Antibiofilm activity of polyethylene glycol-quercetin nanoparticles-loaded gelatin-N,O-carboxymethyl chitosan composite nanogels against Staphylococcus epidermidis.

BACKGROUND: Biofilms, such as those from Staphylococcus epidermidis, are generally insensitive to traditional antimicrobial agents, making it difficult to inhibit their formation. Although quercetin has excellent antibiofilm effects, its clinical applications are limited by the lack of sustained and targeted release at the site of S. epidermidis infection. OBJECTIVES: Polyethylene glycol-quercetin nanoparticles (PQ-NPs)-loaded gelatin-N,O-carboxymethyl chitosan (N,O-CMCS) composite nanogels were prepared and assessed for the on-demand release potential for reducing S. epidermidis biofilm formation. METHODS: The formation mechanism, physicochemical characterization, and antibiofilm activity of PQ-nanogels against S. epidermidis were studied. RESULTS: Physicochemical characterization confirmed that PQ-nanogels had been prepared by the electrostatic interactions between gelatin and N,O-CMCS with sodium tripolyphosphate. The PQ-nanogels exhibited obvious pH and gelatinase-responsive to achieve on-demand release in the micro-environment (pH 5.5 and gelatinase) of S. epidermidis. In addition, PQ-nanogels had excellent antibiofilm activity, and the potential antibiofilm mechanism may enhance its antibiofilm activity by reducing its relative biofilm formation, surface hydrophobicity, exopolysaccharides production, and eDNA production. CONCLUSIONS: This study will guide the development of the dual responsiveness (pH and gelatinase) of nanogels to achieve on-demand release for reducing S. epidermidis biofilm formation.

3D printed cinnamon essential oil/banana peel carbon dots loaded corn starch/gelatin bilayer film with enhanced functionality for food packaging application.

Using 3D printing technology, a gelatin-polyvinyl alcohol­carbon dots (GPC) layer+corn starch-polyvinyl alcohol-cinnamon essential oil (CPC) layer active bilayer film with an external barrier function and an internal controlled-release effect was successfully produced for food preservation. The GPC film was provided with potent antioxidant and UV blocking properties by the banana peel carbon dots (CDs). The cinnamon essential oil (CEO) had the strongest interaction with the film matrix at 3% (w/w), causing the CPC film having the lowest surface wettability, good integrity, and lowest crystallinity. The CEO's stability and releasing effectiveness were greatly enhanced by the creation of a bilayer film. At 60% filling rate of the CPC layer, the bilayer film showed the highest CEO retention after drying and the best CEO release performance. Finally, the created active bilayer film was found to significantly improve the sensory quality stability of the spicy essential oil microcapsule powders. It also successfully extended the mangoes' shelf life by delaying browning and rot.

Production of Antioxidant, Angiotensin-Converting Enzyme Inhibitory and Osteogenic Gelatin Hydrolysate from Labeo rohita Swim Bladder.

Optimization of antioxidants and angiotensin-converting enzyme (ACE) inhibitory potential gelatin hydrolysate production from Labeo rohita (rohu) swim bladder (SBGH) by alcalase using central composite design (CCD) of response surface methodology (RSM) was investigated. The maximum degree of hydrolysis (DH), 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS), total antioxidants (TAO), and ACE inhibitory activity were achieved at 0.1:1.0 (w/w) enzyme to substrate ratio, 61 °C hydrolysis temperature, and 94-min hydrolysis time. The resulting SBGH obtained at 19.92% DH exhibited the DPPH (24.28 µM TE/mg protein), ABTS (34.47 µM TE/mg protein), TAO (12.01 µg AAE/mg protein), and ACE inhibitory (4.91 µg/mg protein) activity. Furthermore, SBGH at 100 µg/ml displayed osteogenic property without any toxic effects on MC3T3-E1 cells. Besides, the protein content of rohu swim bladder gelatin (SBG) and SBGH was 93.68% and 94.98%, respectively. Both SBG and SBGH were rich in glycine, proline, glutamic acid, alanine, arginine, and hydroxyproline amino acids. Therefore, SBGH could be an effective nutraceutical in functional food development.

Creation of Porous, Perfusable Microtubular Networks for Improved Cell Viability in Volumetric Hydrogels.

