Chitosan chemistry review for living organisms encapsulation

Chitosan-grafted Graphene Materials for Drug Delivery in Wound Healing

The effective and prompt treatment of wounds remains a significant challenge in clinical settings. Consequently, recent investigations have led to the development of a novel wound dressing production designed to expedite the process of wound healing with minimal adverse complications. Chitosan, identified as a natural biopolymer, emerges as an appealing option for fabricating environmentally friendly dressings due to its biologically degradable, nonpoisonous, and inherent antimicrobial properties. Concurrently, graphene oxide has garnered attention from researchers as an economical, biocompatible material with non-toxic attributes for applications in wound healing. Chitosan (CS) has been extensively studied in agglutination owing to its advantageous properties, such as Non-toxicity biological compatibility, degradability, and facilitation of collagen precipitation. Nonetheless, its limited Medium mechanical and antibacterial strength characteristics impede its widespread clinical application. In addressing these shortcomings, numerous researchers have embraced nanotechnology, specifically incorporating metal nanoparticles (MNPs), to enhance the mechanical power and targeted germicide features of chitosan multistructures, yielding hopeful outcomes. Additionally, chitosan is a decreasing factor for MNPs, contributing to reduced cytotoxicity. Consequently, the combination of CS with MNPs manifests antibacterial function, superior mechanical power, and anti-inflammatory features, holding significant potential to expedite wound healing. This study delves into based on chitosan graphene materials in the context of wound healing.

Advances in the preparation, applications, challenges, and future trends of polysaccharide-based gels as food-grade delivery systems for probiotics: A review

Probiotics are highly regarded for their multiple functions, such as regulating gut health, enhancing the immune system, and preventing chronic diseases. However, their stability in harsh environments and targeted release remain significant challenges. Therefore, exploring effective protection and delivery strategies to ensure targeted release of probiotics is critically important. Polysaccharides, known for their non-toxicity, excellent biocompatibility, and superior biodegradability, show broad prospects in probiotic delivery by forming physical barriers to protect the probiotics. Particularly, polysaccharide-based gels (PBGs), with their unique "spider-web" like structure, capture and ensure the targeted release of probiotics, significantly enhancing their efficacy. This review discusses common polysaccharides used in PBG preparation, their classification and synthesis in food applications, and the advantages of PBGs as probiotic delivery systems. Despite their potential, challenges such as inconsistent gel properties and the need for improved stability remain. Future research should focus on developing novel PBG materials with higher biodegradability and mechanical strength, optimizing the physicochemical properties and cross-linking methods, as well as designing multilayered structures for more precise release control. Additionally, exploring the co-delivery of probiotics with prebiotics, active ingredients, or multi-strain systems could further enhance the efficacy of probiotic delivery.

Functional potential of chitosan-metal nanostructures: Recent developments and applications

Chitosan (Cs), a naturally occurring biopolymer, has garnered significant interest due to its inherent biocompatibility, biodegradability, and minimal toxicity. This study investigates the effectiveness of various reaction strategies, including acylation, acetylation, and carboxymethylation, to enhance the solubility profile of Cs. This review provides a detailed examination of the rapidly developing field of Cs-based metal complexes and nanoparticles. It delves into the diverse synthesis methodologies employed for their fabrication, specifically focusing on ionic gelation and in-situ reduction techniques. Furthermore, the review offers a comprehensive analysis of the characterization techniques utilized to elucidate the physicochemical properties of these complexes. A range of analytical techniques are utilized, including Ultraviolet-Visible Spectroscopy (UV-Vis), Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and others. By comprehensively exploring a wide range of applications, the review emphasizes the significant potential of Cs in various scientific disciplines. Diagrams, figures, and tables effectively illustrate the synthesis processes, promoting a clear understanding for the reader. Chitosan-metal nanostructures/nanocomposites significantly enhance antimicrobial efficacy, drug delivery, and environmental remediation compared to standard chitosan composites. The integration of metal nanoparticles, such as silver or gold, improves chitosan's effectiveness against a range of pathogens, including resistant bacteria. These nanocomposites facilitate targeted drug delivery and controlled release, boosting therapeutic bioavailability. Additionally, they enhance chitosan's ability to absorb heavy metals and dyes from wastewater, making them effective for environmental applications. Overall, chitosan-metal nanocomposites leverage chitosan's biocompatibility while offering improved functionalities, making them promising materials for diverse applications. This paper sheds light on recent advancements in the applications of Cs metal complexes for various purposes, including cancer treatment, drug delivery enhancement, and the prevention of bacterial and fungal infections.

