Search

Nanofiber materials are commonly used as delivery vehicles for dermatological drugs due to their high surface-area-to-volume ratio, porosity, flexibility, and reproducibility. In this study air-jet spinning was used as a novel and economic method to fabricate corn zein nanofiber meshes with model drugs of varying solubility, molecular weight and charge. The release profiles of these drugs were compared to their release from corn zein films to elucidate the effect of geometry and structure on drug delivery kinetics. In film samples, over 50% of drug was released after only 2 h. However, fiber samples exhibited more sustained release, releasing less than 50% after one day. FTIR, SEM, and DSC were performed on nanofibers and films before and after release of the drugs. Structural analysis revealed that the incorporation of model drugs into the fibers would transform the zein proteins from a random coil network to a more alpha helical structure. Upon release, the protein fiber reverted to its original random coil network. In addition, thermal analysis indicated that fibers can protect the drug molecules in high temperature above 160 °C, while drugs within films will degrade below 130 °C. These findings can likely be attributed to the mechanical infiltration of the drug molecules into the ordered structure of the zein fibers during their solution fabrication. The slow release from fiber samples can be attributed to this biophysical interaction, illustrating that release is dictated by more than diffusion in protein-based carriers. The controlled release of a wide variety of drugs from the air-jet spun corn zein nanofiber meshes demonstrates their success as drug delivery vehicles that can potentially be incorporated into different biological materials in the future., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Biomaterials made from natural proteins and polysaccharides have become increasingly popular in the biomedical field due to their good biocompatibility and tunable biodegradability. However, the low miscibility of polysaccharides with proteins presents challenges in the creation of protein-polysaccharide composite materials. In this study, neat 1-allyl-3-methylimidazolium chloride (AMIMCl) ionic liquid was used to regenerate Thailand gold Bombyx mori silk and microcrystalline cellulose blended films. This solvent was found to not only effectively dissolve both natural polymers, but also preserve the structure and integrity of the polymers. A single glass transition temperature for each blend was found in DSC curves, indicating good miscibility between the Thai silk and cellulose molecules. The structural composition as well as the morphology and thermal stability of blend films were then determined using FTIR, SEM and TGA. It was found that by varying the ratio of Thai silk to cellulose, the thermal and physical properties of the material could be tuned. Blended films tended to be more thermally stable which could be due to the presence of hydrophobic-hydrophobic or electrostatic interactions between the silk and cellulose. These studies offered a new pathway to understand the tunable properties of protein-polysaccharide composite biomaterials with controllable physical and biological properties., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Recent studies have characterized the effects of aqueous ionic liquids on myoglobin unfolding for the broader purposes of understanding their effects on protein structures, stabilities, and ultimately biocompatibilities for future applications. Here, we investigated the effects of four different ionic liquids (ILs) on the thermal stability, unfolding kinetics, and tertiary shape of myoglobin. We compared results for four different ILs: 1-butyl-3-methyl imidazolium tetrafluoroborate (BMIBF4); 1-butyl-3-methyl pyrrolidinium tetrafluoroborate (PyrrBF4); 1-ethyl-3-methyl imidazolium acetate (EMIAc); and tetramethylguanidinium acetate (TMGAc). Results showed that ILs accelerate myoglobin unfolding kinetics both through aqueous solution ionic strength effects and ionic liquid-specific effects. Arrhenius plots of observed rate constants reveal that some ILs lower the energy barrier to unfolding, possibly by destabilizing the native protein state. The magnitude of these ionic liquid effects correlates with their effects on protein thermodynamic stabilities. Hydrogen-deuterium exchange (HDX) experiments using ESI-MS showed that myoglobin exhibits a more open, and presumably less stable, tertiary shape in aqueous IL solutions. Overall, BMIBF4 and TMGAc exhibit the strongest effect on the myoglobin stability, unfolding rate, and tertiary structure while PyrrBF4 and EMIAc have weaker effects under our experimental conditions., (Copyright © 2015 Elsevier B.V. All rights reserved.)