Microgels with controlled network topologies by photocrosslinking-assisted continuous precipitation polymerization.

In this study, we present a new synthesis methodology based on photo-crosslinking-assisted continuous precipitation polymerization which allows controlling the distribution of crosslinks in microgels. In our approach we substituted conventional crosslinking agent by a comonomer carrying photo-crosslinkable 4-oxocyclopent-2-en-1-yl group. Microgel size, morphology, distribution of crosslinks and packing density of the polymer chains are studied as a function of retention time (Rt) in the flow reactor.

Biobased Photopolymer Resin for 3D Printing Containing Dynamic Imine Bonds for Fast Reprocessability.

Acrylic photopolymer resins are widely used in stereolithographic 3D printing. However, the growing demand for such thermosetting resins is weighing on global issues such as waste management and fossil fuel consumption. Therefore, there is an increasing demand for reactive components that are biobased and enable recyclability of the resulting thermoset products.

Tuning the Chiral Structures from Self-Assembled Carbohydrate Derivatives.

Carbohydrates have been regarded as one of the most ideally suited candidates for chirality study via self-assembly owning to their unique chemical structures, abundance, and sustainability. Much efforts have been devoted to design and synthesize diverse carbohydrate derivatives and self-assemble them into various supermolecular morphologies. Nevertheless, still inadequate attention is paid to deeply and comprehensively understand how the carbohydrate structures and self-assembly approaches affect the final morphologies and properties for future demands.

Amphiphilic Crosslinked Four-Armed Poly(lactic--glycolide) Electrospun Membranes for Enhancing Cell Adhesion.

Common poly(lactide--glycolide) (-PLGA) has emerged as a biodegradable and biocompatible material in tissue engineering. However, the poor hydrophilicity and elasticity of -PLGA lead to its limited application in tissue engineering. To this end, an amphiphilic crosslinked four-armed poly(lactic--glycolide) was prepared.

Additive Manufacturing of α-Amino Acid Based Poly(ester amide)s for Biomedical Applications.

α-Amino acid based polyester amides (PEAs) are promising candidates for additive manufacturing (AM), as they unite the flexibility and degradability of polyesters and good thermomechanical properties of polyamides in one structure. Introducing α-amino acids in the PEA structure brings additional advantages such as (i) good cytocompatibility and biodegradability, (ii) providing strong amide bonds, enhancing the hydrogen-bonding network, (iii) the introduction of pendant reactive functional groups, and (iv) providing good cell-polymer interactions. However, the application of α-amino acid based PEAs for AM via fused deposition modeling (FDM), an important manufacturing technique with unique processing characteristics and requirements, is still lacking.

Kinetic modelling of the solid-liquid extraction process of polyphenolic compounds from apple pomace: influence of solvent composition and temperature.

This study aims to assess kinetic modelling of the solid-liquid extraction process of total polyphenolic compounds (TPC) from apple pomace (AP). In this regard, we investigated the effects of temperature and solvent (i.e.

Radical Formation in Sugar-Derived Acetals under Solvent-Free Conditions.

The degradation of acetal derivatives of the diethylester of galactarate (GalX) was investigated by electron paramagnetic resonance (EPR) spectroscopy in the context of solvent-free, high-temperature reactions like polycondensations. It was demonstrated that less substituted cyclic acetals are prone to undergo radical degradation at higher temperatures as a result of hydrogen abstraction. The EPR observations were supported by the synthesis of GalX based polyamides via ester-amide exchange-type polycondensations in solvent-free conditions at high temperatures in the presence and in the absence of radical inhibitors.

Development of Lignin-Based Mesoporous Carbons for the Adsorption of Humic Acid.

There is an increasing urge to make the transition toward biobased materials. Lignin, originating from lignocellulosic biomass, can be potentially valorized as humic acid (HA) adsorbents lignin-based mesoporous carbon (MC). In this work, these materials were synthesized for the first time starting from modified lignin as the carbon precursor, using the soft-template methodology.

Expansion of Ovarian Cancer Stem-like Cells in Poly(ethylene glycol)-Cross-Linked Poly(methyl vinyl ether--maleic acid) and Alginate Double-Network Hydrogels.

