Oral administration of PEDV-dissolved Alg-CS gel induces high and sustained mucosal immunity in mice.

Porcine epidemic diarrhea (PED) is a serious disease in piglets that leads to high mortality. An effective measure that provides higher IgA levels in the intestine and milk is required to decrease losses. Porcine epidemic diarrhea virus (PEDV) was dissolved in calcium alginate (Alg) and combined with chitosan (CS) via electrostatic interactions between cationic chitosan and anionic alginate to create a porous gel (Alg-CS+PEDV). The gel was used to immunize mice orally or in combination with subcutaneous injections of inactivated PEDV vaccine. At 12 and 24 days after immunization, levels of IgA and IgG in Alg-CS+PEDV were higher than with normal PEDV oral administration. At 24 days after immunization, the concentration of IFN-γ in Alg-CS+PEDV was higher than with normal PEDV oral administration. Furthermore, oral administration combining subcutaneous immunization induced higher levels of IgG and IgA than oral administration alone. Our study provides a new method for the preparation and administration of oral vaccines to achieve enhanced mucosal immunity against PEDV.

The efficacy of a paeoniflorin-sodium alginate-gelatin skin scaffold for the treatment of diabetic wound: An in vivo study in a rat model.

OBJECTIVE: To investigate the efficacy of a paeoniflorin-sodium alginate (SA)-gelatin skin scaffold for treating diabetic wound in a rat model. METHODS: Bioinks were prepared using various percentages of paeoniflorin in the total weight of a solution containing SA and gelatin. Skin scaffolds containing 0%, 1%, 3%, 5%, and 10% paeoniflorin were printed using 3D bioprinting technology, and scaffold microstructure was observed with scanning electron microscopy. Skin scaffolds were then used in rats with diabetic wounds. H&E staining, Masson staining, and immunohistochemical staining for IL-1ß and CD31 were performed on days 7 and 14. RESULTS: All skin scaffolds had a mesh-like structure with uniform pore distribution. Wounds healed well in each group, with the 1% and 3% groups demonstrating the most complete healing. H&E staining showed that skin accessory organs had appeared in each group. On day 7, collagen deposition in the 3% group was higher than in the other groups (P＜0.05), and IL-1ß infiltration was lower in the 10% group than in the 3% group (P = 0.002). On day 14, IL-1ß infiltration was not significantly different between the 10% and 3% groups (P = 0.078). The CD31 level was higher in the 3% group than in the other groups on days 7 and 14 (P＜0.05). CONCLUSION: A 3% paeoniflorin-SA-gelatin skin scaffold promoted the healing of diabetic wounds in rats. This scaffold promoted collagen deposition and microvascular regeneration and demonstrated anti-inflammatory properties, suggesting that this scaffold type could be used to treat diabetic wounds.

In vitro evidence of oncofetal antigen and TLR-9 agonist co-delivery by alginate nanovaccines for liver cancer immunotherapy.

Liver cancer is the most common malignant tumor and liver cancer immunotherapy has been one of the research hotspots. To induce antigen-specific antitumor immune responses against liver cancer, we developed antigen and adjuvant co-delivery nanovaccines (APPCs). Polyanionic alginate (ALG) and polycationic polyethyleneimine (PEI) were utilized to co-deliver a glypican-3 peptide antigen and an unmethylated cytosine-phosphate-guanine (CpG) adjuvant by electrostatic interactions. A cellular uptake study confirmed that APPC could promote antigen and adjuvant uptake by dendritic cells (DCs). Importantly, APPC facilitated the endosomal escape of the peptide for antigen delivery into the cytoplasm. In addition, APPC showed significant stimulation of DC maturation in vitro. APPC could also efficiently prime DCs and induce cytotoxic T lymphocyte responses in vivo. The in vitro cell viability assay and the in vivo histocompatibility showed that APPC was non-toxic within the tested concentration. This study demonstrates that the peptide antigen and the CpG adjuvant co-delivery nanovaccine have potential applications in liver cancer immunotherapy.

