I have read many articles regarding osteogenic-induced differentiation of bioactive materials (HA, TCP, Bioactive Glass), and I have observed that when the test is performed through indirect contact, using conditioned medium, usually there is a P precipitation after the incubation, which is related to the addition of the material. In this way, is the indirect contact in vitro test a test unable to properly evaluate the the effects of the ionic dissolution products derived from the bioceramic, as long as the concentration of P has not been properly taken into consideration? Or does this test just show that the P helps in the mineralization of the extracellular matrix process through precipitating on the cell surface, and mostly of the other cellular phenomena are controlled by other ions?
Note: Usually the P concentration significantly varies.
Note 2: Usually, the authors associate the results with Ca variation, and Ca signaling pathways, which usually does not precipitate, or precipitates less than P (in terms of relative percentage).
Rogers: look at what you are reading: in most cases, people do the so-called in vitro incubation test, or the Kokubo test, or the SBF immersion test, which consists in dipping the ceramic into a simulated body fluid, and then report surface analysis by EDX, or sometimes analyze the solution contents and variations, or weight gain or loss of the sample as a function of time.
this gives an idea about the tendency of the material to promote apatite growth on the surface, and this in turn is considered as a sign of bioactivity, whereas in fact it is only related to solubility 'or insolubility, or precipitation of ions. for example apatite can grow even on plain old plastic sheets placed in SBF, so does this make it bioactive???
if you look up papers from Kokubo, you will find that P does not help much, the agent most active in biomineralization is described as hydrated silica, and several consecutive layers of elements are responsible for the building of bioactive coatings, particularly bases such as Na or Ca containing compounds
this is an ever ending story!
- Badges
- Science topic
- Similar topics
- Publishing