Hydroxyapatite Chitosan Research Articles

Protection of Solanum lycopesicum induced by chitosan and chitosan nano-hydroxyapatite against Pepino mosaic virus and Verticillium dahliae

The main of the present study was to prepare chitosan (Chit) and chitosan hydroxyapatite nanoparticle (Chit-nHap) to assess their activities against two major diseases affecting tomato crop: pepino mosaic virus (PepMV) and verticillium wilt caused by the fungus Verticillium dahliae. The synthesized compounds were characterized using X-rays diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electronic microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). In vitro, the application of various concentrations of Chit and Chit-nHap showed significant inhibition of radial mycelial growth against V. dahliae. However, Chit-nHap was found to be more effective than Chit. In greenhouse trials, the disease severity was significantly reduced when Chit and Chit-nHap were sprayed to the leaves at 150 and 250 μg mL−1. The highest concentration of Chit and Chit-nHap reduced leaf alteration index by more than 81% and browning index by 96%. Both compounds also reduced PepMV disease severity and virus accumulation. Protection afforded against PepMV was associated with differential accumulation of H2O2 and with potentiation of the activity of antioxidant enzymes such as catalase, ascorbate peroxidase, guaiacol peroxidase and polyphenol oxidase.

Controlled release of minocycline in hydroxyapatite/chitosan composite for periodontal bone defect repair.

The aim was to obtain bone repair materials with sustained release of minocycline and evaluate the effect in periodontal bone defect repair. Two complex material, hydroxyapatite/chitosan (HA/CS) and minocycline-hydroxyapatite/chitosan (Mino-HA/CS), were prepared by the co-precipitation method. The physical and chemical property, cytotoxicity, release of minocycline and the bacteriostasis examination of the materials were evaluated, they were applied to the rabbit model of mandible bone defect to evaluate their effects on the regeneration of periodontal bone defect. After minocycline was added to HA/CS, the setting time of the material was prolonged, the compressive strength was reduced and the pore size and porosity were increased significantly. The pH value did not change obviously and stayed in the neutral range. Mino-HA/CS could promote the growth of osteoblasts effectively compared with control medium. In vivo, Mino-HA/CS material showed better effect of promoting periodontal bone formation.

Preparation of chitosan/hydroxyapatite composite coating obtained from crab shells on hierarchical micro/nano-textured Ti surface

In this study, crab shell bio-waste was used to fabricate chitosan/hydroxyapatite (CS/HA) coatings on the surface of pure titanium (Ti). HA is the main inorganic component in human bone; it has favorable biocompatibility, bioactivity, and osteoconductivity. CS can promote cell adhesion, proliferation, and differentiation and is highly antibacterial. Additionally, acid etching plus alkaline treatment was adopted to create micro/nano-textured hierarchical topographical features on the surface of Ti samples, and the CS/HA composite coating was then prepared through hydrothermal treatment and added to the chemically pretreated Ti surfaces. A nanoporous network structure was formed after alkali treatment, and the micropores remained after acid etching. The CS/HA layer coated on the strut surface of the porous network structure was thin and did not entirely fill and block the nanoporous network structure. Therefore, this surface contained a favorable three-dimensional microenvironment for cell attachment. The Ti surface exhibited the highest roughness (482.2 nm) after acid etching and alkali treatment, and it presented a superhydrophilic surface (contact angle of less than 10°). Subsequently, when the surface was coated with CS/HA, the roughness slightly decreased to 400.7 nm, and the water contact angle slightly increased to 21.6°. After the CS/HA-coated sample was immersed in simulated body fluid for 7 days, many apatite particles were deposited on the surface, indicating that the coating had favorable bioactivity.

Preparation of Diatom-Doped Bio-Nanocomposite Materials for Bone Tissue Scaffolds

Naturally sourced materials have an important place in bone tissue engineering due to their biocompatibility and biodegradability. Non-diatom, diatom-doped chitosan/hydroxyapatite (CS/HAp) and collagen/chitosan/hydroxyapatite (Col/CS/HAp) as three-dimensional tissue scaffolds were produced by freeze drying technique. It was determined by SEM analysis that CS/HAp, CS/HAp/Di, Col/CS/HAp, Col/CS/HAp/Di scaffolds have 160 μm, 130 μm, 390 μm and 340 μm pores, respectively. The diatoms in the structure have approximately 9-16 μm in length, 8-20 μm in diameter and nanopore sizes of 260-330 nm. Cell culture studies were performed using the 3T3 cell line to study the non-toxic nature of biocomposite scaffolds that support cell attachment and proliferation. The cells in the scaffolds without diatom proliferate in a reticulated manner, whereas in the scaffolds containing diatom the cells were wrapped around the scaffold like a cover. The suggested scaffolds have the potential to meet the basic requirements in biocompatibility, cytocompatibility and interconnected pore structure.