Triple-Configurational Magnetic Robot for Targeted Drug Delivery and Sustained Release.

Active targeted therapy for bowel cancer using untethered microrobots has attracted extensive attention. However, traditional microrobots face challenges, such as issues of mobility, biocompatibility, drug loading, sustained-release capabilities, and targeting accuracy. Here, we propose an untethered triple-configurational magnetic robot (TCMR) that is composed of three geometrically nested parts: actuation and guarding, anchoring and seeding, and drug release part. A targeting magnetic driving system actuates the TCMR along the predetermined trajectory to the target position. The pH-sensitive actuation and guarding part formed by electrodeposition is degraded in the intestinal environment and separates from the two other parts. A majority of magnetic nanoparticles encapsulated in this part are retrieved. The anchoring and seeding part anchors the lesion area and seeds the drug release part in the gaps of intestinal villi by hydrolysis. Ultimately, the drug release part containing the therapeutic completes the sustained release to prolong the duration of the therapeutic agent. Cytotoxicity and therapeutic tests reveal that TCMRs are biocompatible and suitable for targeted therapy and have good therapeutic performance. The newly designed TCMR will provide new ideas for targeted therapy, thus expanding the application scope of robotics technology in the biomedical field.

pH-sensitive chitosan-deoxycholic acid/alginate nanoparticles for oral insulin delivery.

Oral absorption of peptides/proteins is usually compromised by various gastrointestinal tract barriers. To improve delivery efficiency, chitosan-conjugated deoxycholic acid (CS-DCA) coupled with sodium alginate (ALG) was prepared to load insulin into pH-sensitive nanoparticles. The insulin-loaded chitosan-deoxycholic acid/alginate nanoparticles (CDA NPs) were characterized by size (143.3 ± 10.8 nm), zeta potential (19.5 ± 1.6 mV), entrapment efficiency (61.14 ± 1.67%), and insulin drug loading (3.36 ± 0.09%). The CDA NPs exhibited pH-triggered release characteristics in vitro and protected the wrapped insulin from gastric degradation. Stability of the CDA NPs in enzyme-containing simulated gastrointestinal fluids suggested that the NPs could partially protect the wrapped insulin from enzymatic degradation. Additionally, CS-DCA-modified NPs promoted the permeability of Caco-2 cells and enhanced intracellular absorption of FITC-labeled insulin by 9.4 and 1.2-folds, when compared to insulin solution and unmodified NPs, respectively. The positively charged NPs increased intestinal villi adhesion and enhanced insulin absorption in the intestines of diabetic rat models. Furthermore, the hypoglycemic test showed that CDA NPs prolonged insulin release in vivo and exerted a remarkable hypoglycemic effect on diabetic rats with an oral bioavailability of 15%. In conclusion, CDA NPs is a potential oral insulin delivery system.

Gellan gum/alginate-based Ca-enriched acellular bilayer hydrogel with robust interface bonding for effective osteochondral repair.

The treatment of osteochondral (OC) defects remains challenging because of the lack of economical and feasible therapeutic strategies for OC repair and reconstruction. In this study, we report an integrated bilayer hydrogel with robust interface binding force (40 kPa) by facilitating the diffusion of calcium ions to the secondary crosslink of the bilayer hydrogel, in which gellan gum and sodium alginate acted as the chondral layer, gellan gum and hydroxyapatite acted as subchondral layer. This integrated construct has high cytocompatibility, and can seed with mesenchymal stem cells (MSCs) related to different functional protein expression for cartilage and bone formation, respectively. Furthermore, in the rabbit critical-sized osteochondral defect model (4.0 mm in diameter and 8.0 mm in depth), the calcium enriched hydrogel act as a calcium reservoir, promote neovascularization at week 4, and repair the critical defect at week 8, demonstrating the feasible preparation of an acellular hydrogel for OC repair.

Alginate-coated activated charcoal enhances fecal excretion of 2,3,7,8-tetrachlorodibenzo-p-dioxin in mice, with fewer side effects than uncoated one.

