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

Interaction of lysozyme with solid supports cryogels containing imidazole functional group

This paper details the preparation of acrylamide-based supermacroporous cryogels and their application in removing lysozyme from aqueous solutions. N-Vinyl imidazole was copolymerized with acrylamide as a comonomer to impart pseudo-specificity to the cryogels, forming poly(AAm-VIM) cryogel. Characterization studies to assess the physical and chemical properties of the synthesized cryogels involved swelling tests, Fourier Transform Infrared Spectroscopy (FTIR), elemental analysis, Field Emission Scanning Electron Microscopy (FESEM), and Thermogravimetric Analysis (TGA-DTA). To ascertain the optimal conditions for the adsorption process, pH 9.0 (TRIS buffer) was selected for lysozyme adsorption, using the parametres such as initial concentration screening, ionic strength, temperature, and column flow rate. The Langmuir and Freundlich isotherm models were analyzed to assess the adsorption parameters mathematically. The regression coefficient results indicated that lysozyme adsorption aligned more closely with the Langmuir isotherm model. The adsorption process is considered to be thermodynamically physical and spontaneous. SDS-PAGE analysis assessed the purity of lysozyme isolated from an aqueous solution using a poly(AAm-VIM) cryogel column. The inertness and regeneration capacity of poly(AAm-VIM) cryogel affinity columns were assessed using reusability studies conducted during the adsorption-desorption cycle.

Purification and structural characterization of a neutral polysaccharide from Boletus auripes using self-made quaternary chitosan cryogel

The purification of polysaccharides is an essential preliminary step in determining their chemical structure, although it presents significant challenges. In this research, a macro-porous monolith of quaternary chitosan cryogel was synthesized for the purification of a neutral polysaccharide from Boletus auripes. A homogeneous neutral polysaccharide (BAP-1a1) with a weight-average molecular weight of 4.13 × 105 Da and a polydispersity index of 1.28 was successfully isolated. The structure of BAP-1a1 was elucidated through a comprehensive characterization utilizing size exclusion chromatography (SEC) combined with laser light scattering (LLS), infrared spectroscopy, monosaccharide composition analysis, methylation analysis, and nuclear magnetic resonance (NMR) spectroscopy. The results revealed that the BAP-1a1 was characterized as a glucan with a backbone structure consisting of 1,4-α-D-Glcp and 1,3-β-D-Glcp glycosidic linkages in a molar ratio of 2:1. Additionally, a minority of branched chains of 1-α-D-Glcp are attached to 1,3-β-D-Glcp residues at the C6 position. In vitro antioxidant activity assays demonstrated that BAP-1a1 exhibits a dose-dependent scavenging effect on ABTS and DPPH radicals with EC50 values of 0.58 and 1.04 mg/mL, respectively. These findings indicated that Boletus auripes possesses the potential to be utilized as a natural agent in antioxidant functional foods.

Rapid and sensitive quantitation of hen egg-white lysozyme in foods using paper sensor

Hen egg-white lysozyme (HEWL) is commonly used in food preservation and as a substitute for sulfur dioxide in wine production and to prevent late blowing defects in cheese production. However, HEWL is an egg allergen that can cause severe allergic reactions in allergic individuals after accidental ingestion. Therefore, in order to prevent life-threatening health problems caused by consumer allergies, we developed an extremely specific gold immunochromatographic assay (GICA) tolerant to matrix effects for the qualification and quantification of HEWL in food products. First, we prepared a monoclonal antibody (mAb) specific for HEWL. By optimizing the parameters of the sandwich enzyme-linked immunosorbent assay, we performed mAb interaction analysis. We developed GICA strips for the determination of HEWL in foods by combining mAb with colloidal gold. Additionally, considering the complex matrix of foods, standard curves for HEWL-negative milk, cheese, and grape wine samples were established to minimize matrix effects. The calculated limits of detection for the determination of HEWL in milk, cheese, and grape wine were 21.12 ng/mL, 0.89 μg/kg, and 1.61 ng/mL, respectively. The recovery rates of the HEWL-spiked samples were 99.16 %-102.25 %, which were comparable to the HPLC results. Thus, we have successfully developed a rapid, sensitive and specific GICA method for the qualification and quantification of HEWL in milk, cheese and grape wine.

Developing portable and controllable fluorescence capillary imprinted sensor for visual detection Crohn's disease biomarkers

Simultaneous detection of multiple biomarker levels is essential to improve the accuracy of early diagnosis. Introducing capillary will simplify procedure, less time, and reduce reagent consumption for point-of-care testing of biomarkers. Here, we developed a portable and controllable smartphone-integrated fluorescence capillary imprinted sensing platform for the accuracy visual detection of Crohn's disease biomarkers (lysozyme, Fe3+) using single-excitation/double-signal detection. A novel controllable capillary coating strategy was developed by static gas-driven coating method for synthesis uniform fluorescence capillary imprinted sensor (Si-CD/g-CdTe@MIP capillary sensor). When Fe3+ and lysozyme were added, the fluorescence intensity of Si-CD/g-CdTe@MIP capillary sensor was quenched at 426 nm and enhanced at 546 nm, respectively. This Si-CD/g-CdTe@MIP capillary sensor has high sensitivity and selectivity for quantification lysozyme and Fe3+ simultaneously with the detection limit of 0.098 nM and 0.20 nM, respectively. In addition, the smartphone-integrated Si-CD/g-CdTe@MIP capillary sensor was applied for the intelligent detection of lysozyme and Fe3+, in which the detection limit was calculated as 0.32 nM and 0.65 nM. The smartphone-integrated visual Si-CD/g-CdTe@MIP capillary sensor realized ultrasensitive microanalysis (18 μL/time) of biomarkers in health man and Crohn 's patients, providing a novel strategy for early diagnosis of Crohn 's disease.

