Basiliximab

Metal-organic framework (MOF) structures containing different metal ions and 1,3,5-trimesic acid (BTC) were fabricated, as the carriers to immobilize chitinase (Chi) for improving the performance of Chi, for the first time. It was found that the immobilization of Chi on Ca-BTC, Ba-BTC, and Ni-BTC increased its activity. Notably, the specific activity of Chi@Ca-BTC was enhanced by 2.1 times that of free Chi, reaching 16.27 U/mg. The catalytic efficiency and substrate affinity of Chi@Ca-BTC were also remarkably improved, confirmed by the k_cat/K_m enhancement (4.2 times) and K_m value reduction (40 %). Moreover, the half-life of Chi@Ca-BTC at the optimum pH 6.0 and 55 °C was prolonged from 1.8 h to 6.8 h. More than 80 % of enzyme activity was retained after 22 cycles of usage, showing superior reusability. It was proved that Ca²⁺ on MOF surface enhanced the formation of hydrogen bonds between the catalytic key amino acid Glu-405 and substrate, accelerating the enzymatic catalysis. Then, Chi@Ca-BTC was employed as an outstanding biocatalytic platform for the degradation of chitin, with 8.1 times increase in conversion efficiency. Such a MOF-based immobilization strategy for improving enzymatic performance is of considerable reference value in designing advanced immobilized enzyme for various polysaccharide biocatalytic reaction.

Pullulan-based fibers blended with chitosan (Chi) were developed using a rotational spinning method for potential biomedical applications. Aqueous precursor formulations containing 15 % by weight in pullulan and varying Chi concentrations (6 % and 7 %) were optimized to produce nanofibers at elevated temperatures and rotational speeds exceeding 7 k rpm. The highest fiber production yields of approximately 90 % and 65 % were achieved at 13 k rpm for the 6 % and 7 % Chi formulations, respectively. The pullulan-chitosan fibers were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, dynamic mechanical analyzer, powder X-ray diffraction, and rheological property measurements. Morphological analyses revealed nanometric fiber diameters and a decrease in bead formation with increasing rotational speeds. Thermal stability studies, conducted via thermogravimetric and differential thermal analyses, showed that the composite fibers exhibited intermediate degradation behaviors between their individual polymer components, indicating good integration of Chi into the pullulan matrix. Elemental analysis confirmed the successful incorporation of Chi into the fibers, with nitrogen content closely matching theoretical predictions. Functional assessments demonstrated the hemocompatibility of the Pull-Chi fibers with hemolysis rates below 1 %. Additionally, the fibers exhibited superior hemostatic potential, effectively promoting blood clotting in vitro testing. These findings underscore the promise of Pull-Chi fibers as multifunctional biomaterials for applications in wound healing and tissue engineering. Future studies involving animal models are warranted to validate their clinical potential.