Effects of chitosan on plant growth under stress conditions: similarities with plant growth promoting bacteria

The agricultural use of synthetic pesticides, fertilizers, and growth regulators may represent a serious public health and environmental problem worldwide. All this has prompted the exploration of alternative chemical compounds, leading to exploring the potential of chitosan and PGPB in agricultural systems as a potential biotechnological solution to establish novel agricultural production practices that not only result in fewer adverse impacts on health and the environment but also improve the resilience and growth of the plants. In this work, an analysis of the impact of plant growth-promoting bacteria (PGPB) and chitosan on plant growth and protection has been conducted, emphasizing the crucial bioactivities of the resistance of the plants to both biotic and abiotic stressors. These include inducing phytohormone production, mobilization of insoluble soil nutrients, biological nitrogen fixation, ethylene level regulation, controlling soil phytopathogens, etc. Moreover, some relevant aspects of chitin and chitosan are discussed, including their chemical structures, sources, and how their physical properties are related to beneficial effects on agricultural applications and mechanisms of action. The effects of PGPB and chitosan on photosynthesis, germination, root development, and protection against plant diseases have been compared, emphasizing the intriguing similarities and synergistic effects observed in some of these aspects. Although currently there are limited studies focused on the combined application of PGPB and chitosan, it would be important to consider the similarities highlighted in this work, and those that may emerge in future studies or through well-designed investigations, because these could permit advancing towards a greater knowledge of these systems and to obtain better formulations by combining these bioproducts, especially for use in the new contexts of sustainable agriculture. Thus, it seems feasible to augur a promising near future for these combinations, considering the wide range of possibilities offered by chitinous biomaterials for the development of innovative formulations, as well as allowing different application methods. Likewise, the studies related to the PGPB effects on plant growth appear to be expanding due to ongoing research to test on plants the impacts of microorganisms derived from different environments, whether known or recently discovered, making it a very exciting field of research.

Chitosan coating of seeds improves the germination and growth performance of plants: A Rreview

This review article explores the fascinating world of chitosan coating applied to seeds and its profound impacts on enhancing the germination process and growth performance of plants. Chitosan, a biodegradable and non-toxic polysaccharide derived from chitin, has shown remarkable potential in seed treatment due to its bioactive properties. The review discusses the mechanisms of chitosan's effect on plant germination including promoting water uptake, enhancing nutrient absorption, and protecting seeds from biotic and abiotic stresses. Moreover, it evaluates the effects of chitosan on plant growth parameters such as root development, shoot growth, chlorophyll content, and overall yield. The review also discusses the sustainable aspects of chitosan coatings in agriculture, emphasizing their eco-friendly nature and potential for reducing reliance on synthetic chemicals. Overall, the findings underscore the significant benefits of chitosan-coated seeds in improving the overall performance of plants, paving the way for a greener and more productive agricultural future. Finally, the article will conclude with a SWOT analysis discussing the strengths, weaknesses, opportunities, and threats of this technology.

Droplet Microfluidics Powered Hydrogel Microparticles for Stem Cell-Mediated Biomedical Applications

Stem cell-related therapeutic technologies have garnered significant attention of the research community for their multi-faceted applications. To promote the therapeutic effects of stem cells, the strategies for cell microencapsulation in hydrogel microparticles have been widely explored, as the hydrogel microparticles have the potential to facilitate oxygen diffusion and nutrient transport alongside their ability to promote crucial cell-cell and cell-matrix interactions. Despite their significant promise, there is an acute shortage of automated, standardized, and reproducible platforms to further stem cell-related research. Microfluidics offers an intriguing platform to produce stem cell-laden hydrogel microparticles (SCHMs) owing to its ability to manipulate the fluids at the micrometer scale as well as precisely control the structure and composition of microparticles. In this review, the typical biomaterials and crosslinking methods for microfluidic encapsulation of stem cells as well as the progress in droplet-based microfluidics for the fabrication of SCHMs are outlined. Moreover, the important biomedical applications of SCHMs are highlighted, including regenerative medicine, tissue engineering, scale-up production of stem cells, and microenvironmental simulation for fundamental cell studies. Overall, microfluidics holds tremendous potential for enabling the production of diverse hydrogel microparticles and is worthy for various stem cell-related biomedical applications.

