Confocal Laser Scanning Microscopy Images Research Articles

In vitro performance of an autocured universal adhesive system in bonding to dentin

BackgroundThe successful integration of resin-based dental adhesives significantly impacts restorative dentistry, providing efficient and aesthetically pleasing caries treatments. Among various adhesives, one-step self-etching adhesives (1-SEAs) have gained popularity due to their simplicity and short application time. However, concerns have been raised regarding their bonding performance and marginal adaptation characteristics, which differ from two-step self-etching adhesives (2-SEAs) and three-step etch-and-rinse adhesives. Additionally, light-cured bonding materials may encounter challenges in deep cavities and inaccessible areas, necessitating extended light irradiation time. Autocured bonding materials are a potential solution, but limited comparative studies have been conducted on their performance.MethodsIn this in vitro study, we evaluated a new autocured universal bonding material (Bondmer Lightless 2) and compared the results with recent light-cured bonding materials. Microshear bond strength (μSBS) tests were performed on 25 human molars using five different combinations of adhesives and composite resins: Bondmer Lightless 2 with Estelite Bulk Fill Flow (BE group), Bondmer Lightless 2 with a prototype composite resin (BO group), Prime&Bond Universal with SDR flow + (PS group), Scotchbond Universal with Filtek Bulk Fill (SF group), and G-Premio Bond with Gracefil BulkFlo (GG group). The bond strengths and failure modes were assessed using a universal testing machine and scanning electron microscope (SEM), respectively. Marginal adaptation was evaluated using swept-source optical coherence tomography (SS-OCT) and confocal laser scanning microscopy (CLSM) on 40 sound bovine maxillary incisors.ResultsThe μSBS test showed no significant differences in bond strength among the tested groups. Most failure modes were observed at the bond interface between the adhesive and the dentin. The autocured bonding material demonstrated significantly higher marginal adaptation (SI%) than PS, SF, and GG. The CLSM images corresponded with gaps observed in the SS-OCT images, indicating improved marginal sealing in the autocured group.ConclusionsThe new autocured universal bonding material exhibited comparable bond strength to a conventional light-cured material while demonstrating a superior marginal adaptation level. This finding suggested that the autocured material could be a valuable alternative, especially when extended light irradiation would pose a challenge. Further clinical studies would be warranted to evaluate the performance of the autocured bonding material in actual restorative dental practice.

The Design and Optimization of Ceramide NP-Loaded Liposomes to Restore the Skin Barrier.

The impairment of skin integrity derived from derangement of the orthorhombic lateral organization is mainly caused by dysregulation of ceramide amounts in the skin barrier. Ceramides, fatty acids, and cholesterol-containing nano-based formulations have been used to impair the skin barrier. However, there is still a challenge to formulate novel formulations consisting of ceramides due to their chemical structure, poor aqueous solubility, and high molecular weight. In this study, the design and optimization of Ceramide 3 (CER-NP)-loaded liposomes are implemented based on response surface methodology (RSM). The optimum CER-NP-loaded liposome was selected based on its particle size (PS) and polydispersity index (PDI). The optimum CER-NP-loaded liposome was imagined by observing the encapsulation by using a confocal laser scanning microscope (CLSM) within fluorescently labeled CER-NP. The characteristic liquid crystalline phase and lipid chain conformation of CER-NP-loaded liposomes were determined using attenuated total reflectance infrared spectroscopy (ATR-IR). The CER-NP-loaded liposomes were imagined using a field emission scanning electron microscope (FE-SEM). Finally, the in vitro release of CER-NP from liposomes was examined using modified Franz Cells. The experimental and predicted results were well correlated. The CLSM images of optimized liposomes were conformable with the other studies, and the encapsulation efficiency of CER-NP was 93.84 ± 0.87%. ATR-IR analysis supported the characteristics of the CER-NP-loaded liposome. In addition, the lipid chain conformation shows similarity with skin barrier lipid organization. The release pattern of CER-NP liposomes was fitted with the Korsmeyer-Peppas model. The cytotoxicity studies carried out on HaCaT keratinocytes supported the idea that the liposomes for topical administration of CER-NP could be considered relatively safe. In conclusion, the optimized CER-NP-loaded liposomes could have the potential to restore the skin barrier function.

