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This study presents the effect of chitosan on the properties of zinc ferrite nanoparticles suitable for potential biomedical applications. The co‐precipitation method is employed to fabricate these bio‐composites that exhibit excellent microstructural properties. The X‐ray diffractometer (XRD) analysis confirms the presence of a cubic spinel structure in the zinc ferrite‐chitosan bio‐composites, indicative of their crystalline nature. Scanning electron microscope (SEM) imaging revealed spherical particles with a size distribution below 100 nm, demonstrating the successful synthesis of homogenous nanosized particles. Fourier transform infrared spectroscopy (FTIR) spectroscopy analysis identifies the active functional groups within the bio‐composites, providing valuable insights into the molecular structure and interactions present in the synthesized materials. The presence of chitosan is confirmed, highlighting its role in modifying the chemical composition and enhancing the biocompatibility of the samples. UV–vis absorption spectra analysis reveals that the samples exhibits absorbance within the visible range. Vibrating sample magnetometer (VSM) analysis demonstrates the superparamagnetic behavior of the samples. Remarkably, these formulated samples exhibit superparamagnetism with zero coercivity and a magnetization of ≈0.0125 emu g−1 at 5 kOe when doped with chitosan. These properties are crucial for potential biomedical applications making it a promising candidate for various biomedical applications. [ABSTRACT FROM AUTHOR]

Essential oils are composed of volatile components, and rapidly evaporate. It is desirable to formulate them in a cover protecting the essential oils against environmental conditions. Applying nanotechnology to preparing desirable formulations of essential oils can be provided in a cover along with controlled release, increased oil life and greater mobility. In this study, nanoparticles were prepared using polycaprolactone and chitosan aimed at encapsulation of Rosmarinus officinalis and Zataria multiflora essential oils. The nanoparticles were characterized in terms of size, polydispersity, encapsulation efficiency, and scanning electron microscope photomicrographs. The nanoparticles showed a positive surface charge ranging between +11.60 and +29.20 mV and a mean particle radius ranging between 181-407 nm. Encapsulation efficiency was obtained between 75.8-84.4% under different preparation conditions. The LC50 values of fumigant toxicity of R. officinalis essential oil and nanoparticles were equal to 103.53 and 112.64 μL/L air, and for Z. multiflora essential oil and nanoparticles, they were equal to 195.13 and 206.66 μL/L air, respectively for 24 h exposure time against Tribolium confusum. The effectiveness of non- formulated essential oils was significantly (P < 0.05) lower than nanoencapsulated oils in the confused flour beetle adults for a long period under the same condition, due to the sustained release of the essentials provided by the formulation. [ABSTRACT FROM AUTHOR]

Herein, 5-fluorouracil and shikonin (extracted from Fusarium tricinctum) were loaded in chitosan/pectin nanoparticle (CS/PEC-NPs), prepared by blending (B-CS/PEC-NPs) and coating (C-CS/PEC-NPs) methods. The nanoparticles characterized by Fourier Transform Infrared (FTIR), X-ray diffraction (XRD), Energy-dispersive X-ray (EDX), Scanning Electron Microscope (SEM) and Differential Light Scattering (DLS). Then, some properties of the nanoparticles such as drug release rate and the nanoparticles cytotoxicity were studied. The FTIR, XRD, EDX, SEM and DLS results showed that the nanoparticles synthesized properly with an almost spherical morphology, an average size of 82–93 nm for B-CS/PEC-NPs, an average diameter of below 100 nm (mostly 66–89 nm) for C-CS/PEC-NPs, and hydrodynamic diameter of 310–817 nm. The drug release results indicated the lower release rate of drugs for B-CS/PEC-NPs relative to C-CS/PEC-NPs at different pHs, high release rate of drugs for the nanoparticles in the simulated large intestinal fluids containing pectinase, and Korsmeyer-Peppas model for release of the drugs. The results showed more cytotoxicity of B-CS/PEC-NPs containing drugs, especially B-CS/PEC-NPs containing both drugs (B-CS/PEC/5-FU/SHK-NPs) after treating with pectinase (IC 50 of 18.6 μg/mL). In conclusion, despite the limitation of C-CS/PEC-NPs for simultaneous loading of hydrophilic and hydrophobic drugs, B-CS/PEC-NPs showed suitable potency for loading and targeted delivery of the drugs. [ABSTRACT FROM AUTHOR]

