Microencapsulation of immunoglobulin Y: optimization with response surface morphology and controlled release during simulated gastrointestinal digestion

Investigation of delivery mechanism of curcumin loaded in a core of zein with a double-layer shell of chitosan and alginate

The pursuit of efficient drug delivery systems has led to innovative approaches such as matrix and core-shell structures. This study explores these systems with a focus on enhancing the delivery and stability of curcumin, a bioactive compound with therapeutic potential. Matrix systems using zein protein were fabricated through coaxial airflow extrusion with a vibration generator, while core-shell systems were produced using concentric nozzles. Double-layer reservoir systems were also formed by coating chitosan-shelled structures with an alginate solution. Encapsulation of curcumin within each system was confirmed through FTIR and optical microscope analysis, followed by efficiency evaluation, which was measured approximately 86.5 ± 0.7 % for the matrix systems and 90 ± 0.8 % for the core-shell systems. Moreover, the particle sizes of matrix systems were measured in the range of 2000-2100 mμ and the particle sizes of single-layer and double-layer reservoir systems were in the ranges of 1600-1700 mμ and 1500-1700 mμ, respectively. The study investigated the stability of curcumin in these systems under various environmental conditions, including exposure to light, heat, pH variations, ions, and storage. Results demonstrated that the presence of multiple layers significantly enhanced the drug's stability. Afterwards, swelling and drug release profiles were assessed in simulated gastric, intestinal, and colon fluids. The swelling of the matrix, single-layer and double-layer reservoir systems after 29 h were 127.4 %, 146.9 % and 144 %, respectively. The matrix system showed 68.7 % drug release after 29 h, whereas single-layer chitosan-shelled and double-layer chitosan/alginate-shelled reservoir systems released 51.8 % and 45.6 % of the drug, respectively. The release mechanism was explored using zero-order, Korsmeyer-Peppas, and Kopcha kinetic models. Comparative analysis of the experimental results and model fittings indicated a deviation from Fickian diffusion, with erosion becoming more pronounced with each additional layer. In conclusion, the system with a zein core and double-layer chitosan/alginate shell displayed effective drug release regulation and enhanced stability of curcumin, making it a promising candidate for efficient drug delivery.

Layer-by-layer self-assembly embedding of nattokinase in chitosan/γ-polyglutamic acid: Preparation, fibrinolytic activity, stability, and in vitro digestion study

Nattokinase (NK) is a thrombolytic enzyme extracted from natto, which can be used to prevent and treat blood clots. However, it is sensitive to the environment, especially the acidic environment of human stomach acid, and its effect of oral ingestion is minimal. This study aims to increase NK's oral and storage stability by embedding NK in microcapsules prepared with chitosan (CS) and γ-polyglutamic acid (γ-PGA). The paper prepared a double-layer NK oral delivery system by layer self-assembly and characterized its stability and in vitro simulated digestion. According to the research results, the bilayer putamen structure has a protective effect on NK, which not only maintains high activity in various environments (such as acid-base, high temperature) and long-term storage (60 days), but also effectively protects the loaded NK from being destroyed in gastric fluid and achieves its slow release. This work has proved the feasibility of the design of bilayer putamen structure in oral administration and has good fibrolytic activity. Therefore, the novel CS/γ-PGA microcapsules are expected to be used in nutraceutical delivery systems.

Preparation, Characterization and Drug Delivery Research of γ-Polyglutamic Acid Nanoparticles: A Review

γ-Polyglutamic acid is a kind of biomaterial and environmentally friendly polymer material with the characteristics of water solubility and good biocompatibility. It has a wide range of applications in medicine, food, cosmetics and other fields. This article reviews the preparation, characterization and medical applications of γ-polyglutamic acid nanoparticles. Nanoparticles prepared by using γ- polyglutamic acid not only had the traditional advantages of enhancing drug stability and slow-release effect, but also were simple to prepare without any biological toxicity. The current methods of nanoparticle preparation mainly include the ion gel method and solvent exchange method, which use the total electrostatic force, van der Waals force, hydrophobic interaction force and hydrogen bond force between molecules to embed materials with different characteristics. At present, there are more and more studies on the use of γ-polyglutamic acid to encapsulate drugs, and the research on the mechanism of its encapsulation and sustained release has gradually matured. The development and application of polyglutamic acid nanoparticles have broad prospects.