Bacillus-based probiotic cleansers reduce the formation of dry biofilms on common hospital surfaces.

In the absence of liquid suspension, dry biofilms can form upon hard surfaces within a hospital environment, representing a healthcare-associated infection risk. Probiotic cleansers usinggenerally recognized as safe organisms, such as those of the Bacillus genus, represent a potential strategy for the reduction of dry biofilm bioburden. The mechanisms of action and efficacy of these cleaners are, however, poorly understood. To address this, a preventative dry biofilm assay was developed using steel, melamine, and ceramic surfaces to assess the ability of a commercially available Bacillus spp. based probiotic cleanser to reduce the surface bioburden of Escherichia coli and Staphylococcus aureus. Via this assay, phosphate-buffered saline controls were able to generate dry biofilms within 7 days of incubation, with the application of the probiotic cleanser able to prevent >97.7% of dry biofilm formation across both pathogen analogs and surface types. Further to this, surfaces treated with the probiotic mixture alone also showed a reduction in dry biofilm across both pathogen and surface types. Confocal laser scanning microscopy imaging indicated that the probiotic bacteria were able to germinate and colonize surfaces, likely forming a protective layer upon these hard surfaces.

Pickering Emulsions Stabilized by Conjugated Zein-Soybean Polysaccharides Nanoparticles: Fabrication, Characterization and Functional Performance.

This study aims to fabricate zein-based colloidal nanoparticles, which were used to stabilize Pickering emulsions, by conjugation with soybean polysaccharide (SSPS) through the Maillard reaction. The physicochemical properties of the conjugated particles as well as the physical and oxidative stability of the fabricated Pickering emulsion that utilized conjugated colloidal particles with the volumetric ratio of water and oil at 50:50 were investigated. The grafting degree of zein and SSPS was verified through examination of FT-IR and fluorescence. Moreover, the conjugated Zein/SSPS nanoparticles (ZSP) that were prepared after dry heating for 48-72 h exhibit excellent colloidal stability across a range of pH values (4.0-10.0). Further, the wettability of ZSP decreased based on a contact angle analysis of θ~87°. Confocal laser scanning microscopy (CLSM) images indicated that ZSP particles were located around the oil droplets. Additionally, the ZSP effectively improved the oxidative stability of the Pickering emulsions, as demonstrated by a significant decrease in both peroxide value (PV) and thiobarbituric acid reactive substances (TBARS). The results of this study demonstrate that ZSP represents a promising food-grade Pickering emulsifier, capable of not only stabilizing emulsions but also inhibiting their oil oxidation.

Chitosan Nanoparticles for Enhanced Delivery of Sida cordifolia Extract: Formulation, Optimization and Bioactivity Assessment.

In a continuous search for an essential antidiabetic agent, Sida cordifolia hydroalcoholic (SCHA) extract-loaded chitosan nanoparticles (SCHA-CS-NP) were optimized. The Box-Behnken design (BBD Design-Expert software, version 14) with three parameters was used to optimize the nanoparticles after creating them using the ion gelation method. The chitosan and Tween 20 contents and the stirring speed were chosen as the independent variables, and their separate and combined effects on particle size (Y1), polydispersity index (Y2) and entrapment efficiency (Y3) were observed. The optimized formulation showed a particle size of 51 nm, an entrapment efficiency of 84.54% and a polydispersity index of 0.391. Physicochemical characterization, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), a drug release study, an ex vivo permeation study, and an antioxidant study were performed. Confocal laser scanning microscopy (CLSM) images demonstrated that chitosan nanoparticles loaded with rhodamine B-laden SCHA extract had superior penetration compared to the control (rhodamine B solution). Furthermore, compared to conventional ascorbic acid (IC50 = 45 µg/mL), a superior antioxidant activity was discovered for SCHA-CS-NPs (IC50 = 86.45 ± 2.24 µg/mL), while SCHA-CS-NPs also exhibited strong antidiabetic potential (IC50 = 93.71 ± 1.79 µg/mL) compared to standard acarbose (IC50 = 97.25 ± 1.43 µg/mL). The overall results demonstrated that SCHA-CS-NPs are a promising and efficient formulation for oral delivery.