In recent years, the incorporation of nanoparticles and corrosion inhibitors into epoxy coatings has become increasingly important in order to address the growing demand for advanced anti-corrosion coatings. In this study, various amounts of extracted chitin and chitosan nanoparticles from shrimp ranging from 0 to 3% wt. were added to an epoxy coating. The zeta potential of particles and scanning electron microscope were applied to determine average particle size and distribution of particle in the epoxy coating. Thermal stability, adhesion properties and corrosion behavior of reinforced coating were investigated. The epoxy coating with a 2%wt chitin additive showed a more uniform distribution. Fourier transform infrared spectrometry and the thermogravimetric analysis test (TGA) illustrated that the addition of chitin and chitosan additives lead to chemical changes in the structure and improve the thermal stability of epoxy coatings. The addition of 2%wt chitin nanoparticles improved the mechanical properties of the coatings, particularly the adhesion resistance. Corrosion testing revealed that the epoxy coating containing 2% chitin and chitosan nanoparticles exhibited a low corrosion rate, high load transfer resistance, and a double layer capacity when exposed to a 3.5% NaCl solution. • Addition of Chitin & Chitosan nanoparticles enhanced anti-corrosion of epoxy coating. • Chitin nanoparticles fills the pores and lengthens the path of electrolyte diffusion. • More than 2%wt chitin nanoparticles lead to agglomeration and increase corrosion. • Chitin showed better anti-corrosion performance compared to chitosan. [ABSTRACT FROM AUTHOR]

Faba bean is amang the most strategic crops in Egypt and suffering from many destructive diseases especially chocolate spot caused by Botrytis fabae Sard. which can reduce yield production. Effect of chitosan nanoparticles (ChNPs) and silver nanoparticles (AgNPs) with average particle size of 7.54 and 8.043 nm, respectively at five concentrations (20, 40, 60, 80 and 100 ppm), as well as recommended dose of carbendazim (CZ) 100 g/100L (field rate) were studied in vitro against aggressive isolate of Botrytis fabae (B.f4). All concentrations significantly inhibited the radial growth of B.f4 compared with the control treatment. In vitro results showed that ChNPs followed by AgNPs were effective over conventional chemical fungicide CZ. Where the radial growth of B.f4 decreased by increasing concentration of the different materials especially ChNPs at 20-40 ppm recording 73.33% and 100% growth inhibition, respectively. While 100 ppm of AgNPs and recommended dose of CZ rate of 75.33% and 46.11% growth inhibition, respectively. In addition, scan electron microscope (SEM) showed that, the mycelium of B.f4 treated by AgNPs did not have detruation changes at 20 ppm. Contrary to B.f 4 mycelia treated with ChNPs 20 ppm exhibited seriously shrunk after 72 h post treatment in relative to the control. The antifungal effect of ChNPs, showed marked covered distorted mycelia. Most B.f4 spore morphology treated with AgNPs 20 ppm appeared to be shrunk and abnormal shape 72 h post treatment compared with the control. In addition, AgNPs lead to deforming B. fabae spores and explosion of others. On the other hand, spore production of B. fabae treated with ChNPs 20 ppm was completely inhibited 72 h post treatment. The obtained results offers a possibility of developing new manufacturing fungicides using chitosan and silver nanoparticles as substances for save control of faba bean chocolate spot disease and minimize the impact of conventional fungicides in the agri-ecosystem. [ABSTRACT FROM AUTHOR]

