Preparation of food-grade EDC/NHS-crosslinked gelatin nanoparticles and their application for Pickering emulsion stabilization

Active biodegradable bacterial cellulose films with potential to minimize the plastic pollution: Preparation, antibacterial application, and mechanism

Petroleum-based films have triggered a serious global pollution crisis because they are difficult to recycle, degrade, and reuse. Developing alternative sustainable active films represents a powerful strategy to address these issues. Here, a multifunctional biodegradable bacterial cellulose (BC) film incorporated with guanidine-based polymer (PHGH)/gallic acid (GA) was constructed (termed OBC-PHGH/GA). The resulting OBC-PHGH/GA film exhibited a highly interweaved nanofiber network structure with excellent tensile strength and ductility. The OBC-PHGH/GA film showed an excellent antibacterial effect against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) with inhibition efficiencies of ∼99.99 % compared with the OBC film. Moreover, the as-prepared film showed excellent UV-shielding, antioxidant, and antifungal activities, showing great potential in food packaging. More importantly, the OBC-PHGH/GA film can be degraded into safe and reusable sugars, demonstrating outstanding environmental friendliness and sustainability. This work provides a promising and unique strategy for designing and fabricating green active packaging materials.

Preparation of 1,2-benzenedialdehyde-crosslinked oligo-gelatin conjugates and poly-gelatin nanoparticles to stabilize traditional and Pickering emulsions, respectively

This research aimed to develop a desolvation and 1,2-benzenedialdehyde crosslinking method to prepare crosslinked gelatin substances for emulsion stabilization. The oligo-gelatin conjugates and poly-gelatin nanoparticles could be formed at the 1,2-benzenedialdehyde concentration of 50 g/L and ≥ 150 g/L, respectively. The formation mechanism involved intra/inter-molecular amine-benzenedialdehyde-thiol and amine-benzenedialdehyde-amine crosslinking reactions. With increasing 1,2-benzenedialdehyde preparation concentrations (50-450 g/L), the crosslinked gelatin substance sizes increased from 81.5 ± 20.1 nm to 105.5 ± 20.8 nm in the dried state, and increased (from 35 ± 8 nm to 220 ± 36 nm) then decreased to 115 ± 28 nm in the water. Furthermore, the fish oil emulsions stabilized by the crosslinked gelatin substances showed different creaming stability: 250 g/L (43.5 ± 1.5 %) > 350 g/L (41.4 ± 1.0 %) > 450 g/L (37.5 ± 2.2 %) > 150 g/L (11.2 ± 0.4 %) > 50 g/L (0.0 ± 0.0 %). The results suggested this method was useful for preparing oligo-gelatin conjugates and poly-gelatin nanoparticles to stabilize traditional and Pickering emulsions, respectively.

Protein nanoparticles as potent delivery vehicles for polycytosine RNA-binding protein one

Ma et al recently reported in the World Journal of Diabetes that ferroptosis occurs in osteoblasts under high glucose conditions, reflecting diabetes pathology. This condition could be protected by the upregulation of the gene encoding polycytosine RNA-binding protein 1 (PCBP1). Additionally, Ma et al used a lentivirus infection system to express PCBP1. As the authors’ method of administration can be improved in terms of stability and cost, we propose delivering PCBP1 to treat type 2 diabetic osteoporosis by encapsulating it in protein nanoparticles. First, PCBP1 is small and druggable. Second, intravenous injection can help deliver PCBP1 across the mucosa while avoiding acid and enzyme-catalyzed degradation. Furthermore, incorporating PCBP1 into nanoparticles prevents its interaction with water or oxygen and protects PCBP1’s structure and activity. Notably, the safety of the protein materials and the industrialization techniques for large-scale production of protein nanoparticles must be comprehensively investigated before clinical application.

Comparative Study of pH-Responsive and Aggregation Stability of Bosutinib-Loaded Nanogels Comprising Gelatin Methacryloyl, Carboxymethyl Dextran, and Hyaluronic Acid for Controlled Drug Delivery in Colorectal Cancer: An Extensive In Vitro Investigation

This study investigates the use of pH-responsive nanogels for delivering Bosutinib (BOSU) in colon cancer treatment. Nanogels were formulated using three polymers: hyaluronic acid (HA), carboxymethyl dextran (CMD), and gelatin methacryloyl (GelMA). These nanogels achieved high drug entrapment efficiencies (80-90%) through polymer mixing with BOSU, followed by EDC/NHS cross-linking and sonication. The nanogels were stable, with negative zeta potentials (-20 to -30 mV) and particle sizes between 100 and 200 nm. Fourier-transform infrared analysis confirmed successful methacrylation in GelMA nanogels. Sustained BOSU release at pH 5.0 was observed, resembling tumor environments, compared to slower release at normal pH (7.4). Cytotoxicity tests showed 70-80% cell survival reduction in HCT116 colon cancer cells at higher doses, and GelMA-BOSU nanogels notably reduced cell migration. Antiangiogenic effects were confirmed in a chick chorioallantoic membrane model, highlighting the potential of these nanogels for targeted BOSU delivery in colon cancer therapy.

