In a Swedish laboratory, gold particles finer than a hair are transforming the fight against post-operative infections. Like a tiny intelligent heating system, a new technology developed by Chalmers University of Technology could revolutionize current surgical practices. The results, published in the prestigious journal Nano Letters, mark a significant milestone in medical research.
The challenge of post-operative infections
During surgery to install a prosthesis, the body temporarily becomes vulnerable to infections. One in a hundred patients develop an infection, requiring intensive antibiotic treatments. The World Health Organization warns of the risks linked to the overuse of antibiotics. Current treatments, often long and expensive, can extend over several months, considerably affecting patients’ quality of life.
«Every year we observe cases of infections that significantly complicate patient recovery.», explains Professor Martin Andersson. “ Our method offers an alternative to conventional treatments. » Orthopedic surgeons are closely following the development of the technique, seeing major potential in it to reduce post-operative complications.
Imagine millions of golden radiator microscopes, invisible to the naked eye. Like fireflies reacting to light, the nano-rods are activated only under the effect of specific infrared radiation. Nature inspired the researchers: just as certain marine organisms use light to regulate their temperature, gold nanorods transform light energy into heat in a controlled manner.
Maja Uusitalo, doctoral student, compares their action to “molecular mini cookers» : « Bacteria are eliminated by ultra-localized heat, comparable to a drop of hot water on an icy surface. » The nano-rods cover only 10% of the surface of the implant, thus preserving the essential properties of the material, in particular its ability to fuse with the bone.
Pinpoint precision
The researchers determined the ideal size of the gold particles: finer than a hair divided by a thousand. The temperature, measured by X-rays, remains strictly controlled under 120 degrees Celsius. Beyond that, the nano-rods would lose their shape and optical properties. The team developed rigorous protocols to ensure uniform particle distribution across the implant surface.
An orthopedic surgeon could activate the treatment directly after suturing, by simply applying infrared light to the operated area for a few minutes. The procedure would fit perfectly into existing surgical protocols, without significantly extending the duration of the intervention. Laboratory tests show remarkable effectiveness against different bacterial strains, including those resistant to antibiotics.
The Swedish team is currently adapting the technique for different types of implants: dental prostheses, heart valves, breast implants. The first clinical trials are planned for 2025. Researchers are working closely with medical implant manufacturers to optimize large-scale production. Preliminary studies suggest the method could reduce the risk of post-operative infection by up to 90%.
What assessment for what future
The method developed by the Swedish team illustrates the ability of scientists to create elegant solutions to medical challenges. Future applications could extend beyond implants, particularly toward the treatment of superficial infections. Researchers are also exploring the possibility of using alternative materials to gold to make the technology more accessible.
The international medical community is following developments in the technique with interest, which could radically transform the prevention of post-surgical infections.
Illustration caption: The illustration shows how gold nanorobots heat up when illuminated with near-infrared light. At temperatures above 120 degrees Celsius, the gold rods begin to change shape and their optical properties change.
The paper, titled “Photothermal properties of solid-supported gold nanorods,” was published in Nano Letters. DOI: 10.1021/acs.nanolett.4c03472 The researchers behind this study work in the Division of Applied Chemistry, Department of Chemistry and Chemical Engineering, and Chalmers Materials Analysis Laboratory at the University of Chalmers technology.
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