Essential oils (EOs) of greater celandine (GC) roots and leaves were extracted, and gas chromatography–mass spectrometry (GC–MS) was used for analyzing them. Then they were loaded into chitosan nanoparticles (CNPs) using emulsion-ionic gelation method. CNPs loaded with greater celandine root essential oil (GCREO) and leave essential oil (GCLEO) were synthesized (size 76.5–115.3 nm) using an emulsion-ionic gelation method. Fourier Transform Infrared (FT-IR), spectroscopy, scanning electron microscope (SEM), and dynamic light scattering (DLS) were used for characterization of the formed NPs. Good encapsulation efficiency was confirmed for GCREO (62.5%) and GCLEO (69.1%) in CNPs. According to the MTT results, the synthesized NPs showed a dose-dependent effect on MCF-7 cell line. The inhibitory concentration (IC 50) values for GCREO, GCLEO, CSNRs-GCREO and CNPs-GCLEO samples were 126.4, 90.2, 77.6, and 41.5 μg/mL, respectively. The highest rate of apoptosis was obtained in the CNPs-GCLEO group (63.73%). The results revealed that the cytotoxicity of CSNRs-GCREO and CNPs-GCLEO against MCF-7 cell line was significantly higher than that of their free form, implying that encapsulation of GCREO and GCLEO in CNPs is an efficient technique for improving their anti-cancer activity against MCF-7 cell line. [Display omitted] • Greater celandine essential oils were successfully encapsulated into chitosan nanoparticles. • Sizes of greater celandine essential oils-loaded chitosan nanoparticles ranged from 76.5 to 115.3 nm. • Encapsulation in chitosan nanoparticles enhanced the anticancer activity against MCF-7 cell line. • The lowest IC50 value was obtained in the encapsulated leaves essential oil. [ABSTRACT FROM AUTHOR]

In this work, a novel DHA-loaded nanoparticle with PLGA and chitosan (PCSDNP) was successfully prepared. The structure of PCSDNP and DHA-loaded PLGA nanoparticles was measured by transmission electron microscope, scanning electron microscope, and differential scanning calorimeter. The interaction strength between DHA, PLGA, and chitosan was evaluated through Fourier transform infrared spectroscopy. The curves of controlled DHA release and stabilities for different environmental factors of two NPs were evaluated. Importantly, two NPs were almost regularly spherical and the interactions were hydrogen bonds and electrostatic interactions between PLGA and chitosan. These NPs had a good encapsulation rate (80.45%) and high-water solubility than the free DHA molecule. In simulated gastrointestinal fluid, two NPs showed a controlled-release pattern. Overall, PCSDNP had better stability and controlled-release effect with the synergy between CS and PLGA under the conditions of pH (2– 7), ionic strength (0– 500 mM), storage time (0– 42 d), and temperature (30– 80 °C). [Display omitted] [ABSTRACT FROM AUTHOR]

Ionotropic gelation followed by polyelectrolyte complexion was used for the synthesis of nanoparticles based on sodium alginate (NaAL) and chitosan (CS) for encapsulation of ibuprofen (IBP), Fourier transform infrared spectroscopy, differential scanning calorimetry, field-emission scanning electron microscopes, percentage of encapsulation efficiency and loading capacity have been used to confirm the synthesis and encapsulation of IBP. The results obtained show that they have a size of around 100 nm. In vitro drug release and evaluation of anti-inflammatory activity in different media indicate that the nanoparticles are pH-sensitive and permit the protection of the drug against total dissolution in the gastric medium, control its release, and it increases the solubility and biological activity of IBP. The analytical data of the in vitro drug release in the simulated gastric fluid (SGF), simulated interstitial fluid (SIF) and phosphate buffered saline (PBS) were fitted to the different kinetic models (zero-order, first-order, Higuchi, Korsmeyer–Pepass and Kopcha), and the results indicate that IBP is released by diffusion-controlled in SIF and PBS, and by erosion-controlled in the SGF. The toxicity of nanoparticles was tested against Artemia salina that displayed non-toxicity effects. In vitro biodegradation by lysozyme and all the results obtained indicated that a NaAL/CS nanoparticles are a promising system for IBP release that can achieve pseudo-zero-order kinetics. [ABSTRACT FROM AUTHOR]

The chitosan/gelatin hydrogel incorporated with biphasic calcium phosphate nanoparticles (BCP-NPs) as scaffold (CGB) for bone tissue engineering was reported in this article. Such nanocomposite hydrogels were fabricated by using cycled freeze-thawing method, of which physicochemical and biological properties were regulated by adjusting the weight ratio of chitosan/gelatin/BCP-NPs. The needle-like BCP-NPs were dispersed into composites uniformly, and physically cross-linked with chitosan and gelatin, which were identified via Scanning Electron Microscope (SEM) images and Fourier Transform Infrared Spectroscopy (FT-IR) analysis. The porosity, equilibrium swelling ratio, and compressive strength of CGB scaffolds were mainly influenced by the BCP-NPs concentration. In vitro degradation analysis in simulated body fluids (SBF) displayed that CGB scaffolds were degraded up to at least 30 wt% in one month. Also, CCK-8 analysis confirmed that the prepared scaffolds had a good cytocompatibility through in culturing with bone marrow mesenchymal stem cells (BMSCs). Finally, In vivo animal experiments revealed that new bone tissue was observed inside the scaffolds, and gradually increased with increasing months, when implanted CGB scaffolds into large necrotic lesions of rabbit femoral head. The above results suggested that prepared CGB nanocomposites had the potential to be applied in bone tissue engineering. [ABSTRACT FROM AUTHOR]

