Carbohydrates@MOFsElectronic supplementary information (ESI) available: Additional figures, movies and experimental details. Substrates used and their formulas, schematic overviews of the performed syntheses and workups, time-dependent MOF-formation experiments induced by different carbohydrates and concentrations, yield calculations, SEM image of ZIF-8 on glass and paper, FTIR spectra of the starting materials and the obtained products, schematic of the ion-permeable spherical model, kinetics studies, UV-Vis analyses, photographs of solutions using different polysaccharides, and video showing the succesfull biomimetic mineralisation of CM-dextran. See DOI: 10.1039/c8mh01611a

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.