Automated quality evaluation for laser cutting in lithium metal battery production using an instance segmentation convolutional neural network

Separating lithium metal foil into individual anodes is a critical process step in all-solid-state battery production. With the use of nanosecond-pulsed laser cutting, a characteristic quality-decisive cut edge geometry is formed depending on the chosen parameter set. This cut edge can be characterized by micrometer-scale imaging techniques such as confocal laser scanning microscopy. Currently, experimental determination of suitable process parameters is time-consuming and biased by the human measurement approach, while no methods for automated quality assurance are known. This study presents a deep-learning computer vision approach for geometry characterization of lithium foil laser cut edges. The convolutional neural network architecture Mask R-CNN was implemented and applied for categorizing confocal laser scanning microscopy images showing defective and successful cuts, achieving a classification precision of more than 95%. The algorithm was trained for automatic pixel-wise segmentation of the quality-relevant melt superelevation along the cut edge, reaching segmentation accuracies of up to 88%. Influence of the training data set size on the classification and segmentation accuracies was assessed confirming the algorithm’s industrial application potential due to the low number of 246 or fewer original images required. The segmentation masks were combined with topography data of cut edges to obtain quantitative metrics for the quality evaluation of lithium metal electrodes. The presented computer vision pipeline enables the integration of an automated image evaluation for quality inspection of lithium foil laser cutting, promoting industrial production of all-solid-state batteries with lithium metal anode.

Hydrophilic cryogels as potential 3D cell culture materials: Synthesis and characterization of 2‐(methacrylamido) glucopyranose‐based polymer scaffolds

AbstractCell cultures are important techniques to investigate cellular processes in a simplified manner. The most commonly applied 2D models do not simulate most of the in vivo conditions whereas cryogels as promising 3D cell culture materials are able to provide both a structured microenvironment and tailored surface properties, similar to the natural extracellular matrix (ECM). Herein, we present the synthesis and characterization of hydrophilic cryogels with different 2‐(methacrylamido) glucopyranose amounts followed by 3D cell culture experiments with L929 cells. Selected samples are additionally functionalized with fibronectin‐FITC for improved cellular adhesion. The incorporation of different 2‐(methacrylamido) glucopyranose amounts into the cryogels is demonstrated by Fourier‐transform IR (FTIR) and solid‐state NMR (ssNMR). The gels are able to withstand harsh autoclaving conditions as shown by thermogravimetric analysis (TGA) and ssNMR measurements. Pore size measurements by automated scanning electron microscopy (SEM) image analysis reveal similar pore sizes among the entire cryogel series. Confocal laser scanning microscopy (CLSM) images suggest the presence of healthy cells due to the absence of morphological abnormalities among the entire cryogel series. L929 cells settled deeper into the cryogels with increasing MAG content. With additional fibronectin functionalization, the cells are retained much stronger and stay in the upper gel layers.

An automated method to analyze root filling voids and gaps using confocal microscopy images.

This study evaluated the feasibility of an automated method to delimit the required area to quantitatively analyze root filling voids and gaps from cross-sectional confocal laser scanning microscopy (CLSM) images. Root canals of maxillary canines were prepared with rotary instruments and filled by lateral compaction technique using gutta-percha and AH Plus sealer. The roots were stored (100% humidity, 37°C) for a period of 24h and then transversally sectioned to obtain 2-mm-thick slices from the apical and middle thirds. The areas corresponding to filling materials, gaps, and voids were manually delimited or automatically demarked by ImageJ software after converting the images to the RGB color system. Based on manual and automatic delimitations, the percentages of voids and gaps were calculated. Data of voids and gaps between middle and apical thirds were individually compared by paired t-test. Pearson`s correlation test was used to assess the correlation of data between the methods. Irrespective of the method of area delimitation, no difference was observed between the root thirds for both voids and gaps, while the p-values calculated for each method were similar. Almost perfect correlations between the methods were observed for both outcomes. The proposed method to automatically delimit the areas corresponding to filling material, voids, and gaps appears to be a valid method to facilitate the quantitative analysis of defects in root canal fillings using topographic CSLM images.