Several fungal and bacterial strains are known to be able to degrade polymeric chains of cellulose. In this research, two polymorphic forms of celluloses, Cellulose I (C I) and Cellulose II (C II), were incubated with Ochrobactrum anthropi strain producing the cellulolytic enzymes. In the result, nanocrystalline celluloses with distinctive particle sizes distributions, as well as intact supermolecular and chemical structures were produced. The differences in yield of nanometric particles of each polymorphic form were discussed in accordance to crystallographic form of cellulose. Solvent casting method was applied to produce chitosan films filled with 1, 3, and 5 wt% of nanocrystalline C I and nanocrystalline C II. Mechanical testing proved that the tensile properties of the composites were closely related to the polymorphic variety of nanocrystalline cellulose. On the other hand, SEM microphotographs of the produced composites confirmed that good distribution of nanoparticles in the chitosan matrix was crucial for obtaining materials with enhanced mechanical properties. Filling the chitosan matrix with 1 wt% of nanocrystalline C I was determined to be the most effective. POLYM. COMPOS., 39:E448–E456, 2018. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Migration of fibroblasts into wound area is a critical phenomenon in wound healing process. We used an appropriate system to fabricate an electrospun bioactive scaffold with controlled release of PDGF-BB in order to induce migration of primary skin fibroblast cells. First of all, protein-loaded chitosan nanoparticles based on ionic gelation interaction between chitosan and sodium tripolyphosphate were prepared. Then polycaprolactone electrospun fibers containing chitosan nanoparticles or PDGF-BB-loaded chitosan nanoparticles were prepared. Cellular attachment and morphology of cells seeded on scaffolds with or without PDGF-BB were evaluated by using a fluorescence microscope and scanning electron microscopy. Cells were well-oriented 72 h after seeding on the scaffolds containing PDGF-BB. The mean aspect ratio of populations on scaffold containing PDGF-BB-loaded chitosan nanoparticles was significantly greater than those on the scaffold containing chitosan nanoparticles but no PDGF-BB. Furthermore, the Arp2 gene, which is involved in cell protrusion formation, showed about three times more expression at mRNA level, in cells seeding on PDGF-BB-containing scaffold compared to cells seeding on scaffold containing only chitosan nanoparticles, using Real Time PCR test. Finally, under agarose migration assay results demonstrated that cells' chemotaxic behavior was more toward scaffold containing PDGF-BB compared to the PDGF-BB alone or FBS group. In addition, in terms of distance, the cell mass could grow faster, in response to scaffold containing PDGF-BB compared to FBS or PDGF-BB alone; however, the number of migrating cells might be the same or significantly higher in the latter groups. [ABSTRACT FROM AUTHOR]

Conventional chemotherapy poses toxic effects to healthy tissues. A therapeutic system is thus required that can administer, distribute, metabolize, and excrete medicine from human body without damaging healthy cells. This is possible by designing a therapeutic system that can release drug at specific target tissue. In current work, novel chitosan (CS) based polymeric nanoparticles (PNPs) containing N -isopropyl acrylamide (NIPAAM) and 2-(di-isopropyl amino) ethyl methacrylate (DPA) are designed. The presence of available functional groups i.e. OH− (3262 cm−1), –NH 2 (1542 cm−1), and C O (1642 cm−1), was confirmed by Fourier Transform Infra-red Spectrophotometry (FTIR). The surface morphology and average particle size (175 nm) was determined through Scanning Electron Microscope (SEM). X-Ray Diffractometry (XRD) studies confirmed the amorphous nature and excellent thermal stability of PNPs up to 100 °C with only 2.69% mass loss was confirmed by Thermogravimetric analysis (TGA). The pH sensitivity of such PNPs for release of encapsulated doxorubicin at malignant site was investigated. The encapsulation efficiency of PNPs was 89% (4.45 mg/5 mg) for doxorubicin (a chemotherapeutic) measured by using UV–Vis Spectrophotometer. The drug release profile of loaded PNPs was 88% (3.92 mg/4.45 mg) at pH 5.3, in 96 h. PNPs with varying DPA concentration can effectively be used to deliver chemotherapeutic agents with high efficacy. [Display omitted] • The polymeric nanoparticles are prepared by copolymerizing chitosan with N -isopropyl acrylamide and 2-(di-isopropyl amino) ethyl methacrylate. • To avoid cardiotoxic effects, Doxorubicin (DOX) is encapsulated in the PNPs. • The higher DOX encapsulation efficiency of 89% is achieved. • The controlled in vitro release profile of DOX is 88% at the pH 5.3 (endosomal pH) up to 96 h. [ABSTRACT FROM AUTHOR]

