Bioglass helping to mend bones
May 9, 2013–Jose Ramon Sarasua and Aitor Larrañaga, researchers in the materials engineering department of the UPV/EHU-University of the Basque Country, have been studying new materials or implants that are of interest in medicine and in helping to mend bones, in particular. They have in fact measured the effect that the bioglass has on the thermal degradation of polymers currently used in medicine. The results have been published in the journal Polymer Degradation and Stability.
May 9, 2013–Jose Ramon Sarasua and Aitor
Larrañaga, researchers in the materials engineering department of the
UPV/EHU-University of the Basque Country , have been studying new materials or
implants that are of interest in medicine and in helping to mend bones, in particular.
They have in fact measured the effect that the bioglass has on the thermal
degradation of polymers currently used in medicine. The results have been
published in the journal Polymer Degradation and Stability.
Bones are capable of regenerating themselves
if they suffer slight damage. But if the damage is above a certain degree, bone
lacks the capability of mending itself. When breaks are too big, bones need to
be helped. Even today, metal nails or other components are often inserted to
help these breaks to mend. So, once the bone has mended, a second operation has
to be performed to extract these components. The aim of these new
materials or implants is, among other things, to obviate the need for the
These materials or implants that are of
interest in medicine have to meet a number of requirements before they can be
used in therapeutic applications. Among other things, the
materials have to be biocompatible, in other words, they must not damage the
cells or the organism itself. At the same time, being biodegradable is also a
very interesting property, so that the body will easily convert them into
metabolic products that are not toxic. But other factors also have to be taken
into consideration: mechanical robustness and the straightforward nature of the
production process, for example.
With all this in mind, the UPV/EHU
researchers are synthesising and shaping tailor-made bioimplants. The main
component, on the whole, tends to be a biodegradable polymer, in other words,
one that will gradually disappear as the bone occupies its own place. As the
polymer is too soft, bioglass was added to the polymer in this piece of work. Bioglass is a bioactive agent and helps
the bone to regenerate; what is more, it gives the polymer tough mechanical
properties. So the biodegradable polymer/bioglass composite system is stiffer
and tougher than the polymer alone.
These composite systems can be manufactured
by means of thermoplastic processes that use heat, and therefore it is
important to study how these materials respond to heat. In this work, the
biodegradable polymer/bioglass composite systems were found to have a lower
thermal stability compared with the systems without bioglass. In fact, a
reaction occurs between the silicon oxide ions of the bioglass and the carbonyl
groups in the polymers' structure, and so the material degrades and adversely
affects the properties of the end product, and what is more, when the implant
is grafted into the body, it encourages the formation of bi-products that may
be harmful for the cells. This would greatly restrict the application of these systems in medicine. That
is why the UPV/EHU researchers are doing a lot of research to improve the
thermal stability of these systems, and they have in fact published one of
these pieces of work in the journal Polymer Degradation and Stability.
In this case, they are proposing that a chemical transformation of the bioglass
surface be made by means of plasma. So by creating protective layers for the
bioglass particles, the reaction to the polymer is prevented and so the final
product remains undamaged.
“These composites that have a biodegradable
polymer base are candidates with a bright future in mending broken bones or in
regenerating bone defects," said Professor Sarasua.
In fact, after the material has temporarily substituted the bone and encouraged
it to regenerate, it gradually disappears as the bone returns to its proper
"This obviates the need for the second operations required nowadays to
remove nails and other parts that are inserted in order to somehow support the
bones in major breaks above a critical size, with all the advantages that has
from a whole range of perspectives," added Sarasua.