Recent advances on chitosan/hyaluronic acid-based stimuli-responsive hydrogels and composites for cancer treatment: A comprehensive review

Cancer, as leading cause of death, has a high rate of mortality worldwide. Although there is a wide variety of conventional approaches for the treatment of cancer (such as surgery and chemotherapy), they have considerable drawbacks in terms of practicality, treatment efficiency, and cost-effectiveness. Therefore, there is a fundamental requirement for the development of safe and efficient treatment modalities based on breakthrough technologies to suppress cancer. Chitosan (CS) and hyaluronic acid (HA) polysaccharides, as FDA-approved biomaterials for some biomedical applications, are potential biopolymers for the efficient treatment of cancer. CS and HA have high biocompatibility, bioavailability, biodegradability, and immunomodulatory function which guarantee their safety and non-toxicity. CS-/HA-based hydrogels (HGs)/composites stand out for their potential anticancer function, versatile preparation and modification, ease of administration, controlled/sustained drug release, and active and passive drug internalization into target cells which is crucial for efficient treatment of cancer compared with conventional treatment approaches. These HGs/composites can respond to external (magnetic, ultrasound, light, and thermal) and internal (pH, enzyme, redox, and ROS) stimuli as well which further paves the way to their manipulation, targeted drug delivery, practicality, and efficient treatment. The above-mentioned properties of CS-/HA-based HGs/composites are unique and practical in cancer treatment which can ignore the deficiencies of conventional approaches. The present manuscript comprehensively highlights the advances in the practical application of stimuli-responsive HGs/composites based on CS/HA polysaccharides.

Chitosan-based biomaterials promote bone regeneration by regulating macrophage fate

The development of various osteogenic biomaterials has not only promoted the development of bone tissue engineering but also provided more possibilities for bone defect repair. However, most previous studies have focused on the interaction of biomaterials on endogenous or exogenous stem cells involved in the bone regeneration process while neglecting the effect of changes in the immune microenvironment of bone defect sites on bone regeneration after biomaterial implantation into the host. With the development of bone immunology, the role of various immune cells, especially macrophages, in bone regeneration has gradually attracted the attention of researchers. An increasing number of studies have begun to target macrophages to better promote bone regeneration by modulating the fate of macrophages in a spatiotemporally ordered manner to mimic the changes in the immune microenvironment of bone defect sites during the natural repair process of bone tissue. Chitosan is one of the most abundant natural polysaccharides in the world. In recent years, various chitosan-based biomaterials have been widely used in macrophage fate modulation and bone regeneration. In this review, we review the interaction between macrophages and scaffold materials, general information about chitosan, the modulation of macrophage fate by chitosan-based biomaterials, and their application in bone regeneration.

Advances in Functionalized Biocomposites of Living Cells Combined with Metal-Organic Frameworks

Motivated by the remarkable innate characteristics of cells in living organisms, we have found that hybrid materials that combine bioorganisms with nanomaterials have significantly propelled advancements in industrial applications. However, the practical deployment of unmodified living entities is inherently limited due to their sensitivity to environmental fluctuations. To surmount these challenges, an efficacious strategy for the biomimetic mineralization of living organisms with nanomaterials has emerged, demonstrating extraordinary potential in biotechnology. Among them, innovative composites have been engineered by enveloping bioorganisms with a metal-organic framework (MOF) coating. This review systematically summarizes the latest developments in living cells/MOF-based composites, detailing the methodologies employed in structure fabrication and their diverse applications, such as bioentity preservation, sensing, catalysis, photoluminescence, and drug delivery. Moreover, the synergistic benefits arising from the individual compounds are elucidated. This review aspires to illuminate new prospects for fabricating living cells/MOF composites and concludes with a perspective on the prevailing challenges and impending opportunities for future research in this field.

Advances in chitosan-based blends as potential drug delivery systems: A review

During the last decades, the ever-increasing incidence of diseases has led to high rates of mortality throughout the world. On the other hand, the inability and deficiencies of conventional approaches (such as chemotherapy) in the suppression of diseases remain challenging issues. As a result, there is a fundamental requirement to develop novel, biocompatible, bioavailable, and practical nanomaterials to prevent the incidence and mortality of diseases. Chitosan (CS) derivatives and their blends are outstandingly employed as promising drug delivery systems for disease therapy. These biopolymers are indicated more efficient performance against diseases compared with conventional modalities. The CS blends possess improved physicochemical properties, ease of preparation, high affordability, etc. characteristics compared with other biopolymers and even pure CS which result in efficient thermal, mechanical, biochemical, and biomedical features. Also, these blends can be administrated through different routes without a long-term treatment period. Due to the mentioned properties, numerous formulations of CS blends are developed for pharmaceutical sciences to treat diseases. This review article highlights the progressions in the development of CS-based blends as potential drug delivery systems against diseases.