Fabrication of Novel Chitosan–Hydroxyapatite Nanostructured Thin Films for Biomedical Applications

In this study, we develop chitosan–hydroxyapatite (CS–HAp) composite layers that were deposited on Si substrates in radio frequency (RF) magnetron sputtering discharge in argon gas. The composition and structure of CS–HAp composite layers were investigated by analytical techniques, such as Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), metallographic microscopy (MM), and atomic force microscopy (AFM). On the other hand, in the present study the second order derivative of FT-IR–ATR spectra, for compositional analyses of CS–HAp, were used. The SEM, MM, and AFM data have shown the formation of CS–HAp composite layers. The surface of CS–HAp composite layers showed uniform growth (at an Ar gas working pressure of p = 2 × 10−3 mbar). The surface of the CS–HAp composites coatings became more nanostructured, becoming granular as the gas pressure increased from 5 × 10−3 to 1.2 × 10−2 mbar. However, our studies revealed that the surface morphology of the CS–HAp composite layers varies with the Ar gas working pressure. At the same time, optical properties are slightly influenced by Ar pressure. Their unique physicochemical properties make them suitable for various applications in the biomedical field, if we consider the already proven antimicrobial properties of chitosan. The antifungal properties and the capacity of the CS–HAp composite layers to inhibit the development of fungal biofilms were also demonstrated using the Candida albicans ATCC 10231 (C. albicans) fungal strain.

Preparation and characterization of biocomposites based on chitosan and biomimetic hydroxyapatite derived from natural phosphate rocks

Highly porous chitosan/hydroxyapatite (CS/HA) biocomposite scaffolds were prepared using the freeze-gelation method. A starting biomimetic HA powder was synthesized by a wet precipitation method using an abundant natural phosphate (NP) ore as raw material. Then, CS/HA scaffolds with different weight ratios (100/0; 90/10; 80/20; 70/30) have been prepared. The used powders and synthesized scaffolds were characterized by XRF, ICP-MS, FTIR, TG-DSC, XRD, SEM, and cell viability. The results showed that the precipitated raw powder was mainly composed of HA and amorphous calcium phosphate (ACP) with some traces of Mg2+, SiO42−, Sr2+, Na+ and Fe2+ ions which were usually found in such mineral NP precursors. The heat treatment of the raw powder at more than 750 °C leads to the formation of Mg-substituted β-tricalcium phosphate (β-TCMP). Moreover, the culture of human embryonic kidney cells indicated the non-cytotoxicity of the as-prepared powder. On the other hand, the elaborated CS/HA scaffolds exhibited a highly porous structure with well-interconnected pores and homogeneously dispersed HA particles. The measurement of swelling capacity under physiological conditions revealed that the addition of HA to the CS matrix effectively decreased the swelling percentage. The obtained results suggest that the elaborated CS/HA composites may have effective potential as biocompatible scaffolding materials for bone tissue engineering.

Preparation and characterization of magnetic chitosan hydroxyapatite nanoparticles for protein drug delivery and antibacterial activity

Preparation and characterization of magnetic chitosan hydroxyapatite nanoparticles for protein drug delivery and antibacterial activity

Electrochemical characterization of electrophoretically deposited hydroxyapatite/chitosan/graphene oxide composite coating on Mg substrate

Magnesium alloys are promising for hard tissue implants due to stupendous advantages including biodegradability and similar mechanical properties to natural bone. However, high degradation rate in body environment is main disadvantage for widespread applications of Mg alloys. In the present study, the alloy of Mg-4 % Zn- 4 % Sn-0.6 % Ca-0.5 % Mn was at first prepared by casting and subsequent extrusion, then was coated by hydroxyapatite/chitosan (HA/CS) with different graphene oxide (GO) content through electrophoretic deposition method (EPD). The effect of GO value and electrodeposition potential were studied on the morphology, chemical features and corrosion behavior of coating. Accordingly, coated samples were characterized by Fourier Transformation Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM) and Electrochemical Impedance Spectroscopy (EIS). The results revealed the improvement of corrosion resistance for all coated samples and the optimum values of additional GO and applied potential were found to be 1 % and 150 V, respectively. The microstructure of the coatings showed a significant relationship between the soundness of coating and corrosion resistance which might be due to the formation of well dispersed, low porosity and relatively dense composite coating.

