Chitosan is a widely used linear biopolymer composed mainly of glucosamine and to a lesser extent of N-acetylglucosamine units. Many biological activities of chitosan are attributed to its shorter oligomeric chains, which consist of chitosan prepared either by enzyme activity (lysozyme, bacterial chitinase) or chemically by acid-catalyzed hydrolysis (e.g. in the stomach). However, these processes always result in a mixture of shorter chitooligosaccharides with varying degrees of acetylation whereas for relevant results of biological studies it is necessary to work with a precisely defined material. In this review, we provide an overview and comparison of analytical methods leading to the determination of the degree of polymerization (DP), the degree of acetylation (DA), the fraction of acetylation (FA) and the acetylation patterns (PA) of chitooligosaccharide chains and of the current state of knowledge on chitooligosaccharide separation. This review aims to present the most promising routes to well-defined low molecular weight chitosan with low dispersity.

• Klíčová slova
• Acetylation pattern, Analysis, Chitooligosacharides, Chitosan, Separation,
• MeSH
• acetylace MeSH
• chitosan * chemie   MeSH
• oligosacharidy * chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• chitosan * MeSH
• oligochitosan MeSH Prohlížeč
• oligosacharidy * MeSH

This study introduces a novel, sustainable method for synthesizing sub-5 nm palladium nanoparticles (PdNPs) and covalently binding them to chitosan nanofibers (CHITs) using fully oxidized dialdehyde cellulose (DAC). Notably, the DAC acts not only as a reducing and stabilizing agent for PdNPs, but also as a linker for their rapid and spontaneous covalent attachment to CHITs via Schiff base chemistry. This unique approach yields PdNPs with a narrow size distribution (4.7 ± 0.4 nm) and enables the preparation of a stable nanofibrous composite with excellent catalytic efficiency for 4-nitrophenol reduction (TOFPdNPs = 75.2 min-1, kPdNPs = 1.34 min-1; TOFPdNPs-CHIT = 1.18 min-1). The composite's high reusability, attributed to strong covalent binding, marks a significant improvement over traditional PdNPs composites that rely on weak interactions. This is demonstrated on a model of a catalytic device, reflecting industrial applications.

• Klíčová slova
• Chitosan nanofibers, Dialdehyde cellulose, Nanocomposite catalyst, Palladium nanoparticles,
• MeSH
• celulosa * chemie   analogy a deriváty   MeSH
• chitosan * chemie   MeSH
• katalýza MeSH
• kovové nanočástice * chemie   MeSH
• nanovlákna * chemie   MeSH
• nitrofenoly chemie   MeSH
• oxidace-redukce MeSH
• palladium * chemie   MeSH
• Schiffovy báze chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 2,3-dialdehydocellulose MeSH Prohlížeč
• celulosa * MeSH
• chitosan * MeSH
• nitrofenoly MeSH
• palladium * MeSH
• Schiffovy báze MeSH

Biomaterial-associated infections pose severe challenges in modern medicine. Previously, we reported that polyanionic DNA surface coatings repel bacterial adhesion and support osteoblast-like cell attachment in monoculture experiments, candidate for orthopaedic implant coatings. However, monocultures lack the influence of bacteria or bacterial toxins on osteoblast-like cell adhesion to biomaterial surfaces. In this study, co-culture of staphylococcus (S. epidermidis and S. aureus) and SaOS-2 osteosarcoma cells was studied on chitosan-DNA polyelectrolyte multilayer coated glass based on the concept of `the race for the surface`. Staphylococcus was first deposited onto the surface in a microfluidic chamber to mimic peri-operative contamination, and subsequently, SaOS-2 cells were seeded. Both staphylococcus and SaOS-2 cells were cultured together on the surfaces for 24 h under flow. The presence of S. epidermidis decreased SaOS-2 cell number on all surfaces after 24 h. However, the cells that adhered spread equally well in the presence of low virulent S. epidermidis. However, highly virulent S. aureus induced cell death of all adherent SaOS-2 cells on chitosan-DNA multilayer coated glass, a worse outcome than on uncoated glass. The outcome of our co-culture study highlights the limitations of monoculture models. It demonstrates the need for in vitro co-culture assays to meaningfully bridge the gap in lab testing of biomaterials and their clinical evaluations where bacterial infection can occur. The relative failure of cell-adhesive and bacteria-repelling DNA coatings in co-cultures also suggests the need to incorporate bactericidal in addition to non-adhesive functions to protect competitive cell spreading over a long period.

