Ovalbumin Molecules Research Articles

Non-sticky SiNx nanonets for single protein denaturation analysis.

Proteins play crucial roles in nearly all biological activities, with their functional structures deriving from stable folded conformations. Protein denaturation, induced by chemical and physical agents, is a complex process where proteins lose their stable structures, thereby impairing their biological functions. Characterizing protein denaturation at the single-molecule level remains a significant challenge. In this study, we developed non-adhesive silicon nitride nanonets coated with polyethylene glycol to capture individual proteins. We utilized these nanonets to investigate the denaturation of ovalbumin induced by guanidine hydrochloride (Gdn-HCl) and lead chloride. The entire denaturation and renaturation processes of a single ovalbumin molecule were monitored via ionic current measurements through the nanonets. These non-sticky nanonets offer a versatile tool for real-time studies of structural changes during protein denaturation.

Modulation of molecular state and air-water interface adsorption behavior of ovalbumin via interference with its surrounding charge distribution

Herein, pH combined with ionic strength was employed to modulate the charge distribution around ovalbumin molecules, and the whole process (from the water phase to the interface) of film formation and stabilization of ovalbumin at the air-water interface was further analyzed. As the pH continuously rose above the isoelectric point, the molecular surface charge increased. More cations, however, reduced the surface charge through the electrostatic shielding effect. The pH and cationic strength were shown to have a remarkable effect on the aggregate size. Intrinsic fluorescence and excitation emission matrix spectroscopy indicated that the migration of tryptophan and tyrosine was accompanied by a change in the backbone structure and rearrangement of the hydrophilic/hydrophobic side chains. Interfacial adsorption kinetic analysis revealed that low pH and ionic strength generally favored the adsorption and stabilization of ovalbumin. Lissajous plots confirmed that stronger intra-interfacial interactions and viscoelastic-like solid interfaces would be generated under the above conditions. Interfacial dilatational rheology analysis illustrated that in most cases, the interfacial film formed by ovalbumin was dominated by an elastic response and produced a nonlinear viscoelastic response under strain. Overall, the combined effect of low pH (pH 5.0) and ionic strength (25 mmol/L and 50 mmol/L) on the surface charge resulted in superior foam capacity (60.00% for pH 5.0 and 50 mmol/L) and stability (97.87% for pH 5.0 and 25 mmol/L). This study detailed the mechanism by which charge influenced the molecular and interfacial properties of ovalbumin, leading the way for the development of protein-based foam systems.

Formation of amyloid fibrils from ovalbumin under Ohmic heating

Ohmic heating (OH) is an alternative sustainable heating technology that has demonstrated its potential to modify protein structures and aggregates. Furthermore, certain protein aggregates, namely amyloid fibrils (AF), are associated with an enhanced protein functionality, such as gelation. This study evaluates how Ohmic heating (OH) influences the formation of AF structures from ovalbumin source under two electric field strength levels, 8.5 to 10.5 and 24.0–31.0 V/cm, respectively. Hence, AF aggregate formation was assessed over holding times ranging from 30 to 1200 sunder various environmental conditions (3.45 and 67.95 mM NaCl, 80, 85 and 90 °C, pH = 7). AF were formed under all conditions. SDS-PAGE revealed that OH had a higher tendency to preserve native ovalbumin molecules. Furthermore, Congo Red and Thioflavin T stainings indicated that OH reduces the amount of AF structures. This finding was supported by FTIR measurements, which showed OH samples to contain lower amounts of beta-sheets. Field flow fractioning revealed smaller-sized aggregates or aggregate clusters occurred after OH treatment. In contrast, prolonged holding time or higher treatment temperatures increased ThT fluorescence, beta-sheet structures and aggregate as well as cluster sizes. Ionic strength was found to dominate the effects of electric field strength under different environmental conditions.

