Biological activities of chitosan and chitooligosaccharides

Chitosanase-immobilized magnetite-agar gel particles as a highly stable and reusable biocatalyst for enhanced production of physiologically active chitosan oligosaccharides

A novel immobilized chitosanase was developed and utilized to produce chitosan oligosaccharides (COSs) via chitosan hydrolysis. Magnetite-agar gel particles (average particle diameter: 338 μm) were prepared by emulsifying an aqueous agar solution dispersing 200-nm magnetite particles with isooctane containing an emulsifier at 80 °C, followed by cooling the emulsified mixture. The chitosanase from Bacillus pumilus was immobilized on the magnetite-agar gel particles chemically activated by introducing glyoxyl groups with high immobilization yields (>80%), and the observed specific activity of the immobilized chitosanase was 16% of that of the free enzyme. This immobilized chitosanase could be rapidly recovered from aqueous solutions by applying magnetic force. The thermal stability of the immobilized chitosanase improved remarkably compared with that of free chitosanase: the deactivation rate constants at 35 °C of the free and immobilized enzymes were 8.1 × 10-5 and 3.9 × 10-8 s-1, respectively. This immobilized chitosanase could be reused for chitosan hydrolysis at 75 °C and pH 5.6, and 80% of its initial activity was maintained even after 10 cycles of use. COSs with a degree of polymerization (DP) of 2-7 were obtained using this immobilized chitosanase, and the product content of physiologically active COSs (DP ≥ 5) reached approximately 50%.

Antibacterial properties of photo-crosslinked chitosan/methacrylated hyaluronic acid nanoparticles loaded with bacitracin

The current treatments for wounds often fail to produce adequate healing, leaving wounds vulnerable to persistent infections and development of drug-resistant microbial biofilms. New natural-derived nanoparticles were studied to impair bacteria colonization and hinder the formation of biofilms in wounds. The nanoparticles were fabricated through polyelectrolyte complexation of chitosan (CS, polycation) and hyaluronic acid (HA, polyanion). UV-induced photo-crosslinking was used to enhance the stability of the nanoparticles. To achieve this, HA was methacrylated (HAMA, degree of modification of 20 %). Photo-crosslinked nanoparticles obtained from HAMA and CS had a diameter of 478 nm and a more homogeneous size distribution than nanoparticles assembled solely through complexation (742 nm). The nanoparticles were loaded with the antimicrobial agent bacitracin (BC), resulting in nanoparticles with a diameter of 332 nm. The encapsulation of BC was highly efficient (97 %). The BC-loaded nanoparticles showed significant antibacterial activity against gram-positive bacteria Staphylococcus aureus, Methicillin-resistant S. aureus and S. epidermidis. The nanoparticles loaded with BC based on photo-crosslinked HAMA/CS demonstrated inhibition of biofilm formation and a positive effect on the proliferation of mammalian cells (L929). These crosslinked nanoparticles have potential for the long-term treatment of wounds and controlled antibiotic delivery at the location of a lesion.

Effect of Diets with the Addition of Edible Insects on the Development of Atherosclerotic Lesions in ApoE/LDLR-/- Mice

Foods enriched with insects can potentially prevent several health disorders, including cardiovascular diseases, by reducing inflammation and improving antioxidant status. In this study, Tenebrio molitor and Gryllus assimilis were selected to determine the effect on the development of atherosclerosis in ApoE/LDLR-/- mice. Animals were fed AIN-93G-based diets (control) with 10% Tenebrio molitor (TM) and 10% Gryllus assimilis (GA) for 8 weeks. The nutritional value as well as antioxidant activity of selected insects were determined. The lipid profile, liver enzyme activity, and the fatty acid composition of liver and adipose tissue of model mice were evaluated. Quantitative analysis of atherosclerotic lesions in the entire aorta was performed using the en face method, and for aortic roots, the cross-section method was used. The antioxidant status of the GA cricket was significantly higher compared to the TM larvae. The results showed that the area of atherosclerosis (en face method) was not significantly different between groups. Dietary GA reduced plaque formation in the aortic root; additionally, significant differences were observed in sections at 200 and 300 µm compared to other groups. Furthermore, liver enzyme ALT activity was lower in insect-fed groups compared to the control group. The finding suggests that a diet containing edible insect GA potentially prevents atherosclerotic plaque development in the aortic root, due to its high antioxidant activity.

Unveiling the inverse antimicrobial impact of a hetero-chitooligosaccharide on Candida tropicalis growth and biofilm formation

Chitosan and chitooligosaccharide (COS) are renowned for their potent antimicrobial prowess, yet the precise antimicrobial efficacy of COS remains elusive due to scant structural information about the utilized saccharides. This study delves into the antimicrobial potential of COS, spotlighting a distinct hetero-chitooligosaccharide dubbed DACOS. In contrast to other COS, DACOS remarkably fosters the growth of Candida tropicalis planktonic cells and fungal biofilms. Employing gradient alcohol precipitation, DACOS was fractionated, unveiling diverse structural characteristics and differential impacts on C. tropicalis. Notably, in a murine model of systemic candidiasis, DACOS, particularly its 70 % alcohol precipitates, manifests a promotive effect on Candida infection. This research unveils a new pathway for exploring the intricate nexus between the structural attributes of chitosan oligosaccharides and their physiological repercussions, underscoring the imperative of crafting chitosan and COS with meticulously defined structural configurations.

The evaluation of mixed-layer emulsions stabilized by myofibrillar protein-chitosan complex for delivering astaxanthin: Fabrication, characterization, stability and in vitro digestibility

Muscle protein based functional foods have been attracted great interests in novel food designing. Herein, myofibrillar protein (MP)-chitosan (CH) electrostatic complexes were employed to fabricate mixed-layer emulsions to protect and deliver astaxanthin. The MP/CH complex fabricated mixed-layer emulsions displayed higher stability against pH and temperature changes, exhibiting smaller droplet and homogenous distributions. After UV-light irradiation for 8 h, the mixed-layer emulsions had higher astaxanthin retention (69.11 %, 1:1 group). During storage, a lower degree of lipid oxidation, protein oxidation and higher astaxanthin retention were obtained, indicating desirable protections of mixed-layer emulsions. The vitro digestion reveled the mixed-layer emulsions could decrease the release of free fatty acids. Meanwhile, the bioaccessibility of astaxanthin was higher (30.43 %, 2:1 group) than monolayer emulsion. In all, the MP/CH prepared mixed-layer emulsions could protect and deliver fat-soluble bioactive compounds, and contributed to develop muscle protein based functional foods to meet the needs of slow and controlled release.

Advancements in application of chitosan and cyclodextrins in biomedicine and pharmaceutics: recent progress and future trends

The global community is faced with numerous health concerns such as cancer, cardiovascular and neurological diseases, diabetes, joint pain, osteoporosis, among others. With the advancement of research in the fields of materials chemistry and medicine, pharmaceutical technology and biomedical analysis have entered a new stage of development. The utilization of natural oligosaccharides and polysaccharides in pharmaceutical/biomedical studies has gained significant attention. Over the past decade, several studies have shown that chitosan and cyclodextrin have promising biomedical implications in background analysis, ongoing development, and critical applications in biomedical and pharmaceutical research fields. This review introduces different types of saccharides/natural biopolymers such as chitosan and cyclodextrin and discusses their wide-ranging applications in the biomedical/pharmaceutical research area. Recent research advances in pharmaceutics and drug delivery based on cyclodextrin, and their response to smart stimuli, as well as the biological functions of cyclodextrin and chitosan, such as the immunomodulatory effects, antioxidant, and antibacterial properties, have also been discussed, along with their applications in tissue engineering, wound dressing, and drug delivery systems. Finally, the innovative applications of chitosan and cyclodextrin in the pharmaceutical/biomedicine were reviewed, and current challenges, research/technological gaps, and future development opportunities were surveyed.

