Nanoscale Chitosan Research Articles

Influence of solvent variability on the physico-structural properties of nanoscale chitosan biopolymers

Influence of solvent variability on the physico-structural properties of nanoscale chitosan biopolymers

Multi-Functional Chitosan Nanovesicles Loaded with Bioactive Manganese for Potential Wound Healing Applications.

Chronic skin wound is a chronic illness that possesses a risk of infection and sepsis. In particular, infections associated with antibiotic-resistant bacterial strains are challenging to treat. To combat this challenge, a suitable alternative that is complementary to antibiotics is desired for wound healing. In this work, we report multi-functional nanoscale chitosan vesicles loaded with manganese (Chi-Mn) that has potential to serve as a new tool to augment traditional antibiotic treatment for skin wound healing. Chi-Mn showed antioxidant activity increase over time as well as antimicrobial activity against E. coli and P. aeruginosa PA01. The modified motility assay that mimicked a skin wound before bacterial colonization showed inhibition of bacterial growth with Chi-Mn treatment at a low area density of 0.04 µg of Mn per cm2. Furthermore, this study demonstrated the compatibility of Chi-Mn with a commercial antibiotic showing no loss of antimicrobial potency. In vitro cytotoxicity of Chi-Mn was assessed with macrophages and dermal cell lines (J774A.1 and HDF) elucidating biocompatibility at a wide range (2 ppm-256 ppm). A scratch wound assay involving human dermal fibroblast (HDF) cells was performed to assess any negative effect of Chi-Mn on cell migration. Confocal microscopy study confirmed that Chi-Mn tested at the MIC (16 ppm Mn) has no effect on cell migration with respect to control. Overall, this study demonstrated the potential of Chi-Mn nanovesicles for wound healing applications.

Porous chitosan-infused graphitic carbon nitride nanosheets for potential microbicidal and photo-catalytic efficacies

Supply of safe drinking water is a high-risk challenge faced internationally. Hybrid technologies involving nanomaterials can offer possible solutions to this research involving natural biopolymers. Porous chitosan with a high specific surface area has promising properties but its use as a membrane component in water purification is still rarely reported. Graphitic carbon nitride (g-C3N4) is a carbon nitride allotrope with a graphene-like layered structure that gifts unfamiliar physicochemical properties due to the presence of s-triazine fragments. It is a metal-free semiconductor with a band gap of ∼2.7 eV to ∼3.7 eV; which shows better visible light-activated photocatalyst properties. This work aims at synthesizing graphitic carbon nitride–biopolymer composite and exploring its properties in the field of wastewater treatment. The samples were synthesized via a soft chemical process with urea, as the source material. The flake-like morphology is displayed in the microstructural SEM image. The composition of the material was analyzed using EDS. Thermogram shows that the material is stable up to 500 °C and also confirms the formation of graphitic carbon nitride. In XRD spectra the intensity reduction shows the chitosan inclusion at the nitride site. The band gap of the prepared material was identified to be 2.3, 2.4 eV. The structural properties were analyzed using Fourier Transform Infrared Spectrometer and Raman spectroscopy. FTIR spectra and Raman spectra indicate the stretching vibration modes of CN and CN heterocycles and chitosan inclusion in the carbon nitride network. The photocatalytic activity was done in sunlight and a UV lamp with different dyes for doped and undoped g-C3N4. The doped (Porous/Non-porous chitosan) g-C3N4 showed faster dye degradation in sunlight compared to UV light. A biomolecular interaction study was done using Bovine serum albumin. It shows the material interaction with the BSA protein. The anti-microbial activity was performed on the Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli by disk diffusion method, the chitosan doped g-C3N4 showed good inhibitions against bacterial growth. The current work reveals the impact of nanoscale chitosan nanostructures doped on the optical, microstructural, catalytic, and antimicrobial properties of g-C3N4 nanosheets. This work provides new research options for nanocomposite-based photocatalytic nanomaterial g-C3N4 so that the quality of contaminated water could be improved.

Enhanced electrochemiluminescence of Ru(bpy)3 2+ -doped silica nanoparticles by chitosan/Nafion shell@carbon nanotube core-modified electrode.