• Klíčová slova
• Biofilms, Biomaterial-associated infections, Co-culture, Coatings, DNA polyelectrolyte, Flow, Multilayer, Osteoblasts, Pathogens, Race for the surface, Staphylococcus,
• MeSH
• bakteriální adheze účinky léků   MeSH
• biokompatibilní potahované materiály chemie   farmakologie   MeSH
• buněčná adheze účinky léků   MeSH
• chitosan chemie   farmakologie   MeSH
• DNA * chemie   MeSH
• kokultivační techniky MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• osteoblasty * účinky léků   cytologie   MeSH
• polyelektrolyty chemie   farmakologie   MeSH
• povrchové vlastnosti * MeSH
• Staphylococcus aureus * účinky léků   MeSH
• Staphylococcus epidermidis * účinky léků   fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• biokompatibilní potahované materiály MeSH
• chitosan MeSH
• DNA * MeSH
• polyelektrolyty MeSH

Although angiosperm plants generally react to immunity elicitors like chitin or chitosan by the cell wall callose deposition, this response in particular cell types, especially upon chitosan treatment, is not fully understood. Here we show that the growing root hairs (RHs) of Arabidopsis can respond to a mild (0.001%) chitosan treatment by the callose deposition and by a deceleration of the RH growth. We demonstrate that the glucan synthase-like 5/PMR4 is vital for chitosan-induced callose deposition but not for RH growth inhibition. Upon the higher chitosan concentration (0.01%) treatment, RHs do not deposit callose, while growth inhibition is prominent. To understand the molecular and cellular mechanisms underpinning the responses to two chitosan treatments, we analysed early Ca2+ and defence-related signalling, gene expression, cell wall and RH cellular endomembrane modifications. Chitosan-induced callose deposition is also present in the several other plant species, including functionally analogous and evolutionarily only distantly related RH-like structures such as rhizoids of bryophytes. Our results point to the RH callose deposition as a conserved strategy of soil-anchoring plant cells to cope with mild biotic stress. However, high chitosan concentration prominently disturbs RH intracellular dynamics, tip-localised endomembrane compartments, growth and viability, precluding callose deposition.

• Klíčová slova
• arabidopsis, cell wall, defence, gene expression, signalling,
• MeSH
• Arabidopsis * růst a vývoj   účinky léků   metabolismus   fyziologie   MeSH
• buněčná membrána metabolismus   MeSH
• buněčná stěna * metabolismus   MeSH
• chitosan * farmakologie   MeSH
• glukany * metabolismus   MeSH
• glukosyltransferasy metabolismus   MeSH
• kořeny rostlin * růst a vývoj   metabolismus   účinky léků   MeSH
• proteiny huseníčku * metabolismus   genetika   MeSH
• regulace genové exprese u rostlin účinky léků   MeSH
• vápník metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• callose MeSH Prohlížeč
• chitosan * MeSH
• glukany * MeSH
• glukosyltransferasy MeSH
• proteiny huseníčku * MeSH
• vápník MeSH

Accumulation of environmental chitin in the lungs can lead to pulmonary fibrosis, characterized by inflammatory infiltration and fibrosis in acidic chitinase (Chia)-deficient mice. Transgenic expression of Chia in these mice ameliorated the symptoms, indicating the potential of enzyme supplementation as a promising therapeutic strategy for related lung diseases. This study focuses on utilizing hyperactivated human Chia, which exhibits low activity. We achieved significant activation of human Chia by incorporating nine amino acids derived from the crab-eating monkey (Macaca fascicularis) Chia, known for its robust chitin-degrading activity. The modified human Chia retained high activity across a broad pH spectrum and exhibited enhanced thermal stability. The amino acid substitutions associated with hyperactivation of human Chia activity occurred species specifically in monkey Chia. This discovery highlights the potential of hyperactivated Chia in treating pulmonary diseases resulting from chitin accumulation in human lungs.