Using waste biomass to produce 3D-printed artificial biodegradable structures for coastal ecosystem restoration

The loss of ecosystem functions and services caused by rapidly declining coastal marine ecosystems, including corals and bivalve reefs and wetlands, around the world has sparked significant interest in interdisciplinary methods to restore these ecologically and socially important ecosystems. In recent years, 3D-printed artificial biodegradable structures that mimic natural life stages or habitat have emerged as a promising method for coastal marine restoration. The effectiveness of this method relies on the availability of low-cost biodegradable printing polymers and the development of 3D-printed biomimetic structures that efficiently support the growth of plant and sessile animal species without harming the surrounding ecosystem. In this context, we present the potential and pathway for utilizing low-cost biodegradable biopolymers from waste biomass as printing materials to fabricate 3D-printed biodegradable artificial structures for restoring coastal marine ecosystems. Various waste biomass sources can be used to produce inexpensive biopolymers, particularly those with the higher mechanical rigidity required for 3D-printed artificial structures intended to restore marine ecosystems. Advancements in 3D printing methods, as well as biopolymer modifications and blending to address challenges like biopolymer solubility, rheology, chemical composition, crystallinity, plasticity, and heat stability, have enabled the fabrication of robust structures. The ability of 3D-printed structures to support species colonization and protection was found to be greatly influenced by their biopolymer type, surface topography, structure design, and complexity. Considering limited studies on biodegradability and the effect of biodegradation products on marine ecosystems, we highlight the need for investigating the biodegradability of biopolymers in marine conditions as well as the ecotoxicity of the degraded products. Finally, we present the challenges, considerations, and future perspectives for designing tunable biomimetic 3D-printed artificial biodegradable structures from waste biomass biopolymers for large-scale coastal marine restoration.

Chitosan-based nanofibrous scaffolds for biomedical and pharmaceutical applications: A comprehensive review

Nowadays, there is a wide range of deficiencies in treatment of diseases. These limitations are correlated with the inefficient ability of current modalities in the prognosis, diagnosis, and treatment of diseases. Therefore, there is a fundamental need for the development of novel approaches to overcome the mentioned restrictions. Chitosan (CS) nanoparticles, with remarkable physicochemical and mechanical properties, are FDA-approved biomaterials with potential biomedical aspects, like serum stability, biocompatibility, biodegradability, mucoadhesivity, non-immunogenicity, anti-inflammatory, desirable pharmacokinetics and pharmacodynamics, etc. CS-based materials are mentioned as ideal bioactive materials for fabricating nanofibrous scaffolds. Sustained and controlled drug release and in situ gelation are other potential advantages of these scaffolds. This review highlights the latest advances in the fabrication of innovative CS-based nanofibrous scaffolds as potential bioactive materials in regenerative medicine and drug delivery systems, with an outlook on their future applications.

Development of chitosan/carrageenan macrobeads for encapsulation of Paenibacillus polymyxa and its biocontrol efficiency against clubroot disease in Brassica crops

Clubroot, caused by the obligate parasite Plasmodiophora brassicae, is one of the most important diseases of brassicas. The antagonistic bacterium Paenibacillus polymyxa ZF129 can suppress clubroot while its effectiveness is often unstable. To control clubroot more effectively, the macrobeads for controlled release of ZF129 were prepared using microencapsulation technology. Macrobeads with various ratios of chitosan (2 % w/w): carrageenan (0.3 % w/v) were prepared by an ionotropic gelation method and the bacteria ZF129 was loaded into macrobeads. The 1:1 chitosan: carrageenan showed the maximum swelling ratio (634 %), and the maximum survival rate (61.52 ± 1.12 %) after freeze-drying. Fourier transform infrared revealed the electrostatic interactions between chitosan and carrageenan. The macrobeads can efficiently release ZF129 strains into phosphate buffer solution and reach equilibrium in 48 h. The maximum number of bacteria cells to be released in the soil was observed after 25-30 days. The control efficacy of ZF129 macrobeads (chitosan: carrageenan, 1:1) and ZF129 culture against clubroot disease was 76.33 ± 3.65 % and 59.76 ± 4.43 % in greenhouse experiments, respectively and the control efficacy was calculated as 60.74 ± 5.00 % for ZF129 macrobeads and 40.94 ± 4.05 % for ZF129 culture under field experiments, respectively. The ZF129 macrobeads had significant growth-promoting effects on pak choi and Chinese cabbage. The encapsulation method described in this study is a prudent approach toward efficient biopesticides utilization with reduced environmental implications.