[Display omitted] • • Folic acid-chitosan conjugate was synthesized by amidation. • • Characterization of PC-CS/FA-NPs were performed by DLS, FTIR, TGA and SEM. • • The inhibitory effect of PC-CS/FA-NPs on hemolysis of red blood cells was studied. • • The in vitro digestibility of PC-CS/FA-NPs were investigated. Proanthocyanidins have significant biological activity and pharmacological effects and are widely used in food, medicine, and cosmetics. Chitosan nanoparticles loaded with proanthocyanidins have been proven to improve their biological activity. Given some deficiencies of chitosan (CS), the modification of chitosan by folic acid (FA) can obtain new variants with different functions. For this objective, the folic acid conjugated chitosan was designed, and in vitro properties of proanthocyanidins loaded nanoparticles were studied systemically. Firstly, folic acid-chitosan conjugate (FA-CS) was synthesized and characterized. Folate-coupled chitosan-loaded proanthocyanidin nanoparticles (PC-CS/FA-NPs) were prepared by ionic gelation technique using FA-CS as a carrier. The successful nanoparticle synthesis was characterized by dynamic light scattering (DLS) techniques and Fourier transform infrared (FT-IR) spectroscopy. The synthesized nanoparticles exhibited a spherical shape and smooth and uniform distribution features with a size range of less than 300 nm, as observed by a scanning electron microscope (SEM). Meanwhile, PC-CS/FA-NPs had good thermal and gastrointestinal digestive stability and had a protective effect on AAPH-induced erythrocyte oxidative hemolysis. In conclusion, folic acid decorated chitosan nanoparticles improved the stability and bioavailability of proanthocyanidins in gastrointestinal digestion. [ABSTRACT FROM AUTHOR]

Schiff-bases of chitosan (CS) and carboxymethyl chitosan (CMCS)/silver nanoparticles (AgNPs) have been synthesized, characterized, and evaluated as antimicrobial agents against two Gram +ve bacteria (Bacillus cereus and Staphylococcus aureus) and two Gram −ve bacteria (Escherichia coli and Pseudomonas aeruginosa) in addition to Candida albicans as a fungus. The in situ reactions of CS and/or CMCS with some pyrazole aldehyde derivatives in acidic media containing silver nitrate to yield silver nanoparticles loaded onto CS and CMCS/Schiff-bases were carried out. Characterizations of the prepared compounds via FTIR spectroscopy, SEM, TEM, and TGA were carried out. Schiff-bases/silver nanoparticles of CS and CMCS showed higher antimicrobial activity than the blank CS and CMCS. The presence of AgNO3 (3% wt%) displayed high antibacterial efficiencies with inhibition zones in the extent of 19–39 mm. TEM analysis showed that the size of the silver nanoparticles is in the range of 4–28 nm for the prepared nanocomposites. [ABSTRACT FROM AUTHOR]

Highlights: [•] Fine structure of chitin nanofibrils by SEM and XRD methods was examined. [•] Structure and properties of the chitosan/chitin composite fibers. [•] Orientation of chitosan molecules by chitin nanoparticles. [•] Molecular modeling. [Copyright &y& Elsevier]