Activated charcoal (AC) is a potential candidate antidote against dioxins. However, it is difficult to take AC as a supplement on a daily basis, because its long-term ingestion causes side effects such as constipation and deficiency of fat-soluble essential nutrients and hypocholesterolemia. Alginate-coated AC, termed Health Carbon (HC), was developed to decrease the side effects of AC, but its pharmacological effects, including side effects, remains unclear. Here, we show that HC enhanced fecal excretion of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and decreased some side effects of unmodified AC, such as hypocholesterolemia, in male mice. Basal diet mixed with HC or unmodified AC at various concentrations was fed to mice for 16 days following a single intraperitoneal administration of [3H]TCDD. Both HC and unmodified AC at 3% or more significantly increased fecal excretion of [3H]TCDD in comparison with the control basal diet. Consistent with this, [3H]TCDD radioactivity in the liver-a major TCDD storage organ-was markedly decreased by HC at concentrations of 3% and 10%. In an examination of potential side effects, unmodified AC at 10% or more caused significant body weight reduction and at 20% caused significant hypocholesterolemia. In contrast, HC caused weight gain reduction only at a concentration of 20%, and there was no evidence of hypocholesterolemia at any dietary HC concentration. HC not only retains the ability of AC to enhance fecal excretion of TCDD but also reduces some of the side effects of AC.

PDGF-BB/SA/Dex injectable hydrogels accelerate BMSC-mediated functional full thickness skin wound repair by promoting angiogenesis.

Wound healing is a well-orchestrated dynamic and interactive process, which needs a favorable microenvironment and suitable angiogenesis. Platelet derived growth factor-BB (PDGF-BB) plays a crucial role in wound healing. However, the short half-life of PDGF-BB limits its efficacy. In the present study, we successfully synthesized an injectable hydrogel with sodium alginate (SA) and dextran (Dex) as a delivery system to simultaneously deliver PDGF-BB and bone marrow-derived mesenchymal stem cells (BMSCs) in the wound. Our work demonstrates that the PDGF-BB protein enhanced the survival, migration and endothelial cell (EC) differentiation of BMSCs in vitro. The PDGF-BB/SA/Dex hydrogels could sustainably release PDGF-BB with excellent biocompatibility in vitro and in vivo. Besides, these composite hydrogels loaded with BMSCs could accelerate wound healing by improving epithelialization and collagen deposition. In addition, the PDGF-BB/SA/Dex hydrogels promoted the EC-differentiation of transplanted BMSCs and proliferation of hair follicle stem cells in the wound. Furthermore, the expressions of angiogenesis-specific markers, PDGFR-ß, p-PI3K, p-Akt, and p-eNOS, were obviously increased in the PDGF-BB/SA/Dex/BMSCs group. In conclusion, the PDGF-BB/SA/Dex injectable hydrogels could accelerate BMSC-mediated skin wound healing by promoting angiogenesis via the activation of the PDGF-BB/PDGFR-ß-mediated PI3K/Akt/eNOS pathway, which may provide a new therapeutic strategy for stem cell therapy in wound healing.

Encapsulation of Synthesized Plant Growth Regulator Based on Copper(II) Complex in Chitosan/Alginate Microcapsules.

A new copper complex, trans-diaqua-trans-bis [1-hydroxy-1,2-di (methoxycarbonyl) ethenato] copper (abbreviation Cu(II) complex), was synthesized and its plant growth regulation properties were investigated. The results show a sharp dependence of growth regulation activity of the Cu(II) complex on the type of culture and its concentration. New plant growth regulator accelerated the development of the corn root system (the increase in both length and weight) but showed a smaller effect on the development of the wheat and barley root systems. Stimulation of corn growth decreased with increasing Cu(II) complex concentration from 0.0001% to 0.01% (inhibition at high concentrations-0.01%). The development of corn stems was also accelerated but to a lesser extent. Chitosan-coated calcium alginate microcapsules suitable for delivery of Cu(II) complex to plants were prepared and characterized. Analysis of the FTIR spectrum showed that complex molecular interactions between functional groups of microcapsule constituents include mainly electrostatic interactions and hydrogen bonds. Microcapsules surface exhibits a soft granular surface structure with substructures consisting of abundant smaller particles with reduced surface roughness. Release profile analysis showed Fickian diffusion is the rate-controlling mechanism of Cu(II) complex releasing. The obtained results give new insights into the complexity of the interaction between the Cu(II) complex and microcapsule formulation constituents, which can be of great help in accelerating product development for the application in agriculture.