Construction of a layer-by-layer self-assembled rosemarinic acid delivery system on the surface of CFRPEEK implants for enhanced anti-inflammatory and osseointegration activities

Carbon fiber-reinforced polyether ether ketone (CFRPEEK) implants have attracted widespread attention in the field of clinical bone defect repair. However, the surface bioinertness confines the application of CFRPEEK implants. Inspired by the study of rosmarinic acid (RA)-promoted osteogenic differentiation, a self-assembly surface modification method based on electrostatic interactions, involving deposition of sodium carboxymethyl cellulose/chitosan and rosmarinic acid layer by layer on the surface of poly-L-lysine modified hydroxy CFRPEEK (SCPP/CC5@RA), is proposed to introduce RA on the surface of CFRPEEK for bioactivation. After layer-by-layer self-assembly (LBL), the surface of SCPP/CC5@RA exhibits weak electrophoresis (11.43 eV), suitable hydrophilicity, and bioactivity. The results of in vitro studies indicate that the RA release behavior of SCPP/CC5@RA effectively regulates the immune-inflammatory response and promotes the differentiation of osteoblasts. The rapid release of RA (0.17 μg mL-1) in the initial stage can downregulate the secretion of inflammation-related cytokines and significantly reduce oxidative stress levels; the sustained release of RA (0.06 μg mL-1) in the late stage can upregulate the expression of osteogenesis-related genes and induce mineralization of osteoblasts. Moreover, the rabbit tibia defect model demonstrates that the LBL technique can enhance the osseointegration of CFRPEEK implants. Compared with the control group, the bone trabecular thickness of the SCPP/CC5@RA group increases by 1.36 times, and the maximum pushing force increases by 2.67 times. In summary, this study provides a promising LBL based RA delivery system for the development of a dual-functional CFRPEEK implant in the field of bone implant biomaterials.

Chitosan entrapping of sodium alginate / Lycium barbarum polysaccharide gels for the encapsulation, protection and delivery of Lactiplantibacillus plantarum with enhanced viability

To preserve the viability of probiotics during digestion and storage, encapsulation techniques are necessary to withstand the challenges posed by adverse environments. A core-shell structure has been developed to provide protection for probiotics. By utilizing sodium alginate (SA) / Lycium barbarum polysaccharide (LBP) as the core material and chitosan (CS) as the shell, the probiotic load reached 9.676 log CFU/mL. This formulation not only facilitated continuous release in the gastrointestinal tract but also enhanced thermal stability and storage stability. The results obtained from Fourier transform infrared spectroscopy and thermogravimetric analysis confirmed that the addition of LBP and CS affected the microstructure of the gel by enhancing the hydrogen bond force, so as to achieve controlled release. Following the digestion of the gel within the gastrointestinal tract, the released amount was determined to be 9.657 log CFU/mL. The moisture content and storage stability tests confirmed that the encapsulated Lactiplantibacillus plantarum maintained good activity for an extended period at 4 °C, with an encapsulated count of 8.469 log CFU/mL on the 28th day. In conclusion, the newly developed core-shell gel in this study exhibits excellent probiotic protection and delivery capabilities.

Exploring modified chitosan-based gene delivery technologies for therapeutic advancements

One of the critical steps in gene therapy is the successful delivery of the genes. Immunogenicity and toxicity are major issues for viral gene delivery systems. Thus, non-viral vectors are explored. A cationic polysaccharide like chitosan could be used as a nonviral gene delivery vector owing to its significant interaction with negatively charged nucleic acid and biomembrane, providing effective cellular uptake. However, the native chitosan has issues of targetability, unpacking ability, and solubility along with poor buffer capability, hence requiring modifications for effective use in gene delivery. Modified chitosan has shown that the "proton sponge effect" involved in buffering the endosomal pH results in osmotic swelling owing to the accumulation of a greater amount of proton and chloride along with water. The major challenges include limited exploration of chitosan as a gene carrier, the availability of high-purity chitosan for toxicity reduction, and its immunogenicity. The genetic drugs are in their infancy phase and require further exploration for effective delivery of nucleic acid molecules as FDA-approved marketed formulations soon.

