BioGlass is a commercially available type of bioactive glass It is also known as 45S5 glass. It is composed of SiO2, Na2O, CaO and P2O5. Professor Larry Hench developed BioGlass at the University of Florida in the late 1960s. He was challenged by a MASH army officer to develop a material to help regenerate bone, as many Vietnam war veterans suffered badly from bone damage, such that most of them injured in this way lost their limbs.
The key composition features of BioGlass is that it contains less than 60mol% SiO2, high Na2O and CaO contents, high CaO/P2O5 ratio, which makes BioGlass highly reactive to aqueous medium and bioactive.
High bioactivity is the main advantage of BioGlass, while its disadvantage includes mechanical weakness, low fracture toughness due to amorphous 2-dimensional glass network. The bending strength of most BioGlass is in the range of 40-60MPa, which is not enough for load-bearing application. While its Young's modulus is 30-35GPa, very close to that of cortical bone.
BioGlass 8625 is the specific material used by my Hitag S 2048 implants. I have not found a reliable source of accurate information specific to this glass, but am still looking. The only mention of it I have found is in this document which I do not believe to be accurate. It describes Bio Glass 8625 as:
- A soda lime glass
- NOT inert - forming a calcium layer around the capsule
Used by VeriChip, which contains patient information and medical history
Of note: I believe he is specifically discussing the VeriChip here. The calcium layer he references is formed by Anti Migration Coating on the glass, not the glass itself. This is why it is important to find a BioGlass implant that has no coating on it. It is also important to state that the VeriChip is an RFID transponder containing a unique ID code. It does not contain patient information, or medical history, though the ID code it stores is used to access that information in another database.