Chitosan nanoparticle applications in dentistry: a sustainable biopolymer

The epoch of Nano-biomaterials and their application in the field of medicine and dentistry has been long-lived. The application of nanotechnology is extensively used in diagnosis and treatment aspects of oral diseases. The nanomaterials and its structures are being widely involved in the production of medicines and drugs used for the treatment of oral diseases like periodontitis, oral carcinoma, etc. and helps in maintaining the longevity of oral health. Chitosan is a naturally occurring biopolymer derived from chitin which is seen commonly in arthropods. Chitosan nanoparticles are the latest in the trend of nanoparticles used in dentistry and are becoming the most wanted biopolymer for use toward therapeutic interventions. Literature search has also shown that chitosan nanoparticles have anti-tumor effects. This review highlights the various aspects of chitosan nanoparticles and their implications in dentistry.

Marine polysaccharides: Biological activities and applications in drug delivery systems

The ocean is the common home of a large number of marine organisms, including plants, animals, and microorganisms. Researchers can extract thousands of important bioactive components from the oceans and use them extensively to treat and prevent diseases. In contrast, marine polysaccharide macromolecules such as alginate, carrageenan, Laminarin, fucoidan, chitosan, and hyaluronic acid have excellent physicochemical properties, good biocompatibility, and high bioactivity, which ensures their wide applications and strong therapeutic potentials in drug delivery. Drug delivery systems (DDS) based on marine polysaccharides and modified marine polysaccharide molecules have emerged as an innovative technology for controlling drug distribution on temporal, spatial, and dosage scales. They can detect and respond to external stimuli such as pH, temperature, and electric fields. These properties have led to their wide application in the design of novel drug delivery systems such as hydrogels, polymeric micelles, liposomes, microneedles, microspheres, etc. In addition, marine polysaccharide-based DDS not only have smart response properties but also can combine with the unique biological properties of the marine polysaccharide base to exert synergistic therapeutic effects. The biological activities of marine polysaccharides and the design of marine polysaccharide-based DDS are reviewed. Marine polysaccharide-based responsive DDS are expected to provide new strategies and solutions for disease treatment.

Storage stability of Asian seabass oil-in-water Pickering emulsion packed in pouches made from electrospun and solvent casted bilayer films from poly lactic acid/chitosan-gelatin blend containing epigallocatechin gallate

Bilayer pouches were fabricated with chitosan (CS)-fish gelatin (FG) mixture containing epigallocatechin gallate (EGCG) deposited over the poly lactic acid (PLA) film through solvent casting and electrospinning techniques. Pickering emulsions (PE) of Asian seabass depot fat oil stabilized by zein colloidal particles were packed in bilayer pouches and stored at 28 ± 2 °C. The PE packed in pouch containing EGCG had higher emulsion and oxidative stability after 30 days of storage as witnessed by the smaller droplet size and lower values of thiobarbituric acid reactive substances, peroxide, conjugated diene and volatile compounds in comparison with control (PE packed in monolayer PLA pouch) (P < 0.05). EGCG incorporated pouch retained more linoleic acid (C18:2 n-6) and linolenic acid (C18:3 n-9) in emulsion than PLA pouch. Therefore, pouch from bilayer PLA/CS-FG films comprising EGCG could serve as active packaging and extended the shelf life of Pickering emulsion.

Chitosan-Oxidized Pullulan Hydrogels Loaded with Essential Clove Oil: Synthesis, Characterization, Antioxidant and Antimicrobial Properties

Emulsion hydrogels are promising materials for encapsulating and stabilizing high amounts of hydrophobic essential oils in hydrophilic matrices. In this work, clove oil-loaded hydrogels (CS/OP-C) are synthesized by combining covalent and physical cross-linking approaches. First, clove oil (CO) was emulsified and stabilized in a chitosan (CS) solution, which was further hardened by Schiff base covalent cross-linking with oxidized pullulan (OP). Second, the hydrogels were subjected to freeze-thaw cycles and, as a result, the clove oil was stabilized in physically cross-linked polymeric walls. Moreover, due to cryogelation, the obtained hydrogels exhibited sponge-like porous interconnected morphology (160-250 µm). By varying the clove oil content in the starting emulsion and the degree of cross-linking, the hydrogels displayed a high water retention capacity (swelling ratios between 1300 and 2000%), excellent elastic properties with fast shape recovery (20 s) after 70% compression, and controlled in vitro clove oil release in simulated skin conditions for 360 h. Furthermore, the prepared clove oil-loaded hydrogels had a strong scavenging activity of 83% and antibacterial and antifungal properties, showing a bacteriostatic effect after 48 and 72 h against S. aureus and E. coli. Our results recommend the new clove oil-embedded emulsion hydrogels as promising future materials for application as wound dressings.

Protective Effects of Carbonated Chitosan Montmorillonite on Vomitoxin-Induced Intestinal Inflammation

Exposure to vomitoxin (DON) can negatively impact the intestinal health of livestock and poultry, leading to compromised nutrient absorption and utilization, resulting in slowed growth and reduced production efficiency. In this study, we synthesized carbonated chitosan montmorillonite intercalation complexes (CCM) through solution precipitation. The successful formation of intercalation complexes was confirmed by examining functional groups and surface features using infrared spectroscopy and scanning electron microscopy. To assess the impact of CCM on DON-infected mice, we established an experimental mouse model of jejunal inflammation induced by DON infection. We analyzed the effects of CCM on blood biochemical and conventional indices, jejunal inflammatory factors, pathological changes, and the expression of proteins in the MAPK pathways in DON-infected mice. Our results indicate that CCM effectively mitigates the adverse effects of DON on growth performance, jejunal injury, and the inflammatory response in mice. CCM supplementation alleviated the negative effects of DON infection on growth performance and reduced intestinal inflammation in mice. Moreover, CCM supplementation successfully inhibited the activation of the mitogen-activated protein kinase (MAPK) signaling pathway induced by DON. These findings suggest that the mitigating effect of CCM on DON-induced inflammatory injury in the murine jejunum is closely linked to the regulation of the MAPK signaling pathway.

Maximizing crustaceans (shrimp, crab, and lobster) by-products value for optimum valorization practices: A comparative review of their active ingredients, extraction, bioprocesses and applications

BACKGROUND

The processing of the three major crustaceans (shrimp, lobster, and crab) is associated with inevitable by-products, high waste disposal costs, environmental and human health issues, loss of multiple biomaterials (chitin, protein hydrolysates, lipids, astaxanthin and minerals). Nowadays, these bioresources are underutilized owing to the lack of effective and standardized technologies to convert these materials into valued industrial forms.

AIM OF REVIEW

This review aims to provide a holistic overview of the various bioactive ingredients and applications within major crustaceans by-products. This review aims to compare various extraction methods in crustaceans by-products, which will aid identify a more workable platform to minimize waste disposal and maximize its value for best valorization practices.

KEY SCIENTIFIC CONCEPTS OF REVIEW

The fully integrated applications (agriculture, food, cosmetics, pharmaceuticals, paper industries, etc.) of multiple biomaterials from crustaceans by-products are presented. The pros and cons of the various extraction methods, including chemical (acid and alkali), bioprocesses (enzymatic or fermentation), physical (microwave, ultrasound, hot water and carbonic acid process), solvent (ionic liquids, deep eutectic solvents, EDTA) and electrochemistry are detailed. The rapid development of corresponding biotechnological attempts present a simple, fast, effective, clean, and controllable bioprocess for the comprehensive utilization of crustacean waste that has yet to be applied at an industrial level. One feasible way for best valorization practices is to combine innovative extraction techniques with industrially applicable technologies to efficiently recover these valuable components.

