Chitin Nanowhiskers Research Articles

Mucoadhesive polyelectrolyte complexes of fucoidan and chitin nanowhiskers to prolong the antiprotozoal activity of metronidazole

The improvement of the specific pharmacological activity of agents with antimicrobial and antiprotozoal properties (e.g. metronidazole, MET) is of interest for clinical applications in the treatment of bacterial infections. In this work, we prepared the polyelectrolyte complexes (PEC) based on chitin nanowhiskers (CNW) and fucoidan (FUC) with hydrodynamic diameters of 244 and 816 nm, a ζ-potential of about −22 mV and good mucoadhesive properties. The incorporation of MET into PEC particles promoted the sustained release of MET for 10 h and maintained the antiprotozoal activity against clinical isolates of Trichomonas vaginalis for up to 10 h. At concentrations of 1–3 mg/mL (HeLa cell line), the CWN-FUC-MET particles showed no cytotoxicity. The sustained drug release rate, combined with pronounced mucoadhesive properties, improved pharmacological activity, and non-cytotoxicity makes the developed biopolymer delivery systems promising candidates for further clinical trials.

Corrigendum to: “Recent Patents of Micro-arc Oxidation Technology”

A typographical error appeared in terms of repetition of sentences in the manuscript titled “Recent Patents of Micro-arc Oxidation Technology”, 2024; 18(6): e300423216386 [1]. <p> Original: Liu et al. [90] provided a method for micro-arc oxidation of electrolytes and reducing the brittleness of microporous ceramic film. By adding chitin nanowhiskers and Nacetylated chitosan into the electrolyte, the toughness of the ceramic film is improved, and bending brittleness and fragmentation are prevented. <p> Li et al. [91] provided an electrolyte for micro arc oxidation self-lubricating composite ceramic coating. The friction and wear properties of the composite ceramic coating were improved by adding nano additives and micro MoS2 powder into the conventional electrolyte. <p> Liu et al. [90] provided a method for micro-arc oxidation of electrolytes and reducing the brittleness of microporous ceramic film. By adding chitin nanowhiskers and Nacetylated chitosan into the electrolyte, the toughness of the ceramic film is improved, and bending brittleness and fragmentation are prevented. <p> Li et al. [91] provided an electrolyte for micro arc oxidation self-lubricating composite ceramic coating. The friction and wear properties of the composite ceramic coating were improved by adding nano additives and micro MoS2 powder into the conventional electrolyte. <p> Corrected: Liu et al. [90] provided a method for micro-arc oxidation of electrolytes and reducing the brittleness of microporous ceramic film. By adding chitin nanowhiskers and Nacetylated chitosan into the electrolyte, the toughness of the ceramic film is improved, and bending brittleness and fragmentation are prevented. <p> Li et al. [91] provided an electrolyte for micro arc oxidation self-lubricating composite ceramic coating. The friction and wear properties of the composite ceramic coating were improved by adding nano additives and micro MoS2 powder into the conventional electrolyte. <p> The original article can be found online at https://www.eurekaselect.com/article/131347

Chitin Nanowhisker/Gold Nanocluster Hybrids with an Excellent Dispersion Stability via Poly(ethylene glycol) Grafting.

Hybrid nanoparticles composed of chitin nanowhiskers (ChNWs) and gold nanoclusters (AuNCs) having an improved stability were prepared. The grafting of monomethoxypoly(ethylene glycol) (mPEG) and subsequent surface adsorption of AuNCs enabled the steric stabilization of ChNW/AuNC hybrids. mPEGs with terminal formyl groups and diethylacetal protecting groups were grafted via in situ deprotection and reductive amination with the surface amino groups (SAGs) of ChNWs. The treatment of chitin with a 30% sodium hydroxide solution improved the SAG contents of the ChNWs obtained from acid hydrolysis, resulting in an enhancement in mPEG grafting. The obtained sterically stabilized ChNW/AuNC hybrids exhibited remarkable dispersion stability at higher AuNC and electrolyte concentrations.