Foams with Enhanced Rheology for Stopping Bleeding.

Bleeding from injuries to the torso region is a leading cause of fatalities in the military and in young adults. Such bleeding cannot be stopped by applying direct pressure (compression) of a bandage. An alternative is to introduce a foam at the injury site, with the expansion of the foam counteracting the bleeding. Foams with an active hemostatic agent have been tested for this purpose, but the barrier created by these foams is generally not strong enough to resist blood flow. In this paper, we introduce a new class of foams with enhanced rheological properties that enable them to form a more effective barrier to blood loss. These aqueous foams are delivered out of a double-barrelled syringe by combining precursors that produce bubbles of gas (CO2) in situ. In addition, one barrel contains a cationic polymer (hydrophobically modified chitosan, hmC) and the other an anionic polymer (hydrophobically modified alginate, hmA). Both these polymers function as hemostatic agents due to their ability to connect blood cells into networks. The amphiphilic nature of these polymers also enables them to stabilize gas bubbles without the need for additional surfactants. hmC-hmA foams have a mousse-like texture and exhibit a high modulus and yield stress. Their properties are attributed to the binding of hmC and hmA chains (via electrostatic and hydrophobic interactions) to form a coacervate around the gas bubbles. Rheological studies are used to contrast the improved rheology of hmC-hmA foams (where a coacervate arises) with those formed by hmC alone (where there is no such coacervate). Studies with animal wound models also confirm that the hmC-hmA foams are more effective at curtailing bleeding than the hmC foams due to their greater mechanical integrity.

Ultra-purified alginate gel implantation decreases inflammatory cytokine levels, prevents intervertebral disc degeneration, and reduces acute pain after discectomy.

Lumbar intervertebral disc (IVD) herniation causes severe low back pain (LBP), which results in substantial financial and emotional strains. Despite the effectiveness of discectomy, there is no existing treatment for post-operative LBP induced by progressive IVD degeneration. Two key factors of LBP are intradiscal inflammation, indicated by tumour necrosis factor alpha (TNF-α) and interleukin-6 (IL-6), and sensory nerve ingrowth into the inner layer of the annulus fibrosus, triggered by nerve growth factor/high-affinity tyrosine kinase A (TrkA) signalling. In an animal models of discectomy, the bioresorbable ultra-purified alginate (UPAL) gel with an extremely low-toxicity has been effective in acellular tissue repair. We aimed to investigate whether UPAL gel can alleviate LBP using a rat nucleus pulposus (NP) punch model and a rabbit NP aspirate model. In both models, we assessed TNF-α and IL-6 production and TrkA expression within the IVD by immunohistochemistry. Further, histological analysis and behavioural nociception assay were conducted in the rat model. UPAL gel implantation suppressed TNF-α and IL-6 production, downregulated TrkA expression, inhibited IVD degeneration, and reduced nociceptive behaviour. Our results suggest the potential of UPAL gel implantation as an innovative treatment for IVD herniation by reducing LBP and preventing IVD degeneration after discectomy.

Development and statistical optimization of alginate-Neusilin US2 micro-composite beads to elicit gastric stability and sustained action of hesperidin.