Purpose: To prepare and evaluate mucoadhesive nanoparticulate system of ebastine for nasal drug delivery. Methods: The nanoparticles were prepared by ionic gelation method using drug-chitosan weight ratios 1:1, 1:2 and 1:3, and incorporating 0.5 or 0.7 % w/v sodium tripolyphosphate (STPP) and poloxamer 407. The mucoadhesive nanoparticles were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), differential scanning colorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) and evaluated for drug loading, entrapment efficiency, in vitro mucoadhesion, in vitro drug release and ex-vivo permeation Results: FTIR and DSC studies indicate that no chemical interaction occurred between the drug and polymer. Nanoparticle size ranged from 169 to 500 nm. Drug loading and entrapment efficiency increased with increase in chitosan concentration and decreased with increase in poloxamer 407 concentration. The highest drug loading obtained for the nanoparticles was 19.5 %. With increase in polymer (chitosan) concentration (1:1 to 1:3), production yield was unchanged (73.2 to 74.4 % (F6)). Mucoadhesion increased with increase in the concentration of chitosan. In vitro drug release from all the formulations was biphasic, being characterized by a slight 'burst' followed by slow release. At the end of 8 h F6 (1:3) showed drug release of only 86.9 %, indicating sustained release. Ex-vivo permeation of pure ebastine was more rapid than from F6, thus indicating the capability of chitosan to control drug permeation rate through sheep nasal mucosa. Conclusion: The results indicate that a mucoadhesive nanoparticulate system can be used effectively for the nasal delivery of the antihistamine, ebastine. [ABSTRACT FROM AUTHOR]

Oneof the purposes of the project was to develop the method ofpreparation of 3D macroporous hydrogel with a structure of interconnectedpores by the use of noncovalent interactions. The combination of chitosanand noble-metal complexes was investigated as cross-linking agentsfor the preparation of ionic cryogels (ICs). Furthermore, the treatmentof the ICs containing gold complex by glutaraldehyde results in spontaneousformation of gold nanoparticles (AuNPs) and chemical cross-linkingof the cryogel. The characterization of prepared macroporous materialswas carried out by the use of FTIR, SEM, TEM techniques, and textureanalyzer. A new strategy for control of size distribution of AuNPswas suggested. The size distribution of obtained AuNPs and their populationinside of walls of cryogels was estimated. A method for quantifyingunreacted chloroauric acid in the presence of acetic acid was proposed.The possibility of use of prepared cryogels with immobilized AuNPsas a catalytic flow through reactor is shown. [ABSTRACT FROM AUTHOR]

In this paper, we firstly synthesized glycyrrhetinic acid-modified double amino-terminated poloxamer 188 (GA--NH--POLO--NH--GA). The structure of the synthesized compound was confirmed by 'H-NMR and Fourier transform infrared (FT-IR) spectroscopy. Then the nano-particles composed of GA-NH-POLO-NH-GA/chitosan (GA-NH-POLO-NH-GA/CTS) were prepared by an ionic gelation process. The characterization of the nanoparticles was measured by dynamic light scattering (DLS) and scanning electron microscope (SEM). The results showed that the nanoparticles were well dispersed with a spherical shape and the particle size was distributed between 100 nm and 300 nm. The cytotoxicity based on MTT assay against cells (QGY-7703 cells and L929 cells) showed that the nanoparticles had low toxicity and good biocompatibility. The encapsulation efficiency and drug loading of 5-fluorouracil-loaded nano-particles (5-FU nanoparticles) were measured by high-performance liquid chromatography (HPLC) and fluorescence spectroscopy, ultraviolet-visible (UV-vis) absorbance. The encapsula-tion of 5-Fu-loaded CTS nanoparticles was 12.8% and the drug loading was 2.9%, while the encapsulation of 5-Fu-loaded GA-NH-POLO-NH-GA/CTS nanoparticles was 20.9% and the drug loading was 3.36%. The release profile showed that the GA-NH-POLO-NH-GA/CTS nanoparticles were available for sustained release of 5-Fu. The GA--NH--POLO--NH--GA/CTS nanoparticles have a higher affinity to the QGY-7703 cells, so indicated that the GA-NH-POLO-NH-GA/CTS nanoparticles have the capacity of liver-targeting in vitro. [ABSTRACT FROM AUTHOR]

Abstract: In this work chitosan–hyaluronan composite sponge incorporated with chondroitin sulfate nanoparticle (nCS) was developed. The fabrication of hydrogel was based on simple ionic cross-linking using EDC, followed by lyophilization to obtain the composite sponge. nCS suspension was characterized using DLS and SEM and showed a size range of 100–150nm. The composite sponges were characterized using SEM, FT-IR and TG-DTA. Porosity, swelling, biodegradation, blood clotting and platelet activation of the prepared sponges were also evaluated. Nanocomposites showed a porosity of 67% and showed enhanced swelling and blood clotting ability. Cytocompatibility and cell adhesion studies of the sponges were done using human dermal fibroblast (HDF) cells and the nanocomposite sponges showed more than 90% viability. Nanocomposite sponges also showed enhanced proliferation of HDF cells within two days of study. These results indicated that this nanocomposite sponges would be a potential candidate for wound dressing. [Copyright &y& Elsevier]

