Schmidt S.,University of Greifswald |
Scherkus C.,TU Hamburg - Harburg |
Muschiol J.,University of Greifswald |
Menyes U.,Enzymicals AG |
And 6 more authors.
Angewandte Chemie - International Edition | Year: 2015
Poly-ε-caprolactone (PCL) is chemically produced on an industrial scale in spite of the need for hazardous peracetic acid as an oxidation reagent. Although Baeyer-Villiger monooxygenases (BVMO) in principle enable the enzymatic synthesis of ε-caprolactone (ε-CL) directly from cyclohexanone with molecular oxygen, current systems suffer from low productivity and are subject to substrate and product inhibition. The major limitations for such a biocatalytic route to produce this bulk chemical were overcome by combining an alcohol dehydrogenase with a BVMO to enable the efficient oxidation of cyclohexanol to ε-CL. Key to success was a subsequent direct ring-opening oligomerization of in situ formed ε-CL in the aqueous phase by using lipase A from Candida antarctica, thus efficiently solving the product inhibition problem and leading to the formation of oligo-ε-CL at more than 20 gL-1 when starting from 200 mM cyclohexanol. This oligomer is easily chemically polymerized to PCL. Let's polymerize! Oligo-ε-caprolactone was produced in a one-pot enzymatic cascade synthesis starting from cyclohexanol. In the first step, cyclohexanol is oxidized by an alcohol dehydrogenase (ADH) in combination with the cyclohexanone monooxygenase (CHMO) from Acinetobacter calcoaceticus, followed by direct ring-opening oligomerization of ε-caprolactone in an exclusively aqueous phase by lipase A from Candida antarctica (CAL-A). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source
Maier G.,Polymaterials AG
Gummi, Fasern, Kunststoffe | Year: 2015
Plastics are characterised by the possibility to adjust their properties in a wide range according to the requirements for the desired application. Changing the chemical structure allows extensive changes of properties. However, it is economically viable only in situations where the desired application justifies the substantially higher production cost for small scale specialties. On the other hand, the properties of standard polymers can also be adjusted, e. g. by the addition of additives, processing aids, fillers, or reinforcing fibres, but also by components that cause certain effects such as electrical or heat conductivity. Already existing properties can be enhanced, and new ones can be introduced in this way. Almost all technically used plastics are composites, so in principle an adjustment of the recipe is possible. However, the development of an adjusted recipe can be very complex, since many aspects, often with conflicting requirements, must be considered. Mathematical design of experiments - combinatorial plans and statistical experimental design - combined with methods for running a large number of experiments in a short time (high throughput screening) can help to reduce the development costs. Thus, specialities can become economically viable even at low volumes. This is especially interesting for new applications, substantially increased requirements, new base polymers such as bio genic polymers, and developments or reformulations that have become necessary due to unavailability of certain raw materials because of changes in legislation. Source
Maier G.,Polymaterials AG
Angewandte Chemie - International Edition | Year: 2013
On the way to membranes for the separation of industrially important gas pairs, researchers have devised the new ladder polymer PIM-EA-TB, which was found to have remarkable selectivity and permeability for several technically relevant gas pairs. A possible explanation of these observations is given. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source
Polymaterials Ag | Date: 2013-12-17
According to the invention, thermoreversible hydrogels are provided, which are prepared from chain-extended poloxamers, having advantageous properties. In addition, the invention provides thermoreversible hydrogels, including biological materials, and a process for the preparation thereof, thermoreversible hydrogels including living cells, application systems for pharmaceutical applications, and an in-vitro-method for forming a composition on a surface.
Volkmer E.,Ludwig Maximilians University of Munich |
Leicht U.,Ludwig Maximilians University of Munich |
Moritz M.,Ludwig Maximilians University of Munich |
Schwarz C.,Ludwig Maximilians University of Munich |
And 9 more authors.
Journal of Materials Science: Materials in Medicine | Year: 2013
Cell-based regenerative therapies for bone defects usually employ bone precursor cells seeded on solid scaffolds. Thermosensitive hydrogels that harden at body core temperature are promising alternative cell carriers as they are applicable minimally invasively. We modified Pluronic® P123 with different chain extenders and assessed rheology and biocompatibility of the resulting hydrogels. The best candidate was tested in a rat's femoral defect model. All gels hardened above 25 C with butane-diisocyanate-hydrogels (BDI-gels) displaying the highest storage moduli. BDI-gels showed the most favourable biocompatibility and did not affect cellular adipogenic or osteogenic differentiation in vitro. Implantation of BDI-hydrogel into femoral defects did not impede bone healing in vivo as evidenced by μCT and histological analysis. We conclude that thermosensitive BDI-gels are promising alternative cell carriers. The gels harden upon injection in vivo without interfering with bone metabolism. Further experiments will assess the gels' capacity to effectively transport living cells into bone defects. © 2013 Springer Science+Business Media New York. Source