The Alginate-Neusilin US2 micro-composite (MC) beads were fabricated and optimized for oral delivery of hesperidin (HES). A 32 full factorial design encompassing independent variables (factors) such as the concentration of sodium alginate (X1), and Neusilin US2 (X2) and dependant variables (response) such as particle size (Y1), entrapment efficiency (Y2), and swelling degree (Y3). Nine batches were prepared by formulation design employing statistical software JMP 13.2.1. The multiple regression analysis (MLRA) was carried to explore the influence of factor over responses. Further, a prediction profiler was used to trace the optimum concentration of factors based on desirable responses. The optimized beads (OF) were characterized for their morphology and size by motic microscopy and scanning electron microscopy. In vitro release, kinetic studies were performed in simulated gastric and intestinal fluids. In vivo pharmacokinetic studies revealed better absorption of HES from optimized beads (OF) compared to HES suspension which could be due to the prevention of acidic degradation of HES in the stomach. The estimated shelf life of OF formulation was found to be 3.86 years suggested better stability after fabrication. In a nutshell, the developed micro-composite beads of HES could be a better alternative for promising oral sustained delivery of HES.

In-vivo evaluation of Alginate-Pectin hydrogel film loaded with Simvastatin for diabetic wound healing in Streptozotocin-induced diabetic rats.

Previously we developed and characterized a novel hydrogel film wound dressing containing Sodium Alginate and Pectin loaded with Simvastatin with multi-functional properties. This study investigated the in-vivo efficacy of the developed wound dressing on type I diabetic wound model. Experiments were performed on male Wistar rats for the period of 21-days. Animals developed diabetes after intraperitoneal injection (50 mg/kg) of Streptozotocin then randomly divided into different groups. On days 7, 14, and 21 of post-wounding, animals were euthanized and the wounds tissue were harvested for analysis. The wound healing rate, hematology and histological analysis, hydroxyproline assay, and Vascular Endothelial Growth Factor A measurements were noted. The results revealed that the wound dressing healed the wounded area significantly (p < 0.05) higher than the control after 21-day treatment and wound closure was ~99% without any adverse systemic reactions. Histological analysis qualitatively revealed an enhanced re-epithelialization and collagen deposition. Moreover, results also showed an improved rate of collagen synthesis and angiogenesis in the group treated with the hydrogel film loaded with Simvastatin. Thus, the present study demonstrated that developed film holds great potential for the acceleration of diabetic wound healing by its pro-angiogenic effect, faster re-epithelialization and increased collagen deposition.

Model of Chronic Thromboembolic Pulmonary Hypertension in Rats Caused by Repeated Intravenous Administration of Partially Biodegradable Sodium Alginate Microspheres.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare and life-threatening complication of pulmonary embolism. As existing animal models of CTEPH do not fully recapitulate complex disease pathophysiology, we report a new rat model for CTEPH evoked by repetitive embolization of the distal pulmonary artery branches with partially biodegradable alginate microspheres (MSs). MSs (180 ± 28 µm) were intravenously administered eight times at 4-day intervals; control animals received saline. The validity of the model was confirmed using transthoracic echocardiography, exercise testing, catheterization of the right ventricle, and histological examination of the lung and heart. The animals in the CTEPH group demonstrated a stable increase in right ventricular systolic pressure (RVSP) and decreased exercise tolerance. Histopathological examination revealed advanced medial hypertrophy in the small pulmonary arteries associated with fibrosis. The diameter of the main pulmonary artery was significantly larger in the CTEPH group than in the control group. Marinobufagenin and endothelin-1 serum levels were significantly elevated in rats with CTEPH. In conclusion, repetitive administration of alginate MSs in rats resulted in CTEPH development characterized by specific lung vasculature remodeling, reduced exercise tolerance, and a persistent rise in RVSP. The developed model can be used for pre-clinical testing of promising drug candidates.

Alendronate-Decorated Nanoparticles as Bone-Targeted Alendronate Carriers for Potential Osteoporosis Treatment.