2-NBDG Uptake in Gossypium hirsutum in vitro ovules: exploring tissue-specific accumulation and its impact on hexokinase-mediated glycolysis regulation.

Fluorescent glucose derivatives are valuable tools as glucose analogs in plant research to explore metabolic pathways, study enzyme activity, and investigate cellular processes related to glucose metabolism and sugar transport. They allow visualization and tracking of glucose uptake, its utilization, and distribution within plant cells and tissues. This study investigates the phenotypic and metabolic impact of the exogenously fed glucose derivative, 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose) (2-NBDG) on the fibers of Gossypium hirsutum (Upland cotton) ovule in vitro cultures. The presence of 2-NBDG in the culture medium did not lead to macroscopic morphological alterations in ovule and fiber development or to the acquisition of fluorescence or yellow coloration. Confocal laser scanning microscope imaging and chromatographic analysis of cotton ovules' outer rim cross-sections showed that the 2-NBDG is transported from the extracellular space and accumulated inside some outer integument cells, epidermal cells, and fertilized epidermal cells (fibers), but is not incorporated into the cell walls. Untargeted metabolic profiling of the fibers revealed significant changes in the relative levels of metabolites involved in glycolysis and upregulation of alternative energy-related pathways. To provide biochemical and structural evidence for the observed downregulation of glycolysis pathways in the fibers containing 2-NBDG, kinetics analysis and docking simulations were performed on hexokinase from G. hirsutum (GhHxk). Notably, the catalytic activity of heterologously expressed recombinant active GhHxk exhibited a five-fold decrease in reaction rates compared to D-glucose. Furthermore, GhHxk exhibited a linear kinetic behavior in the presence of 2-NBDG instead of the Michaelis-Menten kinetics found for D-glucose. Docking simulations suggested that 2-NBDG interacts with a distinct binding site of GhHxk9, possibly inducing a conformational change. These results highlight the importance of considering fluorescent glucose derivatives as ready-to-use analogs for tracking glucose-related biological processes. However, a direct comparison between their mode of action and its extrapolation into biochemical considerations should go beyond microscopic inspection and include complementary analytical techniques.

Interfacial properties and structure of Pickering emulsions co-stabilized by different charge emulsifiers and zein nanoparticles

The stability of Pickering emulsions can be improved by the synergistic action of colloidal particles and small molecule emulsifiers. In addition, the interaction between particles and different charge emulsifiers at the interface may result in different interfacial film structures, thus affecting the stability of Pickering emulsions. However, little is currently known about the impact of emulsifier charge on the fabrication and characteristics of these co-stabilized Pickering emulsions. Herein, we investigated the influence of Pickering emulsions co-stabilized by zein nanoparticles and anionic (quillaja saponin, QS), non-ionic (Tween 80), or cationic (lauroyl arginate ethyl hydrochloride) emulsifiers on the interfacial properties. The adsorption kinetics and rheological behavior of the molecular emulsifiers at oil/water interfaces were studied. Changes in interfacial structure and adsorption behavior were studied by confocal laser scanning microscopy (CLSM), and quartz crystal microbalance-dissipation (QCM-D) analysis. The dynamic interface characteristics showed that QS has good emulsification performance. The CLSM images indicated that the emulsifier charge impacted the interfacial structure of the Pickering emulsions. The combination of QS and zein nanoparticles formed a coating at the oil/water interface that was denser than for the other two emulsifiers, which improved the stability of the Pickering emulsions. QCM-D revealed that the interfacial film formed by anionic emulsifiers and zein nanoparticles was the thickest (about 6.6 nm). Moreover, anionic emulsifiers and zein nanoparticles stabilized Pickering emulsions provided the best protection against curcumin. These results may be important for optimizing the performance of Pickering emulsions in the food and pharmaceutical industries.