Synthesis, Characterization and Bioactivity of Chitosan Hydroxyapatite Composite Doped with Strontium

Chitosan-hydroxyapatite composite doped with strontium was synthesised via in situ co-precipitation method. Physicochemical properties of the composite obtained were analysed using X-ray diffraction (XRD), infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX) and Thermogravimetry with differential thermal analysis (DT-TGA). The synthesized composite was subjected to bioactivity studies in simulated body fluid (SBF). The calcium release from the sample in SBF was measured using atomic absorption spectroscopy (AAS). The physicochemical properties and bioactivity of the novel composite was compared with that of hydroxyapatite, strontium doped hydroxyapatite and chitosan hydroxyapatite. The in vitro bioactivity studies of the novel composite showed that it has a higher release of Ca2+ in the SBF compared to the other samples. The novel material was also found to induce more Ca2+ deposition after 28 days of immersion in the SBF. Hence, the novel composite material has the potential to be used as biomaterials for clinical application.

Bone remodeling using a three-dimensional chitosan - hydroxyapatite scaffold seeded with hypoxic conditioned human amnion mesenchymal stem cells

Background: Bone regeneration studies involving the use of chitosan–hydroxyapatite (Ch-HA) scaffold seeded with human amnion mesenchymal stem cells (hAMSCs) have largely incorporated tissue engineering experiments. However, at the time of writing, the results of such investigations remain unclear. Purpose: The aim of this study was to determine the osteogenic differentiation of the scaffold Ch-HA that is seeded with hAMSCs in the regeneration of calvaria bone defect. Methods: Ch-HA scaffold of 5 mm diameter and 2 mm height was created by lyophilisation and desalination method. hAMSCs were cultured in hypoxia environment (5% oxygen, 10% carbon dioxide, 15% nitrogen) and seeded on the scaffold. Twenty male Wistar rat subjects (8 – 10 weeks, 200 - 250 grams) were randomly divided into two groups: control and hydroxyapatite scaffold (HAS). Defects (similar size to scaffold size) were created in the calvaria bone of the all-group subjects, but a scaffold was subsequently implanted only in the treatment group members. Control group left without treatment. After observation lasting 1 and 8 weeks, the subjects were examined histologically and immunohistochemically. Statistical analysis was done using ANOVA test. Results: Angiogenesis; expression of vascular endothelial growth factor; bone morphogenetic protein; RunX-2; alkaline phosphatase; type-1 collagen; osteocalcin and the area of new trabecular bone were all significantly greater in the HAS group compared to the control group. Conclusion: The three-dimensional Ch-HA scaffold seeded with hypoxic hAMSCs induced bone remodeling in calvaria defect according to the expression of the osteogenic and angiogenic marker.

A Novel Approach of Chitosan and Its Derivatives Bioactivity Against The Pinworm Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) مقاربة جديدة للنشاط الحيوي للشيتوزان ومشتقاته ضد الدودة الدبوسية توتا أبسلوتا

The present study was carried out to evaluate the relative insecticidal and biological activity of chitosan and its derivativesagainst the 2nd larval instar of T. absoluta compared to the unprecedented insecticide chloroanatrilprole (Coragen) using standardized method of bioassay under laboratory conditions. The larvacidal activity for the different treatments against 2nd instar larvae of T. absoluta were predestined. Also, effect of the tested agents on growth inhibition, antifeedant and life-cycle of the tested insect were determined. The results revealed that chitosan nanoparticles (NPs) was the most effective treatment against 2nd larval instar and eggs deposited per gravid female of T. absoluta. while, chitosan hydroxyapatite nanoparticles (NPs) was the highest effective treatment on growth inhibition and antifeedant. All tested agents disrupted life cycle of the tested insect under laboratory conditions. Therefore, this study suggests the possible using of chitosan and its derivativesas safe alternatives to conventional insecticide and compatible with integrated pest management practices.

Understanding Electrodeposition of Chitosan-Hydroxyapatite Structures for Regeneration of Tubular-Shaped Tissues and Organs.