OBTAINING OXYTETRACYCLINE CONJUGATES WITH PROTEIN CARRIERS

Oxytetracycline is widely used in veterinary medicine for the treatment of animals, as well as growth promoters. They can have adverse effects on human health through animal products if the rules for the use of antibiotics are not followed. The World Health Organization has established maximum residue limits of antibiotics in milk and meat, which require accurate, rapid and inexpensive methods to determine. Immunochromatographic assay (ICA) is ideal for this purpose due to its speed of analysis, high sensitivity and ease of use. This paper describes the results of study on the obtaining an oxytetracycline (OTC) conjugate with bovine serum albumin (BSA) and/or ovalbumin (OVA). OTC has been chemically purified from the antibiotic hydrochloride salt (OTC HC), which is widely used in animal husbandry and is more affordable than its chemically pure analogue. Spectrophotometric analysis of the prepared conjugates and immunization of laboratory animals showed the suitability of OTC, chemically purified from OTC HC, for crosslinking into BSA and/or OVA molecules and obtaining hapten-specific antibodies. The results obtained could be used for the manufacture of ICA components - labeled OTC-specific antibodies and test line antigen.

Combined effects of NaOH, NaCl, and heat on the characteristics of ovalbumin gel and the exploration of the mechanism of transparent gel formation

Salted preserved eggs are made using poultry eggs under the combined action of NaOH, NaCl, and heat. To elucidate the main basis and mechanism of the formation of salted preserved egg white, the effects of NaOH (0.5–2.5%), NaCl (0–1.2%), and heat (72–100 °C) on the properties of ovalbumin (the most abundant protein in poultry egg whites) gel were studied. With increasing NaOH addition, the pH and the absolute value of zeta potential (TAV-ZP) increased, the opacity and Hunter whiteness decreased, and the relaxation time (T2) initially decreased and then increased. With increasing NaCl addition and heating temperature, the pH and TAV-ZP decreased, the opacity and Hunter whiteness increased, and T2 decreased first and then increased. In addition, the hardness and cohesiveness of the ovalbumin gel were greatly modified by NaOH, NaCl, and heat. NaOH contributed to the formation of the gel network structure. In addition, the surface hydrophobicity (H0) analysis result indicated that the tertiary structure of the ovalbumin had changed during the formation of the ovalbumin gel. The correlation analysis results showed that electrostatic repulsion played a vital role in the formation of the transparent ovalbumin gel, and the transparent ovalbumin gel possessed the following characteristics: low aggregation degree, high cross-linking degree, high immobilized water content, gel network structure, and the fully unfolded structure of ovalbumin molecules. In general, the ovalbumin formed a unique gel under the combined action of NaOH, NaCl, and heat. This study could provide theoretical guidance for the processing and control of salted preserved eggs and a reference for highly transparent egg white gel products.

Random cationic copolymers as nanocarriers for ovalbumin

In this study, the utilization of poly[quaternized (2-(dimethylamino)ethyl methacrylate-co-(oligo ethylene glycol)methacrylate)] cationic nanoaggregates and their double-hydrophilic precursors as nanocarriers for ovalbumin delivery purposes is presented. The synthesis of the P(DMAEMA-co-OEGMA) random copolymers through RAFT polymerization was followed by the hydrophilic/hydrophobic chemical modification with methyl iodide (CH3I), 1-iodohexane (C6H13I) and 1-iododecane (C12H25I) of DMAEMA segments. The resulting four copolymers were investigated regarding their self-assembly behavior in aqueous media, further demonstrating the formation of nanoscale aggregates in aqueous media. Owning to the positive surface charges these aggregates were consequently complexed through strong electrostatic interactions with ovalbumin molecules at different OVA(−)/pol(+) charge ratios. Light scattering techniques evidenced the efficacious formation of complexes, whose mass, size, and surface charge are strongly dependent on the mixing ratio, whilst fluorescence spectroscopy, UV–Vis, and ATR-FTIR spectroscopy studies substantiated that no conformational changes of ovalbumin molecules occurred during the complexation process. Moreover, OVA/polymer complexes manifested good colloidal stability in simulated biological environments with the addition of NaCl salt up to salt levels of human blood, and with the FBS interactions studies.

Modification of the antigenicity of cancer cells by conjugates consisting of hyaluronic acid and foreign antigens.