Osteoporosis is a skeletal disorder characterized by a low bone mass and density. Alendronate (Alen), a second-generation bisphosphonate drug, was indicated as the first-line regimen for the treatment of osteoporosis. However, the use of Alen has been limited due to its low bioavailability and gastrointestinal side effects. Herein, Alen-decorated nanoparticles were prepared through ionic cross-linking between poly (lactic-co-glycolic acid), ß-cyclodextrin-modified chitosan (PLGA-CS-CD), and Alen-modified alginate (ALG-Alen) for Alen loading and bone-targeted delivery. Alen was selected as a therapeutic drug and a bone-targeting ligand. The nanoparticles have negatively charged surfaces, and sustained release of Alen from the nanoparticles can be observed. Cytotoxicity detected using cell counting kit-8 (CCK-8) assay and lactate dehydrogenase release test on MC3T3 cells showed that the nanoparticles had good cytocompatibility. A hemolysis test showed that the hemolysis ratios of nanoparticles were <5%, indicating that the nanoparticles had no significant hemolysis effect. Moreover, the Alen-decorated nanoparticles exhibited enhanced binding affinity to the hydroxyapatite (HAp) disks compared with that of nanoparticles without Alen modification. Thus, the Alen-decorated nanoparticles might be developed as promising bone-targeted carriers for the treatment of osteoporosis.

Construction and research on size and phase 'fixed-point remodelling' intelligent drug delivery system.

It is important to enhance penetration depth of nanomedicine and realise rapid drug release simultaneously at targeted tumour for improving anti-tumour efficiency of chemotherapeutic drugs. This project employed sodium alginate (Alg) as matrix material, to establish tumour-responsive nanogels with particle size conversion and drug controlled release functions. Specifically, tumour-targeting peptide CRGDK was conjugated with Alg first (CRGDK-Alg). Then, doxorubicin (DOX) was efficiently encapsulated in CRGDK-FeAlg nanogel during the cross-linking process (CRGDK-FeAlg/DOX). This system was closed during circulation. Once reaching tumour, the particle size of nanogels was reduced to ∼25 nm, which facilitated deep penetration of DOX in tumour tissues. After entering tumour cells, the size of nanogels was further reduced to ∼10 nm and DOX was released simultaneously. Meanwhile, FeAlg efficiently catalysed H2O2 to produce •OH by Fenton reaction, achieving local chemodynamic therapy without O2 mediation. Results showed CRGDK-FeAlg/DOX significantly inhibited tumour proliferation in vivo with V/V0 of 1.13 after treatment, significantly lower than that of control group with V/V0 of 4.79.

Polymeric Microspheres Containing Human Vocal Fold Fibroblasts for Vocal Fold Regeneration.

OBJECTIVE: Most acellular injectable biomaterials for vocal fold (VF) wound treatment have limited regenerative potential due to their fast enzymatic degradation and limited recruitment of native cells postinjection. The injection of cells as therapeutic treatment often results in apoptosis due to stresses within the needle and the immune response of the host. Degradable microspheres may improve treatment effectiveness by increasing cell residence time, shielding cells during injection, and offering early protection against the immune system response. The objective of the present study was to investigate the potential of human VF fibroblasts encapsulated in polymeric microspheres as an injectable therapeutic treatment in vitro. METHODS: Alginate, alginate-poly-L-lysine, and alginate-chitosan microspheres were fabricated using electrospraying and characterized in terms of biocompatibility, swelling, and mechanical properties as well as cytokine production. RESULTS: Alginate microspheres were found to have the most desirable properties for VF regeneration. They were resistant to mechanical challenges. They were found to have a stiffness similar to that reported for native VF-lamina propria. They were found to be biocompatible and increased the proliferation of fibroblasts. Human VF fibroblasts encapsulated in alginate microspheres induced the production of interleukin (IL)-8 and IL-4 at 24 hours. CONCLUSION: The alginate microspheres fabricated in this study were found to offer potential advantages, as cell delivery tool. This study highlights the importance of combining biomaterials and cells to expedite the wound-healing process through cytokine production. Future work is aimed to further analysis of the wound-healing properties the microspheres. LEVEL OF EVIDENCE: NA Laryngoscope, 131:1828-1834, 2021.