From Chitin Nanowhisker Colloidal Dispersions to Anisotropic Microfibers: Structural Evolution in Its Transformation Process as Revealed by Synchrotron Wide-Angle X-ray Diffraction Measurements.

Nanowhiskers in a colloidal dispersion are known to form chiral nematic liquid crystals (CNLC), as seen in a cellulose nanowhisker or so-called cellulose nanocrystal and chitin nanowhisker. In our related work, we clarified that once the thus-created chitin nanowhiskers with surface modified by chitosan (CTWK-CS) in CNLC phase were wet-spun, we could directly obtain anisotropic microfibers containing the highly ordered CTWK-CS. This drastic structural transformation from CNLC to anisotropic microfibers might relate to several important stages, i.e., stage (i) is the alignment of CTWK-CS initiated by a specific concentration and flow to create aggregation in the CNLC state, stage (ii) is the coagulation of CTWK-CS in CNLC to transform to microfibers, and stage (iii) is the drying of the thus-extruded microfibers to allow CTWK-CS alignment. The present work sets up the experimental systems simulating stages (i) and (iii) to reveal the orientational behavior of CTWK-CS and the structural evolution, respectively, by synchrotron 2D WAXD measurement. In stage (i), the high degree of the parallel alignments of CTWK-CS with the chain axis oriented along the flow direction of the colloidal dispersions confirms that the flow and concentration synergistically controlled CTWK-CS alignment. In contrast, for stage (iii), the poor c-axial orientation of CTWK-CS in as-spun wet microfibers gradually changed to the high degree of c-axial orientation along the fiber direction during drying process, indicating a reorientation of CTWK-CS along with dehydration. The present study declares an in situ observation of the direct wet spinning of nanowhiskers about their remarkable alignments in the sheared colloidal dispersions (stage (i)) and their random-to-high reorientation during the drying process of the as-spun wet microfiber (stage (iii)).

Chitosan/magnetic chitin nanowhisker polyelectrolyte membrane for direct methanol fuel cell applications: preparation, characterization, and performance analysis

ABSTRACT A hybrid chitosan-based nanocomposite was fabricated by chitin nanowhiskers coupled with silanized Fe3O4 nanoparticles as a polyelectrolyte membrane for direct methanol fuel cells (DMFCs). The morphological evaluations articulated that the magnetite nanoparticles were uniformly attached to the chitin nanowhiskers. After characterization of the synthesized nanowhiskers, they were incorporated into the chitosan, as a polycationic electrolyte, to investigate the performance of nanocomposite for DMFC applications. An external magnetic field was applied to the magnetic chitin nanowhiskers to induce alignment, and the effects of aligned nanowhiskers, as well as random ones, were also studied. The magnetic chitin nanowhiskers positively influenced the water uptake and proton conductivity due to the formation of hydrogen bonds between the surface functional groups of nanowhiskers and free water molecules. On the other hand, methanol permeation of the chitosan nanocomposites was reduced regarding the tortuous pathways and narrower transportation channels by the presence of nanowhiskers.

Sustainable Production of Chitin Nanowhiskers from Crustacean Biomass Using Cost-Effective Ionic Liquids: Strategies to Avoid Byproduct Formation

Nanochitin, especially in the form of chitin nanowhiskers (ChNWs), represents a significant advance in biopolymer technology due to its high specific surface area, superior tensile strength, and excellent thermal stability. Derived from crustacean waste, which contains 15–40% of chitin, these materials provide a sustainable option that diverts waste from landfills and contributes to environmental conservation. Traditional methods of isolating nanochitin are energy-intensive and generate substantial waste. This study introduces a more sustainable method using inexpensive ionic liquids (ILs) such as [Hmim][HSO4] and [HN222][HSO4], which bypass the costly and destructive steps of traditional procedures. This study also identified the byproduct in IL-mediated chitin hydrolysis reaction as calcium sulfate dihydrate and presented a solution to circumvent the byproduct formation. The effectiveness of the [HN222][HSO4] IL in producing ChNWs from both purified chitin and crustacean biomass was assessed, showing a high yield and maintaining the purity and structural integrity of chitin, thereby demonstrating a significant reduction in the environmental footprint of ChNW production.