The creation of large, volumetric tissue-engineered constructs has long been hindered due to the lack of effective vascularization strategies. Recently, 3D printing has emerged as a viable approach to creating vascular structures; however, its application is limited. Here, we present a simple and controllable technique to produce porous, free-standing, perfusable tubular networks from sacrificial templates of polyelectrolyte complex and coatings of salt-containing citrate-based elastomer poly(1,8-octanediol-co-citrate) (POC). As demonstrated, fully perfusable and interconnected POC tubular networks with channel diameters ranging from 100 to 400 µm were created. Incorporating NaCl particulates into the POC coating enabled the formation of micropores (∼19 µm in diameter) in the tubular wall upon particulate leaching to increase the cross-wall fluid transport. Casting and cross-linking gelatin methacrylate (GelMA) suspended with human osteoblasts over the free-standing porous POC tubular networks led to the fabrication of 3D cell-encapsulated constructs. Compared to the constructs without POC tubular networks, those with either solid or porous wall tubular networks exhibited a significant increase in cell viability and proliferation along with healthy cell morphology, particularly those with porous networks. Taken together, the sacrificial template-assisted approach is effective to fabricate tubular networks with controllable channel diameter and patency, which can be easily incorporated into cell-encapsulated hydrogels or used as tissue-engineering scaffolds to improve cell viability.

Embosphere microspheres size for bronchial artery embolization in patients with hemoptysis caused by bronchiectasis: a retrospective comparative analysis of 500-750 versus 700-900 µm microspheres.

BACKGROUND: Bronchial arterial embolization (BAE) has been accepted as an effective treatment for bronchiectasis-related hemoptysis. However, rare clinical trials compare different sizes of specific embolic agents. This study aims to evaluate whether different Embosphere microsphere sizes change the outcome of BAE. METHODS: A retrospective review was conducted on consecutive patients with bronchiectatic hemoptysis who were scheduled to undergo BAE treatment during a period from January 2018 to December 2022. The patients received BAE using microspheres of different sizes: group A patients were treated with 500-750 µm microspheres, and group B patients were treated with 700-900 µm microspheres. The cost of embolic microspheres (Chinese Yuan, CNY), duration of hospitalization, complications, and hemoptysis-free survival were compared between patients in group A and those in group B. A Cox proportional hazards regression model was used to identify predictors of recurrent hemoptysis. RESULTS: Median follow-up was 30.2 months (range, 20.3-56.5 months). The final analysis included a total of 112 patients (49-77 years of age; 45 men). The patients were divided into two groups: group A (N = 68), which received 500-750 µm Embosphere microspheres, and group B (N = 44), which received 700-900 µm Embosphere microspheres. Except for the cost of embolic microspheres(group A,5314.8 + 1301.5 CNY; group B, 3644.5 + 1192.3 CNY; p = 0.042), there were no statistically significant differences in duration of hospitalization (group A,7.2 + 1.4 days; group B, 8 + 2.4days; p = 0.550), hemoptysis-free survival (group A, 1-year, 2-year, 3-year, 85.9%, 75.8%, 62.9%; group B, 1-year, 2-year, 3-year, 88.4%, 81.2%,59.4%;P = 0.060), and complications(group A,26.5%; group B, 38.6%; p = 0.175) between the two groups. No major complications were observed. The multivariate analysis results revealed that the presence of cystic bronchiectasis (OR 1.61, 95% CI 1.12-2.83; P = 0.001) and systemic arterial-pulmonary shunts (SPSs) (OR 1.52, 95% CI 1.10-2.72; P = 0.028) were independent risk factors for recurrent bleeding. CONCLUSIONS: For the treatment of BAE in patients with bronchiectasis-related hemoptysis, 500-750 µm diameter Embosphere microspheres have a similar efficacy and safety profile compared to 700-900 µm diameter Embosphere microspheres, especially for those without SPSs or cystic bronchiectasis. Furthermore, the utilization of large-sized (700-900 µm) Embosphere microspheres is associated with the reduced cost of an embolic agent.

Exosome-coated oxygen nanobubble-laden hydrogel augments intracellular delivery of exosomes for enhanced wound healing.