In-vitro and ex-vivo antidiabetic, and antioxidant activities of Box-Behnken design optimized Solanum xanthocarpum extract loaded niosomes

One of the most prevalent lifestyle diseases, diabetes mellitus (DM) is brought on by an endocrine issue. DM is frequently accompanied by hyperglycemia, a disease that typically results in an excess of free radicals that stress tissues. The medical community is currently concentrating on creating therapeutic medications with roots in nature to lessen the damage associated with hyperglycemia. Solanum xanthocarpum has a number of medicinal benefits. The investigation aimed to produce and analyze niosomal formulations containing S. xanthocarpum extract (SXE). Niosomes were made by implementing the solvent evaporation process, which was further optimized using Box-Behnken design. Drug release, DPPH assessments, α-amylase inhibition assay, α-glucosidase inhibition assay, and confocal laser scanning microscopy (CLSM) investigation were all performed on the developed formulation (SXE-Ns-Opt). SXE-Ns-Opt displayed a 253.6 nm vesicle size, a PDI of 0.108, 62.4% entrapment efficiency, and 84.01% drug release in 24 h. The rat's intestinal CLSM image indicated that the rhodamine red B-loaded SXE-Ns-Opts had more intestinal penetration than the control. Additionally, the antioxidant effect of the obtained formulation was demonstrated as 89.46% as compared to SXE (78.10%). Additionally, acarbose, SXE, and SXE-Ns-Opt each inhibited the activity of α-amylase by 95.11%, 85.88%, and 89.87%, and also suppressed the enzyme of α-glucosidase by 88.47%, 81.07%, and 85.78%, respectively. To summarise, the establishment of the SXE-Ns-Opt formulation and its characterization demonstrated the legitimacy of the foundation. A promising candidate for the treatment of diabetes mellitus has been shown as in vitro studies, antioxidant against oxidative stress, CLSM of rat's intestine and a high degree of penetration of formulation.

Eradication of dental pathogens using flavonoid rutin mediated silver-selenium nanoparticles

In this study, flavonoid rutin mediated silver-selenium nanoparticles(Rut-AgSeNPs) is biosynthesized and used to treat dental pathogens. The synthesized Rut-AgSeNPs was characterized using UV–visible Spectroscopy (UV–Vis), Scanning Electron Microscope (SEM), Energy-dispersive X-ray Spectroscopy (EDX), X-Ray Diffraction Analysis (XRD), Attenuated Total Reflectance–Fourier Transform Infrared (ATR-FTIR) Spectroscopy, and Confocal Laser Scanning Microscopy (CLSM). The particle size of Rut-AgSeNPs was found between 45 and 190 nm in diameter with spherical (AgNPs) and cylindrical (SeNPs) in shape. FTIR results show that the hydroxyl group of rutin has formed intramolecular hydrogen bonding with particles during the reduction and capping process. XRD pattern confirms the synthesized particles were appeared as crystalline (68.7%) and amorphous (31.3%) structure. Rut-AgSeNPs exhibits excellent antimicrobial activity against dental pathogens such as Streptococcus mutans, Staphylococcus aureus, Escherichia coli and Candida albicans with the MIC value of 12.5 µg/mL, 8.2 µg/mL, 6.6 µg/mL and 2.1 µg/mL, respectively. The susceptibility of dental pathogens was found for Rut-AgSeNPs as follows: C. albicans < E. coli < S. aureus < S. mutans. CLSM image indicates that the Rut-AgSeNPs completely inhibits all the tested pathogens at 12.5 µg/mL. The present study suggests that the synthesized Rut-AgSeNPs might be an effective nanodrug to treat dental pathogens.

Cell-Laden 3D Hydrogels of Type I Collagen Incorporating Bacterial Nanocellulose Fibers.