Multi-functional pH-responsive and biomimetic chitosan-based nanoplexes for targeted delivery of ciprofloxacin against bacterial sepsis

Bacterial sepsis is a mortal syndromic disease characterized by a complex pathophysiology that hinders effective targeted therapy. This study aimed to develop multifunctional, biomimetic and pH-responsive ciprofloxacin-loaded chitosan (CS)/sodium deoxycholic acid (SDC) nanoplexes (CS/SDC) nanoplexes with the ability to target and modulate the TLR4 pathway, activated during sepsis. The formulated nanoplexes were characterized in terms of physicochemical properties, in silico and in vitro potential biological activities. The optimal formulation showed good biocompatibility and stability with appropriate physicochemical parameters. The surface charge changed from negative at pH 7.4 to positive at pH 6.0 accompanied with a significantly faster release of CIP at pH 6.0 compared to 7.4. The biomimicry was elucidated by in silico tools and MST and results confirmed strong binding between the system and TLR4. Furthermore, the system revealed 4- and 2-fold antibacterial enhancement at acidic pH, and 3- and 4-fold better antibiofilm efficacy against Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (P. aeruginosa) respectively, compared to bare CIP. In addition, enhanced bacterial efflux pump inhibition was demonstrated by CS/SDC nanoplexes. Finally, the developed nanosystem showed excellent antioxidant activity against DPPH radicals. Taken together, the study confirmed the multi-functionalities of CS/SDC nanoplexes and their potential benefits in improving bacterial sepsis therapy.

Synthesis and Characterization of Slow-Release Chitosan Oligosaccharide Pyridine Schiff Base Copper Complexes with Antifungal Activity

Herein, a series of chitosan oligosaccharide copper complexes modified with pyridine groups (CPSx-Cu complexes) were successfully prepared via the Schiff base reaction and ion complexation reaction for slow-release fungicide. The structures of the synthesized derivatives were characterized via Fourier transform infrared spectroscopy and 1H and 13C nuclear magnetic resonance spectroscopy, and the unit configuration of the complexes was calculated using Gaussian software. The slow-release performance experiment demonstrated that the cumulative copper ion release rate of CPSx-Cu complexes was dependent on the type of substituents on the pyridine ring. Furthermore, the in vitro and in vivo antifungal activities of the CPSx-Cu complexes were investigated. At a concentration of 0.4 mg/mL, CPSx-Cu complexes completely inhibited the growth of Pythium vexans and Phytophthora capsici. Results indicated that CPSx-Cu complexes with slow-release ability exhibited better antifungal activity than thiodiazole-copper and copper sulfate basic. This study confirmed that combining chitosan oligosaccharide with bioactive pyridine groups and copper ions is an effective approach to further developing slow-release copper fungicides, providing new possibilities for the application of copper fungicides in green agriculture. This study lays the foundation for further studies on biogreen copper fungicides.

Chitosan as excellent bio-macromolecule with myriad of anti-activities in biomedical applications - A review

The aim of the study is to explore the myriad of anti-activities of chitosan - deacylated derivative of chitin in biomedical applications. Chitosan consists of reactive residual amino groups, which can be modified chemically to obtain wide range of derivatives. These derivatives exhibit the controlled physicochemical characteristics, which in turn improve its functional properties. Such derivatives find numerous applications in the field of biomedical science, agriculture, tissue engineering, bone regeneration and environmental science. This study presents a comprehensive overview of the multifarious anti-activities of chitosan and its derivatives in the field of biomedical science including anti-microbial, antioxidant, anti-tumor, anti-HIV, anti-fungal, anti- inflammatory, anti-Alzheimer's, anti-hypertensive and anti-diabetic activity. It briefly details these anti-activities with respect to its mode of action, pharmacological effects and potential applications. It also presents the overview of current research exploring novel derivatives of chitosan and its anti- activities in the recent past. Finally, the review projects the prospective potential of chitosan and its derivatives and expects to encourage the readers to develop new drug delivery systems based on such chitosan derivatives and explore its applications in biomedical science for benefit of mankind.

Chitosan-Based Biomaterial in Wound Healing: A Review

Wound healing is an evolving and intricate technique that is vital to the restoration of tissue integrity and function. Over the past few decades, chitosan a biopolymer derived from chitin, became known as an emerging biomaterial in the field of healing wounds due to its distinctive characteristics including biocompatibility, biodegradability, affinity to biomolecules, and wound-healing activity. This natural polymer exhibits excellent healing capabilities by accelerating the development of new skin cells, reducing inflammation, and preventing infections. Due to its distinct biochemical characteristics and innate antibacterial activity, chitosan has been extensively researched as an antibacterial wound dressing. Chronic wounds, such as diabetic ulcers and liver disease, are a growing medical problem. Chitosan-based biomaterials are a promising solution in the domain of wound care. The article analyzes the depth of chitosan-based biomaterials and their impact on wound healing and also the methods to enhance the advantages of chitosan by incorporating bioactive compounds. This literature review is aimed to improve the understanding and knowledge about biomaterials and their use in wound healing.

Chitinous material bioconversion by three new chitinases from the yeast Mestchnikowia pulcherrima

BACKGROUND

Chitinases are widely distributed enzymes that perform the biotransformation of chitin, one of the most abundant polysaccharides on the biosphere, into useful value-added chitooligosaccharides (COS) with a wide variety of biotechnological applications in food, health, and agricultural fields. One of the most important group of enzymes involved in the degradation of chitin comprises the glycoside hydrolase family 18 (GH18), which harbours endo- and exo-enzymes that act synergistically to depolymerize chitin. The secretion of a chitinase activity from the ubiquitous yeast Mestchnikowia pulcherrima and their involvement in the post-harvest biological control of fungal pathogens was previously reported.

RESULTS

Three new chitinases from M. pulcherrima, MpChit35, MpChit38 and MpChit41, were molecularly characterized and extracellularly expressed in Pichia pastoris to about 91, 90 and 71 mU ml- 1, respectively. The three enzymes hydrolysed colloidal chitin with optimal activity at 45 ºC and pH 4.0-4.5, increased 2-times their activities using 1 mM of Mn2+ and hydrolysed different types of commercial chitosan. The partial separation and characterization of the complex COS mixtures produced from the hydrolysis of chitin and chitosan were achieved by a new anionic chromatography HPAEC-PAD method and mass spectrometry assays. An overview of the predicted structures of these proteins and their catalytic modes of action were also presented. Depicted their high sequence and structural homology, MpChit35 acted as an exo-chitinase producing di-acetyl-chitobiose from chitin while MpChit38 and MpChit41 both acted as endo-chitinases producing tri-acetyl-chitotriose as main final product.

CONCLUSIONS

Three new chitinases from the yeast M. pulcherrima were molecularly characterized and their enzymatic and structural characteristics analysed. These enzymes transformed chitinous materials to fully and partially acetylated COS through different modes of splitting, which make them interesting biocatalysts for deeper structural-function studies on the challenging enzymatic conversion of chitin.

An overview of the potential application of chitosan in meat and meat products

Chitosan is considered the second most ubiquitous polysaccharide next to cellulose. It has gained prominence in various industries including biomedicine, textile, pharmaceutical, cosmetic, and notably, the food industry over the last few decades. The polymer's continual attention within the food industry can be attributed to the increasing popularity of greener means of packaging and demand for foods incorporated with natural alternatives instead of synthetic additives. Its antioxidant, antimicrobial, and film-forming abilities reinforced by the polymer's biocompatible, biodegradable, and nontoxic nature have fostered its usage in food packaging and preservation. Microbial activity and lipid oxidation significantly influence the shelf-life of meat, resulting in unfavorable changes in nutritional and sensory properties during storage. In this review, the scientific studies published in recent years regarding potential applications of chitosan in meat products; and their effects on shelf-life extension and sensory properties are discussed. The utilization of chitosan in the form of films, coatings, and additives in meat products has supported the extension of shelf-life while inducing a positive impact on their organoleptic properties. The nature of chitosan and its compatibility with various materials make it an ideal biopolymer to be used in novel arenas of food technology.