Melatonin in cancer biology: pathways, derivatives, and the promise of targeted delivery

Melatonin, historically recognized for its primary role in regulating circadian rhythms, has expanded its influence particularly due to its wide range of biological activities. It has firmly established itself in cancer research. To highlight its versatility, we delved into how melatonin interacts with key signaling pathways, such as the Wnt/β-Catenin, PI3K, and NF-κB pathways, which play foundational roles in tumor development and progression. Notably, melatonin can intricately modulate these pathways, potentially affecting various cellular functions such as apoptosis, metastasis, and immunity. Additionally, a comprehensive review of current clinical studies provides a dual perspective. These studies confirm melatonin's potential in cancer management but also underscore its inherent limitations, particularly its limited bioavailability, which often relegates it to a supplementary role in treatments. Despite this limitation, there is an ongoing quest for innovative solutions and current advancements include the development of melatonin derivatives and cutting-edge delivery systems. By synthesizing the past, present, and future, this review provides a detailed overview of melatonin's evolving role in oncology, positioning it as a potential cornerstone in future cancer therapeutics.

Advances in polysaccharides for probiotic delivery: Properties, methods, and applications

Probiotics are essential to improve the health of the host, whereas maintaining the viability of probiotics in harsh environments remains a challenge. Polysaccharides have non-toxicity, excellent biocompatibility, and outstanding biodegradability, which can protect probiotics by forming a physical barrier and show a promising prospect for probiotic delivery. In this review, we summarize polysaccharides commonly used for probiotic microencapsulation and introduce the microencapsulation technologies, including extrusion, emulsion, spray drying, freeze drying, and electrohydrodynamics. We discuss strategies for better protection of probiotics and introduce the applications of polysaccharides-encapsulated probiotics in functional food, oral formulation, and animal feed. Finally, we propose the challenges of polysaccharides-based delivery systems in industrial production and application. This review will help provide insight into the advances and challenges of polysaccharides in probiotic delivery.

Advances in chitosan-based hydrogels for pharmaceutical and biomedical applications: A comprehensive review

The treatment of diseases, such as cancer, is one of the most significant issues correlated with human beings health. Hydrogels (HGs) prepared from biocompatible and biodegradable materials, especially biopolymers, have been effectively employed for the sort of pharmaceutical and biomedical applications, including drug delivery systems, biosensors, and tissue engineering. Chitosan (CS), one of the most abundant bio-polysaccharide derived from chitin, is an efficient biomaterial in the prognosis, diagnosis, and treatment of diseases. CS-based HGs possess some potential advantages, like high values of bioactive encapsulation, efficient drug delivery to a target site, sustained drug release, good biocompatibility and biodegradability, high serum stability, non-immunogenicity, etc., which made them practical and useful for pharmaceutical and biomedical applications. In this review, we summarize recent achievements and advances associated with CS-based HGs for drug delivery, regenerative medicine, disease detection and therapy.

Chitosan-glucose derivative as effective wall material for probiotic yeasts microencapsulation

A chitosan-glucose derivative (ChG) with lower antimicrobial activity against whey native probiotic yeast K. marxianus VM004 was synthesized by the Maillard reaction. The ChG derivative was characterized by FT-IR, 1H NMR, and SLS to determine the structure, deacetylation degree (DD), and molecular weight (Mw). In addition, we evaluated the antioxidant, cytotoxic, and antimicrobial activities of ChG. ChG was then used for microencapsulation of K. marxianus VM004 by spray drying. The microcapsules were characterized by evaluating their encapsulation yield, encapsulation efficiency, morphology, tolerance to the gastrointestinal tract, and viability during storage. The results indicated that a non-cytotoxic product with lower MW and DD and higher antioxidant activity than native chitosan was obtained by the Maillard reaction. The yeast ChG microcapsules exhibited an encapsulation efficiency >57 %, improved resistance to gastrointestinal conditions, and enhanced stability during storage. These results demonstrate that ChG may be a promising wall material for the microencapsulation of probiotic yeasts.