There is a growing interest in developing natural hydrogel-based scaffolds to culture cells in a three-dimensional (3D) millieu that better mimics the in vivo cells' microenvironment. A promising approach is to use hydrogels from animal tissues, such as decellularized extracellular matrices; however, they usually exhibit suboptimal mechanical properties compared to native tissue and their composition with hundreds of different protein complicates to elucidate which stimulus triggers cell's responses. As simpler scaffolds, type I collagen hydrogels are used to study cell behavior in mechanobiology even though they are also softer than native tissues. In this work, type I collagen is mixed with bacterial nanocellulose fibers (BCf) to develop reinforced scaffolds with mechanical properties suitable for 3D cell culture. BCf were produced from blended pellicles biosynthesized from Komagataeibacter xylinus. Then, BCf were mixed with concentrated collagen from rat-tail tendons to form composite hydrogels. Confocal laser scanning microscopy and scanning electron microscopy images confirmed the homogeneous macro- and microdistribution of both natural polymers. Porosity analysis confirmed that BCf do not disrupt the scaffold structure. Tensile strength and rheology measurements demonstrated the reinforcement action of BCf (43% increased stiffness) compared to the collagen hydrogel while maintaining the same viscoelastic response. Additionally, this reinforcement of collagen hydrogels with BCf offers the possibility to mix cells before gelation and then proceed to the culture of the 3D cell scaffolds. We obtained scaffolds with human bone marrow-derived mesenchymal stromal cells or human fibroblasts within the composite hydrogels, allowing a homogeneous 3D viable culture for at least 7 days. A smaller surface shrinkage in the reinforced hydrogels compared to type I collagen hydrogels confirmed the strengthening of the composite hydrogels. These collagen hydrogels reinforced with BCf might emerge as a promising platform for 3D in vitro organ modeling, tissue-engineering applications, and suitable to conduct fundamental mechanobiology studies.

Application of Box–Behnken design for the optimization of Plumbago zeylanica extract-loaded niosomes: preparation, characterization and in vitro antidiabetic and antioxidant activity

This study aimed to develop and evaluate a niosomal formulation loaded with Plumbago zeylanica extract (PZE). The solvent evaporation method was used to prepare niosomes and optimized using the Box–Behnken design. The optimized formulation (PZE-Ns-Opt) was characterized for drug release, DPPH assay, α-amylase inhibition assay, α-glucosidase inhibition assay, and confocal laser scanning microscopy (CLSM) study. PZE-Ns-Opt showed a vesicle size of 253.6 nm, PDI of 0.108, entrapment efficiency of 62.4%, and drug release of 84.01%. The CLSM image of the rat’s intestine suggested that the rhodamine red B-loaded PZE-Ns-Opts showed superior penetration compared to the control. Further, the antioxidant activity of the prepared formulation was exhibited as 89.46%±0.016 as compared to PZE (78.10%±0.005). In addition to this, α- amylase activity was inhibited by 95.11%±4.62, 85.88%±2.56, and 89.87%±3.65 by acarbose, PZE, and PZE-Ns-Opt, respectively. In comparison, the α-glucosidase activity was inhibited by 88.47%±1.04, 81.07%±0.50 and 85.78%±0.71 by acarbose, PZE, and PZE-Ns-Opt, respectively. To conclude, the development of PZE-Ns-Opt formulation and its characterization showed the establishment’s authenticity. The in vitro antidiabetic, antioxidant studies expressed the protective effect from oxidative stress, CLSM of rat’s intestine ability to penetrate to great extent and could be a promising candidate for the management of diabetes mellitus.

Morphology of Neutrophils during Their Activation and NETosis: Atomic Force Microscopy Study.