Tumor-specific cytotoxic T-lymphocytes (CTLs) recognize tumor-associated antigens presented on major histocompatibility complex (MHC) class I molecules. However, it is difficult to induce potent CTLs by vaccination because the antigenicity is not so high, compared with that of foreign antigens derived from viruses and microbes. The affinity of binding to MHC class I molecules is proportional to the antigenicity of the antigen that they are presenting. Here, we prepared several conjugates consisting of hyaluronic acid (HA) as a carrier to cancer cells and ovalbumin (OVA) as a foreign protein and changed the antigens on cancer cells from intrinsic antigens to OVA fragments. The conjugate containing multiple HA and OVA molecules (100k4HA-3OVA) adopted a highly condensed structure and was well recognized by recombinant CD44 molecules in quartz crystal microbalance analysis and incorporated into cancer cells (CT26 cells). A mixture of CT26 cells treated with 100k4HA-3OVA and splenocytes including OVA-specific CTLs induced abundant secretion of IFN-γ into the supernatant. At 48 h after mixing with the CTLs, almost all CT26 cells had died. These results indicate that 100k4HA-3OVA is actively internalized into the cells through interaction between HA and CD44. Subsequently, CT26 cells present not only self-antigens, but also OVA fragments on MHC class I molecules and are recognized by OVA-specific CTLs. We thus succeeded in modifying the antigenicity from self- to non-self-antigens on cancer cells. Therefore, this foreign-antigen delivery using HA to cancer cells, followed by antigen replacement, could be used as a novel strategy for treating cancers.

Subvisible Particles Derived by Dropping Stress Enhance Anti-PEG Antibody Production and Clearance of PEGylated Proteins in Mice

Bioconjugation with polyethylene glycol (PEG) is important for protein drug development as it has improved biological stability. In contrast, proteins including PEGylated ones are susceptible to physicochemical stresses. Particularly, protein drugs in solution may form aggregates or subvisible particles if they are exposed to dropping stress during transportation. However, many PEGylation studies have focused on its usefulness, such as the extension of half-life in blood, and changes in the physical properties or biological responses of PEGylated proteins under dropping stress remain unexplored. Here, we prepared four PEGylated ovalbumin (PEG-OVA) molecules conjugated with different lengths (5 or 20 kDa) and numbers (large [L] or small [S]) of PEG, analyzed the formation of subvisible particles under dropping stress, and examined their impact on antibody production and clearance. Under dropping stress, the aggregated particle concentration of 20 kDa PEG-OVA (S) and (L) solutions was approximately 3-fold that of the OVA solution. Moreover, administration of 20 kDa PEG-OVA with dropping stress induced anti-PEG antibody production and clearance of PEG-OVA. As a mechanism, dropping stress could enhance the uptake of 20 kDa PEG-OVA (L) by macrophages. These findings could provide insights into proper transportation conditions to ensure the quality of PEGylated protein drugs.

Functional and structural properties of glycosylation ovalbumin with pectin through wet-heating and ultrasound method

Due to the good functional characteristics and nutritional value, ovalbumin (OVA) has a widely ranges of applications in food industry. But the characteristics of being susceptible to external conditions, such as processing, storage conditions and food ingredients, makes it display a relative lower functional property and limits its applications. Glycosylation is a natural, green approach of protein modifications that has an impact on its functional properties. In this work, we prepared the OVA-pectin conjugates through wet-heating and ultrasound glycosylation to investigate the effects on the functional and structural properties of OVA. Both wet-heating and ultrasound treated OVA at present of pectin showed higher emulsify and foam properties than untreated OVA. The results of particle size, SDS-PAGE, FT-IR, and SEM indicated that the covalent binding of pectin with OVA molecule. This study suggests that wet-heating and ultrasound glycosylation with pectin are promising method to improve the functional properties of OVA.

