Chitosan-bioactive Glass Research Articles

Precision 3D printing of chitosan-bioactive glass inks: Rheological optimization for enhanced shape fidelity in tissue engineering scaffolds

3D printing technology in tissue engineering applications provides several advantages for scaffold development, especially with natural materials, such as chitosan, which provides a biomimetic environment for cellular growth. However, chitosan hydrogel-based inks still show poor printing fidelity. In this article, we overcame this challenge by incorporating bioactive glasses (BG) nanoparticles (up to 5 wt%) into the chitosan hydrogel. The resulting inks were characterized by rheological tests, while their processability was evaluated through measurements of shape fidelity. An indirect cytotoxicity assay was also conducted to evaluate the cell viability of the printed scaffolds. The results indicated that adding BG nanoparticles to the chitosan-based ink modified its rheological properties and improved its shape-fidelity during 3D printing, which we suggest are consequences of hydrogen bonds established between the glass and the chitosan chains. Also, cytotoxicity assessment demonstrated that the resulting scaffold exhibits high cell viability. In conclusion, the proposed composite ink has optimized rheological properties for 3D printing and is promising for applications in tissue engineering.

Enamel changes of bleached teeth following application of an experimental combination of chitosan-bioactive glass

BackgroundConsidering the extensive use of bleaching agents and the occurrence of side effects such as enamel demineralization, this study aimed to assess the enamel changes of bleached teeth following the experimental application of chitosan-bioactive glass (CH-BG).MethodsIn this in vitro study, CH-BG (containing 66% BG) was synthesized and characterized by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Thirty sound human premolars were bleached with 40% hydrogen peroxide, and the weight% of calcium and phosphorus elements of the buccal enamel surface was quantified before and after bleaching by scanning electron microscopy/ energy-dispersive X-ray spectroscopy (SEM, EDX). Depending on the surface treatment of the enamel surface, the specimens were divided into three groups (n = 10): control (no treatment), MI Paste (MI), and CH-BG. Then the specimens were stored in artificial saliva for 14 days. The SEM/EDX analyses were performed again on the enamel surface. Data were analyzed by one-way ANOVA and Tukey’s test and a p-value of < 0.05 was considered statistically significant.ResultsIn all groups, the weight% of calcium and phosphorus elements of enamel decreased after bleaching; this reduction was significant for phosphorus (p < 0.05) and insignificant for calcium (p > 0.05). After 14 days of remineralization, the weight% of both calcium and phosphorus elements was significantly higher compared to their bleached counterparts in both MI and CH-BG groups (p < 0.05). Following the remineralization process, the difference between MI and CH-BG groups was not significant (p > 0.05) but both had a significant difference with the control group in this regard (p < 0.05).ConclusionsThe synthesized CH-BG compound showed an efficacy comparable to that of MI Paste for enamel remineralization of bleached teeth.

Effect of Injectable Platelet Rich Fibrin with Chitosan-Bioactive Glass on Bone Regeneration around Dental Implant

Effect of Injectable Platelet Rich Fibrin with Chitosan-Bioactive Glass on Bone Regeneration around Dental Implant

Chitosan bioactive glass scaffolds for in vivo subcutaneous implantation, toxicity assessment, and diabetic wound healing upon animal model

This study aims to develop chitosan-bioactive glass (BG) scaffolds for diabetic wound healing, toxicity valuation, and subcutaneous implantation in animals for biocompatibility assessment. The scaffolds were prepared by lyophilization technique. In specific BG without sodium (Na), composited with chitosan for better biological activities. The equipped scaffolds were studied for their physiochemical, biological, in vitro and in vivo performances. The chitosan and chitosan-BG (Na free) scaffolds show reliable biocompatibility, cytocompatibility, anti-oxidant, and tissue regeneration. The biocompatibility, toxicity assessments, and diabetic skin wound healing experiments were examined through in vivo studies using Sprague Dawley rats. The extracted tissue samples were analyzed using hematoxylin-eosin- (H and E) and Masson's trichrome staining. Further, tissue excised after scaffold implantation declared non-toxic, non-allergic, and anti-inflammatory nature of chitosan scaffolds. Moreover, the total ribonucleic acid (RNA) expression levels were measured using reverse transcription-polymerase chain reaction (RT-PCR) for the scaffolds against vascular endothelial growth factor (VEGF), and collagen type one (Col-1) primers. Admirably, the scaffolds achieved the best level of skin wound healing via tissue regeneration by increasing epithetical cell formation and collagen deposition. Thus, the biocompatibility, non-toxicity, anti-inflammatory, and wound healing efficiency proved that the chitosan-BG (Na free) scaffold can be readily substantial for wound healing.