Cover Image, Volume 141, Issue 20

Wet spinning of chitin nanowhiskers: Effects of electrolyte composition in coagulation baths on mechanical properties and nanowhisker orientation by Jun Araki and Minami Nakajima. DOI: 10.1002/app.55335 image

Rapid and facile quantification of surface amino groups on chitin nanowhiskers and nanofibers via spectrophotometry

Rapid and facile quantification of surface amino groups on chitin nanowhiskers and nanofibers via spectrophotometry

Wet spinning of chitin nanowhiskers: Effects of electrolyte composition in coagulation baths on mechanical properties and nanowhisker orientation

AbstractFibers composed solely of chitin nanowhiskers (ChNWs) with extreme uniaxial orientation can be successfully wet‐spun into coagulation baths containing 70% ethanol and various types of electrolytes (LiCl, HCl, NaCl, and MgSO4) with ionic strengths (J) of 0.075–0.3. The obtained fibers exhibited high ChNW orientation with degrees of orientation (S) ranging from 0.77 to 0.96. Fibers produced using NaCl‐containing coagulation baths contained residual NaCl crystals that were subsequently removed by rinsing. In contrast, LiCl and MgSO4, which originated from the corresponding baths and similarly remained within the fibers, did not crystallize due to hygroscopic deliquescence and the adaptation of SO42− ions for potential ionic crosslinking, respectively. Spinning with LiCl‐containing baths yielded fibers with maximum Young's modulus, stress at break, and strain at break of 7.9 ± 0.6 GPa, 58.8 MPa, and 1.13%, respectively. These mechanical properties of the unwashed fibers improved with J, while washing out the residual electrolytes and subsequent drying led to a decrease in the Young's modulus and an increase in the stress at break and strain at break. An increase in S was observed only in the fibers obtained using baths with J ≥ 0.3.

Construction of carboxymethyl chitosan/PVA/chitin nanowhiskers multicomponent film activated with Cotylelobium lanceolatum phenolics and in situ SeNP for enhanced packaging application

This work focused on the construction of bioactive packaging films based on carboxymethyl chitosan and poly(vinyl alcohol) (CMP) as polymeric matrix and fortified with chitin nanowhiskers, Cotylelobium lanceolatum phenolic extract (CL) and in situ synthesized nano selenium. Extensive morphological, microstructural, physical and mechanical analysis revealed that the nanofillers were well-dispersed and integrated into CMP matrix. Incorporation of the extract and nano selenium produced excellent UV blocking properties without seriously compromising the transparency of the composite (CMP/CNW/CLNS1) film. Moreover, blending of CMP with the filler materials significantly elevated (p < 0.05) the surface hydrophobicity (WCA by 35.4°), water barrier (by 53.86 %), tensile strength (from 29.35 to 33.09 MPa), elongation at break (from 64.28 to 96.48 %), and thermal properties of the resultant CMP/CNW/CLNS1 film, with concomitant reduction in water solubility and swellability. Furthermore, the CMP/CNW/CLNS films exhibited remarkable improvement in antioxidant properties. When used for packaging of peeled fresh garlic cloves, the CMP/CNW/CLNS1 film pouch, not the plain CMP or CMP/CNW film pouches, inhibited weight loss, oxidative browning, and the emergence of black mold on the packaged cloves. The developed CMP/CNW/CLNS1 film demonstrated enhanced capacity to safeguard the quality of packaged food and improved shelf life. Therefore, the present study suggests that incorporation of CNW/CLNS into carboxymethyl chitosan/PVA films is a suitable and facile strategy for the fabrication of films with improved mechanical, physico-chemical and functional properties with great potential for application as a sustainable active packaging material in the food industry.