A novel multifunctional vaccine platform with dendritic cell-targeting and pH-responsive for cancer immunotherapy: Antigen-directed biomimetic fabrication of a cabbage-like mannatide-zinc-antigen hybrid microparticles

Cancer vaccines, featuring with high-specificity and long-term immune memory effect, have received tremendous attention in the field of cancer immunotherapy. However, most current developed antigen-encapsulated multifunctional cancer vaccines are subjected to limited antigen loading capacity, low yield, complicated preparation process, inefficient antigen delivery, and potential systemic toxicity. Herein, a facile biomimetic strategy is reported to fabricate a multifunctional cancer vaccine with high antigen loading capacity, dendritic cells-targeting and pH-responsive. As a proof of strategy, we directly use model antigen ovalbumin (OVA) and dendritic cells-targeting molecule mannatide as organic templates, zinc (II) as inorganic component to construct antigen and mannatide co-loaded hybrid microparticles vaccine. These formed mannatide-zinc-ovalbumin hybrid microparticles (M-Zn-OVA HMPs) owns cabbage-like morphology with particle size of ~1.7 μm, high antigen loading capacity of 11.7%, high yield of 84.6%, good stability, and favorable biocompatibility. Taking advantage of high antigen loading, pH-responsive, and dendritic cells-targeting molecule, M−Zn−OVA HMPs can target deliver antigen to dendritic cells, and effectively maturation of dendritic cells to induce robust immune responses. As a result, such M−Zn−OVA HMPs shows outstanding prophylactic efficacy toward B16-OVA and E.G7-OVA tumors. Moreover, M−Zn−OVA HMPs demonstrates excellent therapeutic efficacy against established B16-OVA and E.G7-OVA tumors, and the therapeutic efficacy can be further enhanced when used in combination with anti-programmed death-1 (anti-PD-1) checkpoint blockade. Therefore, our work may present a facile and versatile strategy for large-scale fabrication of multifunctional vaccines for cancer immunotherapy.

Interaction mechanism between resveratrol and ovalbumin based on fluorescence spectroscopy and molecular dynamic simulation

Proteins act as excellent biological carriers for resveratrol (RES) delivery. However, the interaction between RES and proteins remains unclear. In this work, ovalbumin (OVA) was selected as a protein model based on fluorescence spectroscopy and molecular dynamic (MD) simulation to investigate the interaction mechanism between RES and OVA. Fluorescence spectroscopy coupled with the Stern–Volmer equation verified the static fluorescence quenching types of RES and OVA. The static quenching binding affinity is 1.41 × 104 L/mol. The number of stoichiometric binding values with approximately 1.0 indicates that one RES molecule could bind to only one OVA molecule. The simultaneous fluorescence and three-dimensional fluorescence spectra of the interaction between RES and OVA demonstrated the altered conformation and microenvironment of OVA. The microenvironment formed by tryptophan or tyrosine residues increased polarity and weakened hydrophobicity. Through MD simulation techniques, hydrogen bonds and hydrophobic interactions promoted RES–OVA complexation. MD results showed that RES likely interacted with OVA residues ALA-326, GLN-325, SER-165, GLN-162, LEU-161, LYS-290, TYR-291, and LEU-293. RES and OVA formed a more stable complex because of various forces. Therefore, studying the interaction of RES and OVA helps expand the potential applications of OVA as a RES delivery system.

Structural characteristics and foaming properties of ovalbumin - Caffeic acid complex

In this study, we investigated the effects of different caffeic acid (CA) concentrations on the ovalbumin structure and foaming properties. When the concentration of CA was 0.18 mg/mL, the surface hydrophobicity of ovalbumin decreased from 705.37 to 542.79, the sulfhydryl content decreased from 4.15 μmol/g to 2.26 μmol/g, and the foaming ability and stability increased by 72% and 71%, respectively. We observed that hydrophobic interactions represented the main binding force between CA and ovalbumin. Using circular dichroism spectroscopy (α-Helix increased from 7.2% to 13.9%) and endogenous fluorescence spectra (Reduction of fluorescence intensity and redshift), it showed that CA affected the secondary and tertiary ovalbumin structure, thus increasing the flexible structure. The increase in particle size Increased from 10.26 nm to 65.97 nm indicated that CA acted as a crosslinking agent between the ovalbumin molecules and increased the viscosity of the system through hydrophobic interactions. Although the increase in ovalbumin aggregation and the decrease in hydrophobicity were not conducive to the foaming properties of ovalbumin solutions, the increase in solubility, absolute potential, and flexible molecular structure contributed to the improvement of the foaming properties. All results showed that CA could improve the foaming properties of ovalbumin, a potential food-grade foaming agent.

