Microscopic titanium particles weaken the bonding of hip, knee, and other joint replacements, according to research published online in Proceedings of the National Academy of Sciences by researchers at the University of California, San Diego (UCSD) School of Medicine and the Jacobs School of Engineering. The team demonstrated that titanium implants are safe in large blocks, but at the microscopic level, wear and tear can generate micrometer-sized particles.
"As replacement joints are becoming increasingly common in aging populations, our results explain how such devices fail and suggest that improvements should be made in artificial joint design," said the studys senior author K.L. Paul Sung, Ph.D., UCSD professor of orthopedic surgery and adjunct professor of cellular bioengineering.
The team measured how titanium particles affected the bonding strength of pins implanted in rat thighs. The pins were shown to come out more easily when the titanium particles were present, with the smallest and largest particles causing the greatest weakening. The researchers demonstrated how different-sized titanium particles affected bone-building cells called osteoblasts and bone-destroying cells called osteoclasts. Microscopic studies revealed osteoblasts did not form proper adhesions, with small- and medium-sized titanium particles concentrated inside cells. Increased production of the protein RANKL by osteoblasts recruited and activated osteoclasts at the insertion sites, further weakening the bone. Larger titanium particles also activated metalloproteinases, which chop up the extracellular matrix that holds cells together.
Sue Pondrom | EurekAlert!
Cryo-electron microscopy achieves unprecedented resolution using new computational methods
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Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
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