Triggerable Prodrug Nanocoating Enables On-Demand Activation of Microbial and Small-Molecular Therapeutics for Combination Treatment

The synergy of living microbial and small-molecular therapeutics has been widely explored for treating a variety of diseases, while current combination strategies often suffer from low bioavailability, heterogeneous spatiotemporal distribution, and premature drug release. Here, the use of a triggerable prodrug nanocoating is reported to enable the on-demand activation of microbial and small-molecular therapeutics for combination treatment. As a proof-of-concept study, a reactive oxygen species-responsive aromatic thioacetal linker is employed to prepare cationic chitosan-drug conjugates, which can form a nanocoating on the surface of living bacteria via electrostatic interaction. Following administration, the wrapped bacteria can be prevented from in vivo insults by the shielding effect of the nanocoating and be co-delivered with the conjugated drug in a spatiotemporally synchronous manner. Upon reaching the lesion site, the upgraded reactive oxygen species trigger in situ cleavage of the thioacetal linker, resulting in the release of the conjugated drug and a linker-derived therapeutic cinnamaldehyde. Meanwhile, a charge reversal achieved by the generation of negatively charged thiolated chitosan induces the dissociation of the nanocoating, leading to synchronous release of the living bacteria. The adequate activation of the combined therapeutics at the lesion site exhibits superior synergistic treatment efficacy, as demonstrated by an in vivo assessment using a mouse model of colitis. This work presents an appealing approach to combine living microbial and small-molecular therapeutics for advanced therapy of diseases.

Encapsulation in Oxygen-Loaded Nanobubbles Enhances the Antimicrobial Effectiveness of Photoactivated Curcumin

In both healthcare and agriculture, antibiotic resistance is an alarming issue. Biocompatible and biodegradable ingredients (e.g., curcumin) are given priority in "green" criteria supported by the Next Generation EU platform. The solubility and stability of curcumin would be significantly improved if it were enclosed in nanobubbles (NB), and photoactivation with the correct wavelength of light can increase its antibacterial efficacy. A continuous release of curcumin over a prolonged period was provided by using innovative chitosan-shelled carriers, i.e., curcumin-containing nanobubbles (Curc-CS-NBs) and oxygen-loaded curcumin-containing nanobubbles (Curc-Oxy-CS-NBs). The results demonstrated that after photoactivation, both types of NBs exhibited increased effectiveness. For Staphylococcus aureus, the minimum inhibitory concentration (MIC) for Curc-CS-NBs remained at 46 µg/mL following photodynamic activation, whereas it drastically dropped to 12 µg/mL for Curc-Oxy-CS-NBs. Enterococcus faecalis shows a decreased MIC for Curc-CS-NB and Curc-Oxy-CS-NB (23 and 46 µg/mL, respectively). All bacterial strains were more effectively killed by NBs that had both oxygen and LED irradiation. A combination of Curc-Oxy-CS-NB and photodynamic stimulation led to a killing of microorganisms due to ROS-induced bacterial membrane leakage. This approach was particularly effective against Escherichia coli. In conclusion, this work shows that Curc-CS-NBs and Curc-Oxy-CS-exhibit extremely powerful antibacterial properties and represent a potential strategy to prevent antibiotic resistance and encourage the use of eco-friendly substitutes in agriculture and healthcare.

FOF1-ATPase Motor-Embedded Chromatophore as Drug Delivery System: Extraction, Cargo Loading Ability and Mucus Penetration Ability

Mucosal drug delivery permits direct and prompt drug absorption, which is capable of reducing undesirable decomposition that occurs before absorption. However, mucus clearance of those mucosal drug delivery systems strongly retards their actual application. Herein, we propose chromatophore nanoparticles embedded with FOF1-ATPase motors to promote mucus penetration. The FOF1-ATPase motor-embedded chromatophores were firstly extracted from Thermus thermophilus by using a gradient centrifugation method. Then, the model drug (curcumin) was loaded onto the chromatophores. The drug loading efficiency and entrapment efficiency were optimized by using different loading approaches. The activity, motility, stability and mucus permeation of the drug-loaded chromatophore nanoparticles were thoroughly investigated. Both the in vitro and in vivo studies revealed that the FOF1-ATPase motor-embedded chromatophore successfully enhanced mucus penetration glioma therapy. This study indicates that the FOF1-ATPase motor-embedded chromatophore is a promising alternative as a mucosal drug delivery system.

Quaternized chitosan (nano)fibers: A journey from preparation to high performance applications

The industrial production of chitosan, initiated over 50 years ago, has transformed its application across diverse industries, agriculture, and medicine. To enhance its properties, numerous chitosan derivatives have been synthesized. The quaternization of chitosan has proven beneficial, as it not only enhances its properties but also imparts water solubility, expanding its potential for a wider range of applications. Specifically, the utilization of quaternized chitosan-based nanofibers has leveraged the synergistic benefits of quaternized chitosan (including hydrophilicity, bioadhesiveness, antimicrobial, antioxidant, hemostatic, and antiviral activities, as well as ionic conductivity) in combination with the distinctive characteristics of nanofibers (such as a high aspect ratio and 3D architecture). This combination has permitted numerous possibilities, spanning from wound dressings, air and water filters, drug delivery scaffolds, antimicrobial textiles, to energy storage systems and alkaline fuel cells. In this comprehensive review, we examine the preparation methods, properties, and applications of various composite fibers containing quaternized chitosan. The advantages and disadvantages of each method and composition are meticulously summarized, while relevant diagrams and figures illustrate the key findings.