A simple preparation process for the monodispersed pH-sensitive core-shell magnetic microspheres was carried out consisting of chitosan self-assembled on magnetic iron oxide nanoparticles. Meanwhile, glucoamylase was immobilized as a model enzyme on this carrier of FeO/CS microspheres by ionic adsorption. The morphology, inner structure, and high magnetic sensitivity of the resulting magnetic chitosan microspheres were studied, respectively, with a field emission scanning electron microscope (SEM), transmission electron microscope (TEM), FT-IR spectroscopy, thermogravimetric analysis (TGA), and a vibrating sample magnetometer (VSM). Subsequently, the properties of glucoamylase immobilized on the regenerated supports were also investigated by determining storage stability, pH stability, reusability, magnetic response, and regeneration of supports. The results from characterization and determination remarkably indicated that the immobilized glucoamylase obtained presents excellent storage stability, pH stability, reusability, magnetic response, and regeneration of supports. Therefore, this kind of magnetic FeO/CS microspheres with perfect monodispersity should be an ideal support for enzyme immobilization. [ABSTRACT FROM AUTHOR]

Abstract: A novel nano-adsorbent, β-cyclodextrin–chitosan (CDC) modified Fe3O4 nanoparticles (CDCM) is fabricated for removal of methyl blue (MB) from aqueous solution by grafting CDC onto the magnetite surface. The characteristics results of FTIR, SEM and XRD show that CDC is grafted onto Fe3O4 nanoparticles. The grafted CDC on the Fe3O4 nanoparticles contributes to an enhancement of the adsorption capacity because of the strong abilities of CDCM, which includes the multiple hydroxyl, carboxyl groups, amino groups and the formation of an inclusion complex due to the β-CD molecules through host–guest interactions, to adsorb MB. The adsorption of MB onto CDCM is found to be dependent on pH and temperature. Adsorption equilibrium is achieved in 50min and the adsorption kinetics of MB is found to follow a pseudo-second-order kinetic model. Equilibrium data for MB adsorption are fitted well by Langmuir isotherm model. The maximum adsorption capacity for MB is estimated to be 2.78g/g at 30°C. The CDCM was stable and easily recovered. Moreover the adsorption capacity was about 90% of the initial saturation adsorption capacity after being used four times. [Copyright &y& Elsevier]

Nanoparticles consisting of human therapeutic drugs are suggested as a promising strategy for targeted and localized drug delivery to tumor cells. In this study, 5-fluorouracil (5-FU) encapsulated chitosan nanoparticles were prepared in order to investigate potentials of localized drug delivery for tumor environment due to pH sensitivity of chitosan nanoparticles. Optimization of chitosan and 5-FU encapsulated nanoparticles production revealed 148.8±1.1 nmand 243.1±17.9 nmparticle size diameters with narrow size distributions, which are confirmed by scanning electron microscope (SEM) images. The challenge was to investigate drug delivery of 5-FU encapsulated chitosan nanoparticles due to varied pH changes. To achieve this objective, pH sensitivity of prepared chitosan nanoparticle was evaluated and results showed a significant swelling response for pH 5 with particle diameter of ∼450 nm. In vitro release studies indicated a controlled and sustained release of 5-FU from chitosan nanoparticles with the release amounts of 29.1-60.8% due to varied pH environments after 408 h of the incubation period. pH sensitivity is confirmed by mathematical modeling of release kinetics since chitosan nanoparticles showed stimuli-induced release. Results suggested that 5-FU encapsulated chitosan nanoparticles can be launched as pH-responsive smart drug delivery agents for possible applications of cancer treatments [ABSTRACT FROM AUTHOR]