Wound healing is an obvious clinical concern that can be hindered by inadequate angiogenesis, inflammation, and chronic hypoxia. While exosomes derived from adipose tissue-derived stem cells have shown promise in accelerating healing by carrying therapeutic growth factors and microRNAs, intracellular cargo delivery is compromised in hypoxic tissues due to activated hypoxia-induced endocytic recycling. To address this challenge, we have developed a strategy to coat oxygen nanobubbles with exosomes and incorporate them into a polyvinyl alcohol/gelatin hybrid hydrogel. This approach not only alleviates wound hypoxia but also offers an efficient means of delivering exosome-coated nanoparticles in hypoxic conditions. The self-healing properties of the hydrogel, along with its component, gelatin, aids in hemostasis, while its crosslinking bonds facilitate hydrogen peroxide decomposition, to ameliorate wound inflammation. Here, we show the potential of this multifunctional hydrogel for enhanced healing, promoting angiogenesis, facilitating exosome delivery, mitigating hypoxia, and inhibiting inflammation in a male rat full-thickness wound model.

Biomaterial-based combinatorial approach of aescin-comprised zein-coated gelatin nanoparticles alleviates synovial inflammation in experimental inflammatory arthritis.

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that mostly affects joints. Although RA therapy has made significant progress, difficulties including extensive medication metabolism and its quick clearance result in its inadequate bioavailability. The anti-inflammatory effect of zein was reported with other medications, but it has certain limitations. There are reports on the anti-oxidant and anti-inflammatory effect of aescin, which exhibits low bioavailability for the treatment of rheumatoid arthritis. Also, the combinatorial effect of zein with other effective drug delivery systems is still under investigation for the treatment of experimental collagen-induced rheumatoid arthritis. The focus of this study was to formulate and define the characteristics of zein-coated gelatin nanoparticles encapsulated with aescin (Ze@Aes-GNPs) and to assess and contrast the therapeutic effectiveness of Ze@Aes-GNPs towards collagen-induced RA in Wistar rats. Nanoprecipitation and the layer-by-layer coating process were used to fabricate Ze@Aes-GNPs and their hydrodynamic diameter was determined to be 182 nm. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to further validate the size, shape, and surface morphology of Ze@Aes-GNPs. When tested against foreskin fibroblasts (BJ), these nanoparticles demonstrated significantly high cytocompatibility. Both Aes and Ze@Aes-GNPs were effective in treating arthritis, as shown by the decreased edoema, erythema, and swelling of the joints, between which Ze@Aes-GNPs were more effective. Further, it was demonstrated that Aes and Ze@Aes-GNPs reduced the levels of oxidative stress (articular elastase, lipid peroxidation, catalase, superoxide dismutase and nitric oxide) and inflammatory indicators (TNF-α, IL-1ß and myeloperoxidase). The histopathology findings further demonstrated that Ze@Aes-GNPs considerably reduced the infiltration of inflammatory cells at the ankle joint cartilage compared to Aes. Additionally, immunohistochemistry examination showed that treatment with Ze@Aes-GNPs suppressed the expression of pro-inflammatory markers (COX-2 and IL-6) while increasing the expression of SOD1. In summary, the experiments indicated that Aes and Ze@Aes-GNPs lowered the severity of arthritis, and critically, Ze@Aes-GNPs showed better effectiveness in comparison to Aes. This suppression of oxidative stress and inflammation was likely driven by Aes and Ze@Aes-GNPs.

Enzymatically produced acylglycerol and glycerin monostearate additives improved the characteristics of gelatin-stabilized omega-3 emulsions and microcapsules.

The impacts of enzymatically produced acylglycerol and glycerin monostearate on the characteristics of gelatin-stabilized omega-3 emulsions and microcapsules were investigated. Tuna oil was enzymatically produced and the resulting acylglycerol was mixed with tuna oil at 12.5% (w/w) to prepare a novel oil phase. This oil phase was stabilized by gelatin to prepare oil-in-water emulsions and subsequent microcapsules via complex coacervation. The tuna oil with glycerin monostearate (GMS) at 1 and 2% (w/w) were used as controls. Results showed that both acylglycerol and GMS significantly reduced the emulsion droplet size and zeta potential, while increasing the viscoelasticity and stability. The diacylglycerol/monoacylglycerol were involved in the oil/water interfacial layer formation by lowering interfacial tension and increasing droplet surface hydrophobicity. Overall, the changed emulsion properties promoted the complex coacervation and contributed to the formation of microcapsules with improved oxidative stability. Therefore, enzymatically produced acylglycerol can develop high-quality stable omega-3 microencapsulated novel food ingredients.

