Spontaneous and efficient adsorption of lysozyme from aqueous solutions by naturally polyanion gel beads

Selective isolation and sensitive detection of lysozyme using aptamer based magnetic adsorbent and a new quartz crystal microbalance system

Magnetic chitosan beads and quartz crystal microbalance chip were decorated with lysozyme specific aptamer for isolation and detection of lysozyme, respectively. The lysozyme specific aptamer was immobilized on poly (dopamine) coated magnetic chitosan beads and the chip via Schiff base reaction. The percentage of the removal efficiency and purity of the isolated lysozyme from egg white were 87.6% and 91.8%, respectively. Further, the sensor system was contacted with different concentrations of lysozyme and other test proteins. This sensor system provided a method for the label-free, concentration-dependent, and selective detection of lysozyme with an observed detection limit of 17.9 ± 0.6 ng/mL. The sensor system was very selective and not significantly responded to the other tested proteins such as ovalbumin, trypsin, cytochrome C, and glucose oxidase. The prepared new sensor system showed a good durability and a high sensitivity for determination of lysozyme from solutions and whole egg white.

Protein release from nanocellulose and alginate hydrogels: The study of adsorption and desorption kinetics

This work presents a study of the lysozyme release from crosslinked TEMPO nanocellulose (TOCNF) and alginate (ALG) hydrogels in a medium with different ionic strength and temperature. The main objective is to develop a mathematical model for a detailed study of the concurrent action of diffusion mechanism and adsorption/desorption kinetics. Model fit parameters provide important information about the initial (maximum) adsorption rate and its deceleration with increasing ionic strength of the release medium. Similarly, the initial (minimum) desorption rate and its acceleration with increasing salt concentration can be determined. The model leads us to the conclusion that the initial adsorption rate is higher in the case of TOCNF, but due to fewer electrostatic interactions and morphology as well as topography of the surface, it decreases to a negligible value much faster than in the case of ALG, where the diffusion process becomes dominant.

Shapeable and underwater super-elastic cellulose nanofiber/alginate cryogels by freezing-induced oxa-Michael reaction for efficient protein purification

Construction of monolithic cryogels that can efficiently adsorb proteins is of great significance in biotechnological and pharmaceutical industries. Herein, a novel approach is presented to fabricate microfibrillated cellulose (MFC)/sodium alginate (SA) cryogels by using freezing-induced oxa-Michael reaction at -12 °C. Thanks to the controllable reactiveness of divinyl sulfone (DVS), cryo-concentrated pH increase activates the oxa-Michael reaction between DVS and hydroxyl groups of MFCs and SAs. The obtained composite cryogel exhibits outstanding underwater shape recovery and excellent fatigue resistance. Moreover, the MFC/SAs reveal a high lysozyme adsorption capacity of 294.12 mg/g, surpassing most of absorbent materials previously reported. Furthermore, the cryogel-packed column can purify lysozyme continuously from chicken egg white, highlighting its outstanding practical application performance. Reuse experiments indicated that over 90% of lysozyme extraction capacity was retained after 6 cycles. This work provides a new avenue to design and develop next-generation chromatographic media of natural polysaccharide-based cryogel for protein purification.

Alginic Acid Polymer-Hydroxyapatite Composites for Bone Tissue Engineering

Natural bone is a composite organic-inorganic material, containing hydroxyapatite (HAP) as an inorganic phase. In this review, applications of natural alginic acid (ALGH) polymer for the fabrication of composites containing HAP are described. ALGH is used as a biocompatible structure directing, capping and dispersing agent for the synthesis of HAP. Many advanced techniques for the fabrication of ALGH-HAP composites are attributed to the ability of ALGH to promote biomineralization. Gel-forming and film-forming properties of ALGH are key factors for the development of colloidal manufacturing techniques. Electrochemical fabrication techniques are based on strong ALGH adsorption on HAP, pH-dependent charge and solubility of ALGH. Functional properties of advanced composite ALGH-HAP films and coatings, scaffolds, biocements, gels and beads are described. The composites are loaded with other functional materials, such as antimicrobial agents, drugs, proteins and enzymes. Moreover, the composites provided a platform for their loading with cells for the fabrication of composites with enhanced properties for various biomedical applications. This review summarizes manufacturing strategies, mechanisms and outlines future trends in the development of functional biocomposites.

Strong and weak cation-exchange groups generated cryogels films for adsorption and purification of lysozyme from chicken egg white

Here, the macroporous poly(hydroxylmethyl methacrylate/glycidyl methacrylate [p(HEMA-GMA)] cryogels with large porous surface were prepared, and then the epoxy groups of the p(HEMA-GMA) cryogels were systematically modified into strong and weak cationic groups. The effects of initial protein concentrations, adsorption time, pH, salt concentrations and temperatures on adsorption efficiency of cation exchange cryogels for lysozyme were determined. The maximum lysozyme adsorption capacities of strong and weak cation exchange cryogels were found to be 188.3 and 79.7 mg/g cryogel at 25 °C, respectively. The performance of the strong cationic cryogel was evaluated by purification of lysozyme from egg white. The activity of the isolated lysozyme was found to be 21,347 U/mg. The cationic cryogel maintained its expected high adsorption capacity and efficiency of the purification levels during repeated adsorption desorption processes. Finally, the purpose of this work is the design a cation exchange system for purification of lysozyme from egg-white.

Investigation of Hydrodynamic Behavior of Alginate Aerogel Particles in a Laboratory Scale Wurster Fluidized Bed

The effects of design and operating parameters on the superficial velocity at the onset of circulatory motion and the residence time of alginate aerogel particles in a laboratory scale Wurster fluidized bed were investigated. Several sets of experiments were conducted by varying Wurster tube diameter, Wurster tube length, batch volume and partition gap height. The superficial velocities for Wurster tube with 10 cm diameter were lower than the tube with 8 cm diameter. Superficial velocities increased with increasing batch volume and partition gap height. Moreover, increasing batch volume and partition gap height led to a decrease in the particle residence time in the Wurster tube. The results showed that there is an upper limit for each parameter in order to obtain a circulatory motion of the particles. It was found that the partition gap height should be 2 cm for proper particle circulation. Maximum batch volume for the tube with 10 cm diameter was found as 500 mL whereas maximum batch volume was 250 mL for the tube with 8 cm diameter. The fluidization behavior of the aerogel particles investigated in this study could be described by the general fluidization diagrams in the literature.

Mineralized calcium carbonate/xanthan gum microspheres for lysozyme adsorption

Calcium carbonate/xanthan gum (Ca₂CO₃/XG) microspheres were prepared using biomimetic mineralization method for lysozyme (Ly) adsorption. The morphology of Ca₂CO₃/XG microspheres was characterized by field emission scanning electron microscope (FE-SEM). The Ly adsorption behavior was verified by Fourier transform infrared (FTIR) and in situ fluorescence microscope images. The effects of pHs on lysozyme adsorption were investigated as well. It was revealed that CaCO₃/XG microspheres could immobilize lysozyme efficiently via electrostatic interactions with adsorption rate and adsorption quantity of 58.55 ± 0.56% and 18.7 ± 1.2 μg/mg as the pH was 7.0. Comparatively, the values markedly improved to 80.97 ± 0.15% and 24.3 ± 0.1 μg/mg respectively as the pH was 9.0 (p < 0.05). Additionally, UV and fluorescence spectrum showed that Ly maintained its original secondary structure during the adsorption/desorption process. The study therefore demonstrated that CaCO₃/XG microspheres can be used as a practical and efficient support for Ly adsorption and desorption.