Poly(vinyl alcohol)/chitosan hydrogel incorporating chitooligosaccharide-gentisic acid conjugate with antioxidant and antibacterial properties as a potential wound dressing

The design and development of wound dressing with antioxidant and antibacterial properties to accelerate wound healing remain challenging. In this study, we synthesize a chitooligosaccharide-gentisic acid (COS-GSA) conjugate using the free-radical grafting method, and fabricate a poly(vinyl alcohol) (PVA)/chitosan (CH)/COS-GSA (PVA/CH/CG) hydrogel using a freeze-thaw method. We characterize the synthesized COS-GSA conjugates using through polyphenol assay, absorbance, and 1H NMR spectroscopy and evaluate their antioxidant properties. The COS-GSA conjugates are successfully synthesized and exhibit better antioxidant properties than pristine COSs. Subsequently, the fabricated hydrogel is characterized based on its morphological analysis, rheological properties, water contact angle, swelling, degradation, water retention properties, and COS-GSA release profiles. Finally, the biocompatibility of the fabricated hydrogel is evaluated on HDF and HaCaT cells through indirect and direct cytotoxicity. The PVA/CH/CG hydrogel exhibited significantly higher antioxidant properties (DPPH, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and hydrogen peroxide (H2O2) scavenging activities) and antibacterial activities (Staphylococcus aureus and Pseudomonas aeruginosa) compared to other fabricated hydrogels such as PVA, PVA/CH, and PVA/CH/COS (PVA/CH/C). These results provide evidence that PVA/CH/CG hydrogels with antioxidant, antibacterial, and non-cytotoxic properties have great potential for wound-dressing applications.

Research Progress of Chitosan-based Multifunctional Nanoparticles in Cancer Targeted Therapy

Conventional tumor therapeutic modalities, such as radiotherapy, chemotherapy, and surgery, involve low tumor inhibition efficiency, non-targeted drug delivery, and side effects. The development of novel and practical nano-drug delivery systems (DDSs) for targeted tumor therapy has become particularly important. Among various bioactive nanoparticles, chitosan is considered a suitable candidate for drug delivery due to its nontoxicity, good biocompatibility, and biodegradability. The amino and hydroxyl groups of chitosan endow it with the diverse function of chemical modification, thereby improving its physical and biological properties to meet the requirements of advanced biomedical applications. Therefore, it is necessary to review the property and applications of chitosan- based materials in biomedicine. In this review, the characteristics of chitosan related to its applications are first introduced, and then the preparation and modification of chitosan-based nanoparticles, including the function tailoring of chitosan-modified nanoparticles, are demonstrated and discussed. Finally, the opportunities and challenges of chitosan- based nanomaterials in this emerging field are proposed from the perspective of the rational and systematic design for the biomedicine field.

Chitosan as a Control Tool for Insect Pest Management: A Review

Chitosan, a polysaccharide derived from the deacetylation of chitin, is a versatile and eco-friendly biopolymer with several applications. Chitosan is recognized for its biodegradability, biocompatibility, and non-toxicity, beyond its antimicrobial, antioxidant, and antitumoral activities. Thanks to its properties, chitosan is used in many fields including medicine, pharmacy, cosmetics, textile, nutrition, and agriculture. This review focuses on chitosan's role as a tool in insect pest control, particularly for agriculture, foodstuff, and public health pests. Different formulations, including plain chitosan, chitosan coating, chitosan with nematodes, chitosan's modifications, and chitosan nanoparticles, are explored. Biological assays using these formulations highlighted the use of chitosan-essential oil nanoparticles as an effective tool for pest control, due to their enhanced mobility and essential oils' prolonged release over time. Chitosan's derivatives with alkyl, benzyl, and acyl groups showed good activity against insect pests due to improved solubility and enhanced activity compared to plain chitosan. Thus, the purpose of this review is to provide the reader with updated information concerning the use and potential applications of chitosan formulations as pest control tools.

Formulation and antibacterial properties of lollipops containing of chitosan- zinc oxide nano particles on planktonic and biofilm forms of Streptococcus mutans and Lactobacillus acidophilus

This study aimed to formulate and characterize the experimental lollipops containing chitosan- zinc oxide nanoparticles (CH-ZnO NPs) and investigate their antimicrobial effects against some cariogenic bacteria. The CH-ZnO NPs were synthesized and characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) analysis, and Transmission electron microscope (TEM). Then, four groups were made, including lollipops coated with 2 and 4 ml of CH-ZnO NPs, 0.7 ml CH-ZnO NPs incorporated lollipops, and those with no CH-ZnO NPs. Their antibacterial effectiveness against Streptococcus mutans and Lactobacillus acidophilus was evaluated by direct contact test and tissue culture plate method in planktonic and biofilm phases, respectively. Chlorhexidine mouthrinse (CHX) was used as a positive control group. In the planktonic phase, the antibacterial properties of both groups coated with CH-ZnO NPs were comparable and significantly higher than incorporated ones. There was no significant difference between CHX and the lollipops coated with 4 ml of NPs against S. mutans and CHX and two coated groups against L. acidophilus. None of the experimental lollipops in the biofilm phase could reduce both bacteria counts. The experimental lollipops coated with 2 and 4 ml of CH-ZnO NPs could reveal favorable antimicrobial properties against two cariogenic bacteria in the planktonic phase.

A topical thermosensitive hydrogel system with cyclosporine A PEG-PCL micelles alleviates ulcerative colitis induced by TNBS in mice

Ulcerative colitis (UC) is an idiopathic, chronic, relapsing disease. In most cases, only the distal colon is affected, and the colonic stasis or fast colonic transit through the inflamed colon usually results in reduced exposure of the distal inflamed colon. Although the immunosuppressant cyclosporine A (CsA) has been used in patients with severe colitis who do not respond to corticosteroids, the clinical application of CsA remains limited due to the systemic toxicities and insufficient accumulation at the site of action for the intravenous and oral routes. In this study, we loaded CsA into the amphipathic poly(ethylene glycol)-poly(ε-caprolactone) (PEG-PCL) micelles and then embedded them in hydrogels consisting of chitosan, poloxamer 188, and poloxamer 407 to construct a thermosensitive and mucoadhesive hydrogel drug delivery system (PLCP). The PLCP presented a high drug-loading capacity and showed a stable and rapid gelation rate after rectal administration into the body. Compared to CsA-loaded micelles and Sandimmun (Neoral®), the developed thermosensitive gel exhibited prolonged retention on the inflamed colon, as seen from in vitro adhesion and in vivo distribution experiments. It also fast mitigated colitis symptoms in TNBS-treated mice by regulating the expression levels of proinflammatory cytokines (TNF-α, IL-1β, COX-2, and iNOS2), anti-inflammatory cytokines (IL-10, Nrf2, NQO1, and HO-1), and other relevant biochemical factors. Our results suggested that CsA-loaded micelle thermal hydrogel system could be a promising strategy by enhancing the retention in the diseased colon and promoting the relief and recovery of UC.

Nutritional intervention is promising in alleviating liver injury during tuberculosis treatment: a review

Liver injury is a main adverse effect of first-line tuberculosis drugs. Current management of tuberculosis-drug-induced liver injury (TBLI) mainly relies on withdrawing tuberculosis drugs when necessary. No effective treatment exists. Various nutrients and functional food ingredients may play a protective role in TBLI. However, a comprehensive review has not been conducted to compare the effects of these nutrients and functional food ingredients. We searched Pubmed and Web of Science databases from the earliest date of the database to March 2023. All available in-vitro, animal and clinical studies that examined the effects of nutritional intervention on TBLI were included. The underlying mechanism was briefly reviewed. Folic acid, quercetin, curcumin, Lactobacillus casei, spirulina and Moringa oleifera possessed moderate evidence to have a beneficial effect on alleviating TBLI mostly based on animal studies. The evidence of other nutritional interventions on TBLI was weak. Alleviating oxidative stress and apoptosis were the leading mechanisms for the beneficial effects of nutritional intervention on TBLI. In conclusion, a few nutritional interventions are promising for alleviating TBLI including folic acid, quercetin, curcumin, L. casei, spirulina and M. oleifera, the effectiveness and safety of which need further confirmation by well-designed randomized controlled trials. The mechanisms for the protective role of these nutritional interventions on TBLI warrant further study, particularly by establishing the animal model of TBLI using the tuberculosis drugs separately.