Modulating peppermint oil flavor release properties of emulsion-filled protein gels: Impact of cross-linking method and matrix composition.

For some food applications, it is desirable to control the flavor release profiles of volatile flavor compounds. In this study, the effects of crosslinking method and protein composition on the flavor release properties of emulsion-filled protein hydrogels were explored, using peppermint essential oil as a model volatile compound. Emulsion-filled protein gels with different properties were prepared using different crosslinking methods and gelatin concentrations. Flavor release from the emulsion gels was then monitored using an electronic nose, gas chromatography-mass spectrometry (GC-MS), and sensory evaluation. Enzyme-crosslinked gels had greater hardness and storage modulus than heat-crosslinked ones. The hardness and storage modulus of the gels increased with increasing gelatin concentration. For similar gel compositions, flavor release and sensory perception were faster from the heat-crosslinked gels than the enzyme-crosslinked ones. For the same crosslinking method, flavor release and perception decreased with increasing gelatin concentration, which was attributed to retardation of flavor diffusion through the hydrogel matrix. Overall, this study shows that the release of hydrophobic aromatic substances can be modulated by controlling the composition and crosslinking of protein hydrogels, which may be useful for certain food applications.

ICA/SDF-1α/PBMSCs loaded onto alginate and gelatin cross-linked scaffolds promote damaged cartilage repair.

A three-dimensional alginate-coated scaffold (GAIS) was constructed in the present study to showcase the multidifferentiation potential of peripheral blood mesenchymal stem cells (PBMSCs) and to investigate the role and mechanism by which Icariin (ICA)/stromal cell-derived factor (SDF-1α)/PBMSCs promote damaged articular repair. In addition, the ability of ICA, in combination with SDF-1α, to promote the migration and proliferation of stem cells was validated through the utilization of CCK-8 and migration experiments. The combination of ICA and SDF-1α inhibited the differentiation of PBMSCs into cartilage, as demonstrated by in vivo experiments and histological staining. Both PCR and western blot experiments showed that GAIS could upregulate the expression of particular genes in chondrocytes. In comparison to scaffolds devoid of alginate (G0), PBMSCs seeded into GAIS scaffolds exhibited a greater rate of proliferation, and the conditioned medium derived from scaffolds containing SDF-1α enhanced the capacity for cell migration. Moreover, after a 12-week treatment period, GAIS, when successfully transplanted into osteochondral defects of mice, was found to promote cartilage regeneration and repair. The findings, therefore, demonstrate that GAIS enhanced the in vitro capabilities of PBMSCs, including proliferation, migration, homing and chondrogenic differentiation. In addition, ICA and SDF-1α effectively collaborated to support cartilage formation in vivo. Thus, the ICA/SDF-1α/PBMSC-loaded biodegradable alginate-gelatin scaffolds showcase considerable potential for use in cartilage repair.

The orchestration of sustained drug delivery by bacterial cellulose/gelatin nanocomposites reinforced with carboxylic carbon nanotubes.

Recently, modifying bacterial cellulose (BC) by compositing it with other nano-biomaterials has become inevitable to achieve its desired properties in drug delivery. To address this, our study endeavors to utilize an in-situ fabrication method for the creation of a multifunctional BC/gelatin (BC/Gel) platform reinforced with carboxylic multi-walled carbon nanotubes (cMWCNTs) as a sustainable delivery model of biomolecules. Incipiently, cMWCNTs were loaded with human serum albumin (HSA) as a drug model, with an optimized nanoparticle-to-protein ratio of 1:5 and loading efficiency of 90.0 ± 1.0 % before incorporation into BC/Gel hydrogels. By comparison, nanocomposition improved the surface area and overall porosity of BC/Gel up to 58.0 ± 1.3 m2/g and 85.5 ± 1.1 %, respectively. Likewise, significant wettability of 44.0 ± 0.1° and dramatic biodegradation rate of 36.9 ± 1.2 % were other exceptionally gained attributes. Meanwhile, with a Zero-order kinetic mechanism, CNT-HSA integration facilitated the controlled release of 56.0 ± 0.9 % HSA over 7 days. Drug-loaded nanocomposites showcased >70 % viability during in vitro cellular trials using Human Foreskin Fibroblasts (HFF). Overall, BC/Gel/CNT-HSA nanocomposite exhibited favorable cell behavior, devoid of cytotoxic manifestations. Consequently, this BC-based nanocomposite scaffold implicates the premiere capability in the sustained delivery of an extended range of protein biomolecules, offering a promising therapeutic avenue for bolstering tissue regeneration.