Ovotransferrin, an alternative and potential protein for diverse food and nutritional applications

Ovotransferrin(OVT)is a protein found in many types of egg white and has a wide range of functional properties. It has 50% homology with human/bovine lactoferrin, and is expected to be one of the most important alternative proteins for use in food and nutritional applications. This paper mainly reviews the structural characteristics and chemical properties of OVT, as well as its extraction and purification methods. It also systematically describes the various biological activities of OVT and its applications in food and medical industries. The challenges and limitations in the research of OVT were suggested. This review recommends some possible methods such as nanoparticle carriers and microencapsulation to improve the bioavailability and stability of OVT. In addition, this review highlights several strategies to overcome the limitations of OVT in terms of preparation and purification. This review systematically summarizes the recent advances in OVT and will provide guidance for the its development for food and nutritional applications.

Preparation and characterization of lysozyme loaded cryogel for heavy metal removal

In the present study, monolithic poly(N-isopropylacrylamide-acrylamide)-acrilic acid (poly(npam-aam)-aac) cryogels were made. Swelling tests, SEM, XRD, and ATR-FTIR analyses revealed distinct cryogel and lysozyme-loaded cryogel properties. The equilibrium swelling degree was 6.2 g H2O/g cryogel. The created poly(npam-aam)-aac with pores of 10-100 μm was obviously seen in SEM images. Lysozyme adsorption capacity on poly(npam-aam)-aac was found to be 260 mg/g at pH 7.4 and 40 °C. After that, we used lysozyme adsorbed cryogel for the removal of the model heavy metal ion (cadmium). A series of pH, duration, and ionic strengths were used to conduct Cd2+ adsorption experiments. The results showed that the new adsorbent had a considerable chemical affinity for Cd2+ ions in its ability to bind them under eye ocular conditions (pH 7.4, 32-36 °C, 0,15 M NaCl). The traditional Langmuir adsorption model was the most suitable, achieving maximum uptake of ∼185 mg/g. Chemical adsorption was found to be the rate-controlling step, and the process was also compatible with the pseudo-second-order model. For the treatment of ocular pathologies, the most effective enzyme, lysozyme, must show its function. That is why there is a need for using lysozyme, and lysozyme is selected as a lignad to adsorb heavy metal ions because of its high heavy metal binding affinity. This material could be used for the treatment of ocular pathologies in the future.

Breakthrough Curve Modeling and Analysis for Lysozyme Adsorption by Tris(hydroxymethyl)aminomethane Affinity Nanofiber Membrane

In this study, a polyacrylonitrile nanofiber membrane was first hydrolyzed and then functionalized with tris(hydroxymethyl)aminomethane (P-Tris), then used as an affinity nanofiber membrane for lysozyme adsorption in membrane chromatography. The dynamic adsorption behavior of lysozyme was investigated in a flow system under various operating parameters, including adsorption pHs, initial feed lysozyme concentration, loading flow rate, and the number of stacked membrane layers. Four different kinetic models, pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion kinetic models, were applied to experimental data from breakthrough curves of lysozyme. The results showed that the dynamic adsorption results were fitted well with the pseudo-second-order kinetic model. The breakthrough curve experimental results show significant differences in the breakthrough time, the dynamic binding capacity, the length of the mass transfer zone, and the utilization rate of the membrane bed under different operating parameters. Four dynamic adsorption models (i.e., Bohart-Adams, Thomas, Yoon-Nelson, and BDST models) were used to analyze the breakthrough curve characteristics of the dynamic adsorption experiments. Among them, the Yoon-Nelson model was the best model to fit the breakthrough curve. However, some of the theoretical results based on the Thomas and Bohart-Adams model analyses of the breakthrough curve fit well with the experimental data, with an error percentage of <5%. The Bohart-Adams model has the largest difference from the experimental results; hence it is not suitable for breakthrough curve analysis. These results significantly impact dynamic kinetics studies and breakthrough curve characteristic analysis in membrane bed chromatography.

Rapid detection of heterocyclic aromatic amines in cakes by digital imaging colorimetry based on magnetic solid phase extraction with sulfonated hyper-cross-linked polymers

To improve the hydrophobicity and poor separability of hyper-cross-linked polymers (HCPs) in extraction, a porous magnetic adsorbent (Fe₃O₄@SHCP) was constructed by facile post-modification to introduce sulfonic acid groups and magnetic nanoparticles for the magnetic solid-phase extraction of heterocyclic aromatic amines (HAAs). Owing to the double extraction mechanism adopted by Fe₃O₄@SHCP, it has a high extraction efficiency for HAAs. Coupled with high-performance liquid chromatography (HPLC), 5 HAAs in baked cakes were detected at one time. Under optimal extraction conditions, the enrichment factor of HAAs was up to 952-986, with LODs at 0.05-0.3 ng·g^-1. Based on the HPLC method, novel digital imaging colorimetry (DIC) was developed to accurately and rapidly monitor HAAs in cakes. Additionally, the established DIC method has been used to successfully evaluate the effect of baking temperature and duration on HAAs in baked cakes.

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.