Although Ru(bpy)3 2+ -doped silica nanoparticles have been widely explored as the labelling tags for electrochemiluminescence (ECL) sensing different targets, the poor electrical conductive properties of the silica nano-matrix greatly limit their ECL sensitivity. Therefore, a novel scheme to overcome this drawback on Ru(bpy)3 2+ -doped silica nanoparticles ECL is desirable. Here, a new scheme for this purpose was developed based on electrochemically depositing a nanoscale chitosan hydrogel layer on the carbon nanotube (CNT) surface to form chitosan hydrogel shell@CNT core nanocomposites. In this case, the nanoscale chitosan hydrogel layer only formed on the CNT surface due to the superior electrocatalytic effect of CNT on H+ reduction compared with the basic glass carbon electrode. Due to both the superhydrophilic properties and polyelectrolyte features of nanoscale chitosan hydrogel on the CNT surface, chemical affinity as well as the electric conductivity between Ru(bpy)3 2+ -doped silica nanoparticles and CNT were obviously enhanced, and then the ECL effectivity of Ru(bpy)3 2+ inside silica nanoparticles was improved. Furthermore, based on the discriminative interaction of these Ru(bpy)3 2+ -doped silica nanoparticles towards both the ssDNA probes and the ssDNA probe/miRNA complex, as well as the specific adsorption effect of these nanoparticles on the nanoscale chitosan shell@Nafion/CNT core-modified glass carbon electrode, a highly sensitive ECL method for miRNA determination was developed and successfully used to detect miRNA in human serum samples.

Comparative effects of dietary micro- and nano-scale chitosan on the growth performance, non-specific immunity, and resistance of silver carp Hypophthalmichthys molitrix against Staphylococcus aureus infection

Globally, with the expansion of aquaculture, the demand for functional feeds is continuously increasing, and effort is in progress to improve the efficiency of the feed additives. Herein, nano-scale chitosan (CNP) with an average size 0.001). Our results indicate the improved efficiency of CNPs and recommend it as a feed additive to enhance fish productivity and fish immune response towards the invading pathogens.

Physicochemical and Morphological Transformations of Chitosan Nanoparticles across the Gastrointestinal Tract and Cellular Toxicity in an In Vitro Model of the Small Intestinal Epithelium.

Nanoscale chitosan materials exhibit size-specific properties that make them useful in agri-food and biomedical applications. Chitosan nanoparticles (Chnps) are being explored as nanocarrier platforms to increase oral bioavailability of drugs and nutraceuticals, but little is known of their fate and transformations in the gastrointestinal tract (GIT) or of their potential toxicity. Here, the GIT fate and cytotoxicity of Chnps, soluble starch-coated Chnps (SS-Chnps), and bulk chitosan powder (Chp), were assessed using a 3-phase simulated digestion and an in vitro cellular small intestinal epithelium model. Physico-chemical characterization revealed dissolution of Chp, but not of Chnps or SS-Chnps, during the gastric phase of digestion, stability of the starch coating of SS-Chnps in the oral and gastric phases, and agglomeration of all materials during the small intestinal phase. A slight but significant (10%, p < 0.01) increase in cytotoxicity (LDH release) was observed with exposure to digested Chnps but not Chp or SS-Chnps.

3D chitosan scaffolds impair NLRP3 inflammasome response in macrophages

Chitosan (Ch) is used in different biomedical applications to promote tissue repair. However, tissue injury caused by biomaterial implantation lead to the release of danger signals that engage different inflammatory pathways on the host. Different implanted materials activate the inflammasome leading to the modulation of the immune response. Here we have studied how macroscopic biomaterials, Ch scaffolds with different chemical composition: 4% or 15% degree of acetylation (DA) modulate the activation of the NLRP3 inflammasome in vitro. For that, we assessed the NLRP3 inflammasome in bone marrow derived mouse macrophages (BMDM) and human macrophages cultured within 3D Ch scaffolds. We found that both Ch scaffolds did not trigger the NLRP3 inflammasome activation in macrophages. Furthermore, BMDMs and human macrophages cultured in both Ch scaffolds presented a reduction in the number of apoptosis-associated speck-like protein containing a caspase activating recruitment domain (ASC) specks and in IL-1β release upon classical NLRP3 inflammasome stimulation. We also found a decrease in proIL-1β in BMDMs after priming with LPS when cultured in Ch scaffolds with DA 4% DA after priming with LPS when compared to Ch scaffolds with 15% DA or to macrophages cultured in cell-culture plates. Our results shows that 3D Ch scaffolds with different DA impair NLRP3 inflammasome priming and activation. Statement of SignificanceIn this research work we have assessed the role of the NLRP3 inflammasome in the macrophage response to 3D chitosan scaffolds with different degrees of acetylation (DA). To our knowledge this is the first work that demonstrates the modulatory capacity of 3D porous chitosan scaffolds in the NLRP3 inflammasome activation, because our results show that Ch scaffolds impair NLRP3 inflammasome assembly in macrophages.Interestingly, our results are in contrast with studies reported in the literature that indicate that chitosan is a powerful activator of the NLRP3 inflammasome in nanoscale chitosan products. Our studies that were performed in large scale chitosan scaffolds, stress out that the process of phagocytosis is pivotal in inflammasome assembly and activation, are rather important since they clearly illustrate the different role of the inflammasome in the biological response to large scale and nanoscale biomaterials.