Production of IgY against iron permease Ftr1 from Candida albicans and evaluation of its antifungal activity using Galleria mellonella as a model of systemic infection

Candida albicans is one of the leading pathological agents of mucosal and deep tissue infections. Considering that the variety of antifungals is restricted and that toxicity limits their use, immunotherapies against pathogenic fungi have been viewed as alternatives with reduced adverse effects. In this context, C. albicans has a protein used to capture iron from the environment and the host, known as the high-affinity iron permease Ftr1. This protein may be a new target of action for novel antifungal therapies, as it influences the virulence of this yeast. Thus, the aim of the present study was to produce and conduct the biological characterization of IgY antibodies against C. albicans Ftr1. Immunization of laying hens with an Ftr1-derived peptide resulted in IgY antibodies extracted from egg yolks capable of binding to the antigen with high affinity (avidity index = 66.6 ± 0.3%). These antibodies reduced the growth and even eliminated C. albicans under iron restriction, a favorable condition for the expression of Ftr1. This also occurred with a mutant strain that does not produce Ftr1 in the presence of iron, a circumstance in which the protein analog of iron permease, Ftr2, is expressed. Furthermore, the survival of G. mellonella larvae infected with C. albicans and treated with the antibodies was 90% higher than the control group, which did not receive treatment (p < 0.0001). Therefore, our data suggest that IgY antibodies against Ftr1 from C. albicans can inhibit yeast propagation by blocking iron uptake.

Physicochemical properties of bone marrow mesenchymal stem cells encapsulated in microcapsules combined with calcium phosphate cement and their ectopic bone formation

Calcium phosphate bone cement (CPC) serves as an excellent scaffold material for bone tissue engineering owing to its good biocompatibility, injectability, self-setting property and three-dimensional porous structure. However, its clinical use is limited due to the cytotoxic effect of its setting reaction on cells and difficulties in degradation into bone. In this study, bone marrow mesenchymal stem cells (BMSCs) were encapsulated in alginate chitosan alginate (ACA) microcapsules and compounded with calcium phosphate bone cement. Changes in the compressive strength, porosity, injectability and collapsibility of CPC at different volume ratios of microcapsules were evaluated. At a 40% volume ratio of microcapsules, the composite scaffold displayed high porosity and injectability with good collapsibility and compressive strength. Cell live/dead double staining, Cell Counting Kit-8 (CCK-8) assays and scanning electron microscopy were used to detect the viability, proliferation and adhesion of cells after cell microcapsules were combined with CPC. The results revealed that cells protected by microcapsules proliferated and adhered better than those that were directly combined with CPC paste, and cell microcapsules could effectively form macropores in scaffold material. The composite was subsequently implanted subcutaneously on the backs of nude mice, and ectopic osteogenesis of the scaffold was detected via haematoxylin-eosin (H&amp;E), Masson’s trichrome and Goldner’s trichrome staining. CPC clearly displayed better new bone formation function and degradability after addition of pure microcapsules and cell microcapsules. Furthermore, the cell microcapsule treatment group showed greater osteogenesis than the pure microcapsule group. Collectively, these results indicate that BMSCs encapsulated in ACA microcapsules combined with CPC composite scaffolds have good application prospects as bone tissue engineering materials.