Autoantigen presentation by splenic dendritic cells is required for RBC-specific autoimmunity.

Failure of humoral tolerance to red blood cell (RBC) antigens may lead to autoimmune hemolytic anemia (AIHA), a severe and sometimes fatal disease. Previous studies have shown that although tolerance is robust in HOD mice, autoantibodies are generated upon adoptive transfer of OTII CD4+ T cells, which are specific for an epitope contained within the HOD antigen. These data imply that antigen-presenting cells (APCs) are presenting RBC-derived autoantigen(s) and are capable of driving T-cell activation. Given that multiple APCs participate in erythrophagocytosis, we used a transgenic approach to determine which cellular subsets were required for autoantigen presentation and subsequent autoreactive T-cell activation. HOD mice, which express an RBC-specific antigen consisting of hen egg lysozyme, ovalbumin, and human blood group molecule Duffy, were bred with IAbfl/fl and Cre-expressing transgenic animals to generate mice that lack I-Ab expression on particular cell subsets. OTII CD4+ T cell proliferation was assessed in vivo in HOD+ I-Abfl/fl xCre+ mice and in vitro upon coculture with sorted APCs. Analysis of HOD+ I-Abfl/fl xCre+ mice demonstrated that splenic conventional dendritic cells (DCs), but not macrophages or monocytes, were required for autoantigen presentation to OTII CD4+ T cells. Subsequent in vitro coculture experiments revealed that both CD8+ and CD8- DC subsets participate in erythrophagocytosis, present RBC-derived autoantigen and stimulate autoreactive T-cell proliferation. These data suggest that if erythrocyte T-cell tolerance fails, DCs are capable of initiating autoimmune responses. As such, targeting DCs may be a fruitful strategy for AIHA therapies.

Design and Fabrication of Silicon Nanowire-Based Biosensors with Integration of Critical Factors: Toward Ultrasensitive Specific Detection of Biomolecules.

As critical factors affecting the sensing performance of silicon nanowire (SiNW) biosensors, the structure, functional interface, and detection target were analyzed and designed to improve sensing performance. For an improved understanding of the dependence of sensor structure on sensitivity, a simple theoretical analysis was proposed to predict the sensitivity of biosensors with different SiNW types, widths, and doping concentrations. Based on the theoretical analysis, a biosensor integrating optimized critical factors was designed and fabricated. Optimizations focusing on the following aspects are considered: (1) employing n-type SiNW and controlling the impurity doping concentration of SiNW at approximately 2 × 1016-6 × 1016 atoms/cm3 to obtain a suitable charge density, (2) minimizing the SiNW width to 16.0 nm to increase the surface area-to-volume ratio, (3) using a native oxide layer on SiNW as a gate insulator to transport the captured charge molecules closer to the SiNW surface, (4) modifying the SiNW surface by 2-aminoethylphosphonic acid coupling to form a high-density self-assembled monolayer for enhancing the stability bound molecules, and (5) functionalizing the SiNW with ovalbumin molecules for specifically capturing the target immunoglobulin G (IgG) molecules. The sensing performance was evaluated by detecting IgG with concentrations ranging from 6 aM to 600 nM and control experiments. The SiNW biosensor revealed ultrahigh sensitivity and specific detection of target IgG with a measured limit of detection of 6 aM. The integration of the critical SiNW biosensor factors provides a significant possibility of a rapid and ultrasensitive diagnosis of diseases at their early stages.