• Klíčová slova
• acidic chitinase (Chia), amino acid substitutions, chitin, enzyme engineering, evolution, exon swapping, hyperactivation, primate lineage, treating pulmonary diseases,
• MeSH
• aktivace enzymů účinky léků   MeSH
• chitin metabolismus   chemie   MeSH
• chitinasy * metabolismus   genetika   chemie   MeSH
• koncentrace vodíkových iontů MeSH
• lidé MeSH
• Macaca fascicularis MeSH
• myši MeSH
• plíce metabolismus   patologie   enzymologie   MeSH
• stabilita enzymů MeSH
• substituce aminokyselin MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• CHIA protein, human MeSH Prohlížeč
• chitin MeSH
• chitinasy * MeSH

YKL-40 is structurally similar to chitotriosidase (CHIT1), an active chitinase, but it lacks chitin-degrading activity while retaining chitin-binding capability. Elevated YKL-40 levels are associated with inflammatory diseases and cancers, making it a valuable biomarker. We previously reported that the W69T substitution in YKL-40 significantly reduces its chitin-binding affinity, identifying W69 as a crucial binding site. In this study, we establish a novel chitin-binding affinity evaluation method using a three-step buffer system to assess the binding strength and specificity of chitin-binding proteins and apply it to characterize YKL-40's binding mechanism. Our findings confirm that YKL-40, through its key residue W69, exhibits highly specific and robust affinity to chitin. Unlike CHIT1, which has both a catalytic domain (CatD) and a chitin-binding domain (CBD) that allow for diverse binding and degradation activities, YKL-40 lacks a CBD and is specialized for specific chitin recognition without degrading it. Comparative analysis with YKL-39, which does not contain a corresponding W69 residue, highlights the unique role of this residue in YKL-40's chitin-binding activity that is potentially linked to immune and inflammatory responses. Our evaluation method clarifies YKL-40's binding properties and provides a versatile approach applicable to other chitin-binding proteins.

• Klíčová slova
• W69 residue, YKL-39, YKL-40, catalytic domain (CatD), chitin, chitin-binding activity, chitin-binding affinity assay, chitin-binding domain (CBD), chitinase-like proteins (CLPs), chitotriosidase (CHIT1),
• MeSH
• chitin * metabolismus   chemie   MeSH
• hexosaminidasy * metabolismus   chemie   MeSH
• katalytická doména MeSH
• lidé MeSH
• protein CHI3L1 * metabolismus   MeSH
• vazba proteinů * MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• CHI3L1 protein, human MeSH Prohlížeč
• chitin * MeSH
• chitotriosidase MeSH Prohlížeč
• hexosaminidasy * MeSH
• protein CHI3L1 * MeSH

Biodegradable films derived from polysaccharides are increasingly considered eco-friendly alternatives to synthetic packaging in the food industry. The study's purpose was to improve the antimicrobial properties of biopolymer-based films made from starch, chitosan, alginate, and their blends (starch/chitosan and starch/alginate) and to evaluate the effects of modifiers, i.e., plant extracts, plasticizers, cross-linking agents, and nanofillers. Films were prepared via the Solution Casting Method and modified with various plasticizers, calcium chloride, oxidized sucrose, and nanofiber cellulose (NC). Chestnut, nettle, grape, and graviola extracts were tested for antimicrobial activity against Staphylococcus epidermidis, Escherichia coli, and Candida albicans. The film's mechanical and hydrophilic properties were studied as well. The chestnut extract showed the strongest antimicrobial properties, leading to its incorporation in all the films. The chitosan films displayed better antibacterial activity against Gram-positive than Gram-negative bacteria but were ineffective against C. albicans. NC significantly improved the mechanical and antimicrobial properties of the chitosan films. The alginate films, modified with various plasticizers cross-linked with calcium chloride, demonstrated the highest antimicrobial efficacy against E. coli. The starch films, cross-linked with oxidized sucrose, exhibited slightly lower antimicrobial resistance due to a more compact structure. Films such as ALG6 and ALG5, including plasticizers EPGOS and PGOS, respectively, indicated optimal hydrophilicity and mechanical properties and achieved the best antimicrobial performance against all the investigated microorganisms. All these findings highlight the potential of these biodegradable films for food packaging, offering enhanced antimicrobial activity that prolongs shelf life and reduces spoilage, making them promising candidates for sustainable food preservation.