A better understanding of cancer stem cells (CSCs) is essential for research on cancer therapy and drug resistance. Currently, increasingly more investigations are focused on obtaining CSCs to study the mechanism of their enhanced malignancy. In this work, three kinds of double-network hydrogels (PEMM/alginate), consisting of poly(ethylene glycol) (PEG) covalently cross-linked poly(methyl vinyl ether--maleic acid) (P(MVE--MA)) (network 1, denoted as PEMM) and Sr (or Ca, Fe) ionically cross-linked alginates (network 2, denoted as SrAlg, CaAlg, or FeAlg), were prepared.

Self-Assembled Supramolecular Hybrid Hydrogels Based on Host-Guest Interaction: Formation and Application in 3D Cell Culture.

In recent decades, in vitro three-dimensional (3D) cell culture has been rapidly developed and widely used in many biomedical fields. Based on this background, a kind of self-assembled supramolecular hybrid hydrogel materials based on host-guest interaction of β-cyclodextrin (βCD) and adamantane (Ad) is designed for 3D cell culture. First, βCD is grafted to poly(methyl vinyl ether--maleic acid) (PMM) to obtain the host polymers of βCD-grafted-PMM (PMM-βCD).

Chitooligosaccharides for wound healing biomaterials engineering.

Chitooligosaccharides (CHOS) are oligomers of β-(1-4) linked N-acetylglucosamine and D-glucosamine that are produced from chitin or chitosan using different enzymatic or chemical methods. CHOS are water-soluble and non-cytotoxic with diverse bioactivities such as antibacterial, anti-inflammation, anti-obesity, anti-tumor and antioxidant. These biological features make CHOS promising compounds for several medical and food applications.

Additive Manufacturing Using Melt Extruded Thermoplastics for Tissue Engineering.

Melt extrusion of thermoplastic materials is an important technique for fabricating tissue engineering scaffolds by additive manufacturing methods. Scaffold manufacturing is commonly achieved by one of the following extrusion-based techniques: fused deposition modelling (FDM), 3D-fiber deposition (3DF), and bioextrusion. FDM needs the input material to be strictly in the form of a filament, whereas 3DF and bioextrusion can be used to process input material in several forms, such as pellets or powder.

Thermoresponsive Poly(2-propyl-2-oxazoline) Surfaces of Glass for Nonenzymatic Cell Harvesting.

As one of the nonenzymatic cell-harvesting technologies, a thermal-responsive surface based on poly(2-oxazoline)s has achieved initial success in supporting the adhesion and thermal-induced detachment of animal cells. However, because of the laborious preparation procedure, this technique was only limited to research purposes. In this work, through using poly(glycidyl methacrylate) (PGMA) as the anchor layer, poly(2-propyl-2-oxazoline)s (PPOx) were grafted onto glass wafers through a facile two-step coating and annealing procedure for nonenzymatic cell harvesting.

Hydrothermal polymerization towards fully biobased polyazomethines.

Microwave assisted polycondensation for the synthesis of (partially) biobased polyazomethines in water (hydrothermal polymerization) was investigated for the first time in this study. The polyazomethines prepared via this environmentally friendly and simple method show comparable characteristics as the polymers prepared via traditional methods in organic solvents.

The Forgotten Pyrazines: Exploring the Dakin-West Reaction.

Pyrazines are an underreported class of N-heterocycles available from nitrogen-rich biomass presenting an interesting functional alternative for current aromatics. In this work, access to pyrazines obtained from amino acids by using the 90 year old Dakin-West reaction was explored. After a qualitative screening several functional proteinogenic amino acids proved good substrates for this reaction, which were successfully scaled to multigram scale synthesis of the corresponding intermediate α-acetamido ketones.

Formation of cyclic structures in the cationic ring-opening polymerization of 1,3-dioxolane.

The cationic ring-opening polymerization of acetals is prone to cyclization of the polymer chains. This is also the case for the polymerization of 1,3-dioxolane. Literature states that this cyclization can be reduced by applying the Active Monomer mechanism, at least if no competition with the Active Chain End mechanism occurs.

UV-Curable Biobased Polyacrylates Based on a Multifunctional Monomer Derived from Furfural.