Ferulic acid-ovalbumin protein nanoparticles: Structure and foaming behavior

Egg white was known for its excellent foaming properties, and some reports had studied the effect of polyphenol such as green tea on the foaming properties. However, ovalbumin, as the most abundant component of egg white protein, few literatures have reported the effects of polyphenols on its structure and foam property. In this study, ferulic acid (FA) was selected to explore the influence of polyphenol on the structure and foaming properties of ovalbumin (OVA). Results showed that hydrophobic interaction and hydrogen chemical bonds were the main driving force. FA could induce a significant decrease of free-SH content (12.76–3.72 μmol/g), a slight decline of surface hydrophobicity (716.39–577.65). Meanwhile, combined with the results of fluorescence spectroscopy and circular dichroism spectroscopy, we conclude that FA changed the structures and molecular flexibility of OVA. The increase of particle size and absolute zeta-potential showed there was a little aggregation between OVA molecules, proved FA could act as a cross-linker between OVA proteins. This behavior makes the adjacent films more firm and stable, therefore improved the foaming properties. This study suggested that FA could be a potential foaming agent to modify the foaming properties of OVA in the foam-related food industry.

Fabrication of antioxidant emulsifiers from natural ingredients: Conjugation of egg white proteins with catechin and chlorogenic acid

There is considerable interest in developing dual functionality ingredients for application within the food industry. In this study, catechin (CT) and chlorogenic acid (CA) were conjugated to egg white protein (EWP) by using a free radical method to create antioxidant emulsifiers. The CT and CA contents of the antioxidant emulsifiers were 2.76% and 7.13%, respectively, and CT and CA modification altered the isoelectric point value of EWP to a lower pH. Amino acid analysis showed that CT was primarily conjugated to EWP through Tyr, His, Lys, Arg, Cys, and Trp residues, whereas CA was conjugated through Cys, Tyr and Trp residues. Combined liquid chromatography and mass spectrometry had identified numerous cross-linking sites after trypsin, chymotrypsin, and Glu-C protease + trypsin digestion, and this finding was consistent with the amino acid analysis results. In addition, 63 oxidation sites were detected in ovalbumin, ovotransferrin, and lysozyme molecules. The antioxidant activities of EWP–CT and EWP–CA conjugates were 2.5- and 4.5- fold (2-diphenyl-1-picrylhydrazyl radical scavenging activities) 2.4- and 4.9- fold (ferric reducing powers) higher than those of the unmodified EWP, respectively. Confocal laser scanning fluorescence microscopy revealed that the aggregation stability of the emulsions was improved when CT or CA was conjugated to EWP. The improved emulsification properties are possibly attributed to a decrease in surface hydrophobicity. Our results show that effective antioxidant emulsifiers can be fabricated by conjugating polyphenols to EWP.

Stabilization of the air-liquid interface in sponge cake batter by surface-active proteins and lipids: A foaming protocol based approach

The presence of protein and lipid from wheat flour and eggs at the air-liquid interface (ALI) in sponge cake batter has been studied through a foaming protocol. Sponge cake batter was either prepared from flour, sugar, eggs and leavening agents only or from these ingredients and exogenous lipids (ELs, i.e. a combination of mono- and diacylglycerols and polyglycerol esters of fatty acids). The foaming protocol consisted of whipping diluted sponge cake batter into foam. The foam was considered to be a model for the ALI in sponge cake batter. Foam fractions were then isolated at multiple time points after whipping and chemically analyzed (i.e. lipid and proteins contents and their compositions). In absence of ELs, lipids were not enriched in the foam whereas proteins were. Under such conditions, proteins were more important for stabilizing the ALI than lipids. Size-exclusion high performance liquid chromatography profiles revealed that of all proteins in the system ovalbumin and wheat α- and γ-gliadins had the highest affinity for the ALI. Ovalbumin molecules unfolded and formed intermolecular disulfide bonds at the ALI. Furthermore, flour lipids had higher affinity for the ALI than egg lipids. When ELs were used, foam protein and lipid content and composition essentially remained constant over the experimental time period. In such case, they dominated the ALI and greatly contributed to its stability. Use of ELs decreased batter density and increased batter viscosity, cake volume and cake softness. Hence, it is clear that including ELs in the sponge cake recipe led to high batter and cake quality.

