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Thu Sep 21 08:02:14 PDT 2023
Medgadget (Medical Technology) Daily Digest (Unofficial)
(https://www.medgadget.com/2023/09/etched-nanopillars-kill-bacteria-fungi-on-titanium-implants.html) Etched Nanopillars Kill Bacteria, Fungi on Titanium Implants
Sep 20th 2023, 14:45
Researchers at RMIT in Australia have developed a drug-free approach to kill bacteria and fungi that can infect surfaces on medical implants. Such pathogens can cause serious and difficult-to-treat infections around medical implants, sometimes requiring the removal of the implant. In addition, many microbes are increasingly resistant to common antibiotics, highlighting the need for drug-free approaches. This new technique is inspired by the nanopillars present on dragonfly wings, which can skewer microbial cells, killing them. The researchers used a relatively simple plasma etching technique to create such nanopillars on titanium surfaces, and tested their ability to kill multi-drug resistant Candida cells, a fungal pathogen behind many medical device infections.
Medical implants can rectify many unfortunate clinical situations, but they can also harbor microbes that can colonize the surfaces of the device after implantation. This typically leads to a nasty infection, which is often complicated by biofilm formation, and may require the eventual removal of the implant. Antimicrobial drug resistance is a further complication, and this has inspired these researchers to create a drug-free surface modification that can kill microbes indiscriminately.
They used a plasma etching technique to create tiny pillars on titanium, which is used in many medical implants. The tiny spikes are approximately the height of a bacterial cell, and when a cell settles on the surface, the spikes can lead to perforations in the cell that can cause its death. In studies so far, the researchers have shown that if the cell does not die outright, it will still perish a little later because of the damage it sustained.
“The fact that cells died after initial contact with the surface — some by being ruptured and others by programmed cell death soon after — suggests that resistance to these surfaces will not be developed,” said Elena Ivanova, a researcher involved in the study. “This is a significant finding and also suggests that the way we measure the effectiveness of antimicrobial surfaces may need to be rethought. This latest study suggests that it may not be entirely necessary for all surfaces to eliminate all pathogens immediately upon contact if we can show that the surfaces are causing programmed cell death in the surviving cells, meaning they die regardless.”
An intact Candida cell on polished titanium surface (left), and a ruptured Candida cell on the micro-spiked titanium surface (right).
While it is easy to visualize the antimicrobial activity as a simple skewering action, it is more like a stretching action, as the cells are pulled by different pillars. “It’s like stretching a latex glove,” said Ivanova. “As it slowly stretches, the weakest point in the latex will become thinner and eventually tear. This new surface modification technique could have potential applications in medical devices but could also be easily tweaked for dental applications or for other materials like stainless steel benches used in food production and agriculture.”
Study in journal Advanced Materials Interfaces: (https://onlinelibrary.wiley.com/doi/10.1002/admi.202300314) Apoptosis of Multi‐Drug Resistant Candida Species on Microstructured Titanium Surfaces
Via: (https://www.rmit.edu.au/news/all-news/2023/aug/antifungal-titanium) RMIT
(https://www.medgadget.com/2023/09/growth-factor-loaded-microparticles-enhance-3d-bioprinted-muscle.html) Growth Factor-Loaded Microparticles Enhance 3D Bioprinted Muscle
Sep 20th 2023, 14:29
Researchers at the Terasaki Institute in Los Angeles have developed a new method to create 3D printed muscle constructs with enhanced muscle cell alignment and maturation. The technique involves creating microparticles loaded with insulin-like growth factor (IGF) using a microfluidic platform. Then, these particles are included in a bioink that also incorporates myoblast cells and a gelatin-based hydrogel. Once 3D printed, the resulting constructs show enhanced cell growth, elongation, and alignment, and in some cases even began to spontaneously contract after a ten day incubation. The Terasaki researchers hope that their innovation will help pave the way for fully functional, lab-created muscle transplants for human patients.
Skeletal muscle is clearly crucial for movement and basic activity. If such muscle becomes injured or has to be removed because of injury or disease, then a patient’s quality of life can change significantly as their ability to move and perform daily activities is affected. Moreover, other closely associated tissues, such as lymph or blood vessels, may also be affected, leading to additional complications. At present, the main treatment option is to remove healthy muscle from elsewhere in the body and transplant it to the region where it is required.
However, this is not ideal. Not only is this strategy highly invasive, damaging healthy tissue to repair an injury elsewhere, but it can have mixed results, with issues such as incomplete innervation affecting the transplant performance and limiting the activity of the transplanted muscle. These issues have prompted scientists to attempt to create lab-grown alternatives using biomaterials.
3D bioprinting represents a very useful technique in this context, allowing researchers to print constructs in various shapes and sizes very rapidly. These researchers used this approach, but enhanced it with the judicious inclusion of slow-release growth factors to influence cell activity within the construct.
They included microparticles in the bioink that release IGF slowly within the construct over a period of days, helping to steer the included myoblasts cells towards a skeletal muscle phenotype. So far, the method appears to help in encouraging the cells to elongate and align, just like the real thing, and some constructs even demonstrated muscle contractions.
“The sustained release of IGF-1 facilitates the maturation and alignment of muscle cells, which is a crucial step in muscle tissue repair and regeneration,” said Ali Khademhosseini, a researcher involved in the study. “There is great potential for using this strategy for the therapeutic creation of functional, contractile muscle tissue.”
Study in journal Macromolecular Bioscience: (https://onlinelibrary.wiley.com/doi/10.1002/mabi.202300276) Enhanced Maturation of 3D Bioprinted Skeletal Muscle Tissue Constructs Encapsulating Soluble Factor‐Releasing Microparticles
Via: (https://terasaki.org/institute/news/pr/bioink-to-enhance-3d-bioprinted-skeletal-muscle.html) Terasaki Institute
Michael Reeder LCPC
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