Carbohydrates@MOFs

MOFs have demonstrated outstanding properties for the protection and controlled release of different bio-entities, from proteins to living cells. Carbohydrates, as pure molecules or as a component of proteins and cells, perform essential biological functions. Thus, an understanding of the role of carbohydrates in the formation of MOF-based bio-composites will facilitate their application to biotechnology and medicine. Here, we investigate the role of carbohydrate molecular weight and chemical functionalization in the formation of carbohydrate@MOF composites. We find that chemical functionalization, such as carboxylation, that leads to an enhancement of metal cation concentration at the surface of the molecule triggers the rapid self-assembly of the MOF material, zeolitic-imidazolate framework 8 (ZIF-8). Furthermore, we determine the encapsulation efficiency and measure the release properties of the carbohydrate under controlled conditions. Our findings show that MOFs can be used to prepare a new class of biocomposites for the delivery of carbohydrate-based therapeutics.Efwita Astria, Martin Thonhofer … Weibin Liang … David M. Huang, Christian J. Doonan, Paolo Falcaro ... et al

Chemical vapor deposition of carbohydrate-based polymers: a proof of concept study

The aim of this work is to investigate if vinyl-modified carbohydrate compounds are suitable monomers for thin film polymerization via chemical vapor deposition in a proof-of-concept study. Synthetic carbohydrate-based polymers are explored as biodegradable, biocompatible, and biorenewable materials. A thin film of synthetic polymers bearing sugar residues can also offer a good surface for cell attachment, and thus might be applied in biomaterials and tissue engineering. The possibility of having such thin film deposited from the vapor phase would ease the implementation in complex device architectures. For a proof-of-concept study, sugar vinyl compound monomers are synthesized starting from methyl α-d-glucopyranoside and polymerized by initiated chemical vapor deposition (iCVD) leading to a thin polymer layer on a Si-substrate. Thus, a successful vapor polymerization of the sugar compounds could be demonstrated. Infrared spectroscopy shows that no unwanted crosslinking reactions take place during the vapor deposition. The solubility of the polymers in water was observed in situ by spectroscopic ellipsometry. Graphical abstract: [Figure not available: see fulltext.]

The European Polysaccharide Network of Excellence (EPNOE) research roadmap 2040 : Advanced strategies for exploiting the vast potential of polysaccharides as renewable bioresources

Polysaccharides are among the most abundant bioresources on earth and consequently need to play a pivotal role when addressing existential scientific challenges like climate change and the shift from fossil-based to sustainable biobased materials. The Research Roadmap 2040 of the European Polysaccharide Network of Excellence (EPNOE) provides an expert's view on how future research and development strategies need to evolve to fully exploit the vast potential of polysaccharides as renewable bioresources. It is addressed to academic researchers, companies, as well as policymakers and covers five strategic areas that are of great importance in the context of polysaccharide related research: (I) Materials & Engineering, (II) Food & Nutrition, (III) Biomedical Applications, (IV) Chemistry, Biology & Physics, and (V) Skills & Education. Each section summarizes the state of research, identifies challenges that are currently faced, project achievements and developments that are expected in the upcoming 20 years, and finally provides outlines on how future research activities need to evolve.

Structural and mechanistic insight into N-glycan processing by endo-α-mannosidase

N-linked glycans play key roles in protein folding, stability, and function. Biosynthetic modification of N-linked glycans, within the endoplasmic reticulum, features sequential trimming and readornment steps. One unusual enzyme, endo-α-mannosidase, cleaves mannoside linkages internally within an N-linked glycan chain, short circuiting the classical N-glycan biosynthetic pathway. Here, using two bacterial orthologs, we present the first structural and mechanistic dissection of endo-α-mannosidase. Structures solved at resolutions 1.7–2.1 Å reveal a (β/α)8 barrel fold in which the catalytic center is present in a long substrate-binding groove, consistent with cleavage within the N-glycan chain. Enzymatic cleavage of authentic Glc1/3Man9GlcNAc2 yields Glc1/3-Man. Using the bespoke substrate α-Glc-1,3-α-Man fluoride, the enzyme was shown to act with retention of anomeric configuration. Complexes with the established endo-α-mannosidase inhibitor α-Glc-1,3-deoxymannonojirimycin and a newly developed inhibitor, α-Glc-1,3-isofagomine, and with the reducing-end product α-1,2-mannobiose structurally define the -2 to +2 subsites of the enzyme. These structural and mechanistic data provide a foundation upon which to develop new enzyme inhibitors targeting the hijacking of N-glycan synthesis in viral disease and cancer