Advances in continuous polymer analysis in flow with application towards biopolymers

Biopolymers, polymers derived from renewable biomass sources, have gained increasing attention in recent years due to their potential to replace traditional petroleum-based polymers in a range of applications. Among the many advantages of biopolymers can be included their biocompatibility, excellent mechanical properties, and availability from renewable feedstock. However, the development of biopolymers has been limited by a lack of understanding of their properties and processing behaviours. Continuous analysis techniques have the potential to hasten progress in this area by providing real-time insights into the properties and processing of biopolymers. Significant research in polymer chemistry has focused on petroleum-derived polymers and has thus provided a wealth of synthetic and analytical methodologies which may be applied to the biopolymer field. Of particular note is the application of flow technology in polymer science and its implications for accelerating progress towards more sustainable and environmentally friendly alternatives to traditional petroleum-based polymers. In this mini review we have outlined several of the most prominent use cases for biopolymers along with the current state-of-the art in continuous analysis of polymers in flow, including defining and differentiating atline, inline, online and offline analysis. We have found several examples for continuous flow analysis which have direct application to the biopolymer field, and we demonstrate an atline continuous polymer analysis method using size exclusion chromatography.

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Recent progressions in biomedical and pharmaceutical applications of chitosan nanoparticles: A comprehensive review

Nowadays, the most common approaches in the prognosis, diagnosis, and treatment of diseases are along with undeniable limitations. Thus, the ever-increasing need for using biocompatible natural materials and novel practical modalities is required. Applying biomaterials, such as chitosan nanoparticles (CS NPs: FDA-approved long-chain polymer of N-acetyl-glucosamine and D-glucosamine for some pharmaceutical applications), can serve as an appropriate alternative to overcome these limitations. Recently, the biomedical applications of CS NPs have extensively been investigated. These NPs and their derivatives can not only prepare through different physical and chemical approaches but also modify with various molecules and bioactive materials. The potential properties of CS NPs, such as biocompatibility, biodegradability, serum stability, solubility, non-immunogenicity, anti-inflammatory properties, appropriate pharmacokinetics and pharmacodynamics, and so forth, have made them excellent candidates for biomedical applications. Therefore, CS NPs have efficiently applied for various biomedical applications, like regenerative medicine and tissue engineering, biosensors for the detection of microorganisms, and drug delivery systems (DDS) for the suppression of diseases. These NPs possess a high level of biosafety. In summary, CS NPs have the potential ability for biomedical and clinical applications, and it would be remarkably beneficial to develop new generations of CS-based material for the future of medicine.

Novel Scaffold Based on Chitosan Hydrogels/Phthalated Cashew Gum for Supporting Human Dental Pulp Stem Cells

Hydrogels are structures that have value for application in the area of tissue engineering because they mimic the extracellular matrix. Naturally obtained polysaccharides, such as chitosan (CH) and cashew gum, are materials with the ability to form polymeric networks due to their physicochemical properties. This research aimed to develop a scaffold based on chitosan and phthalated cashew tree gum and test it as a support for the growth of human mesenchymal stem cells. In this study, phthalation in cashew gum (PCG) was performed by using a solvent-free route. PCG-CH scaffold was developed by polyelectrolyte complexation, and its ability to support adherent stem cell growth was evaluated. The scaffold showed a high swelling rate. The pore sizes of the scaffold were analyzed by scanning electron microscopy. Human dental pulp stem cells (hDPSCs) were isolated, expanded, and characterized for their potential to differentiate into mesenchymal lineages and for their immunophenotypic profile. Isolated mesenchymal stem cells presented fibroblastoid morphology, plastic adhesion capacity, and differentiation in osteogenic, adipogenic, and chondrogenic lineages. Mesenchymal stem cells were cultured in scaffolds to assess cell adhesion and growth. The cells seeded on the scaffold showed typical morphology, attachment, and adequate distribution inside the matrix pores. Thus, cells seeded in the scaffold may improve the osteoinductive and osteoconductive properties of these biomaterials.