Production of succinic acid in basket and mobile bed bioreactors-Comparative analysis of substrate mass transfer aspects

The glucose mass transfer in the biosynthesis of succinic acid with immobilized Actinobacillus succinogenes cells has been comparatively analyzed for a bioreactor with mobile bed vs. a stationary basket bioreactor. The process has been considered to occur under substrate and product inhibitory effects. The results indicated that the bioreactor with mobile bed is more efficient for biocatalyst particles with a diameter over 3 mm, while the basket bioreactor is more efficient for smaller biocatalyst particles and basket bed thickness below 5 mm. The performances of both configurations of immobilized A. succinogenes cell beds were found to be superior to the column packed bed bioreactor.

Helium Plasma Effects on Polymer Surfaces:from Plasma Parameters and Surface Properties towards Bioengineering Applications

Plasma treatment is necessary to optimize the performance of biomaterial surfaces.It enhances and regulates the performance of biomaterial su rfaces,creating an effective interface with the human body.Plasma treatments have the ability to modify the chemical com position and physical structu re of a surface while leaving its properties unaffected.They possess the ability to modify material su rfaces,eliminate contaminants,conduct investigations on cancer therapy,and facilitate wound healing.The subject of study in question involves the integration of plasma science and technology with biology and medicine.Using a helium plasma jet source,applying up to 18 kV,with an average power of 10 W,polymer foils were treated for 60 s.Plasma treatment has the ability to alter the chemical composition and physical structure of a su rface while maintaining its quality.This investigation involved the application of helium plasma at atmospheric pressure to polyamide 6 and polyethylene terephthalate sheets.The inquiry involves monitoring and assessing the plasma source and polymer materials,as well as analyzing the impacts of plasma therapy.Calculating the mean power of the discharge aids in assessing the economic efficacy of the plasma source.Electric discharge in helium at atmospheric pressure has beneficial effects in technology,where it increases the surface free energy of polymer materials.In biomedicine,it is used to investigate cytotoxicity and cell survival,particularly in direct blood exposure situations that can expedite coagulation.Comprehending the specific parameters that influence the plasma source in the desired manner for the intended application is of utmost im portance.

Advanced PEG-tyramine biomaterial ink for precision engineering of perfusable and flexible small-diameter vascular constructs via coaxial printing

Vascularization is crucial for providing nutrients and oxygen to cells while removing waste.Despite advances in 3D-bioprinting,the fabrication of structures with void spaces and channels remains challenging.This study presents a novel approach to create robust yet flexible and permeable small(600-1300μm)artificial vessels in a single processing step using 3D coaxial extrusion printing of a biomaterial ink,based on tyramine-modified polyethylene glycol(PEG-Tyr).We combined the gelatin biocompatibility/activity,robustness of PEG-Tyr and alginate with the shear-thinning properties of methylcellulose(MC)in a new biomaterial ink for the fabrication of bioinspired vessels.Chemical characterization using NMR and FTIR spectroscopy confirmed the successful modification of PEG with Tyr and rheo-logical characterization indicated that the addition of PEG-Tyr decreased the viscosity of the ink.Enzyme-mediated crosslinking of PEG-Tyr allowed the formation of covalent crosslinks within the hydrogel chains,ensuring its stability.PEG-Tyr units improved the mechanical properties of the material,resulting in stretchable and elastic constructs without compromising cell viability and adhesion.The printed vessel structures displayed uniform wall thickness,shape retention,improved elasticity,permeability,and colonization by endothelial-derived-EA.hy926 cells.The chorioallantoic membrane(CAM)and in vivo assays demonstrated the hydrogel’s ability to support neoangiogenesis.The hydrogel material with PEG-Tyr modification holds promise for vascular tissue engineering applications,providing a flexible,biocompatible,and functional platform for the fabrication of vascular structures.