Antibacterial and antioxidative hydrogel dressings based on tannic acid-gelatin/oxidized sodium alginate loaded with zinc oxide nanoparticles for promoting wound healing

Wound infection resulting in delayed wound healing and wound deterioration remains a clinical challenge. Recently, multifunctional hydrogel dressing was a promising strategy which has attracted wide attention in preventing wound infection and promoting wound healing. In this study, a hybrid hydrogel made of gelatin (GL), tannic acid (TA), oxidized sodium alginate (OSA), and zinc oxide nanoparticles (ZnO NPs) was prepared mainly by double network cross-linking approach, named tannic acid-gelatin/oxidized sodium alginate/zinc oxide (TA-GL/OSA/ZnO). The composite hydrogels exhibited improved mechanical properties, which provided by TA modified the structure of GL network, Schiff base reaction between GL and OSA, and the strengthening effect of ZnO NPs. Meanwhile, the composite hydrogel showed high antibacterial activity against Staphylococcus aureus (S. aureus) (97.8 % ± 0.9 %) and Escherichia coli (E. coli) (96.6 % ± 1.2 %), attributed to the synergistic effect of TA and ZnO NPs. Furthermore, benefiting from the good antioxidative properties of TA, the sustain-released Zn2+ with the good capability to kill bacteria, and promoting the regeneration of skin epithelial tissues in BALB/c mice constantly, the multifunctional hydrogel had a significant therapeutic effect on wound healing and broad application prospects.

Effect of glycation with three polysaccharides on the structural and emulsifying properties of ovalbumin

Herein, three types of ovalbumin (OA)-polysaccharide conjugates were prepared with three polysaccharides (XG: xanthan gum; GG: guar gum; KGM: konjac glucomannan) for the fish oil emulsion stabilization. The glycation did not change the spectra bands and secondary structure percentages of OA, whereas it decreased the molecular surface hydrophobicity of OA. The initial emulsion droplet sizes were dependent on the polysaccharide types, OA preparation concentrations, polysaccharide: OA mass ratios, and glycation pH. The emulsion stability was mainly dependent on the polysaccharide types, polysaccharide: OA mass ratios, and glycation pH. However, it was minorly dependent on the OA preparation concentrations. The emulsions stabilized by conjugates with high polysaccharide: OA mass ratios (e.g., ≥3:5 for OA-GG) or appropriate glycation pH (e.g., 5.0-6.1 for OA-XG) showed no obvious creaming during the room temperature storage. This work provided basic knowledge on the structural modification and functional application of a protein.

Effects of five tissue sources of silver carp by-products on the structure, physicochemical and emulsifying properties of gelatin

The effects of tissue sources on gelatin's physicochemical and functional properties remain unclear. This work aimed to analyze the effects of five tissue sources on the properties of fish gelatins. Five gelatins were extracted from different silver carp by-products (skin, scale, fin, head, and bone) and the effects of tissue sources on the gelatin's properties were studied. The gelatin's β-sheet percentages and total sodium dodecyl sulfate-polyacrylamide gel electrophoresis band intensities (β, α1, and α2 chains) showed similar dependence to the tissue sources: skin ≈ scale > fin ≈ head > bone. Bone-related gelatins (from head and bone) showed lower water-holding capacity and fat-binding capacity values than the other gelatins. Tissue sources significantly affected the gelatin's gel strength values: skin ≈ fin > scale > bone ≈ head. Scale and bone gelatin solutions had significantly lower rheological apparent viscosities than other by-product gelatin solutions. The interfacial tension and rheological apparent viscosity values of the fish oil-loaded gelatin-stabilized emulsions depended on the gelatin tissue sources and gelatin concentrations. In particular, skin, scale, and fin gelatins induced no obvious emulsion creaming at the gelatin concentration of 10 g/L during the emulsion storage. Bone-related gelatins induced higher emulsion creaming index values for the emulsions with 10 g/L of gelatins during the emulsion storage. This work confirmed tissue sources could significantly affect the properties of gelatins. Five tissue sources had different effects on the structural, physicochemical, and emulsifying properties of silver carp by-product gelatins. Especially, the gelatins from different silver carp by-products showed different water-holding and fat-binding capacities, gel strengths, interfacial tension, rheological apparent viscosities, and emulsion stabilization abilities. These properties are important considerations for the application of silver carp by-product gelatins in food and other industries.