Comparative Evaluation of the In Vitro Cytotoxicity of a Series of Chitosans and Chitooligosaccharides Water-Soluble at Physiological pH

Chitosans (CS) have been of great interest due to their properties and numerous applications. However, CS have poor solubility in neutral and basic media, which limits their use in these conditions. In contrast, chitooligosaccharides (COS) have better solubility in water and lower viscosity in aqueous solutions whilst maintaining interesting biological properties. CS and COS, unlike other sugars, are not single polymers with a defined structure but are groups of molecules with modifiable structural parameters, allowing the adaptation and optimization of their properties. The great versatility of CS and COS makes these molecules very attractive for different applications, such as cryopreservation. Here, we investigated the effect of the degree of polymerization (DP), degree of N-acetylation (DA) and concentration of a series of synthesized CS and COS, water-soluble at physiological pH, on their cytotoxicity in an L929 fibroblast cell culture. Our results demonstrated that CS and COS showed no sign of toxicity regarding cell viability at low concentrations (≤10 mg/mL), independently of their DP and DA, whereas a compromising effect on cell viability was observed at a high concentration (100 mg/mL).

Polysaccharide-based biosorbents for cholesterol and bile salts in gastric-intestinal passage: Advances and future trends

Cholesterol is one of the hazard elements for many cardiovascular diseases, but many cholesterol-lowering drugs are expensive and unhealthy. Therefore, it is necessary to develop edible and safe biosorbents to reduce excess cholesterol and bile salts in the gastric-intestinal passage. Polysaccharide-based biosorbents offer a feasible strategy for decreasing them. This review summarized polysaccharide-based biosorbents that have been developed for adsorbing cholesterol and bile salts from the gastric-intestinal passage and analyzed common modification methods for these adsorbents. Finally, the adsorption models were also elucidated. Polysaccharides, including β-cyclodextrin, pectin, chitin/chitosan, dietary fiber extract, and cellulose, have been proposed for adsorbing cholesterol and bile salts in the gastric-intestinal passage as biosorbents. This is mainly due to the retention of pores, the capture of the viscosity network, and the help of hydrophobic interactions. In spite of this, the adsorption capacity of polysaccharides is still limited. Therefore, the modifications for them became the most popular areas in the recent studies of in vitro cholesterol adsorption. Chemical approaches namely grafting, (1) acetylation, (2) hydroxypropylation, (3) carboxymethylation, and (4) amination are considered to modify the polysaccharides for higher adsorption ability. Moreover, ultrasonic/microwave/pressure treatment and micron technology (microfluidization, micronization, and ball milling) are effective physical modification methods, while the biological approach mainly refers to enzymatic hydrolysis and microbial fermentation. The adsorption models are generally explained by two adsorption isotherms and two adsorption kinetics. In sum, it is reckoned that further food applications will follow soon.

Preparation of water-soluble chitosan oligosaccharides by oxidative hydrolysis of chitosan powder with hydrogen peroxide

Chitosan (CS) is only soluble in weak acid medium, thereby limiting its wide utilisation in the field of biomedicine, food, and agriculture. In this report, we present a method for preparing water-soluble CS oligosaccharides (COSs) at high concentration (∼10%, w/v) via the oxidative hydrolysis of CS powder with molecular weight (Mw) ∼90,000 g/mol) in 2% H2O2 solution at ambient temperature by a two-step process, namely, the heterogeneous hydrolysis step and homogeneous hydrolysis step. The resultant COSs were characterised by gel permeation chromatography (GPC), fourier transforms infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-Vis), proton nuclear magnetic resonance spectroscopy (1H NMR) and X-ray diffraction (XRD) spectroscopy. The resulting products were composed of COSs (Mw of 2000-6600 g/mol) that were completely soluble in water. The results also indicated that the structure of COSs was almost unchanged compared with the original CS unless Mw was low. Accordingly, COSs with low Mw (∼2000 g/mol) and high concentration (10%, w/v) could be effectively prepared by the oxidative hydrolysis of CS powder using hydrogen peroxide under ambient conditions.

Immune response, hematological traits, biochemical blood parameters, and histological status of laying hens influenced by dietary chitosan-oligosaccharides

This experiment aimed to examine the effect of chitosan-oligosaccharides (COS) supplementation in laying hens' diets affected their immune response, hematological characteristics, blood biochemical parameters, and histological status. At the age of 34 wk, 200 laying hens and 20 cocks of the Mandarah chicken strain were allotted into four groups, each consisting of 50 hens and five cocks. The first group acted as a control group, fed on a basal diet. The second, third, and fourth experimental groups each received 0.1, 0.2, and 0.5 g/kg of COS in addition to a base diet. Birds received COS at various dosages had significantly (P ˂ 0.05) increased serum concentration of immunoglobulins, avian influenza, and Newcastle disease antibodies compared with the control birds. Moreover, adding COS at level 0.2 g/kg diet insignificantly enhanced immune response than the rest of the treatment groups. Also, treated birds with COS at different levels had insignificantly improved hematological parameters such as red blood cells, white blood cells, hemoglobin and hematocrit compared to the control group. Birds fed COS at all levels had significantly decreased serum cholesterol, triglycerides, Ca++ and alanine aminotransferase concentrations compared with control birds. In addition, compared to the control group, chitosan-treated birds showed enhanced histological examination of the small intestine, isthmus, and testis, notably in birds given COS at 0.1 g/kg diet compared to other treated birds. Cocks fed COS at all levels improved testicular tissues and increased the number and diameter of seminiferous tubules compared with control birds Morphological examination of the ileum showed increased villi number, height, and crypt depth. It is possible to conclude that laying hens' physiological performance and general health can be effectively improved by using chitosan at 0.1 or 2 g/kg diet levels enhanced immune response.

Influence of dietary chitosan-oligosaccharides supplementation on productive and reproductive performance of laying hens

This experiment aimed to ascertain whether adding chitosan-oligosaccharides (COS) to the diet will affect Mandarah laying hens’ productivity and reproductive efficiency. At the age of 34 weeks, 120 laying hens and 12 cocks of the Mandarah chicken strain were separated into four groups, each consisting of 30 hens and three cocks. The 1st group served as a control group, receiving only a basic diet. The 2nd, 3rd, and 4th experimental groups received 0.1, 0.2, and 0.5 g/kg of chitosan-oligosaccharides as an addition to the base diet, respectively. According to the findings of this study, the majority of the analyzed attributes differed significantly between treatment groups. Comparing the COS-treated birds to the control birds, the COS-treated birds significantly increased egg production, improved feed conversion, haugh unit score, shell thickness, fertility, hatchability, ovary weight, and the number of yellow ovarian follicles as well as blood estradiol-17β (E2) and testosterone concentrations. Furthermore, compared to the other treated groups, introducing COS at a level 0.1 g/kg diet resulted in the best laying rate, egg mass, and feed conversion. The highest percentage of fertility, hatchability of hatching eggs, ovary weight, number of yellow ovarian follicles, and serum E2 concentration was also found in birds fed COS at a dose of 0.2 g/kg feed. In addition, compared to the control diet, COS treatment at 0.1, 0.2, and 0.5 g/kg enhanced relative economic efficiency by 464.43, 457.41, and 352.75%, respectively. It is concluded that chitosan improves economic efficiency, reproductive performance, productivity in laying hens, and overall health when used at a 0.1 g/kg diet.