Effects of Ti6Al4V mechanical and thermal surface modification on the adhesion of a chitosan-bioactive glass coating

Biomedical implants interact with human tissues introducing significant perturbation into the body. Implant surfaces can be then functionalized enabling better biocompatibility. At the same time, the additional use of a coating provides further functions such as corrosion protection, osteointegration, and drug delivery. In this context, a composite made of chitosan and bioactive glass nanoparticles has been used for coating Ti6Al4V alloy samples processed beforehand using different processes, i.e., polishing, milling, grit blasting, and electrical discharge machining. Experiments have been carried out to correlate substrate surface conditions and coating effectiveness in terms of scratch resistance with the final aim to obtain suitable guidelines to improve substrate-coating performances.Graphical

Porosity Pattern of 3D Chitosan/Bioactive Glass Tissue Engineering Scaffolds Prepared for Bone Regeneration

Aim: The study was conducted to investigate the obtained external and internal porosity and the pore-interconnectivity of specific fabricated bioactive composite tissue engineering scaffolds for bone regeneration in dental applications. Materials and Methods: In this study, the bioactive glass [M] was elaborated as a quaternary system to be incorporated into the chitosan [C] scaffold preparation on a magnetic stirrer to provide bioactivity and better strength properties for the attempted composite scaffolds [C/ M] of variable compositions. The homogenous chitosan/bioactive glass mix was poured into tailor-made cylindrical molds [10cm×10cm]; a freeze-dryer program was used for the creation of uniform and interconnected macropores for all prepared chitosan-based scaffolds. The morphology of fabricated chitosan [C] and chitosan-bioactive glass [C/ M] composite scaffolds was studied by a scanning electron microscope [SEM] and a mercury porosimeter. In addition, the in-vitro biodegradation rate of all elaborated scaffolds was reported after immersing the prepared scaffolds in a simulated body fluid [SBF] solution. Furthermore, for every prepared scaffold composition, characterization was performed for phase identification, microstructure, porosity, bioactivity, and mechanical properties using an X-ray diffraction analysis [XRD], an X-ray Fourier transfer infrared spectroscopy [FTIR], a mercury porosimetry, a scanning electron microscopy [SEM] coupled to an energy-dispersive X-ray spectrometry [EDS] and a universal testing machine, respectively. Results: All the prepared porous chitosan-based composite materials showed pore sizes suitable for osteoblasts seeding, with relatively larger pore sizes for the C scaffolds. Conclusion: The smart blending of the prepared bioactive glass [M] with the chitosan matrix offered some advantages, such as the formation of an apatite layer for cell adhesion upon the scaffold surfaces, the reasonable decrease in scaffold pore size, and the relative increase in compressive strength that were enhanced by the incorporation of [M]. Therefore, the morphology, microstructure, and mechanical behavior of the elaborated stress loaded biocomposite tissue engineering scaffolds seem highly dependent on their critical contented bioactive glass.

Electrophoretic deposition of chitosan-bioactive glass nanocomposite coatings on AZ91 Mg alloy for biomedical applications

Magnesium (Mg) and alloys have received great attention in orthopedic applications due to their biodegradation and mechanical properties. However, the high degradation rate of Mg alloys has limited their orthopedic applications. To reduce the corrosion rate and enhance the surface bioactivity of Mg alloy, chitosan-bioactive glass (CS-BG) nanocomposite coatings were performed by electrophoretic deposition (EPD) method. For this purpose, initially 63 mol% SiO2, 28 mol% CaO, 9 mol% P2O5 bioactive glass (63S BG) nanoparticles were synthesized and fully characterized. The effect of acetic acid concentration in EPD solution on morphology of CS-BG coatings was investigated. Also, the effect of BG concentration on morphology, adhesion, wetting, roughness, bioactivity and corrosion of CS-BG coatings was evaluated. Overall, the results demonstrated that BG concentration of 0.4 g/l in CS-BG coatings showed the best corrosion resistance and bioactivity.