Effects of the extraction temperatures on the protein contents, gelatin purities, physicochemical properties, and functional properties of tilapia scale gelatins

Herein, the effects of the extraction temperatures (45, 55, 65, 75, and 85 °C) on the protein contents, gelatin purities, physicochemical properties, and functional properties of tilapia scale gelatins were studied. Among these temperatures, 65 °C was the best extraction temperature to obtain good production yield (16.0 % ± 0.3 %), good protein contents (excellent total amino acid composition of 94.20 ± 0.76 g/100 g of gelatin, the highest hydrophobic amino acids percentage of 32.68 ± 0.24 g/100 g of gelatin), appropriate ATR-FTIR spectra peaks (Amides A, B, I, II, and III), high β-sheet percentage (38.2 % ± 1.3 %), the highest purity of the gelatin structures (280, 140, and 125 kDa), the lowest nanoparticle sizes in atomic force microscopy results, the highest water-holding capacity (25.3 % ± 0.9 %), the highest fat-binding capacity (16.9 % ± 0.1 %), high foaming properties (foaming capacity of 151.7 % ± 7.6 % and foaming stability of 145.8 % ± 6.3 %), the lowest interfacial tension (2.1 ± 0.2 mN/m), the lowest emulsifying activity index (16.5 % ± 0.9 %), the highest emulsifying stability index (88.9 % ± 5.1 %), highest emulsion viscosity (1462 ± 17 mPa·s at the rotary speed of 6 rpm), the lowest initial droplet sizes, and lowest emulsion creaming index (6.9 % ± 0.7 %). This work provided a useful guide to choosing extraction temperature for gelatin extraction and a useful theory on the relationship between compositions and properties of a protein sample.

The Impact of Surface Modifier on Magnetic Nanoparticle Properties and Their Application in CD3+T Cell Separation

Fe3O4 nanoparticles occupy a pivotal position in the realm of nanobiology due to their nontoxic, biocompatible, and superparamagnetic properties. This study examines the influence of surface modifiers on the properties of magnetic nanoparticles. Poly(methacrylic acid) (PMAA), poly(4-styrenesulfonic acid-co-maleic acid) sodium salt (PSSM), trisodium citrate (TSC), carboxymethylcellulose (CMC), and carboxymethylated-dextran 40 (CMD40) were introduced into a one-pot solvothermal method to synthesize magnetic nanoparticles. TEM, the 4-(bromomethyl)-6,7-dimethoxy coumarin (BMMC) absorption assay, and the Bradford method were employed to characterize the diameter, carboxyl content, and protein immobilization ability of the nanoparticles, respectively. The findings revealed that CMD40-modified magnetic nanoparticles (CMD40-MNPs) exhibited the highest carboxyl content and streptavidin (SA) immobilization content, reaching 6.5 × 10-7 mol/mg and 375 μg/mg, respectively. In contrast, CMC-modified magnetic nanoparticles displayed opposite trends. This is primarily attributed to dextran's unique molecular structure, which enhances its water solubility and biocompatibility, thereby facilitating contact with Fe3O4 nanoparticles in aqueous solutions. CMD40-MNPs possess a saturation magnetization value of 60.90 emu/g and can be collected within (60 ± 5) s using a standard magnetic separator. Cytotoxicity assays demonstrated that CMD40-MNPs are nontoxic to cells. A cell sorting strategy utilizing the binding of SA-CMD40-MNPs and biotin antihuman CD3 antibody-modified cell suspensions was employed to isolate CD3+T cells. The results indicate that the purity and efficiency of targeted CD3+T cells are 85.2% and 61.5%, respectively.

Tilapia head gelatins to stabilize fish oil emulsions and the effect of extraction methods

The preparation and use of gelatins from fish by-products have attracted much attention in the field of food science. Herein, four types of tilapia head gelatins were extracted and characterized: hot water-pretreated gelatin (HWG), acetic acid-pretreated gelatin (AAG), sodium hydroxide-pretreated gelatin (SHG), and pepsin enzyme-pretreated gelatin (PEG). The gel strength values followed the order: PEG (74 ± 1 Bloom) > AAG (66 ± 1) > HWG (59 ± 1) > SHG (34 ± 1). The foaming properties, fish oil emulsion viscosity, emulsion activity, and emulsion stabilization ability followed this order: PEG > HWG ≥ AAG > SHG. The effect mechanisms of extraction methods and gelatin concentrations on the emulsion stability involved the interfacial tension, emulsion viscosity, and fat-binding capacity. This work provided important knowledge for analyzing the relations between the structure and function of gelatin. It also provided a high-value application method of fish wastes.