Chitin nanowhisker-containing photo-crosslinked antimicrobial gelatin films

Nearly 57 Mt of food waste are generated annually in the EU for many reasons, for instance, because of microbial food spoilage. So, actions to reduce food loss and waste are needed and active packaging could offer a new approach towards this aim. In this study, antimicrobial gelatin films were prepared via the solution casting technique and their physicochemical, optical, mechanical, structural, barrier and antimicrobial properties were analysed. First, gelatin films were photo-crosslinked with riboflavin and the photo-curation time (0–4 h) was optimized. The optimal crosslinking time was 2 h since the solubility dropped down from 100% to 30% after 2 or 4 h of UV exposure. Then, 2 types of chitin nanowhiskers (CNWs) obtained via acid hydrolysis (AH) and TEMPO-mediated oxidation processes were added in 2 concentrations (2 and 4 wt %) into the film-forming solution (FFS) as reinforcements before film photo-crosslinking. The AH-CNW at 4 wt % was chosen as an optimal CNW type and concentration because they further decreased the solubility (∼24%) of films and improved mechanical properties up to values similar to those of commercially available synthetic packaging films. Finally, various concentrations (0, 7.5, 15 and 30 wt %) of the antimicrobial compound (Nisin A®) were added to the optimized formulation which showed good antimicrobial properties on both spoilage and pathogen strains, as well as over the native microbiota of chilled sea bream fillets, sliced cold-smoked salmon and chicken breast fillets. The developed films displayed promising properties as antimicrobial packaging for myosistem foods.

Carboxylated chitin nanowhiskers enhanced stabilization of Pickering and high internal phase Pickering emulsions

Pickering emulsions stabilized by the emulsifiers derived from biobased materials have been widely used in food related fields. In the current study, Pickering emulsions possessing internal phase volume fractions (ɸ) from 0.5 to 0.8 were successfully prepared by mechanical emulsification methods using carboxylated chitin nanowhiskers (C-ChNWs) as the emulsifiers. C-ChNWs suspensions obtained by ammonium persulfate (APS) oxidation showed high stability and possessed a Zeta potential of −48.9 mV. FTIR and XRD analyses indicated the α-chitin crystal structure could be maintained following APS oxidation. The C-ChNWs could form a three-dimensional network structure at the interface and endow the emulsion with high stability and viscoelastic features. Morphology results demonstrated these were oil-in-water emulsions. Moreover, the prepared high internal phase Pickering emulsions (HIPPEs; ɸ >0.74) showed good texture characteristics for high-resolution 3D printing. This work further validated the potential of nanochitin derived from biomass as an outstanding Pickering emulsion stabilizer.

The Effects of the Deacetylation of Chitin Nanowhiskers on the Performance of PCL/PLA Bio-Nanocomposites.

The multiple roles of organic nanofillers in biodegradable nanocomposites (NC) with a blend-based matrix is not yet fully understood. This work highlights combination of reinforcing and structure-directing effects of chitin nanowhiskers (CNW) with different degrees of deacetylation (DA), i.e., content of primary or secondary amines on their surface, in the nanocomposite with the PCL/PLA 1:1 matrix. Of importance is the fact that aminolysis with CNW leading to chain scission of both polyesters, especially of PLA, is practically independent of DA. DA also does not influence thermal stability. At the same time, the more marked chain scission/CNW grafting for PLA in comparison to PCL, causing changes in rheological parameters of components and related structural alterations, has crucial effects on mechanical properties in systems with a bicontinuous structure. Favourable combinations of multiple effects of CNW leads to enhanced mechanical performance at low 1% content only, whereas negative effects of structural changes, particularly of changed continuity, may eliminate the reinforcing effects of CNW at higher contents. The explanation of both synergistic and antagonistic effects of structures formed is based on the correspondence of experimental results with respective basic model calculations.