Nonsurgical Treatment of Periodontitis in Menopausal Patients: A Randomized Control Trial.

Background: Menopause is typically accompanied by significant systemic and oral manifestations, including hormonal changes and increased susceptibility to periodontal disease, which may involve inflammatory biomarkers like aspartate aminotransferase (AST) and osteocalcin in gingival crevicular fluid (GCF). The study is aimed at evaluating the effectiveness of regular inoculation of polyunsaturated fatty acids (PUFAs) as an adjunctive treatment for menopausal women's periodontitis. Methods: Twenty elderly women with chronic periodontitis were split evenly into two groups by random assignment. Patients in group II (the research group) were given soft gelatin capsules containing PUFAs to be consumed directly once daily for 12 months, as opposed to group I (the control group), who received soft gelatin capsules containing some olive oil (placebo). Scaling and root planning (SRP) were used to address periodontal disease in all cases. Results: At baseline, six and twelve months after treatment, clinical indicators and AST and osteocalcin amounts in the GCF were noted. By the conclusion of the research period, all observed clinical measurements had changed significantly and improved. In addition, there had been a significant decrease in AST levels and a nonsignificant decrease in osteocalcin levels in group II compared to group I. Conclusions: Menopausal women with periodontitis who take omega-3 fatty acid supplements in addition to SRP have better oral health. Significant improvements in clinical indicators and a notable decrease in AST levels within the GCF were observed. However, further research with larger cohorts and extended duration is needed to validate these findings and explain potential mechanisms. This trial is registered with NCT06254118.

Microencapsulation of Lactobacillus plantarum with Improved Survivability Using Pufferfish Skin Gelatin-Based Wall Materials.

To improve the survivability of probiotics, Lactobacillus plantarum was microencapsulated using pufferfish skin gelatin (PSG)-based wall materials by spray-drying. This work investigated the protective effect of three different pH-dependent proteins (sodium caseinate (SC), soy protein isolate (SPI), and whey protein isolate (WPI)) combined with PSG on L. plantarum. The experimental results of spray-drying with an inlet temperature of 120 °C and an outlet temperature of 80 °C, storage at 4 °C for 6 months, simulated digestion, and turbidity indicated that PSG/SC had better stability and encapsulation effects and was more suitable to encapsulate L. plantarum than PSG/SPI and PSG/WPI. The optimum preparation conditions for L. plantarum microcapsules were a PSG/SC mass ratio of 2:1, an SC concentration of 20 g/L, and a cell concentration of 10 g/L. The encapsulation efficiency of the obtained microcapsules was 95.0%, and the survival rate was 94.2% in simulated gastric fluid for 2 h and 98.0% in simulated intestinal fluid for 2 h. Amino acid composition analysis exhibited that the imino acid and aspartic acid contents of PSG were 27.98 and 26.16 g/100 g protein, respectively, which was much higher than commercial bovine gelatin. This characteristic was favorable to the high encapsulation efficiency and stability of microcapsules. In vitro release experiments showed that the PSG/SC microcapsules did not disintegrate in simulated gastric fluid for 2 h but could completely release in simulated intestinal fluid for 2 h, which can maintain the high survivability of L. plantarum in simulated digestion. In general, this study demonstrated that microcapsules using PSG/SC as wall materials can effectively improve the survivability of probiotics and have great potential for application in probiotic products.

Printing GelMA bioinks: a strategy for buildingin vitromodel to study nanoparticle-based minocycline release and cellular protection under oxidative stress.

