TECHNOLOGY NEWS
Nanoscale Diamond Coatings Add Strength to Medical Devices
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Rho-BeSt developed custom equipment to create diamond films composed of individual crystals as thin as 5 nm.
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Scoring a 10 on the Mohs scale of mineral hardn s, diamond is the hardest naturally occurring mineral. Rho-BeSt Hartstoffbeschichtungs GmbH (Innsbruck, Austria) has taken advantage of the mineral’s natural strength by developing a coating composed of nanocrystalline diamond. Using patented technology, the company can produce diamonds as small as 5 nm, approximately 10,000 smaller than a typical human hair.
The company’s Rho-BeSt nanocrystalline diamond coating can be used to provide strength and biocompatibility to biosensors, medical instruments, and ceramic, tungsten carbide, and titanium implants. In experiments involving 400-nm diamond films, the coating promoted cell growth, adhesion, and differentiation of living cells. Because the film can be applied to uneven surfaces, it also has shown promise in experiments with dental implants. In these experiments, the coating was used in conjunction with bone morphogenetic protein-2 to positively influence cell behaviour and osseointegration.
The material’s biocompatibility is derived from the diamond’s crystal lattice structure of carbon atoms, which also provides resistance to radiation and abrasive chemicals. In addition, the fineness of the coating imparts a highly smooth surface, comparable to that of Teflon. As a result of its thinness, the coating can be applied so that the original form of the substrate is retained. This is especially useful for electronics applications where precise microarchitecture is required.
The firm can use different surface treatment processes to provide additional properties for the films. When a conductive, nonreactive, hydrophobic, and nonabsorbing surface is desired, the hydrogen-terminated coating can be applied using a special treatment. Similarly, the film can be made hydrophilic through oxygen termination.
At present, the coating must be applied to a substrate at temperatures between 550° and 800°C, and the maximal area of the diamond coating is 100 320 mm2. The company intends to introduce more flexibility into the process, making the treatment suitable for a greater range of applications. Current research involves surface treatment of biosensors.