Confocal microscopy and fluorescence staining of cellular structures are commonly used to study neutrophil activation and NETosis. However, they do not reveal the specific characteristics of the neutrophil membrane surface, its nanostructure, and morphology. The aim of this study was to reveal the topography and nanosurface characteristics of neutrophils during activation and NETosis using atomic force microscopy (AFM). We showed the main stages of neutrophil activation and NETosis, which include control cell spreading, cell fragment formation, fusion of nuclear segments, membrane disruption, release of neutrophil extracellular traps (NETs), and final cell disintegration. Changes in neutrophil membrane nanosurface parameters during activation and NETosis were quantified. It was shown that with increasing activation time there was a decrease in the spectral intensity of the spatial periods. Exposure to the activator A23187 resulted in an increase in the number and average size of cell fragments over time. Exposure to the activators A23187 and PMA (phorbol 12-myristate 13-acetate) caused the same pattern of cell transformation from spherical cells with segmented nuclei to disrupted cells with NET release. A23187 induced NETosis earlier than PMA, but PMA resulted in more cells with NETosis at the end of the specified time interval (180 min). In our study, we used AFM as the main research tool. Confocal laser-scanning microscopy (CLSM) images are provided for identification and detailed analysis of the phenomena studied. In this way, we exploited the advantages of both techniques.

The effect of milk fat content on microstructure and rheological properties of rennet casein gel emulsions

Cheese is described as an emulsion gel, in which the dispersed phase comprises milk fat globules while the continuous phase consists of a casein gel network. By embedding fat into the casein network, it is possible to tailor the viscoelastic and physiochemical properties of casein emulsion gels and design customized cheese products. In this study, we incorporated 0.1, 7, 11, and 18% (w/w) milk fat in casein gels made from renneted skimmed milk curd and investigated its effect on microstructure, rheological properties, and melting behavior of the gels. Confocal laser scanning microscopy images revealed the presence of larger fat globules and serum pockets in samples with a fat content >11%, which also led to a more porous protein gel network structure. A higher proportion of water with high mobility, observed by low-field nuclear magnetic resonance, confirmed the presence of more or larger serum pockets in gels with the highest fat content. Rheological analysis showed that casein gels exhibited a behavior typical of weak solid viscoelastic materials. Increasing fat content increased gels strength, as revealed by a rise in storage modulus, but made them more susceptible to deformation. The gel-sol transition temperature increased from 65.5 ± 0.7 to 71.9 ± 0.2 °C with increased fat content due to the relatively lower moisture content in gels with a fat content >11%. The results obtained provided a better understanding of the possibility to modulate structural and rheological properties of casein emulsion gels emulsified with milk fat.

Effect of sesbania gum on the rheological, textural, and microstructural characteristics of CaSO4-induced soy protein isolate gels

This study evaluated the rheological, textural, and microstructural characteristics of CaSO4-induced soy protein isolate (SPI) gels in the presence of various sesbania gum (SG) concentrations. The results showed that SG significantly increased the storage modulus (G′), loss modulus (G″), and mechanical strength, especially, in adding 0.3 wt% SG. Furthermore, the gel microstructures varied from homogenous to slight phase separation with a continuous protein phase followed by significant phase separation, depending on SG concentration. The fractal dimension of the gels calculated from confocal laser scanning microscopy (CLSM) images decreased gradually with increased SG concentrations. The denser microstructure in the local regions is related to improving the water-holding capacity (WHC). Fourier transform infrared spectroscopy (FTIR) spectra confirmed that hydrogen bonds are crucial in maintaining the three-dimensional network structure of the SPI-SG gels. A lower concentration (0.1–0.3 wt%) of SG facilitates the formation of the gel; however, if the concentration of SG becomes 0.4 wt% or 0.5 wt%, SPI-SG interactions are inhibited by the entangled galactomannan chains, resulting in significant phase separation. Our findings suggested the great potential of SG in modulating the properties and structure of CaSO4-induced SPI gels, obtaining novel SPI-based food gel products with improved texture.

Effect of Heat Treatment on Yellow Field Pea (Pisum sativum) Protein Concentrate Coupled with Membrane Ultrafiltration on Emulsification Properties of the Isolated >50 kDa Proteins.