Physicochemical properties and interfacial dilatational rheological behavior at air-water interface of high intensity ultrasound modified ovalbumin: Effect of ionic strength

High intensity ultrasound (HIUS), as an efficient modification method, generally improves the interfacial properties of globular proteins. Herein, to better understand the intrinsic relationship between the foaming property and the interface behavior of HIUS-treated ovalbumin (OVA). The main purpose of this work was to investigate the correlation between the physicochemical properties of high intensity ultrasound (HIUS)-treated ovalbumin (OVA) and interfacial dilatational rheological behavior at air-water interface with different salt ionic strength. The results showed that HIUS treatment resulted in aggregation of OVA dominated by hydrophobic interaction. The size of HIUS-treated OVA gradually increased due to the charge shielding effect caused by the increase of salt ionic strength, while the surface net potential and free sulfhydryl content of the OVA particle were progressively reduced. As a result, the HIUS treated-OVA exhibited the highest diffusion rate and the amount of protein adsorbed at the air-water interface with salt ionic concentrations of 50 mM and 100 mM, respectively. On the other hand, the modified-OVA contact with the air-water interface led to an exposure of aromatic residues, the content of α–helix, β-helix, and β-turn decreased by 6.3%, increased by 10.3%, and decreased by 5.5%, respectively, and there was no salt ion strength dependence. Moreover, the conformational changes resulted in a thiol-disulfide interchange reaction between the OVA molecules at the interface, which was the main contribution to the viscoelastic properties of OVA absorbed layer. These findings provide better insights for an in-depth understanding of the foaming mechanism of ultrasound treated OVA.

Rational design and fabrication of surface molecularly imprinted polymers based on multi-boronic acid sites for selective capture glycoproteins

Increasing the number of recognition sites is an available way to improve the efficiency of the identification of surface molecular imprinting polymers. In this work, glycoprotein imprinted nanoparticles (SiO2-MIPs) based on multi-boronic acid sites are prepared via surface imprinting processes. Polyethylene polyamine (PPI), containing enough active amino groups, is firstly grafted to the surface of silica nanoparticles. Boronic acid molecules are post-modified onto silica nanoparticles via amine aldehyde condensation reaction, and then dopamine (DA) as the monomer is adopted to form a surface imprinted polymer layer onto the functionalized silica nanoparticles under a gentle condition after binding the template ovalbumin (OVA) molecules. As-prepared SiO2-MIPs have quick adsorption kinetics (rebinding equilibrium at 60 min), high maximum adsorption capacity (243.4 mg g−1), excellent adsorption selectivity (imprinting factor towards OVA is 4.82,), and good reusability after seven regeneration cycles (a slight decrease of about 5%). Furthermore, the high density of boronic acids and imprinting effect both play a key role in the enhanced recognition and rebinding OVA. Moreover, this work overcomes the influence of steric hindrance and then the OVA molecules can access the recognition sites of SiO2-MIPs easily.

Interconnecting Bone Nanoparticles by Ovalbumin Molecules to Build a Three-Dimensional Low-Density and Tough Material

Natural building blocks like proteins and hydroxyapatite (HA) are found in abundance. However, their effective utilization to fabricate environment-friendly, strong, stiff, and tough materials remains a challenge. This work reports on the synthesis of a layered material from entirely natural building blocks. A simple process to extract HA from bones, while keeping collagen intact, is presented. These HA nanocrystals have a high aspect ratio as a result of the extraction method that largely retains the pristine nature of the HA. To fabricate the materials, polymerized egg white is used to induce toughness to the crystals where it acts like aload transfer entity between the crystals. As shown by atomic force microscope modulus mapping, the result is a layered material with a modulus that ranges from 3 to 180 GPa. Furthermore, the material exhibits self-stiffening behavior. Hydrogen and ionic bonds are likely to regulate the chemical interactions at the egg white/HA interface and are likely to be responsible for the observed high toughness and stiffness, respectively. The use of the HA/egg white composite as printed scaffolds is also demonstrated together with their biocompatibility.