Tubular-shaped hydrogel structures were obtained in the process of cathodic electrodeposition from a chitosan–hydroxyapatite solution carried out in a cylindrical geometry. The impact of the initial concentration of solution components (i.e., chitosan, hydroxyapatite, and lactic acid) and process parameters (i.e., time and voltage) on the mass and structural properties of deposit was examined. Commercially available chitosan differs in average molecular weight and deacetylation degree; therefore, these parameters were also studied. The application of Fourier-transform infrared spectroscopy, scanning electron microscopy, and time-of-flight secondary ion mass spectrometry allowed obtaining fundamental information about the type of bonds and interactions created in electrodeposited structures. Biocompatible tubular implants are highly desired in the field of regeneration or replacement of tubular-shaped tissues and organs; therefore, the possibility of obtaining deposits with the desired structural properties is highly anticipated.

Fabrication and Characterization of Polycaprolactone/Chitosan-Hydroxyapatite Hybrid Implants for Peripheral Nerve Regeneration.

Major efforts for the advancement of tubular-shaped implant fabrication focused recently on the development of 3D printing methods that can enable the fabrication of complete devices in a single printing process. However, the main limitation of these solutions is the use of non-biocompatible polymers. Therefore, a new technology for obtaining hybrid implants that employ polymer extrusion and electrophoretic deposition is applied. The fabricated structures are made of two layers: polycaprolactone skeleton and chitosan–hydroxyapatite electrodeposit. Both of them can be functionalized by incorporation of mechanical or biological cues that favor ingrowth, guidance, and correct targeting of axons. The electrodeposition process is conducted at different voltages in order to determine the influence of this process on the structural, chemical, and mechanical properties of implants. In addition, changes in mechanical properties of implants during their incubation in phosphate-buffered solution (pH 7.4) at 37 °C up to 28 days are examined. The presented technology, being low-cost and relatively simple, shall find a broad scope of applications in customized nerve tissue engineering.

Mechanical Behavior of Hydroxyapatite-Chitosan Composite: Effect of Processing Parameters

Three-dimensional hydroxyapatite-chitosan (HA-CS) composites were formulated via solid-liquid technic and freeze-drying. The prepared composites had an apatitic nature, which was demonstrated by X-ray diffraction and Infrared spectroscopy analyses. The impact of the solid/liquid (S/L) ratio and the content and the molecular weight of the polymer on the composite mechanical strength was investigated. An increase in the S/L ratio from 0.5 to 1 resulted in an increase in the compressive strength for HA-CSL (CS low molecular weight: CSL) from 0.08 ± 0.02 to 1.95 ± 0.39 MPa and from 0.3 ± 0.06 to 2.40 ± 0.51 MPa for the HA-CSM (CS medium molecular weight: CSM). Moreover, the increase in the amount (1 to 5 wt%) and the molecular weight of the polymer increased the mechanical strength of the composite. The highest compressive strength value (up to 2.40 ± 0.51 MPa) was obtained for HA-CSM (5 wt% of CS) formulated at an S/L of 1. The dissolution tests of the HA-CS composites confirmed their cohesion and mechanical stability in an aqueous solution. Both polymer and apatite are assumed to work together, giving the synergism needed to make effective cylindrical composites, and could serve as a promising candidate for bone repair in the orthopedic field.

Two-step strategy for constructing hierarchical pore structured chitosan–hydroxyapatite composite scaffolds for bone tissue engineering

Chitosan (CS) combined with hydroxyapatite (HA) was injected into a composite braid, and a hierarchical pore structure scaffold was obtained by freeze drying and cold atmospheric plasma (CAP) technology. The CS/HA/braid scaffold with hierarchical pore structure was analyzed and characterized by scanning electronic microscopy, Fourier transform infrared spectroscopy, true color confocal microscopy, improved liquid replacement method, and phosphate buffer solution immersion. The mechanical properties and degradation ability of the scaffold were evaluated through compression test and degradation test. Results showed that HA addition endowed the core of the scaffold with macroscopic pore sizes of 80–180 μm, and CAP treatment endowed the shell of the scaffold with microscopic pore sizes ≤10 μm. All scaffolds exhibited high porosity and swelling rates of ≥80 % and ≥300 %, respectively. The scaffold with a hierarchical pore structure had good mechanical properties and twice the degradation rate. In addition, the treated scaffold precipitated intact spherical HA crystals. Under the synergistic effect of HA and CAP treatment, scaffolds achieved 277.6 % cell viability compared with pure CS scaffold. Overall, this method was feasible for preparing bone scaffolds with hierarchical pore structure for potential bone tissue engineering.

