Tiny Gold “Frying Pans” Kill Bacteria on Implants, Reducing Antibiotic Need
https://scitechdaily.com/tiny-gold-frying-pans-kill-bacteria-on-implants-reducing-antibiotic-need/
Excerpt:
Gold nanorods heated by NIR light create antibacterial surfaces on implants, reducing infection risks during surgeries and potentially decreasing antibiotic resistance.
A new technology developed at Chalmers University of Technology in Sweden may play a crucial role in combating antibiotic resistance, especially in surgical procedures like hip and knee implant insertions. The technique involves heating tiny gold nanorods with near-infrared (NIR) light to sterilize the implant surface by killing bacteria. Researchers have recently published a study that deepens the understanding of how these gold rods respond to light and how to accurately measure their temperature.
Infections can occur during surgical procedures, with the risk increasing significantly when foreign materials, such as knee prostheses, are implanted into the body. The presence of the material weakens the body’s immune system and antibiotic treatments are commonly used. If infected, high doses of antibiotics are often required with long treatment times, sometimes lifelong......
Heat kills the bacteria on the implant surface
The technology developed by the researchers at Chalmers is a method in which nanometre-sized rods of gold are attached to the implant surface. When near-infrared (NIR) light hits the surface of the implant, the rods heat up and act as tiny heating elements. Because the heating elements are so small, there is a very local heating, which kills any bacteria on the surface of the implant without heating the surrounding tissue.
“The gold rods absorb the light, the electrons in the gold are set in motion, and finally the nanorods emit heat. You could say that the gold nanorods work like small frying pans that fry the bacteria to death,”......
.....“The trick is to tailor the size of the rods. If you make them a little smaller or a little bigger, they absorb light of the wrong wavelengths. We want the light that is absorbed to penetrate skin and tissue well. Because once the implant is inside the body, the light must be able to reach the surface of the prosthesis,” says Martin Andersson, Professor and research leader at Chalmers.
.....” The temperature must not exceed 120 degrees Celsius, as higher temperatures cause the nanorods to lose their shape and transform into spheres. As a result, they lose their optical properties and can no longer absorb NIR light effectively, which prevents the rods from heating up” says Maja Uusitalo.
She points out that the heating is very local with low energy transfer to the surroundings. This is crucial to avoid causing any damage to the surrounding tissue.
The researchers hope that the method can be used on many different implant materials, such as titanium or different plastics.
.....“We can control when the surface should be antibacterial and when it should not. When we turn off the light, the surface is no longer antibacterial and reverts to its original state. This is an advantage because many antibacterial surfaces usually have negative effects on healing,” says Martin Andersson.
The goal is to eventually bring this technology into healthcare.
.....All bacteria die from the heat from the gold nanorods, but even ordinary cells can be damaged during treatment.
“If a few human cells are destroyed during the NIR heating process the body quickly regenerates new ones, so the impact on healing is minimal,” says Martin Andersson.
UCLA Chemists Shatter 100-Year-Old Chemistry Rule – Textbooks Need a Rewrite
https://scitechdaily.com/ucla-chemists-shatter-100-year-old-chemistry-rule-textbooks-need-a-rewrite/
Excerpt:
UCLA Chemists Challenge Century-Old Rule
UCLA chemists have discovered a major flaw in a fundamental rule of organic chemistry that has held for 100 years. They say it’s time to rewrite the textbooks.
Organic molecules, which are primarily made of carbon, have specific shapes and arrangements of atoms. Molecules called olefins contain double bonds, or alkenes, between two carbon atoms. Typically, these atoms and their attached groups lie in the same 3D plane, and deviations from this structure are rare.
The rule being questioned, known as Bredt’s rule, was established in 1924. It asserts that molecules cannot have a double bond at the “bridgehead” position—the junction of a bridged bicyclic molecule—because this position would distort the geometry of the double bond. Bredt’s rule has constrained the design of synthetic molecules by preventing chemists from creating certain structures. Since olefins play a critical role in pharmaceutical research, Bredt’s rule has limited the types of molecules that scientists could envision, potentially holding back innovations in drug discovery.
Researchers Break the Mold With Anti-Bredt Olefins
A new paper published on November 1 by UCLA scientists in the journal Science has invalidated that idea. They show how to make several kinds of molecules that violate Bredt’s rule, called anti-Bredt olefins, or ABOs, allowing chemists to find practical ways to make and use them in reactions.
“People aren’t exploring anti-Bredt olefins because they think they can’t,” said corresponding author Neil Garg, the Kenneth N. Trueblood Distinguished Professor of Chemistry and Biochemistry at UCLA. “We shouldn’t have rules like this — or if we have them, they should only exist with the constant reminder that they’re guidelines, not rules. It destroys creativity when we have rules that supposedly can’t be overcome.”
Practical Applications: Developing Useful Chemical Reactions
Garg’s lab treated molecules called silyl (pseudo)halides with a fluoride source to induce an elimination reaction that forms ABOs. Because ABOs are highly unstable, they included another chemical that can “trap” the unstable ABO molecules and yield products that can be isolated. The resulting reaction indicated that ABOs can be generated and trapped to give structures of practical value.
“There’s a big push in the pharmaceutical industry to develop chemical reactions that give three-dimensional structures like ours because they can be used to discover new medicines,” Garg said. “What this study shows is that contrary to one hundred years of conventional wisdom, chemists can make and use anti-Bredt olefins to make value-added products.”
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More proof that science is never settled.