• Klíčová slova
• antimicrobial, biofilms, environmentally friendly, food packaging,
• MeSH
• algináty chemie   MeSH
• antiinfekční látky * farmakologie   chemie   MeSH
• biopolymery chemie   farmakologie   MeSH
• Candida albicans * účinky léků   MeSH
• chitosan * chemie   farmakologie   MeSH
• Escherichia coli účinky léků   růst a vývoj   MeSH
• mikrobiální testy citlivosti MeSH
• obaly potravin * metody   MeSH
• rostlinné extrakty chemie   farmakologie   MeSH
• škrob * chemie   MeSH
• Staphylococcus epidermidis účinky léků   MeSH
• zvláčňovadla chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• algináty MeSH
• antiinfekční látky * MeSH
• biopolymery MeSH
• chitosan * MeSH
• rostlinné extrakty MeSH
• škrob * MeSH
• zvláčňovadla MeSH

In recent years, the chorioallantoic membrane (CAM) has emerged as a crucial component of biocompatibility testing for biomaterials designed for regenerative strategies and tissue engineering applications. This study explores angiogenic potential of an innovative acellular and porous biopolymer scaffold, based on polyhydroxybutyrate and chitosan (PHB/CHIT), using the ex ovo quail CAM assay as an alternative to the conventional chick CAM test. On embryonic day 6 (ED6), we placed the tested biomaterials on the CAM alone or soaked them with various substances, including vascular endothelial growth factor (VEGF-A), saline, or the endogenous angiogenesis inhibitor Angiostatin. After 72 h (ED9), we analyzed blood vessels formation, a sign of ongoing angiogenesis, in the vicinity of the scaffold and within its pores. We employed marker for cell proliferation (PHH3), embryonic endothelium (WGA, SNA), myofibroblasts (α-SMA), and endothelial cells (QH1) for morphological and histochemical analysis. Our findings demonstrated the robust angiogenic potential of the untreated scaffold without additional influence from the angiogenic factor VEGF-A. Furthermore, gene expression analysis revealed an upregulation of pro-angiogenic growth factors, including VEGF-A, ANG-2, and VE-Cadherin after 5 days of implantation, indicative of a pro-angiogenic microenvironment. These results underscore the inherent angiogenic potential of the PHB/CHIT composite. Additionally, monitoring of CAM microvilli growing to the scaffold provides a methodology for investigating the biocompatibility of materials using the ex ovo quail CAM assay as a suitable alternative model compared to the chicken CAM platform. This approach offers a rapid screening method for biomaterials in the field of tissue repair/regeneration and engineering.

• Klíčová slova
• Angiogenesis, Avian animal model, Bone regeneration, Chitosan, Polyhydroxybutyrate,
• MeSH
• biokompatibilní materiály * farmakologie   MeSH
• chitosan * farmakologie   MeSH
• chorioalantoická membrána * účinky léků   MeSH
• fyziologická neovaskularizace účinky léků   MeSH
• křepelky a křepelovití embryologie   MeSH
• testování materiálů MeSH
• tkáňové podpůrné struktury chemie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• biokompatibilní materiály * MeSH
• chitosan * MeSH