Calcium-Alginate-Chitosan Nanoparticle as a Potential Solution for Pesticide Removal, a Computational Approach

Pesticides have a significant negative impact on the environment, non-target organisms, and human health. To address these issues, sustainable pest management practices and government regulations are necessary. However, biotechnology can provide additional solutions, such as the use of polyelectrolyte complexes to encapsulate and remove pesticides from water sources. We introduce a computational methodology to evaluate the capture capabilities of Calcium-Alginate-Chitosan (CAC) nanoparticles for a broad range of pesticides. By employing ensemble-docking and molecular dynamics simulations, we investigate the intermolecular interactions and absorption/adsorption characteristics between the CAC nanoparticles and selected pesticides. Our findings reveal that charged pesticide molecules exhibit more than double capture rates compared to neutral counterparts, owing to their stronger affinity for the CAC nanoparticles. Non-covalent interactions, such as van der Waals forces, π-π stacking, and hydrogen bonds, are identified as key factors which stabilized the capture and physisorption of pesticides. Density profile analysis confirms the localization of pesticides adsorbed onto the surface or absorbed into the polymer matrix, depending on their chemical nature. The mobility and diffusion behavior of captured compounds within the nanoparticle matrix is assessed using mean square displacement and diffusion coefficients. Compounds with high capture levels exhibit limited mobility, indicative of effective absorption and adsorption. Intermolecular interaction analysis highlights the significance of hydrogen bonds and electrostatic interactions in the pesticide-polymer association. Notably, two promising candidates, an antibiotic derived from tetracycline and a rodenticide, demonstrate a strong affinity for CAC nanoparticles. This computational methodology offers a reliable and efficient screening approach for identifying effective pesticide capture agents, contributing to the development of eco-friendly strategies for pesticide removal.

Grafted chitosan thin films of various degrees of acetylation as a reusable platform for the investigation of biological interactions

Surface treatment by adhesive polymers is a promising solution to immobilize and study bacteria cells through microscopic assays and, for example, control their growth or determine their susceptibility to antibiotic treatment. The stability of such functional films in wet conditions is crucial, as the film degradation would compromise a persistent use of the coated devices. In this work, low roughness chitosan thin films of degrees of acetylation (DA) ranging from 0.5 % to 49 % were chemically grafted onto silicon and glass substrates and we have demonstrated how the physicochemical properties of the surfaces and the bacterial response were DA-dependent. A fully deacetylated chitosan film presented an anhydrous crystalline structure while the hydrated crystalline allomorph was the preferred structure at higher DA. Moreover, their hydrophilicity increased at higher DA, leading to higher film swelling. Low DA chitosan-grafted substrate favored bacterial growth away from the surface and could be envisioned as bacteriostatic surfaces. Contrarily, an optimum of Escherichia coli adhesion was found for substrates modified with chitosan of DA = 35 %: these surfaces are adapted for the study of bacterial growth and antibiotic testing, with the possibility of reusing the substrates without affecting the grafted film - ideal for limiting single-use devices.

Synergistic effect of Mn-Si-COS on wound immune microenvironment by inhibiting excessive skin fibrosis mediated with ROS/TGF-β1/Smad7 signal

Excessive oxidative stress and inflammation often impede wound healing and ultimately lead to excessive skin fibrosis formation. It was known that the structural properties of biomaterials can affect the healing and immune response of surrounding tissues. In this work, a composite structure of Mn-Si-chitooligosaccharides (COS) was designed (COS@Mn-MSN) and the ability of regulating wound microenvironment for inhibiting skin fibrosis was investigated. In order to reduce the negative effects of Mn, the nano-level Mn was doped into MSN to minimize its content. The results show that Mn in COS@Mn-MSN showed significant ability of scavenging excess intracellular ROS within 1 d. The Si released from COS@Mn-MSN can shift M2 macrophage polarization in the later stage (1-3 d), showing anti-inflammatory effect. Macrophage (RAW264.7) were activated alternatively by COS released from COS@Mn-MSN, with upregulated expression of anti-inflammatory factors (IL-10 and CD206) and downregulated expression of pro-inflammatory factors (TNF-α, CD80, and IL-1β) in the whole time. The expression of fibrosis associated factor TGF-β1 and CD26 in fibroblast cells (L929) were inhibited by COS and Si. Besides, the inflammatory microenvironment mediated by COS@Mn-MSN downregulated Smad-7 gene expression and upregulated Col-1α gene expression. With the function of reducing oxidative stress (0-1 d), the TGF-β1 inhibition (1-3 d) and anti-inflammatory effects (0-3 d), COS@Mn-MSN could inhibit excessive skin fibrosis formation mediated with ROS/TGF-β1/Smad7 signal. Therefore, the prepared COS@Mn-MSN shows great potential to active scarless wound therapy.

Impact of the Functional Coating of Silver Nanoparticles on their In Vivo Performance and Biosafety

OBJECTIVE AND SIGNIFICANCE

Silver nanoparticles (AgNPs) have become an interesting therapeutic modality and drug delivery platform. Herein, we aimed to investigate the impact of functional coating on the in vivo performance of AgNPs as an economic and scalable method to modulate their behavior.

METHODS

AgNPs were coated with chitosan (CHI) as a model biopolymer using a one-pot reduction-based method, where CHI of two molecular weight ranges were investigated. The resultant CHI-coated AgNPs (AgNPs-CHI) were characterized using UV-VIS spectroscopy, DLS, and TEM. AgNPs were administered intravenously to rats and their biodistribution and serum levels of hepato-renal function markers were monitored 24 h later compared to plain AgNO₃ as a positive control.

RESULTS

UV-VIS spectroscopy confirmed the successful coating of AgNPs with CHI. DLS revealed the superiority of medium molecular weight CHI over its low molecular weight counterpart. AgNPs-CHI demonstrated a semi-complete clearance from the systemic circulation, a liver-dominated tissue tropism, and a limited renal exposure. On the other hand, AgNO₃ was poorly cleared from the circulation, with a relatively high renal exposure and a non-specific tissue tropism. AgNPs-CHI were well-tolerated by the liver and kidney without signs of toxicity or inflammation, in contrary with AgNO₃ which resulted in a significant elevation of Creatinine (CRE), Urea, and Total Protein (TP), suggesting a significant nephrotoxicity and inflammation.

CONCLUSIONS

Functional coating of AgNPs with CHI substantially modulated their in vivo behavior, promoting their hepatic selectivity and biotolerability, which can be invested in the development of drug delivery systems for the treatment of liver diseases.

Development of a novel chitosan-based two-photon fluorescent nanoprobe with enhanced stability for the specific detection of endogenous H2O2

Hydrogen peroxide (H₂O₂) acts as an important reactive oxygen species (ROS) and maintains the redox equilibrium in organisms. Imbalance of H₂O₂ concentration is associated with the development of many diseases. Traditional small molecular based fluorescent probes often show drawbacks of cytotoxicity and easily metabolic clearance. Herein, a chitosan-based two-photon fluorescent nanoprobe (DC-BI) was constructed and applied for H₂O₂ detection in live organisms. DC-BI was composed by chitosan nanoparticles and a two-photon fluorophore of naphthalimide analogues (BI) with H₂O₂-responsive property. The structure of DC-BI was characterized by NMR, FTIR, XPS, XRD, DLS and MLS analyses. As study shown, the nanoprobe DC-BI exhibited improved distribution stability and smaller cytotoxicity. In the presence of H₂O₂, both the absorption and emission spectra show dramatic changes, the fluorescence intensity at 580 nm obviously enhanced. Furthermore, fluorescence imaging results indicate that DC-BI is capable of imaging endogenous H₂O₂ in cells and zebrafish. The design and development of chitosan-based nanoprobe DC-BI has provided a general example of nanoprobe construction with excellent distribution stability, two-photon property, and biocompatibility.