Preparation and characterization of egg yolk immunoglobulin loaded chitosan-liposome assisted by supercritical carbon dioxide

The egg yolk immunoglobulin (IgY) loaded chitosan-liposomes (IgY-CS-LP) were prepared and assisted by supercritical carbon dioxide (SCCO₂). The effects of phospholipid type and SCCO₂ pressure on particle size, zeta potential, encapsulation efficiency, structural properties and stabilities were investigated. The results showed that the liposomes prepared by egg yolk phosphatidylcholine (EPC) had better homogeneity and higher encapsulation rate than those by soybean phosphatidylcholine (SPC). With the increase in critical pressure, the particle size decreased dramatically and became more uniform. Under pressure of 20 MPa, it showed a preferable stability on IgY-CS-LP and superior encapsulation efficiency of IgY (76.85%). Besides, IgY could be wrapped in the phospholipid layer which has strong interaction with chitosan. The results suggested that chitosan liposome complex could form an effective carrier for IgY with method of SCCO₂, which can solve the problem of IgY inactivation in vivo, so as to enhance human immunity and other effects.

A comprehensive update: gastrointestinal microflora, gastric cancer and gastric premalignant condition, and intervention by traditional Chinese medicine

With the recent upsurge of studies in the field of microbiology, we have learned more about the complexity of the gastrointestinal microecosystem. More than 30 genera and 1000 species of gastrointestinal microflora have been found. The structure of the normal microflora is relatively stable, and is in an interdependent and restricted dynamic equilibrium with the body. In recent years, studies have shown that there is a potential relationship between gastrointestinal microflora imbalance and gastric cancer (GC) and precancerous lesions. So, restoring the balance of gastrointestinal microflora is of great significance. Moreover, intervention in gastric premalignant condition (GPC), also known as precancerous lesion of gastric cancer (PLGC), has been the focus of current clinical studies. The holistic view of traditional Chinese medicine (TCM) is consistent with the microecology concept, and oral TCM can play a two-way regulatory role directly with the microflora in the digestive tract, restoring the homeostasis of gastrointestinal microflora to prevent canceration. However, large gaps in knowledge remain to be addressed. This review aims to provide new ideas and a reference for clinical practice.

Gastrointestinal toxicities associated with immune checkpoint inhibitors: a disproportionality analysis leveraging VigiBase, the WHO Adverse Drug Reaction Database

With the improvement of people's living standards, gastrointestinal adverse reactions caused by various adverse factors have attracted more and more people's attention. A recent study has indicated that coronavirus disease 2019 (COVID-19) could also invade the gastrointestinal tract, leading to gastrointestinal adverse reactions (Song et al., 2020). In recent years, immunotherapy has provided certain effects for some patients with advanced malignant tumors. A microencapsulation of immunoglobulin Y (IgY) was reported to provide an effective way to preserve IgY and improve its performance in the gastrointestinal tract (Zhang J et al., 2020). Immune checkpoint inhibitors (ICIs) can significantly improve the survival of some advanced malignant tumors, especially metastatic malignant melanoma and lung cancer (Afzal et al., 2018; Madden and Kasler, 2019). They include anti-cytotoxic T lymphocyte-associated antigen-4 (anti-CTLA-4) antibodies (ipilimumab and tremelimumab), anti-programmed cell death protein 1 (anti-PD-1) antibodies (nivolumab and pembrolizumab), and anti-programmed death-ligand 1 (anti-PD-L1) antibodies (atezolizumab, avelumab, and durvalumab) (Baxi et al., 2018). Previous studies have shown that ICI combination therapy, such as nivolumab plus ipilimumab, has particular efficacy in lung cancer, renal cell carcinoma, and malignant melanoma (Wolchok et al., 2017; Derosa et al., 2018; Doroshow et al., 2019). However, ICIs may also lead to many immune-related adverse events (irAEs), even causing severe complications in certain cases. The most well-established toxicities from ICI therapy are gastrointestinal irAEs, including enteritis, enterocolitis, microscopic colitis, and gastritis, which have attracted public attention in recent years; reports of such events associated with ICI therapy also have increased (Tandon et al., 2018; de Malet et al., 2019). These gastrointestinal irAEs may generally respond well to corticosteroids and infliximab (Haanen et al., 2017). Although most of these irAEs are low-grade, a lack of detection and timely treatment may incur severe or fatal complications.