The controlled polymerization of a new biobased monomer, 4-oxocyclopent-2-en-1-yl acrylate (4CPA), was established via reversible addition-fragmentation chain transfer (RAFT) (co)polymerization to yield polymers bearing pendent cyclopentenone units. 4CPA contains two reactive functionalities, namely, a vinyl group and an internal double bond, and is an unsymmetrical monomer. Therefore, competition between the internal double bond and the vinyl group eventually leads to gel formation.

Towards High-performance Materials Based on Carbohydrate-Derived Polyamide Blends.

A bio-derived monomer called 2,3:4,5-di--isopropylidene-galactarate acid/ester (GalXMe) has great potential in polymer production. The unique properties of this molecule, such as its rigidity and bulkiness, contribute to the good thermal properties and appealing transparency of the material. The main problem, however, is that like other biobased materials, the polymers derived thereof are very brittle.

A Prospective Life Cycle Assessment (LCA) of Monomer Synthesis: Comparison of Biocatalytic and Oxidative Chemistry.

Biotechnological processes are typically perceived to be greener than chemical processes. A life cycle assessment (LCA) was performed to compare the chemical and biochemical synthesis of lactones obtained by Baeyer-Villiger oxidation. The LCA is prospective (based on experiments at a small scale with primary data) because the process is at an early stage.

Solvent-Free Method for the Copolymerization of Labile Sugar-Derived Building Blocks into Polyamides.

This research focuses on the preparation of biobased copolyamides containing biacetalized galactaric acid (GalX), namely, 2,3:4,5-di--isopropylidene-galactaric acid (GalXMe) and 2,3:4,5-di--methylene-galactaric acid (GalXH), in bulk by melt polycondensation of salt monomers. In order to allow the incorporation of temperature-sensitive sugar-derived building blocks into copolyamides at temperatures below the degradation temperature of the monomers and below their melting temperatures, a clever selection of salt monomers is required, such that the sugar-derived salt monomer dissolves in the other salt monomers. The polymerization was investigated by temperature dependent FT-IR and optical microscopy.

Toward Upscaled Biocatalytic Preparation of Lactone Building Blocks for Polymer Applications.

Although Baeyer-Villiger monooxygenases (BVMOs) have gained attention in recent years, there are few cases of their upscaled application for lactone synthesis. A thermostable cyclohexanone monooxygenase from (TmCHMO) was applied to the oxidation of 3,3,5-trimethylcyclohexanone using a glucose dehydrogenase (GDH) for cofactor regeneration. The reaction progress was improved by optimizing the biocatalyst loading, with investigation into oxygen limitations.

Elastic materials for tissue engineering applications: Natural, synthetic, and hybrid polymers.

Unlabelled: Elastin and collagen are the two main components of elastic tissues and provide the tissue with elasticity and mechanical strength, respectively. Whereas collagen is adequately produced in vitro, production of elastin in tissue-engineered constructs is often inadequate when engineering elastic tissues. Therefore, elasticity has to be artificially introduced into tissue-engineered scaffolds.

Application of a thermostable Baeyer-Villiger monooxygenase for the synthesis of branched polyester precursors.

Background: It is widely accepted that the poor thermostability of Baeyer-Villiger monooxygenases limits their use as biocatalysts for applied biocatalysis in industrial applications. The goal of this study was to investigate the biocatalytic oxidation of 3,3,5-trimethylcyclohexanone using a thermostable cyclohexanone monooxygenase from Thermocrispum municipale (TmCHMO) for the synthesis of branched ϵ-caprolactone derivatives as building blocks for tuned polymeric backbones. In this multi-enzymatic reaction, the thermostable cyclohexanone monooxygenase was fused to a phosphite dehydrogenase (PTDH) in order to ensure co-factor regeneration.

Quantification of biases in predictions of protein stability changes upon mutations.

Motivation: Bioinformatics tools that predict protein stability changes upon point mutations have made a lot of progress in the last decades and have become accurate and fast enough to make computational mutagenesis experiments feasible, even on a proteome scale. Despite these achievements, they still suffer from important issues that must be solved to allow further improving their performances and utilizing them to deepen our insights into protein folding and stability mechanisms. One of these problems is their bias toward the learning datasets which, being dominated by destabilizing mutations, causes predictions to be better for destabilizing than for stabilizing mutations.