The aim of this paper was to determine the emulsification properties of protein aggregates obtained from heat pretreated yellow field pea protein concentrate (PPC). PPC dispersions were prepared in distilled water (adjusted to pH 3.0, 5.0, 7.0, or 9.0), heated in a water bath (100 °C) for 30 min, centrifuged and the supernatant passed first through a 30 kDa membrane and, then, the first retentate (>30 kDa) through a 50 kDa membrane. The 50 kDa membrane separation yielded a second retentate (>50 kDa proteins), which was isolated for emulsification studies. The near UV circular dichroic spectra of the protein samples showed more unfolded structures at pH 3.0 and 5.0 than at pH 7.0 and 9.0. The presence of small and spherical oil droplets of emulsions stabilized by the >50 kDa proteins at pH 3.0, 7.0, and 9.0 was confirmed by confocal laser scanning microscopy images. Emulsions stabilized at pH 7.0 and 9.0 had a narrower size distribution range than at pH 3.0 and 5.0. A narrow oil droplet size distribution range and lower interfacial protein concentrations of the emulsions stabilized by the >50 kDa proteins were observed at the corresponding pH of the heat treatment when compared to other pH values. Emulsions stabilized by the >50 kDa proteins exhibited a relatively low flocculation and coalescence index, which infers relative stability. The results from this work suggest that heat pretreatment of the PPC led to the formation of new protein aggregates, especially FT9 with enhanced emulsification properties, at some of the test conditions when compared to the unheated PPC.

Effect of the addition of pregelatinized rice starch paste on the retrogradation of rice starch gel

The effect of the addition of pregelatinized rice starch paste (PRSP) on the retrogradation of rice starch (RS) gels was investigated using rheometer, X-ray diffraction (XRD), differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS) and confocal laser scanning microscopy (CLSM). A decrease in the storage modulus of RS gels after short-term storage was found after adding PRSP. The XRD results revealed that the retrogradation degree of RS gels with added PRSP was lower than in the absence of PRSP, suggesting that the addition of PRSP could restrain the long-term retrogradation of rice starch. Moreover, the lower enthalpy changes of RS gels with added PRSP after retrogradation suggested that the progress of amylopectin crystallization was delayed due to PRSP incorporation. SAXS analysis showed that adding PRSP inhibited swelling of RS and decreased the size of aggregation during storage, which suppressed starch retrogradation. In addition, CLSM images indicated that PRSP could form continuous network in which the RS granules embedded, and that gels with PRSP exhibited greater phase separation after 15 d storage. These results suggested that the addition of PRSP inhibited the retrogradation of RS gels. The inhibitory effect is mainly due to PRSP altering the gel formation type and prohibiting the excessive swelling of rice starch granules during gelatinization. This study could provide new insights for the production of rice products and for prolonging their shelf life during storage.

Carbon Coated Iron-Cobalt Nanoparticles for Magnetic Particle Imaging.

Magnetic particle imaging (MPI) is an emerging imaging modality that provides direct and quantitative mapping of iron oxide tracers. To achieve high sensitivity and good spatial resolution images, a magnetic nanoparticle with a higher contrast intensity needs to be developed. Currently, a majority of MPIs being developed for potential clinical application are composed of iron oxide nanoparticles with a spherical shape. In this project, we intend to report development of high-performance carbon (C) coated iron-cobalt (FeCo) nanoparticles (FeCo/C) and investigate their feasibility as a MPI agent. We have synthesized FeCo/C through a facile and simple method at mild temperature that is safe, easy, and up-scalable. We studied the structural and functional relationships and biocompatibility of this MPI agent in vitro. However, to enhance the aqueous solubility and biocompatibility, the surface of FeCo/C was modified with polyethylene glycol (PEG). We found that variation in the ratio of Fe and Co plays a vital role in their physical properties and functionality. In vitro imaging confirms that the Fe3Co1/C nanoparticle has highly competitive MPI intensity compared to VivoTrax, a commercially available MPI agent. Confocal laser scanning microscopy imaging with Rhodamine B labeled FeCo/C displays cellular internalization by the A375 cancer cells. The in vitro toxicity analysis concludes that there is no significant toxicity of FeCo/C nanoparticles. Therefore, the newly developed MPI agent holds strong promise for biomedical imaging and could be further validated in vivo in small animals.