Highlighting the essential role of chitosan (CS), known for its biocompatibility, biodegradability, and ability to promote cell adhesion and proliferation, this study explores its utility in modulating the biomimetic mineralization of calcium phosphate (CaP). This approach holds promise for developing biomaterials suitable for bone regeneration. However, the interactions between the CS surface and in situ precipitated CaP still require further exploration. In the theoretical section, molecular dynamics (MD) simulations demonstrate that, at an appropriate pH level during the prenucleation stage, calcium ions (Ca2+) and hydrogen phosphate ions (HPO42-) form Posner-like clusters. Additionally, the interaction between these clusters and the CS molecule enhances system stability. Together, these phenomena facilitate the transition to subsequent heterogeneous nucleation on the surface of the organic matrix, which is a more controlled process than homogeneous nucleation in solution. Dynamic simulation results suggest that CS acts as a stabilizing matrix at pH 8.0 during biomimetic mineralization. In the experimental section, the effects of pH and the molecular weight of CS were investigated, with a focus on their impact on the crystal structure of the resulting material. X-ray diffraction and scanning electron microscopy analyses reveal that, under conditions of approximately pH 8.0 and a CS molecular weight of 20 000 g/mol, and controlled ion concentration, ultrasound radiation, and temperature, the dominant CaP phases in the material are carbonate-doped hydroxyapatite (CHA) and octacalcium phosphate (OCP). These findings suggest that CS, when adjusted for molecular weight and pH, facilitates the formation of CaP crystal phases that closely resemble the natural inorganic composition of bone, highlighting its protective and regulatory roles in the growth and maturation of crystals during mineralization. The theoretical predictions and experimental outcomes confirm the crucial role of CS as a templating agent, enabling the development of a biomimetic mineralization pathway. CS's ability to guide this process may prove valuable in the design of materials for bone tissue engineering, particularly in developing effective materials for bone tissue healing and regeneration.

• Klíčová slova
• biomimetic mineralization, carbonate-doped hydroxyapatite, chitosan, molecular dynamics simulation, octacalcium phosphate, ultrasonic radiation,
• MeSH
• biomimetické materiály chemie   MeSH
• chitosan * chemie   MeSH
• fosforečnany vápenaté * chemie   MeSH
• koncentrace vodíkových iontů MeSH
• krystalizace MeSH
• simulace molekulární dynamiky * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• calcium phosphate MeSH Prohlížeč
• chitosan * MeSH
• fosforečnany vápenaté * MeSH

Adsorptive removal of phosphate plays a crucial role in mitigating eutrophication. Herein, the Zr/Fe embedded chitosan/alginate hydrogel bead (Zr/Fe/CS/Alg) is reported as an effective phosphate adsorbent. This polymer nanocomposite is synthesized by the in-situ reduction of the metals on the polymer matrix. The synthesized adsorbent was characterized by the FTIR, SEM-EDX, TGA, BET, and XPS. The adsorbent showed a maximum phosphate adsorption capacity of 221.72 mg/g at pH 3. The experimental data fit well with the Freundlich isotherm and pseudo-second-order kinetics model, indicating a heterogeneous multilayer surface formation and a chemisorption-dominated adsorption process. Density Functional Theory (DFT) and Monte Carlo (MC) calculations revealed high negative adsorption energy due to the chemisorption of phosphate on the adsorbent. Hence, the major interactions such as electrostatic attraction, hydrogen bonding, and inner-sphere complexation of phosphate adsorption and Zr/Fe/CS/Alg hydrogel beads were investigated from the experimental and computational analysis. The negative values of thermodynamic parameters indicated a spontaneous, exothermic, and less random adsorption process. The synthesized adsorbent exhibited excellent selectivity toward phosphate and maintained 73 % efficiency after six adsorption/desorption cycles. The Zr/Fe/CS/Alg hydrogel beads reduced the phosphate concentration in real wastewater samples from 19.02 mg/L to 0.985 mg/L, suggesting that these nanocomposite hydrogel beads could be a promising adsorbent for real-world applications.

• Klíčová slova
• Adsorption, Alginate, Chitosan, Fe-Zr-polymer nanocomposite, Phosphate removal, Wastewater,
• MeSH
• adsorpce MeSH
• algináty * chemie   MeSH
• chemické látky znečišťující vodu * chemie   izolace a purifikace   MeSH
• chitosan * chemie   MeSH
• čištění vody * metody   MeSH
• fosfáty * chemie   izolace a purifikace   MeSH
• hydrogely * chemie   MeSH
• kinetika MeSH
• koncentrace vodíkových iontů MeSH
• odpadní voda * chemie   MeSH
• termodynamika MeSH
• železo * chemie   MeSH
• zirkonium * chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• algináty * MeSH
• chemické látky znečišťující vodu * MeSH
• chitosan * MeSH
• fosfáty * MeSH
• hydrogely * MeSH
• odpadní voda * MeSH
• železo * MeSH
• zirkonium * MeSH