Boosting hair growth through follicular delivery of Melatonin through lecithin-enhanced Pickering emulsion stabilized by chitosan-dextran nanoparticles in testosterone induced androgenic alopecia rat model

The strategy in this work was loading Melatonin (MEL), the powerful antioxidant photosensitive molecule, in novel Pickering emulsions (PEs) stabilized by chitosan-dextran sulphate nanoparticles (CS-DS NPs) and enhanced by lecithin, for treatment of androgenic alopecia (AGA). Biodegradable CS-DS NPs dispersion was prepared by polyelectrolyte complexation and optimized for PEs stabilization. PEs were characterized for droplet size, zeta potential, morphology, photostability and antioxidant activity. Ex-vivo permeation study through rat full thickness skin was conducted with optimized formula. Differential tape stripping trailed by cyanoacrylate skin surface biopsy was executed, for quantifying MEL in skin compartments and hair follicles. In-vivo evaluation of MEL PE hair growth activity was performed on testosterone induced AGA rat model. Visual inspection followed by anagen to telogen phase ratio (A/T) and histopathological examinations were conducted and compared with marketed 5% minoxidil spray "Rogaine ®". Data showed that PE improved MEL antioxidant activity and photostability. Ex-vivo results displayed MEL PE high follicular deposition. In-vivo study demonstrated that MEL PE treated testosterone induced AGA rat group, restored hair loss and produced maximum hair regeneration along with prolonged anagen phase amongst tested groups. The histopathological examination revealed that MEL PE prolonged anagen stage, increased follicular density and A/T ratio by 1.5-fold. The results suggested that lecithin-enhanced PE stabilized by CS-DS NPs was found to be an effective approach to enhance photostability, antioxidant activity and follicular delivery of MEL. Thus, MEL-loaded PE could be a promising competitor to commercially marketed Minoxidil for treatment of AGA.

Interfacial adsorption behavior of the Aspergillus oryzae lipase-chitosan complex and stability evaluation of the resultant Pickering emulsion

To prompt the application of the chitosan (CS)-Aspergillus oryzae lipase (AOL) complex in the construction of novel biphasic catalysis medium, its Pickering emulsion stabilization ability as well as adsorption behavior in the oil-water interface were investigated and the stability of resultant emulsion was evaluated. The results indicated that the CS-AOL complex assembled in mass ratio 1:5 was an effective Pickering stabilizer and up to 90 % AOL could be retained in the emulsion interface. Quartz crystal microbalance with dissipation monitoring suggested that the CS-AOL complex spontaneously absorbed to oil-water interface; absorption dynamics analysis revealed that the adsorption was driven by diffusion accompanied by rapid structural rearrangement; while interfacial dilatational rheology demonstrated the formation of an elastic film in the oil-water interface. The Pickering emulsions were pseudoplastic and that in oil fraction 0.6 exhibited the elastic behavior in contrast to the viscous behavior in oil fractions 0.2 and 0.4. The Pickering emulsion exhibited excellent stability against storage for up to 28 d, pHs 2.0-12.0, heating at 25-90 °C, and up to 500 mmol/L NaCl, and the corresponding interfacial AOL retentions exceeded 80 % during exposure to these conditions. Hence, the CS-AOL complex could be used as a stabilizer to construct Pickering emulsion-based biphasic catalysis systems.

Effects of Dietary Rare Earth Chitosan Chelate on Performance, Egg Quality, Immune and Antioxidant Capacity, and Intestinal Digestive Enzyme Activity of Laying Hens

Rare earth chitosan chelate salt (RECC) is a potential feed additive and is a product of the chelation effect between rare earth ions and chitosan. This research study aims to explore the effects of dietary RECC on performance, egg quality, intestinal digestive function, and the immune and antioxidant capacity of laying hens in the late phase of production. A total of 360 56-week-old Dawu Jinfeng laying hens were randomly allotted into four treatment groups with six replicates per treatment and 15 birds per replicate. The laying hens were fed the basal diet supplemented with, respectively, 0 (control: CON), 100 (R1), 200 (R2), and 400 (R3) mg/kg for 8 weeks. Dietary RECC significantly improved average daily feed intake (ADFI) and average daily egg yield in both linear and quadratic manner (p < 0.05). In addition, albumen height and HU were improved significantly (p < 0.05) in a dose-dependent manner of RECC. In addition, a significant decrease (p < 0.05) in serum TP, IgA, and MDA for the R1 group and IgG in the R2 group were notable, while the increase in serum TP and decrease in T-AOC were found for R3 dietary group compared to CON (p < 0.05). The level of intestinal IL-2 and TNF-α was decreased by dietary RECC (p < 0.01). The activities of the digestive enzyme (α-Amylase, lipase, and Trypsin) showed a quadratic change with an increase and then decrease in response to increasing dose of RECC, 200 mg/kg RECC significantly increased the activity of lipase and Trypsin (p < 0.01). Supplementation of dietary RECC at low doses compared to higher doses impacted positive effects on the antioxidant capacity and immune function (p < 0.05). The utilization of RECC as a feed additive in the diet of aged laying hens exerted beneficial effects on egg production, albumen quality, humoral immunity, inflammatory response, and activity of digestive enzymes. Thus, the regulation of antioxidant capacity and duodenal function via increased enzyme activity and immune and inflammatory response were critical to the improvement of laying performance and egg quality in aged hens. The optimal supplemental dose is 100-200 mg/kg.

A review on extraction of polysaccharides from crustacean wastes and their environmental applications

Disposal of biodegradable waste of seashells leads to an environmental imbalance. A tremendous amount of wastes produced from flourishing shell fish industries while preparing crustaceans for human consumption can be directed towards proper utilization. The review of the present study focuses on these polysaccharides from crustaceans and a few important industrial applications. This review aimed to emphasize the current research on structural analyses and extraction of polysaccharides. The article summarises the properties of chitin, chitosan, and chitooligosaccharides and their derivatives that make them non-toxic, biodegradable, and biocompatible. Different extraction methods of chitin, chitosan, and chitooligosaccharides have been discussed in detail. Additionally, this information outlines possible uses for derivatives of chitin, chitosan, and chitooligosaccharides in the environmental, pharmaceutical, agricultural, and food industries. Additionally, it is essential to the textile, cosmetic, and enzyme-immobilization industries. This review focuses on new, insightful suggestions for raising the value of crustacean shell waste by repurposing a highly valuable material.

Preparation of highly stable and ultrasmooth chemically grafted thin films of chitosan

Chitosan-coated surfaces are of great interest for biomedical applications (antibacterial coatings, implants, would healing, single-cell microfluidics…). However, one major limitation of chitosan-based systems is the high solubility of the polymer under acidic aqueous conditions. Herein, we describe a simple procedure to prepare extremely smooth and stable chitosan coatings. In detail, chitosan films with a low degree of N-acetylation and of thicknesses varying from 40 nm to 10 μm were grafted onto epoxy-functionalized silicon wafers via an optimized water-temperature treatment (WTT). The formation of a grafted chitosan network insoluble in acidic aqueous media (pH 3.5) was evidenced and the films were stable for at least 2 days at pH 3.5. The film morphology and the swelling behavior were characterized by atomic force microscopy (AFM) and neutron reflectivity, which showed that the film roughness was extremely low. The physical cross-linking of the films was demonstrated using infrared spectroscopy, dynamic mechanical analysis (DMA) and wide-angle X-ray scattering (WAXS). Finally, we show that the swelling behavior of such films was largely influenced by the environmental conditions, such as the pH or ionic strength of the solution.

Natural antimicrobial oligosaccharides in the food industry

An increase in the number of antibiotic resistance genes burdens the environment and affects human health. Additionally, people have developed a cautious attitude toward chemical preservatives. This attitude has promoted the search for new natural antimicrobial substances. Oligosaccharides from various sources have been studied for their antimicrobial and prebiotic effects. Antimicrobial oligosaccharides have several advantages such as being produced from renewable resources and showing antimicrobial properties similar to those of chemical preservatives. Their excellent broad-spectrum antibacterial properties are primarily because of various synergistic effects, including destruction of pathogen cell wall. Additionally, the adhesion of harmful microorganisms and the role of harmful factors may be reduced by oligosaccharides. Some natural oligosaccharides were also shown to stimulate the growth probiotic organisms. Therefore, antimicrobial oligosaccharides have the potential to meet food processing industry requirements in the future. The latest progress in research on the antimicrobial activity of different oligosaccharides is demonstrated in this review. The possible mechanism of action of these antimicrobial oligosaccharides is summarized with respect to their direct and indirect effects. Finally, the extended applications of oligosaccharides from the food source industry to food processing are discussed.

