We present herein a new class of resin formulations for stereolithography, named FlexSL, with a broad bandwidth of tunable mechanical properties. The novel polyether(meth)acrylate based material class has outstanding material characteristics in combination with the advantages of being a biocompatible (meth)acrylate based processing material. FlexSL shows very promising results in several initial biocompatibility tests. This emphasizes its non-toxic behavior in a biomedical environment, caused mainly by the (meth)acrylate based core components. A short overview of mechanical and processing properties will be given in the end. The herein presented novel FlexSL materials show a significant lower cytotoxicity in contrast to commercial applied acrylic stereolithography resins. Further biocompatibility tests according to ISO 10993 protocols are planned. On the one hand, there are technical applications for this material (e.g. flaps, tubes, hoses, cables, sealing parts, connectors and other technical rubber-like applications), and on the other hand, broad fields of potential biomedical applications in which the FlexSL materials can be beneficial are obvious. Especially these could be small series production of medical products with special flexible material requirements. In addition, the usage for individual soft hearing aid shells, intra-operative planning services and tools like intra-op cutting templates and sawing guides is very attractive. The possibility to modify the FlexSL resins also for high-resolution applications makes it possible to manufacture now very flexible micro-prototypes with outstanding material characteristics and very fine structures with a minimum resolution of 20 mym and a layer thickness of minimal 5 myrn. These resin formulations are applicable and adjustable to other stereolithographic equipment available on the market.
Large bone defects require fabricated bone constructs that consist of three main components: an artificial extracellular matrix scaffold, stem cells with the potential to differentiate into osteoblasts, and bioactive substances, such as osteoinductive growth factors to direct the growth and differentiation of cells toward osteogenic lineage within the scaffold.
Biomass in general, wood and grasses in particular represent attractive renewable sources for the fabrication of so-called building block chemicals (1). Thus, environmentally benign antimicrobial nanoparticles based on a silver-infused lignin core were recently reported underlying the high potential for valorization of lignin (2). The contribution presents specific correlations regarding the structural differences of lignins depending on both: source (wood vs. grass) and isolation procedure (Kraft vs. Organosolv). Special focus will be drawn on detailed structure deviations caused by Miscanthus genotypes (M. gigantheus, M. robustus, M. sisnensis).
Synthesis of Substituted Hydroxyapatite for Application in Bone Tissue Engineering and Drug Delivery
(2019)
Introduction: After cellulose, lignin represents the most abundant biopolymer on earth that accounts for up to 18-35 % by weight of lignocellulose biomass. Today, it is a by-product of the paper and pulping industry. Although lignin is available in huge amounts, mainly in form of so called black liquor produced via Kraft-pulping, processes for the valorization of lignin are still limited [1]. Due to its hyperbranched polyphenol-like structure, lignin gained increasing interest as biobased building block for polymer synthesis [2]. The present work is focused on extraction and purification of lignin from industrial black liquor and synthesis of lignin-based polyurethanes.
Spektroskopische Qualifizierung und Quantifizierung von Hyaluronsäure in Nahrungsergänzungsmitteln
(2023)
To respond to the increasing demand for hyaluronic acid (HA) in dietary supplements (DSs) and nutricosmetics marketed for the treatment of osteoarthritis or moistening, it is essential to have an accurate and reliable method for its analysis in the final products. The study aimed to develop and validate alternative method for the quality control of HA in DSs using low-field (LF) and high-field (HF) nuclear magnetic resonance (NMR) spectroscopy at 80 MHz and 600 MHz, respectively. Moreover, chondroitin sulphate (CH), another active ingredient in DSs, can be simultaneously quantified. The 1H-NMR methods have been successfully validated in terms of limit of detection (LOD) and limit of quantitation (LOQ), which were found to be 0.1 mg/mL and 0.2 mg/mL (80 MHz) as well as 0.2 mg/mL and 0.6 mg/mL (600 MHz). Recovery rates were estimated to be between 92 and 120% on both spectrometers; precision including sample preparation was found to be 4.2% and 8.0% for 600 MHz and 80 MHz, respectively. Quantitative results obtained by HF and LF NMR were comparable for 16 DSs with varying matrix. HF NMR experiments at 70 ℃ serve as a simple and efficient quality control tool for HA and CH in multicomponent DSs. Benchtop NMR measurements, upon preceding acid hydrolysis, offer a cost-effective and cryogen-free alternative for analyzing DSs in the absence of CH and paramagnetic matrix components.
