27 6 月, 2022

Novel patching material for bone defects

TSUKUBA, Japan, Jun 27, 2022 - (ACN Newswire via SEAPRWire.com) - Ceramics and metals have been used for a while as structural materials to repair bones and joints. In the past, scientists engineered bioinert materials, which do not bond to bones directly; bioactive materials that can bond to bones; and bio-absorbable materials that are categorized in bioactive materials but they are absorbed by the body over time and are replaced by advancing bone tissue. A new bio-responsive ceramic can be used to repair bone defectsWith an enzyme found in blood, different types of salts were converted to hydroxyapatite, a bone mineralNow, a fourth type of bone repairing materials has been found: a bio-responsive ceramic that interacts with an enzyme found in blood to be absorbed into the body at a precise and predictable rate.The research was done by Taishi Yokoi, an associate professor at the Institute of Biomaterials and Bioengineering at Tokyo Medical and Dental University, and his colleagues. The study was published in May in Science and Technology of Advanced Materials."Extending healthy life expectancy is an important issue for all of us," Yokoi says. "Bone repairing materials aid in the recovery of bone defects and help improve quality of life."At the heart of this discovery is a biological reaction: an enzyme called alkaline phosphatase (ALP), which is present in human serum and reacts with various phosphate esters to generate bone mineral known as hydroxyapatite.The scientists mimicked this process using a simulated body fluid that contained the enzyme ALP. They placed four different salts in a simulated body fluid containing or lacking the enzyme ALP. The salts were calcium salts of methyl phosphate (CaMeP), ethyl phosphate (CaEtP), butyl phosphate (CaBuP) and dodecyl phosphate (CaDoP). The phosphate component of each of these salts has an alkyl group at its end - a chain composed of hydrogen and carbon atoms - of differing lengths.The scientists found that the first three salts were converted to hydroxyapatite, but only in the presence of ALP. Interestingly, the length of the alkyl group on the phosphate ester determined the rate at which this reaction happens. With more research, the scientists think that this could allow greater control of the bone healing process in the body."We expect the findings of this study will be applied towards designing and developing novel bone-repairing materials with precisely controlled degradation and resorption rates inside the body," says Yokoi. Further informationTaishi YokoiTokyo Medical and Dental UniversityEmail: yokoi.taishi.bcr@tmd.ac.jpResearch paper: https://www.tandfonline.com/doi/full/10.1080/14686996.2022.2074801About Science and Technology of Advanced Materials (STAM)Open access journal STAM publishes outstanding research articles across all aspects of materials science, including functional and structural materials, theoretical analyses, and properties of materials. https://www.tandfonline.com/STAMMikiko TanifujiSTAM Publishing Director Email: TANIFUJI.Mikiko@nims.go.jpPress release distributed by Asia Research News for Science and Technology of Advanced Materials. Copyright 2022 ACN Newswire. All rights reserved. (via SEAPRWire)

26 1 月, 2021

Materials coloured like a peacock

Tsukuba, Japan, Jan 26, 2021 - (ACN Newswire) - Melanin-like compounds can be precisely designed and arranged to colour materials using a mechanism similar to that found in a peacock's feathers. Chemist Michinari Kohri of Chiba University in Japan reviewed the latest research on these 'melanin-mimetic materials' and their potential applications for the journal Science and Technology of Advanced Materials.Scientists are developing materials inspired by the structural colours in a peacock's feathers. (Credit: Takashi Tsujino)Melanin and melanin-like compounds absorb some of the light that is scattered from the microstructures within materials. Scientists are finding ways to control this phenomenon to give a variety of iridescent and non-iridescent colours. (Credit: Michinari Kohri)Melanin is a dark pigment that gives hair and skin its colour. It is also essential for the bright colours we see in some organisms. When light interacts with the structures of feathers, wings and shells of many organisms, like peacocks, butterflies and jewel beetles, it is scattered, appearing white. But when melanin is interspersed within these structures, some of the scattered light is absorbed, producing various colours. Scientists are looking for ways to mimic these so-called 'structural colour' changes of living organisms in synthetic materials."Vivid structural colours can be obtained by constructing microstructures containing a light-absorbing black material made of natural or artificial melanin," says Kohri. "Research in this area is progressing rapidly worldwide."A leading contender is a compound called polydopamine. It is made of a material naturally found in the body, so it is biocompatible. It is also dark, so it absorbs light like melanin. Scientists found they could control polydopamine's iridescence - how much the colour changes as the angle of light hitting it shifts, similar to a peacock's feather. They achieved this by altering the particle size or by adding compounds that react to a magnetic field.Scientists are also investigating particles formed of a polystyrene core and a polydopamine shell. Changing the diameter of the inner core, for example, leads to different colours. Making the polydopamine shell thicker causes the particles to be less closely packed, leading to non-iridescent structural colour, which remains the same regardless of the light angle.Scientists have also toyed with controlling colour and angle-dependence by changing the shapes of polystyrene/polydopamine particles, making them hollow on the inside, and adding multiple coatings to the external shell.Polydopamine particles are showing potential for a variety of applications. For example, they can be used as inks to dye fabrics or in cosmetics. They could help prove a product is real versus counterfeit by shifting colour with strong light, wetting, or temperature changes. Finally, scientists have found that adding these particles to rubber causes it to change colour when stretched or relaxed, which could be useful for sensing local stress and strain in bridges.Further informationMichinari Kohri Chiba UniversityEmail: kohri@faculty.chiba-u.jpAbout Science and Technology of Advanced Materials JournalOpen access journal STAM publishes outstanding research articles across all aspects of materials science, including functional and structural materials, theoretical analyses, and properties of materials.Chikashi NishimuraSTAM Publishing DirectorNISHIMURA.Chikashi@nims.go.jpPress release distributed by ResearchSEA for Science and Technology of Advanced Materials. Copyright 2021 ACN Newswire. All rights reserved. www.acnnewswire.com