Hi Class! Last week, Ayomiposi Loye gave us a talk on Bulk Metallic Glasses (BMGs) for Biomedical Applications. I feel really excited to learn that BMGs have so many applications in biomedical devices. This is mainly because BMGs have good mechanical properties and biocompatibility, and the ability to be fabricated into desired shapes, which are ideal for versatile implant applications.
Unlike most metals, BMGs have a tendency to avoid crystallization when solidified. It is their amorphous structure that yields many advantages including remarkable properties of high strength (three times that of steel), elasticity, corrosion resistance and durability – all of which exceed that of currently used biomaterials. Most notable, however, is their unique processability that allows them to be molded like plastics with nano-scale precision and complex geometries.
This processing capability has only come with the recent emergence of thermoplastic forming (TPF), which decouples the fast cooling process from the molding process, allowing the time needed for precision net-shaping. For biomedical applications, biocompatibility of BMGs must also be considered. Their in vitro and in vivo study results indicated that the BMGs are compatible with cell growth and tissue function. Moreover, the ability to independently vary the chemistry, atomic structure, and surface topography – unique to BMGs – revealed the individual contribution of each on biocompatibility.
Researchers have targeted three applications: (1) bone replacement, (2) soft tissue implants (i.e., stents), and (3) surface patterning to program cellular response (i.e., synthetic membranes such as artificial kidneys). It is important that the shape and bulk properties of biomaterials mimic the tissues they replace and that surface chemistry and topography elicit the appropriate cellular response.
In a nutshell, BMGs are a promising biomaterial due to their superior mechanical properties and corrosion and wear resistance over currently metallic biomaterials. The in vitro and in vivo results indicate that the BMGs are in general nontoxic to cells and compatible with cell growth and tissue function. TPF-based processing methods for BMG were developed which satisfy the required precision and repeatability to shape intricate geometries used in biomedical applications. The ability to precisely net-shape complex geometries combined in a single processing step with patterning the surface will enable us to program desirable and predictable cellular response into a 3-D biomaterial.