Utilization of Breadfruit (Artocarpus altilis) Peel Waste and Blood Clam Shell Waste (Anadara granosa) as Raw Materials for Glycerol-Plasticized Degradable Bioplastic Production

Nowadays, the world needs solutions to manage the ever-growing plastic waste problem. Plastics cannot decay easily in natural environment for example, PET took about 23 to 48 years to decay naturally in the environment. Therefore, it is urgently needed to find an alternative to these types of plastics, namely degradable plastics. One type of degradable plastic, called starch-based bioplastic can be made using starchy materials from Breadfruit peel. This, is in combination with Blood Clam shell – derived chitin nanowhiskers as reinforcer and glycerol as plasticizer. In this research, bioplastic is synthesized using starch extracted from Breadfruit (Artocarpus altilis) peel waste, reinforcing agent chitin nanowhisker (CNW) made from Blood Clam (Anadara granosa) shell waste, and glycerol as plasticizer. Furthermore, the plastic was tested according to general standard plastic tests including Tensile Strength, Water Uptake and Soil Burial test. Soil burial test results showed that in the period of less than 15 days, the bioplastic was completely decomposed. Water uptake test results showed that the bioplastic made from breadfruit peel starch and Blood Cam-derived CNW achieved water uptake numbers as high as 94,077 %, Tensile strength test showed that the bioplastic made from breadfruit waste starch and Blood clam-derived CNW of 0.0994 MPa was almost two times stronger than bioplastic made without the addition CNW of 0.0587 MPa and was also stronger than conventional plastics.

Carrageenan/Chitin Nanowhiskers Cryogels for Vaginal Delivery of Metronidazole.

The development of polymeric carriers based on partially deacetylated chitin nanowhiskers (CNWs) and anionic sulfated polysaccharides is an attractive strategy for improved vaginal delivery with modified drug release profiles. This study focuses on the development of metronidazole (MET)-containing cryogels based on carrageenan (CRG) and CNWs. The desired cryogels were obtained by electrostatic interactions between the amino groups of CNWs and the sulfate groups of CRG and by the formation of additional hydrogen bonds, as well as by entanglement of carrageenan macrochains. It was shown that the introduction of 5% CNWs significantly increased the strength of the initial hydrogel and ensured the formation of a homogeneous cryogel structure, resulting in sustained MET release within 24 h. At the same time, when the CNW content was increased to 10%, the system collapsed with the formation of discrete cryogels, demonstrating MET release within 12 h. The mechanism of prolonged drug release was mediated by polymer swelling and chain relaxation in the polymer matrix and correlated well with the Korsmeyer-Peppas and Peppas-Sahlin models. In vitro tests showed that the developed cryogels had a prolonged (24 h) antiprotozoal effect against Trichomonas, including MET-resistant strains. Thus, the new cryogels with MET may be promising dosage forms for the treatment of vaginal infections.

Effect of chitin nanowhiskers on structural and physical properties of konjac glucomannan hydrogels nanocomposites

Konjac glucomannan (KGM) has been widely studied because of its excellent gelling properties. However, the freeze-thaw stability and weak gel strength significantly limit its industrial application. To solve these issues, we innovatively introduced oxidized chitin nanowhiskers (O-ChNWs) under heating and alkaline conditions, thus achieving the improvement of the properties of KGM gels. In this study, rheological measurement and textural analysis were performed to verify the physicochemical properties of the as-prepared KGM/O-ChNWs. Results showed that the KGM/O-ChNWs dispersion exhibited a typical non-Newtonian pseudoplastic fluid behavior and the mechanical property of the gels enhanced with the amount of O-ChNWs increasing. Also, Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) was applied to elucidate the interaction between KGM and O-ChNWs. It showed that both strong hydrogen bonding and amide bonds could be formed to stabilize the KGM/O-ChNWs structure. Additionally, morphological images show that O-ChNWs can influence the original KGM structure and then form more uniform pores. Furthermore, thermogravimetric (TGA) analysis and freeze-thaw measurement demonstrated that O-ChNWs could obviously improve the thermal and freeze-thaw stability of the nanocomposite gels. Taken together, this current work can provide new insights into existing KGM gel systems and stimulate the development of additional KGM-based nanocomposite gels with the desired mechanical strength and freeze-thaw stability.