Nanoparticles integrating natural and synthetic polymers for in vivo insulin delivery.

The aims of the current study were to develop insulin-loaded nanoparticles comprised of various polymers at different compositions, and to evaluate their ability to lower blood glucose levels in diabetic rats following subcutaneous and oral administrations. Several combinations of natural and synthetic polymers have been utilized for preparation of nanoparticles including, chitosan, alginate, albumin and Pluronic. Nanosized (170 nm-800 nm) spherical particles of high encapsulation efficiency (15-52%) have been prepared. Composition and ratios between the integrated polymers played a pivotal role in determining size, zeta potential, and in vivo hypoglycemic activity of particles. After subcutaneous and oral administration in diabetic rats, some of the insulin-loaded nanoparticles were able to induce much higher hypoglycemic effect as compared to the unloaded free insulin. For instance, subcutaneous injection of nanoparticles comprised of chitosan combined with sodium tripolyphosphate, Pluronic or alginate/calcium chloride, resulted in comparable hypoglycemic effects to free insulin, at two-fold lower dose. Nanoparticles were well-tolerated after oral administration in rats, as evidenced by by measuring levels of alanine aminotransferase, aspartate aminotransferases, albumin, creatinine and urea. This study indicates that characteristics and delivery efficiency of nanomaterials can be controlled via utilizing several natural/synthetic polymers and by fine-tuning of combination ratio between polymers.

Immunogenicity evaluating of the SLNs-alginate conjugate against Pseudomonas aeruginosa.

P. aeruginosa is of particular importance due to its numerous pathogens and the spread of its multidrug-resistant strains around the world. Hence there is a need to develop an effective vaccine to prevent the diseases with P. aeruginosa. The aim of present study was to evaluate the immunogenicity of alginate (Alg) antigen in conjugation with SLN as a candidate for nanovaccine against P. aeruginosa in mouse model. Alginate is a weak immunogen, but the immune responses produced by alginate are effective in killing Pseudomonas bacteria. To increase the immunogenicity of alginate, SLN was used that is useful in drug delivery and can boost prolonged effectiveness. The results of ELISA and opsonophagocytosis tests showed that Alg-SLN conjugate has a better ability to stimulate the immune system to produce more immunoglobulins with better performance compared to alginate antigen alone. The challenge test also demonstrated that the Alg-SLN treated mice showed a higher level of immunity than the mice treated with pure alginate against infections caused by P. aeruginosa. Overally the findings showed the efficacy of new prepared vaccine to induce immunogenicity, and therefore it can be considered as a candidate for a strong vaccine against P. aeruginosa.

Effect of locust bean gum-sodium alginate coatings incorporated with daphnetin emulsions on the quality of Scophthalmus maximus at refrigerated condition.

In this study, the microbiological, physicochemical, and flavor changes of turbot (Scophthalmus maximus) coated with a composite active coating of locust bean gum (LBG) and sodium alginate (SA) supplemented with daphnetin emulsions (0.16, 0.32, 0.64 mg·mL-1) were determined during 18 days of refrigerated storage (4 ± 1 °C). Results showed that LBG-SA coatings containing 0.32 mg·mL-1 daphnetin emulsions could significantly lower the total viable count (TVC), psychrophiles, Pseudomonas spp. and H2S-producing bacteria counts, and inhibit the productions of off-flavor compounds including the total volatile basic nitrogen (TVB-N), trimethylamine (TMA) and ATP-related compounds. 32 volatile compounds were identified by solid phase microextraction combined with gas chromatography-mass spectrometer method (SPME-GC/MS) during refrigerated storage and the treated turbot samples significantly lowered the relative content of fishy flavor compounds. Further, the LBG-SA coatings containing daphnetin could also delay the myofibril degradation of the turbot samples. These results indicated that the LBG-SA coatings with 0.32 mg·mL-1 daphnetin were a potential alternative way to improve the quality of turbot during refrigerated storage.