Electrophoretic deposition of Bioactive glass – Chitosan nanocomposite coatings on Ti-6Al-4V for orthopedic applications

Chitosan-Bioactive glass (CS-BG) nanocomposite coatings were developed on the Ti-6Al-4 V alloy to investigate the effect of the BG content on the adhesion strength, bioactivity, bio-corrosion, wettability and roughness. For this purpose, BG nanoparticles were synthesized using a sol-gel process. Three nanocomposite coatings with different concentrations of BG (0.5, 1 and 1.5 g/L) were fabricated through cathodic electrophoretic deposition (EPD). The surface morphology and composition of the coatings revealed the formation of compact coatings with a uniform distribution of BG nanoparticles. Increasing the BG content enhanced the deposition rate of CS-BG nanocomposite coatings and raised the coating thickness. Moreover, the CS-BG coating containing 1.5 g/L BG showed the best corrosion performance owing to the more uniform distribution of BG nanoparticles and its higher thickness. Also, increasing the BG concentration improved the adhesion strength, raised the roughness, and promoted wettability. Further, in-vitro bioactivity evaluation of the coated and uncoated specimens in SBF revealed that the formation of bone-like apatite was significantly encouraged on the surface of CS-BG coatings, as compared to the Ti-6Al-4 V uncoated sample. So, the apatite-forming ability of the coatings was improved by increasing the BG content. For in vitro investigation, osteoblast-like cell line MG63 were cultured on Ti-6Al-4 V substrate coated with CS-BG and cellular behavior was evaluated. Results demonstrated good cell attachment with no significant levels of cytotoxicity during 5 days of culture. Therefore, the electrophoretic deposition of the CS-1.5 g/L BG coating could successfully enhance the adhesion strength, bioactivity, corrosion and cellular performance of the substrate.

Evaluation of the effect of hyaluronic acid and chitosan biocomposite natural polymers in alveolar ridge preservation: an experimental study in dogs

Alveolar ridge preservation procedures became a famous procedures after tooth extraction. Different approaches and materials had been studied. Faster and new bone formation is the concept. Objective: To evaluate the early stages of alveolar bone healing of tooth extraction sockets filled with bioactive composite (chitosan-bioactive glass) CH-MB scaffold soaked in hyaluronic acid (HAL) in a canine model. Materials and Methods: Six mongrel dogs were involved in this study; they were divided into two groups according to sacrifice time (three and six weeks). Each of these groups includes three animals. Animals were subjected to extraction of the third premolar bilaterally. The right extraction socket received bioactive composite (chitosan-bioactive glass) CH-MB scaffold soaked in 0.2 % hyaluronic acid, while the left side had received chitosan-bioactive glass scaffold CH-MB only. The healing extraction sockets were evaluated by (Fourier Transfer Infra-Red spectroscopy) FTIR; where three variables were studied: Matrix quality, degree of crystallinity and degree of calcifications.Results: Hyaluronic acid (HLA) treated groups showed significant results at 6 weeks over all other groups as regard collagen content and crystal maturity. While, degree of calcification showed non-significant results. Moreover, HLA groups showed significant increase from 3 weeks to 6 weeks over non treated groups.Conclusion: Hyaluronic acid was effective in extraction socket healing as regard collagen content at 3 and 6 weeks and crystal maturity especially at 6 weeks. While degree of calcification was negatively affected. It was postulated that HLA sustained its release on the biocomposite scaffold for 6 weeks postoperatively.