Development and mechanical properties of soy protein fibrils-chitin nanowhiskers complex gel

To enrich the use of protein-polysaccharide complex gel as texture assistance, we introduced a soy protein fibrils-chitin nanowhiskers complex gel system. Firstly, a stable positively charged chitin nanowhiskers (CNW) suspension and amyloid-like soy protein fibrils (SPF) were fabricated. We found that the self-assembled SPF and CNW formed complex with each other at pH 5.0–8.0 due to attractive interactions caused by their carrying opposite electrical charges. Then, the MTGase-induced SPF-CNW complex gel were formed and investigated by instrumental analysis. The results showed that the presence of CNW significantly increased the β-Sheet structure in complex gel and the rheological modules of complex gel were pH-dependent and showing G' > G" at all pHs. The SPF-CNW complex gel showed a strong and elastic textural property during compression test at pH 6.0. Meanwhile, the frequency scan showed that the SPF-CNW system is less dependent on the frequency and belonged to the typical physical gel. According to the results of SEM and CLSM images, the SPF, CNW and complex gel presented spherical shape, rod shape and linear alignment microstructure, respectively. We inferred that the CNW provided a framework for gel formation and introduced rigidity to the SPF gel. Thanks to the attractive interactions, the SPF molecules were attached to the growth of CNW to form a longer fiber structure. After the gelation process, the aggregates further interacted with each other and finally form complex gel with linear, ordered and compact microstructure.

The potential of rice bran waste (Oryza sativa L.) and shrimp shell waste as chitin nanowhisker with glycerol plasticizer in the production of bioplastic

Bioplastics are plastics made from biopolymers as an alternative to commercial plastics to reduce environmental pollution. Starch from rice bran waste is an essential biopolymer material, and chitin from shrimp shell waste; can be converted into chitin nanowhiskers (CNWs) that can strengthen biopolymer materials. A glycerol plasticizer was added to improve its elasticity. This research aims to determine the potential of starch from rice bran waste and CNWs from shrimp shell waste as ingredients in the production of bioplastics with the addition of glycerol plasticizer and its degradation property through soil burial testing. This fundamental research consists of chitin extraction, CNW production, starch extraction, bioplastic production, tensile strength testing, water uptake testing and soil burial testing on the sand, humus, and compost. The use of rice bran starch and shrimp shell CNW as ingredients in the production of bioplastics are deemed potential. This bioplastic exhibited low mechanical properties such as tensile strength and water uptake but outstanding degradation in the soil burial testing.

Isolation of Chitin Nano-whiskers Directly from Crustacean Biomass Waste in a Single Step with Acidic Ionic Liquids

Isolation of Chitin Nano-whiskers Directly from Crustacean Biomass Waste in a Single Step with Acidic Ionic Liquids

PH-Sensitive Drug Delivery System Based on Chitin Nanowhiskers-Sodium Alginate Polyelectrolyte Complex.

Polyelectrolyte complexes (PECs), based on partially deacetylated chitin nanowhiskers (CNWs) and anionic polysaccharides, are characterized by their variability of properties (particle size, ζ-potential, and pH-sensitivity) depending on the preparation conditions, thereby allowing the development of polymeric nanoplatforms with a sustained release profile for active pharmaceutical substances. This study is focused on the development of hydrogels based on PECs of CNWs and sodium alginate (ALG) for potential vaginal administration that provide controlled pH-dependent antibiotic release in an acidic vaginal environment, as well as prolonged pharmacological action due to both the sustained drug release profile and the mucoadhesive properties of the polysaccharides. The desired hydrogels were formed as a result of both electrostatic interactions between CNWs and ALG (PEC formation), and the subsequent molecular entanglement of ALG chains, and the formation of additional hydrogen bonds. Metronidazole (MET) delivery systems with the desired properties were obtained at pH 5.5 and an CNW:ALG ratio of 1:2. The MET–CNW–ALG microparticles in the hydrogel composition had an apparent hydrodynamic diameter of approximately 1.7 µm and a ζ-potential of −43 mV. In vitro release studies showed a prolonged pH-sensitive drug release from the designed hydrogels; 37 and 67% of MET were released within 24 h at pH 7.4 and pH 4.5, respectively. The introduction of CNWs into the MET–ALG system not only prolonged the drug release, but also increased the mucoadhesive properties by about 1.3 times. Thus, novel CNW–ALG hydrogels are promising carriers for pH sensitive drug delivery carriers.