Magnesium/polymer composite biomaterial for biomedical applications
Developed by: Instituto de Investigación Sanitaria Hospital La Paz
Description and essential characteristics
The technology consists of a biocompatible, resorbable and biodegradable material made of a mixture based on a biocompatible and biodegradable copolymer that contains polylactic acid (PLA) and particles of magnesium (Mg).
The particle size of Mg used for the manufacture of the composite is selected depending on its application. Particle sizes lower than 50 microns are used for osteosynthesis applications (bone repair), whereas particle sizes between 50 and 250 microns are required for tissue engineering approaches (bone regeneration).
The method for obtaining the biomaterial consists of the following steps:
a) Mixing the matrix-forming polymer and magnesium particles with an organic solvent that facilitates the dispersion of the magnesium particles in the polymeric matrix.
b) Evaporation of the organic solvent from the product obtained in step (a).
c) Thermomechanical processing to compact and shape the product obtained in step (b) at specific temperature ranges.
Mg/polymer composite exhibits superior mechanical properties (strength, elastic modulus) to those of dense or porous resorbable polymers. The PLA used for the manufacture of the composite will depend on its application, using semicrystalline forms (L-PLA) when higher mechanical performance (or a longer degradation period) is required, or amorphous forms (DL-PLA) if the application involves lower mechanical loading (or shorter resorption times). Copolymers could also be used to modulate both mechanical properties and degradation rates.
The advantages of using Mg include its biocompatibility and its osteoconductive properties. Furthermore, the ions released during its degradation are soluble in physiological media and are readily excreted in urine. Reinforcement of the polymer with Mg improves the mechanical properties of the composite, which are similar to those of human bone, thus favouring the load transfer at the bone/material interface.
Additionally, the use of a completely biodegradable material provides important advantages in relation to the use of conventional metal alloys, such as elimination of the stress shielding effect and the possibility of post-operative diagnosis using electromagnetic fields.
Manufacture of biomedical devices and implants for bone repair and/or regeneration.
Bone tissue engineering.
Estado de protección
Spanish patent P201030950, granted in January 2013.
International patent application PCT/ES2011/070440.