Influence of proteins on the corrosion behavior of a chitosan-bioactive glass coated magnesium alloy

The current study explored the degradation behavior of a WE43 Mg alloy during immersion tests in Dulbecco's Modified Eagle's Medium (DMEM) for 3d and 7d, for a bare alloy surface as well as for samples with surface pre-treatment, and finally for samples coated with chitosan-bioactive glass. The immersion tests were conducted with and without addition of serum, to study the influence of proteins on the degradation process. Mass-loss was measured to determine the corrosion rate after 3d and 7d of immersion. The samples were analyzed by SEM with respect to their surface morphology and the chemical composition was screened by high-resolution XPS. The results demonstrate not only a significant, time-dependent influence of serum addition on the corrosion behavior of the materials studied, but noteworthy is that depending on the sample type, proteins in solution were observed to either accelerate or inhibit corrosion. These results are discussed in correlation to observed changes in surface chemistry taking place upon immersion in the absence and presence of proteins.

Protein-adsorption and Ca-phosphate formation on chitosan-bioactive glass composite coatings

In the last years, chitosan-bioactive glass (BG) composites have been developed and investigated as bioactive coatings for orthopedic applications. The increase of bioactivity occurs due to the stimulation of calcium-phosphate/hydroxyapatite formation on the surface while the coating is degrading. In the present work, protein adsorption and its influence on calcium-phosphate precipitation was studied for the first time on such composite coatings. The experiments involved coating of 316L stainless steel substrates with chitosan (Ch) and chitosan-bioactive glass (Ch-BG) and immersion of the coated samples in two different bovine serum albumin (BSA) containing solutions, namely DI H2O (with pH adjusted to about 7.2 with diluted NaOH) and simulated body fluid (SBF). In order to investigate the influence of protein adsorption on calcium-phosphate precipitation, samples were also immersed in DI H2O and in SBF without BSA. Samples were analyzed by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Surface analysis revealed that adsorption of BSA takes place on all studied samples and that protein adsorption is influenced by the presence of Ca2+ and PO43− ions. Bioactivity in the form of hydroxyapatite pre-stage formation is significantly increased on Ch-BG composite coating as compared with bare stainless steel surface. However, calcium-phosphate precipitation in SBF is reduced by the presence of BSA.

Electrophoretic deposition and characterization of chitosan/bioactive glass composite coatings on Mg alloy substrates

Electrophoretic deposition of chitosan-bioactive glass (45S5 composition) composite coatings on magnesium alloy (WE43) substrates was investigated. Two types of substrates were considered, one was the bare, non-pre-treated substrate, while the other one had been treated in Dulbecco’s Modified Eagle Medium (DMEM). The protective effect of the coatings (of ∼2μm in thickness) against corrosion was tested using electrochemical impedance spectroscopy and the coatings’ bioactive behaviour was determined in simulated body fluid. A tribo-mechanical characterization of the coatings was performed. Overall, results confirmed the importance of pre-treating the substrate to corrosion protective chitosan-bioactive glass coatings on WE43 alloy.

Developing surface pre-treatments for electrophoretic deposition of biofunctional chitosan-bioactive glass coatings on a WE43 magnesium alloy

The use of Mg alloys as biodegradable implants requires optimizing the surface performance. A high number of surface modification and coating approaches have been previously explored, for instance to make magnesium and its alloys more corrosion resistant. The current study focuses on developing surface pre-treatments as a corrosion protection and primer for further surface modifications by electrophoretic deposition (EPD) of bioadaptive chitosan-bioactive glass coatings. For this, different surface treatments were tested on a WE43 Mg alloy. These treatments include immersion in Dulbecco’s Modified Eagle’s Medium (DMEM), a calcium phosphate treatment, immersion in hydrofluoric acid, and a hydrothermal procedure in NaOH. The resulting coatings were analyzed in view of the surface morphology and composition by SEM/EDX, as well as in view of their short-term corrosion protection ability by electrochemistry. Finally, the suitability of the different pre-treatments as an interfacial protection layer for subsequent EPD of a chitosan/bioactive glass-coating was explored.

