Polymeric biomaterials derived from lactic acid have extensive uses in medical applications, especially in the context of biodegradable sutures. They are widely used in the architecture of cardiac tissue, as support for drugs, and biodegradable fixation devices for the repair of small broken bones such as the ones in the hands, joints and feet.
These orthopaedic implants are gradually metabolised and naturally assimilated by the body. Their mass is progressively transferred into the broken bone, helping the healing process and thereby eliminating the need for a second intervention.
These new materials are obtained through molecular catalysis, and require breaking the cyclic dimer of lactic acid “lactide” to obtain polylactic acid (PLA). The lactide is a renewable natural resource that occurs as a by-product of the fermentation of biomass with high starch content, such as maize, wheat, or sugar beet. As in every polymerisation process, a catalyst is required and in this case the active compound must be a metal.
Consequently, this catalytic process has been studied with different metals such as tin, yttrium, titanium, aluminium and other lanthanides. However, since on some occasions residues of the catalyst can be incorporated into the polymer, it is important to preserve the biocompatibility and zero toxicity of the PLA by insuring that the metallic catalyst used is biologically benign and does not have a negative impact on tissue. These medical uses have favoured the use of metals like magnesium, calcium or zinc, all of them common inside the human body.
On a different front, PLAs are being investigated as a possible raw material of many manufactured products, since they present similar and in some cases better properties than traditional polymers that are derived from the bioresistant poly (a-olefin), with the significant added benefit of biodegradation.
While their production costs were considered too high in the past, recent developments in the treatment and production combined with the contrasting ecological hazard represented by petroleum derived polymers have brought these types of biodegradable polymers to very competitive positions.
One of the most recent and relevant examples that confirm this growing expansion, is the joint endeavour by Cargill. Inc., and The Dow Chemical Co., who have recently announced the mass production of many tons of PLAs.
The scientific community shows a growing interest to find catalysts that are capable of producing such biomaterials with well defined microstructures, since this defines the mechanical properties, the biodegradability, and the overall usability of the material.
With this in mind, the research group from the URJC, formed by Dr Andrés Garcés and Carlos Alonso and coordinated by Dr Luis Fernando Sánchez-Barba, is working in collaboration with the UCLM to develop different families of catalysts based on magnesium and zinc and stabilised by ligands like heteroscorpionate of they type “NNN”, capable of polymerising the ε-caprolactone and the lactide in a controlled manner. These are extremely active initiators with a chemical formula of [M(R)(NNN)] (M = Mg, Zn) that achieve a productivity of 21.000 Kg of poly-ε- caprolactone (PLC) produced per mol of Mg each hour at room temperature.
Moreover, some of these initiators allow for a controlled growth of the PLA’s microstructure. This is linked to the influence that the heteroscorpionate exerts during the process of opening the cyclic dimmer, which in turn grants control over the future specifications and applications of the produced material such as a high molecular mass, crystallinity as well as high fusion temperature (165ºC), all of it generating a great interest from industry.
This study has been published in the latest editions of the Inorganic Chemistry & Organometallics magazine.
Gabinete de prensa | alfa
What the world's tiniest 'monster truck' reveals
23.08.2017 | American Chemical Society
Treating arthritis with algae
23.08.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
23.08.2017 | Life Sciences
23.08.2017 | Life Sciences
23.08.2017 | Physics and Astronomy