Owing to its thermoresponsive and photocrosslinking characteristics, gelatin methacryloyl (GelMA)-based biomaterials have gained widespread usage as a novel and promising bioink for three-dimensional bioprinting and diverse biomedical applications. However, the flow behaviors of GelMA during the sol-gel transition, which are dependent on time and temperature, present significant challenges in printing thick scaffolds while maintaining high printability and cell viability. Moreover, the tunable properties and photocrosslinking capabilities of GelMA underscore its potential for localized drug delivery applications. Previous research has demonstrated the successful incorporation of minocycline (MH) into GelMA scaffolds for therapeutic applications. However, achieving a prolonged and sustained release of concentrated MH remains a challenge, primarily due to its small molecular size. The primary aim of this study is to investigate an optimal extrusion printing method for GelMA bioink in extrusion bioprinting, emphasizing its flow behaviors that are influenced by time and temperature. Additionally, this research seeks to explore the potential of GelMA bioink as a carrier for the sustained release of MH, specifically targeting cellular protection against oxidative stress. The material properties of GelMA were assessed and further optimization of the printing process was conducted considering both printability and cell survival. To achieve sustained drug release within GelMA, the study employed a mechanism using metal ion mediation to facilitate the interaction between MH, dextran sulfate (DS), and magnesium, leading to the formation of nanoparticle complexes (MH-DS). Furthermore, a GelMA-basedin vitromodel was developed in order to investigate the cellular protective properties of MH against oxidative stress. The experimental results revealed that the printability and cell viability of GelMA are significantly influenced by the printing duration, nozzle temperature, and GelMA concentrations. Optimal printing conditions were identified based on a thorough assessment of both printability and cell viability. Scaffolds printed under these optimal conditions exhibited exceptional printability and sustained high cell viability. Notably, it was found that lower GelMA concentrations reduced the initial burst release of MH from the MH-dextran sulfate (MH-DS) complexes, thus favoring more controlled, sustained release profiles. Additionally, MH released under these conditions significantly enhanced fibroblast viability in anin vitromodel simulating oxidative stress.

Enhanced antibacterial activity of porous chitosan-based hydrogels crosslinked with gelatin and metal ions.

Addressing the increasing drug resistance in pathogenic microbes, a significant threat to public health, calls for the development of innovative antibacterial agents with versatile capabilities. To enhance the antimicrobial activity of non-toxic biomaterials in this regard, this study focuses on novel, cost-effective chitosan (CS)-based hydrogels, crosslinked using gelatin (GEL), formaldehyde, and metallic salts (Ag+, Cu2+, and Zn2+). These hydrogels are formed by mixing CS and GEL with formaldehyde, creating iminium ion crosslinks with metallic salts without hazardous crosslinkers. Characterization techniques like FTIR, XRD, FESEM, EDX, and rheological tests were employed. FTIR analysis showed metal ions binding to amino and hydroxyl groups on CS, enhancing hydrogelation. FESEM revealed that freeze-dried hydrogels possess a crosslinked, porous structure influenced by various metal ions. Antibacterial testing against gram-negative and gram-positive bacteria demonstrated significant bacterial growth inhibition. CS-based hydrogels containing metal ions showed reduced MIC and MBC values against Staphylococcus aureus (0.5, 8, 16 µg/mL) and Escherichia coli (1, 16, 8 µg/mL) for CS-g-GEL-Ag+, CS-g-GEL-Cu2+, and CS-g-GEL-Zn2+. MTT assay results confirmed high biocompatibility (84.27%, 85.24%, 84.96% viability at 10 µg/mL) for CS-based hydrogels towards HFF-1 cells over 48 h. Therefore, due to their non-toxic nature, these CS hydrogels are promising for antibacterial applications.

A tough and bioadhesive injectable hydrogel formed with maleimidyl alginate and pristine gelatin.

Injectable hydrogels have wide applications in clinical practice. However, the development of tough and bioadhesive ones based on biopolymers, along with biofriendly and robust crosslinking strategies, still represents a great challenge. Herein, we report an injectable hydrogel composed of maleimidyl alginate and pristine gelatin, for which the precursor solutions could self-crosslink via mild Michael-type addition without any catalyst or external energy upon mixing. This hydrogel is tough and bioadhesive, which can maintain intactness as well as adherence to the defect of porcine skin under fierce bending and twisting, warm water bath, and boiling water shower. Besides, it is biocompatible, bioactive and biodegradable, which could support the growth and remodeling of cells by affording an extracellular matrix-like environment. As a proof of application, we demonstrate that this hydrogel could significantly accelerate diabetic skin wound healing, thereby holding great potential in healthcare.

Self-Assembling Gelatin-Curdlan Fibril Hydrogels for Oriented Neural Cell Growth.