Preparation, Optimization, and Characterization of Bovine Bone Gelatin/Sodium Carboxymethyl Cellulose Nanoemulsion Containing Thymol

The aim of this study is to produce a biodegradable food packaging material that reduces environmental pollution and protects food safety. The effects of total solids content, substrate ratio, polyphenol content, and magnetic stirring time on bovine bone gelatin/sodium carboxymethylcellulose nanoemulsion (BBG/SCMC-NE) were investigated using particle size, PDI, turbidity, rheological properties, and zeta potential as evaluation indexes. The micro, structural, antioxidant, encapsulation, and release properties were characterized after deriving its optimal preparation process. The results showed that the nanoemulsion was optimally prepared with a total solids content of 2%, a substrate ratio of 9:1, a polyphenol content of 0.2%, and a magnetic stirring time of 60 min. SEM showed that the nanoemulsion showed a dense and uniform reticulated structure. FTIR and XRD results showed that covalent cross-linking of proteins and polysaccharides altered the structure of gelatin molecular chains to a more compact form but did not change its semi-crystalline structure. DSC showed that the 9:1 BBG/SCMC-NE had a higher thermal denaturation temperature and greater thermal stability, and its DPPH scavenging rate could reach 79.25% and encapsulation rate up to 90.88%, with excellent slow-release performance. The results of the study provide basic guidance for the preparation of stable active food packaging with excellent properties.

Gelatin nanocarriers assembled by a self-immolative cross-linker for targeted cancer therapy

With a number of outstanding properties, gelatin is an ideal candidate for assembling nanoplatforms in biomedical applications. Generally, gelatin nanocarriers are cross-linked by aldehydes to improve their stability in water solution. However, aldehydes could cause multiple toxicities and their cross-linking products are uncontrollable. Here, we first used a self-immolative cross-linker to assemble gelatin nanocarriers for the controlled release of drugs and targeted cancer therapy. The cross-linker contains a disulphide bridge and two symmetrical succinimidyl-esters, endowing it with multiple functions: 1) to cross-link the gelatin nanocarriers and thus improve their stability in water; 2) to conjugate the drug and tumor-targeting ligands with nanocarriers through covalent linkage; 3) to redox-responsively degrade the nanocarriers through hydrolysis of disulphide bridge; and 4) to produce traceless drug molecules through self-immolative reaction. Good biocompatibility and controllable drug release were demonstrated by in vitro experiments. Both qualitative and quantitative analyses confirmed the intracellular uptake of the nanocarriers by using doxorubicin (DOX) as a drug model and phenylboronic acid (PBA) as the targeting ligand. In vivo results demonstrated high therapeutic efficiency and low toxic side effects of the DOX loaded nanocarriers against artificial liver tumors.

Preparation and characterization of nisin-loaded chitosan nanoparticles functionalized with DNase I for the removal of Listeria monocytogenes biofilms

Listeria monocytogenes biofilms represent a continuous source of contamination, leading to serious food safety concerns and economic losses. This study aims to develop novel nisin-loaded chitosan nanoparticles (CSNPs) functionalized with DNase I and evaluate its antibiofilm activity against L. monocytogenes on food contact surfaces. Nisin-loaded CSNPs (CS-N) were first prepared by ionic cross-linking, and DNase I was covalently grafted on the surface (DNase-CS-N). The NPs were subsequently characterized by Zetasizer Nano, transmission electron microscopy, Fourier transform infrared (FT-IR), and X-ray diffraction (XRD). The antibiofilm activity of NPs was evaluated against L. monocytogenes on polyurethane (PU). The DNase-CS-N was fabricated and characterized with quality attributes (particle size-427.0 ± 15.1 nm, polydispersity [PDI]-0.114 ± 0.034, zeta potential-+52.5 ± 0.2 mV, encapsulation efficiency-46.5% ± 3.6%, DNase conjugate rate-70.4% ± 0.2). FT-IR and XRD verified the loading of nisin and binding of DNase I with chitosan. The DNase-CS-N caused a 3 log colony-forming unit (CFU)/cm2 reduction of L. monocytogenes biofilm cells, significantly higher than those in CSNPs (1.4 log), CS-N (1.8 log), and CS-N in combination with DNase I (2.2 log) treatment groups. In conclusion, nisin-loaded CSNPs functionalized with DNase I were successfully prepared and characterized with smooth surface and nearly spherical shape, high surface positive charge, and good stability, which is effective to eradicate L. monocytogenes biofilm cells on food contact surfaces, exhibiting great potential as antibiofilm agents in food industry. PRACTICAL APPLICATION: Listeria monocytogenes biofilms are a common safety hazard in food processing. In this study, novel nanoparticles were successfully constructed and are expected to be a promising antibiofilm agent in the food industry.