Abstract: A novel biosensor for detecting glucose had been constructed by the immobilization of glucose oxidase (GOD) on chitosan-boron-doped carbon-coated nickel (BCNi) nanoparticle modified electrode. The GOD-chitosan-BCNi bionanocomposite film was characterized with scanning electron microscope (SEM). The film was propitious to the immobilization of GOD and to the retention of its bioactivity. The direct electrochemistry and electrocatalysis of GOD on modified electrode had been investigated by cyclic voltammogram (CV) and amperometric measurements. The GOD displayed a pair of stable, well-defined and quasi-reversible redox peaks in pH 7.0 phosphate buffer solution (PBS). Furthermore, the biosensor was applied to detect glucose with a broad linear range from 2.50×10−5 to 1.19×10−3 M, the detection limit was brought down to 8.33×10−6 M at a signal to noise ratio of 3 and with an applied potential of −0.2V. The proposed biosensor showed rapid response (within 3s), low detection limit, high affinity to glucose and accepted storage stability over one-month period, which demonstrated that the chitosan-BCNi film has potential applications in the immobilization of other third-generation enzyme biosensors. [Copyright &y& Elsevier]

Abstract: The encapsulation of ascorbyl palmitate (AP) in chitosan particles was carried out by droplet formation via an oil-in-water emulsion, followed by droplet solidification via ionic gelation using sodium triphosphate pentabasic (TPP) as a cross-linking agent. The success of AP encapsulation was confirmed by FT-IR, UV–vis spectrophotometry, TGA, and XRD techniques. The obtained AP-loaded chitosan particles were spherical in shape with an average diameter of 30–100nm as observed by SEM and TEM. Loading capacity (LC) and encapsulation efficiency (EE) of AP in the nanoparticles were about 8–20% and 39–77%, respectively, when the initial AP concentration was in the range of 25–150% (w/w) of chitosan. Augmentation of the initial AP concentration led to an increase of LC and a reduction of EE. The amount of AP released from the nanoparticles in ethanol and tris buffer (pH∼8.0) increased with increasing LC and decreasing TPP concentration. [Copyright &y& Elsevier]

In this study, we report the physico-chemical and biological properties of a novel biodegradable composite scaffold made of nano-hydroxyapatite and natural derived polymers of chitosan and carboxymethyl cellulose, namely, n-HA/CS/CMC, which was prepared by freeze-drying method. The physico-chemical properties of n-HA/CS/CMC scaffold were tested by infrared absorption spectra (IR), transmission electron microscope(TEM), scanning electron microscope(SEM), universal material testing machine and phosphate buffer solution (PBS) soaking experiment. Besides, the biological properties were evaluated by MG63 cells and Mesenchymal stem cells (MSCs) culture experiment in vitro and a short period implantation study in vivo. The results show that the composite scaffold is mainly formed through the ionic crossing-linking of the two polyions between CS and CMC, and n-HA is incorporated into the polyelectrolyte matrix of CS-CMC without agglomeration, which endows the scaffold with good physico-chemical properties such as highly interconnected porous structure, high compressive strength and good structural stability and degradation. More important, the results of cells attached, proliferated on the scaffold indicate that the scaffold is non-toxic and has good cell biocompatibility, and the results of implantation experiment in vivo further confirm that the scaffold has good tissue biocompatibility. All the above results suggest that the novel degradable n-HA/CS/CMC composite scaffold has a great potential to be used as bone tissue engineering material. [ABSTRACT FROM AUTHOR]

• Melatonin/chitosan/hydroxypropyl methylcellulose nanoparticle was synthesized. • pH-responsive property for sustained melatonin release was shown. • Encapsulated melatonin nanoparticles showed high cytotoxicity against breast cancer cells. This work describes the development of novel pH-sensitive nanoparticles (NPs) for the delivery of melatonin (MLT) in breast cancer therapy. The MLT was encapsulated in composite NPs consisting of chitosan (CTS) and hydroxypropyl methylcellulose (HPMC) crosslinked in the presence of tripolyphosphate (TPP). The structure of the composite NPs was characterized using fourier transform infrared (FT-IR), wide angle X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). The release behavior of MLT from the composite NPs were investigated in acidic and neutral medium in vitro. Cytotoxicity of MLT encapsulated in the NPs toward MDA-MB-231 breast cancer cells was measured using thiazolyl blue tetrazolium bromide assay (MTT) and compared with that of the free MLT. Results demonstrate that MLT encapsulated in CTS/HPMC NPs had higher toxicity toward the MDA-MB-231 cancer cells compared to the free MLT, thus making the NPs potentially useful in breast cancer therapy. [ABSTRACT FROM AUTHOR]