The ex vivo replication of the highly helical and fibril structures of load-bearing soft tissue is a challenging goal for the study of hydrogels. Inspired by nature, we prepared tissue-like physical gels based on curdlan and gelatin by self-assembly. The hybrid gels have a flexible fibril-matrix architecture, and the fibril orientation is highly tunable. The tensile strength of the gels can be tuned from ∼1.1 to ∼16.5 MPa. The coil-helix transition and nanofibril formation process in the self-assembly system was thoroughly investigated. These helical gels exhibit excellent cell compatibility, which supports adhesion and oriented growth of neural cells. Furthermore, the oriented nanofibrils in the gel are found to be associated with an upregulated expression of regeneration-related genes like N-cadherin (Cdh2) and neural growth factor (NGF). Owing to the strength and biomimetic structure, these gels have great potential in tissue engineering applications.

Improved hydration property of tissue adhesive/hemostatic microparticle based on hydrophobically-modified Alaska pollock gelatin.

The management of bleeding is an important aspect of endoscopic surgery to avoid excessive blood loss and minimize pain. In clinical settings, sprayable hemostatic particles are used for their easy delivery, adaptability to irregular shapes, and rapid hydration. However, conventional hemostatic particles present challenges associated with tissue adhesion. In a previous study, we reported tissue adhesive microparticles (C10-sa-MPs) derived from Alaska pollock gelatin modified with decyl groups (C10-sa-ApGltn) using secondary amines as linkages. The C10-sa-MPs adhere to soft tissues through a hydration mechanism. However, their application as a hemostatic agent was limited by their long hydration times, attributed to their high hydrophobicity. In this study, we present a new type microparticle, C10-am-MPs, synthesized by incorporating decanoyl group modifications into ApGltn (C10-am-ApGltn), using amide bonds as linkages. C10-am-MPs exhibited enhanced hydration characteristics compared to C10-sa-MPs, attributed to superior water absorption facilitated by amide bonds rather than secondary amines. Furthermore, C10-am-MPs demonstrated comparable tissue adhesion properties and underwater adhesion stability to C10-sa-MPs. Notably, C10-am-MPs exhibited accelerated blood coagulation in vitro compared to C10-sa-MPs. The application of C10-am-MPs in an in vivo rat liver hemorrhage model resulted in a hemostatic effect comparable to a commercially available hemostatic particle. These findings highlight the potential utility of C10-am-MPs as an effective hemostatic agent for endoscopic procedures and surgical interventions.

Gelatin but not type I collagen promotes bacteria phagocytosis in PMA-treated U937 human lymphoma cells.

PURPOSE: Besides comprising scaffolding, extracellular matrix components modulate many biological processes including inflammation and cell differentiation. We previously found precoating cell plates with extracellular matrix collagen I, or its denatured product gelatin, causes aggregation of macrophage-like human lymphoma U937 cells, which are induced to differentiation by phorbol myristate treatment. In the present study, we investigated the influence of gelatin or collagen I precoating on the bacteria phagocytosis in PMA-stimulated U937 cells. MATERIALS AND METHODS: Colony forming units of phagocytosed bacteria, Giemsa-staining of cells with phagocytosed bacteria, confocal microscopic and flow cytometric analysis of cells with phagocytosed FITC-labeled bacteria and non-bioactive latex beats were conducted. RESULTS: Gelatin precoating enhances the phagocytosis of both Gram-negative and positive bacteria, as shown by the increased colony forming units of bacteria phagocytosed by cells, and increased intracellular bacteria observed after Giemsa-staining. But collagen I has no marked influence. Confocal microscopy reveals that both live and dead FITC-bacteria were phagocytosed more in the cells with gelatin-coating but not collagen-coating. Of note, both gelatin and collagen I coating had no influence on the phagocytosis of non-bioactive latex beads. Since gelatin-coating increases autophagy but collagen I has no such impact, we are curious about the role of autophagy. Inhibiting autophagy reduced the phagocytosis of bacteria, in cells with gelatin-coating, while stimulating autophagy enhanced phagocytosis. CONCLUSION: This study finds the bacteria-phagocytosis stimulatory effect of gelatin in PMA-treated U937 cells and reveals the positive regulatory role of autophagy, predicting the potential use of gelatin products in anti-bacterial therapy.