Neurogenic Hypertension, the Blood-Brain Barrier, and the Potential Role of Targeted Nanotherapeutics

Hypertension is a major health concern globally. Elevated blood pressure, initiated and maintained by the brain, is defined as neurogenic hypertension (NH), which accounts for nearly half of all hypertension cases. A significant increase in angiotensin II-mediated sympathetic nervous system activity within the brain is known to be the key driving force behind NH. Blood pressure control in NH has been demonstrated through intracerebrovascular injection of agents that reduce the sympathetic influence on cardiac functions. However, traditional antihypertensive agents lack effective brain permeation, making NH management extremely challenging. Therefore, developing strategies that allow brain-targeted delivery of antihypertensives at the therapeutic level is crucial. Targeting nanotherapeutics have become popular in delivering therapeutics to hard-to-reach regions of the body, including the brain. Despite the frequent use of nanotherapeutics in other pathological conditions such as cancer, their use in hypertension has received very little attention. This review discusses the underlying pathophysiology and current management strategies for NH, as well as the potential role of targeted therapeutics in improving current treatment strategies.

Basella alba stem extract integrated poly (vinyl alcohol)/chitosan composite films: A promising bio-material for wound healing

Natural extract-based bio-composite material for wound healing is gaining much attention due to risk of infection and high cost of commercial wound dressing film causes serious problem on the human well-being. Herein, the study outlines the preparation of Poly (vinyl alcohol)/Chitosan/Basella alba stem extract (BAE) based bio-composite film through solvent casting technique and well characterized for wound healing application. Incorporation of BAE into Poly (vinyl alcohol)/Chitosan matrix has shown existence of secondary interactions confirmed by FT-IR analysis. Good morphology, thermal stability and significant improvement in flexibility (∼63.38 %) of the films were confirmed by SEM, TGA and Mechanical test results, respectively. Hydrophilic property (∼9.04 %), water vapor transmission rate (∼70.07 %), swelling ability (∼14.7 %) and degradation rate (∼14.04 %) were enhanced with increase in BAE content. In-vitro studies have shown good antibacterial activity against foremost infectious bacterial strains S. aureus and E. coli. Additionally, BAE integrated Poly (vinyl alcohol)/Chitosan film has amplified anti-inflammatory (∼79.38 %) property, hemocompatibility and excellent biocompatibility (94.9 %) was displayed by cytotoxicity results. Moreover, in-vitro scratch assay and cell adhesion test results illustrated prominent wound healing (96.5 %) and adhesion. Overall results of the present work proclaim that developed bio-composite film could be utilized as a biomaterial in wound care applications.

Effect of a carrageenan/chitosan coating with allyl isothiocyanate on microbial spoilage and quality of chicken breast

Approximately 3.7% of poultry meat is lost due to spoilage each year in the United States. The objective of this study was to determine the efficacy of a layered carrageenan/chitosan coating in combination with an application of two concentrations of allyl isothiocyanate (AITC) against lactic acid bacteria, aerobic bacteria, and yeast and mold during storage of chicken breast for 21 d. Additionally, the rancidity, color, and pH of the chicken breast as indicators of non-microbial quality were evaluated. The combination of carrageenan/chitosan coating with 20 and 200 ppm AITC reduced (P ≤ 0.05) yeast and mold populations by 3 log₁₀ CFU/g at d 21 compared to the untreated control. The carrageenan/chitosan coating with 20 and 200 ppm AITC delayed aerobic spoilage by 3 and 12 d, respectively, compared to the untreated control; aerobic bacteria populations on the samples treated with 200 ppm AITC remained below the threshold for spoilage (∼6 log₁₀ CFU/g) for the duration of storage. The pH of the 20 ppm and 200 ppm AITC-treated chicken breast was unaltered (P > 0.05) at the end of storage and was lower than the pH of the untreated and coating-only-treated control chicken breast at d 18 through the end of storage (P ≤ 0.05). The application of the coating alone did not (P > 0.05) affect L*, a*, and b* values of the chicken breast at the end of storage compared to the uncoated control. The carrageenan/chitosan coating with 20 and 200 ppm AITC prevented decreases in the lightness (L* values) of the chicken breast at the end of storage (P ≤ 0.05) compared to the control and coating-only-treated samples. The coating alone or with AITC did not (P > 0.05) impact the rancidity of the chicken breast over the 21-d storage period, thus showing potential to be used as antimicrobial packaging to increase shelf life of fresh poultry.

Chitin Derived Small Molecule AVR-48 Reprograms the Resting Macrophages to an Intermediate Phenotype and Decrease Pseudomonas aeruginosa Mouse Lung Infection

AVR-48 is a structural derivative of chitin previously shown by our laboratory to significantly decrease lung injury parameters in LPS, hyperoxia and sepsis-induced rodent models. The current study objectives are to determine the cellular mechanism of action and demonstrate efficacy in a mouse bacterial lung infection model. For in vitro receptor binding and macrophage polarization studies, C57Bl/6J mouse derived spleens and human peripheral blood mononuclear cells (hPBMCs) were treated with AVR-48 ± LPS or biotin conjugated AVR-48. Different macrophage types were determined using flow cytometry and secreted cytokines were measured using ELISA. In vivo, a CD-1 mouse Pseudomonas aeruginosa lung infection was treated with AVR-48, assessing bacterial colony forming unit (CFU), IL-10 and IL-17A levels in lung and blood samples. AVR-48 binds to both the toll-like receptor 4 (TLR4) and the CD163 receptor on mouse monocytes. In hPBMCs, frequency of intermediate macrophages increased upon AVR-48 treatment for 72 h. Increased bacterial phagocytosis/intracellular killing were observed in THP-1 cells and reduction in CFU in CD-1 mouse lungs. Binding of AVR-48 to both TLR4 and CD163 receptors bring the macrophages to an intermediary stage, resulting in increased phagocytosis and decreased inflammation, altogether providing an optimal immune balance for treating lung injury and infection.

Chitosan as a Functional Carrier for the Local Delivery Anti-Inflammatory Systems Containing Scutellariae baicalensis radix Extract

The aim of the study was to establish the influence of chitosan on the preparation of systems containing Scutellariae baicalensis radix extract and to demonstrate the potential of anti-inflammatory action for the treatment of periodontitis. In the first stage, the impact of the variables (extraction mixture composition, temperature, and the number of extraction cycles) on the extracted samples' biological characteristics was analyzed using the Design of Experiments (DoE) approach. The best conditions for baicalin, baicalein, and wogonin extraction from Scutellariae baicalensis radix were 80% methanol in the extraction mixture, 70 °C, and 4 cycles per 60 min. The DoE approach can be used to choose the best chitosan system parameters with equal success. An increase in the deacetylation degree of chitosan used in the system improved the potential for reducing free radicals and inhibiting the hyaluronidase enzyme. Also, increasing the degree of chitosan deacetylation results in increased resistance of the carrier to biodegradation and an extended baicalin release profile, which is also associated with an increase in the viscosity of the chitosan-based system. In total, the system of a freeze-dried extract with chitosan 90/500 in the ratio of 2:1 (system S9) turns out to be the one with the best physicochemical (high percentage of baicalin release and the highest viscosity conditioning the prolonged stay at the site of administration) and biological properties (the highest antioxidant and anti-inflammatory activities), resulting in the highest potential for use in the treatment of oral inflammatory diseases.