Hydroxyapatite formation with the interface of chitin and chitosan

Hydroxyapatite (HA) film atop artificial implants surface can provide bioactive, osteoconductive and bone-similar interface. Traditional technique utilizes collagen coating to induce HA mineralization via charged functional groups. However, collagen loss as aging might lead to unstable interface. In this study, we presume that chitin (CH) with acetamide group chelates calcium ion and chitosan (CS) with amine group chelates phosphate ion, providing an ambiance for the HA crystallite formation. The presumption is evidenced by molar conductivity experiments. Besides, the hydrogen bonds of CH and electrostatic repulsion force of CS render different molecular architecture for the tunnel-connected structure. Furthermore, it forms porous morphology after HA mineralization evidenced by SEM images. Interestingly, mixing CH and CS provides the interface for Ca2+/PO43- capturing, rendering the formation of micro-crystallite with the 1.69/1.7 for the ratio of calcium to phosphate, being evidenced by EDX and AES experiments. Moreover, crystallinity index is calculated with XRD and FTIR spectra that CH–CS–HA possesses the highest crystallite to amorphous ratio. The HA film also shows good biocompatibility through L929 MTT test with 100% cell viability for the potential bio-applications. By the tapping-mode of AFM, the Young's modulus of CH–CS–HA surface is estimated to be 2.04 GPa near that of native bone.

Novel chitosan-hydroxyapatite macroporous composites for biomedical applications

Composites made of natural and/or naturally-derived polymers intended for biomedical applications are expected to exhibit structures analogous to the natural ones, as well as valuable properties as biologic compatibility and activity, and the ability to allow new, biologically recognizable interactions/signals with the host tissue. Under these circumstances, novel chitosan-hydroxyapatite (Cs-HAp) macroporous composites were prepared through a simple procedure and subsequently characterized by the means of Fourier transformed infrared spectrometry (FTIR), scanning electron microscopy (SEM), X-ray diffractometry (XRD), and mechanical tests. Experimental data confirmed the materials have high porosity, originating in the structure of Cs, and good mechanical properties, due to the presence of HAp, which enables them to be further employed in various biomedical applications, but only when low to moderate loads were used.

Chitosan-Hydroxyapatite Composite Layers Generated in Radio Frequency Magnetron Sputtering Discharge: From Plasma to Structural and Morphological Analysis of Layers.

Chitosan–hydroxyapatite composite layers were deposited on Si substrates in radio frequency magnetron sputtering discharges. The plasma parameters calculated from the current–voltage radio frequency-compensated Langmuir probe characteristics indicate a huge difference between the electron temperature in the plasma and at the sample holder. These findings aid in the understanding of the coagulation pattern of hydroxyapatite–chitosan macromolecules on the substrate surface. An increase in the sizes of the spherical-shape grain-like structures formed on the coating surface with the plasma electron number density was observed. The link between the chemical composition of the chitosan–hydroxyapatite composite film and the species sputtered from the target or produced by excitation/ionization mechanisms in the plasma was determined on the basis of X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and residual gas mass spectrometry analysis.

Mechanical strength improvement of chitosan/hydroxyapatite scaffolds by coating and cross-linking

Coating and cross-linking have been widely used to improve the properties of materials in tissue engineering. A chitosan/hydroxyapatite (CS/HA) comby scaffold with high porosity was prepared via a 3D printed pore-forming mold. The scaffold was then treated with gelatin (Gel) coating and was cross-linked by glutaraldehyde (GA) in order to improve the mechanical strength. The materials were characterized by infrared spectroscopy (IR) and X-ray diffraction (XRD). The structure of the scaffolds was observed by Scanning Electron Microscopy (SEM). Compression tests were carried out to evaluate the strength of the scaffolds. The behaviors and responses of preosteoblast cells on the scaffolds were studied as well. The results showed that gelatin coating and cross-linking significantly enhanced the mechanical strength of the porous scaffolds. Cell culture experiment indicated that the scaffold had good cytocompatibility. The combined application of 3DP structure construction and biopolymer coating/cross-linking would offer some new ideas in fabrication of porous scaffolds with enhanced strength and good biocompatibility for tissue engineering.

Porous Scaffold Implantation for Bone Fractures Healing

The objective of this research was to evaluate the efficacy of Low Level Therapy of Continuous Diode Laser on porous Hydroxyapatite–Chitosan–Collagen scaffold implantation by daily clinical observation, weekly radiographic findings and histopathological examination at the end of 3rd, 6th, 9th and 12th weeks after surgery. Fifty Healthy adult rabbits of both sexes were used to induced diaphyseal Femur and to remove about (1±0.05 cm) of bone, as empty space filler.