromised academic journals Organized scientific fraud is becoming increasingly common, ranging from fabricated research to the buying and selling of authorship and citations, according [...]
Scientists Unlock a New Way to Hear the Brain’s Hidden Language
Scientists can finally hear the brain’s quietest messages—unlocking the hidden code behind how neurons think, decide, and remember. Scientists have created a new protein that can capture the incoming chemical signals received by brain [...]
Does being infected or vaccinated first influence COVID-19 immunity?
A new study analyzing the immune response to COVID-19 in a Catalan cohort of health workers sheds light on an important question: does it matter whether a person was first infected or first vaccinated? [...]
We May Never Know if AI Is Conscious, Says Cambridge Philosopher
As claims about conscious AI grow louder, a Cambridge philosopher argues that we lack the evidence to know whether machines can truly be conscious, let alone morally significant. A philosopher at the University of [...]
AI Helped Scientists Stop a Virus With One Tiny Change
Using AI, researchers identified one tiny molecular interaction that viruses need to infect cells. Disrupting it stopped the virus before infection could begin. Washington State University scientists have uncovered a method to interfere with a key [...]
Deadly Hospital Fungus May Finally Have a Weakness
A deadly, drug-resistant hospital fungus may finally have a weakness—and scientists think they’ve found it. Researchers have identified a genetic process that could open the door to new treatments for a dangerous fungal infection [...]
Fever-Proof Bird Flu Variant Could Fuel the Next Pandemic
Bird flu viruses present a significant risk to humans because they can continue replicating at temperatures higher than a typical fever. Fever is one of the body’s main tools for slowing or stopping viral [...]
What could the future of nanoscience look like?
Society has a lot to thank for nanoscience. From improved health monitoring to reducing the size of electronics, scientists’ ability to delve deeper and better understand chemistry at the nanoscale has opened up numerous [...]