The use of slow releasing nanoparticle encapsulated Azadirachtin formulations for the management of Caryedon serratus O. (groundnut bruchid).

Nanobiotechnology is one of the emerging fields and its interventions in agriculture is been attracting the scientific community. Herein, the authors first to report on control of groundnut bruchid (Caryedon serratus O.) using nanoscale zinc oxide (ZnONPs) particles and nanoscale chitosan (CNPs) particles-based Azadirachtin formulations. ZnONPs and CNPs were prepared using sol-gel and ion tropic gelation techniques, respectively. Neem seed kernel extract (NSKE) 5% and Neem oil (3000 and 1000 ppm) were encapsulated using the prepared nanoscale materials and characterised using the techniques such as dynamic light scattering, high-resolution transmission electron microscopy. Spherical-shaped nanoparticles were formed after encapsulation with the required bio-materials (ZnONPs 33.1 nm; CNPs 78.8 nm; neem oil encapsulated (3000 ppm) ZnONPs 182.9 nm; NSKE encapsulated ZnONPs 84.9 nm) and observed that the particles are stable (52.3 mV for ZnONPs, -36.2 mV for CNPs, -43.0 mV for neem oil encapsulated (3000 ppm) ZnONPs and -39.4 mV for NSKE encapsulated ZnONPs). NSKE encapsulated CNPs were able to contain groundnut bruchid up to 180 days with 54.61% weight loss compared to other formulations tested. Thus biomaterial encapsulated nanoscale material formulations are proved to be effective in controlling stored grain pests to reduce huge economic losses.

Facile Synthesis and Characterization of Chitosan Nanofibers by Oil/Water Emulsion Method

A facial approach for the synthesis of surfactant free, biodegradable and eco-friendly chitosan nanofibers (CS-NFS) was prepared by Oil/Water Emulsion method. The morphology of the CS-NFS was examined by field emission scanning electron microscopy (FE-SEM). FE-SEM images show the nanoscale chitosan nanofibers formation with sizes in the ranges of ~100-200 nm. Physiochemical characterizations of the CS-NFS were analyzed by Fourier transform infrared spectroscopy (FT-IR), UV-visible spectroscopy and thermogravimetric analysis. The CS-NFS are expected to be useful in electrical, optical and electrochemical devices.

Prospects of Nanostructure Materials and Their Composites as Antimicrobial Agents.

Nanostructured materials (NSMs) have increasingly been used as a substitute for antibiotics and additives in various products to impart microbicidal effect. In particular, use of silver nanoparticles (AgNPs) has garnered huge researchers' attention as potent bactericidal agent due to the inherent antimicrobial property of the silver metal. Moreover, other nanomaterials (carbon nanotubes, fullerenes, graphene, chitosan, etc.) have also been studied for their antimicrobial effects in order ensure their application in widespread domains. The present review exclusively emphasizes on materials that possess antimicrobial activity in nanoscale range and describes their various modes of antimicrobial action. It also entails broad classification of NSMs along with their application in various fields. For instance, use of AgNPs in consumer products, gold nanoparticles (AuNPs) in drug delivery. Likewise, use of zinc oxide nanoparticles (ZnO-NPs) and titanium dioxide nanoparticles (TiO2-NPs) as additives in consumer merchandises and nanoscale chitosan (NCH) in medical products and wastewater treatment. Furthermore, this review briefly discusses the current scenario of antimicrobial nanostructured materials (aNSMs), limitations of current research and their future prospects. To put various perceptive insights on the recent advancements of such antimicrobials, an extended table is incorporated, which describes effect of NSMs of different dimensions on test microorganisms along with their potential widespread applications.