Modification of electrophoretic deposition of chitosan–bioactive glass–hydroxyapatite nanocomposite coatings for orthopedic applications by changing voltage and deposition time

This article presents electrophoretic depositions of chitosan (CS), bioactive glass (BG), and hydroxyapatite (HA) applied on titanium (Ti) substrate from ethanol-based suspension. The strategy was utilized to modify the deposition of particles with different values of sizes and Zeta potentials, and consequently obtain desirable nanocomposite coating. SEM studies showed that uniform distribution of particles was obtained on isolated substrate at pH 4.5. Moreover, modified deposition of BG microparticles (<37µm) and HA nanoparticles (<150nm) in chitosan matrix was reached by changing voltage and deposition time. The results of X-ray diffraction (XRD) revealed a composite with high content of HA was fabricated at pH 4.5, V=20V, and t=15min. The deposition mechanism at the initial and final times was significantly related to self-assembly of HA nanoparticles that chelated by cationic macromolecular chains and located on BG microparticles, and CS-coated particulates of HA nanoparticles, respectively. The results of potentiodynamic polarization and electrochemical impedance spectroscopy studies demonstrated that the CS–BG–HA composite coating acts as a barrier layer in corrected simulated body fluid (C-SBF).

Evaluation of the kinetic and relaxation time of gentamicin sulfate released from hybrid biomaterial Bioglass-chitosan scaffolds

Chitosan scaffolds, combined with bioactive glass 46S6, were prepared to serve as gentamicin sulfate delivery in situ systems for bone biomaterials. This work presents a study about the effect of the ratio chitosan/bioactive glass (CH/BG) on the release of gentamicin sulfate and on the bioactivity during in vitro experiments.SEM observations allowed understanding the bond between the glass grains and the chitosan matrix. In vitro results showed that scaffolds form a hydroxyapatite (HA) Ca10(PO4)6(OH)2 after 15 days of immersion in a simulated body fluid (SBF).The interest of this study is to see that the increase of the content of bioactive glass in the chitosan matrix slows the release of gentamicin sulfate in the liquid medium. Starting concentration of gentamicin sulfate has an influence on the relaxation time of the scaffolds. Indeed, an increasing concentration delays the return to a new equilibrium. Contents of chitosan and bioactive glass do not affect the relaxation time. Synthesized scaffolds could be adapted to a clinical situation: severity and type of infection, weight and age of the patient.

Tissue-engineered chitosan/bioactive glass bone scaffolds integrated with PLGA nanoparticles: A therapeutic design for on-demand drug delivery

A controlled-release drug delivery system can be achieved by incorporating biomolecules within biodegradable nanoparticles (NPs) and further inclusion of such carriers into tissue-engineered scaffolds. The objective of this study was to evaluate the effect of adding poly(lactic-co-glycolic) acid (PLGA) NPs on a chitosan-bioactive glass (CH-BG) scaffold. Two groups of scaffolds, with and without NPs, were prepared by lypholization and the drug release was studied. It was shown that the incorporation of the NPs increased the mechanical strength of the scaffolds, while the swelling behavior slightly decreased as a result of adding NPs. The results demonstrated that while the addition of NPs did not affect the morphology of the scaffold, the system had a potential to be used as a controlled-release platform of model drugs to the bone once implanted. Furthermore, the ability to control NP size together with targeted delivery may result in favorable biodistribution and development of clinically relevant targeted therapies.

Long-term antibiotic delivery by chitosan-based composite coatings with bone regenerative potential

Composite coatings with bone-bioactivity and drug-eluting capacity are considered as promising materials for titanium bone implants. In this work, drug-eluting chitosan-bioactive glass coatings were fabricated by a single-step electrophoretic deposition technique. Drug-loading and -releasing capacity of the composite coatings were carried out using the vancomycin antibiotic. Uniform coatings with a thickness of ∼55μm containing 23.7wt% bioactive glass particles and various amounts of the antibiotic (380–630μg/cm2) were produced. The coatings were bioactive in terms of apatite-forming ability in simulated body fluid and showed favorable cell adhesion and growth. In vitro biological tests also indicated that the composite coatings had better cellular affinity than pristine chitosan coatings. The in vitro elution kinetics of the composite coating revealed an initial burst release of around 40% of the drug within the first elution step of 1h and following by a continuous eluting over 4 weeks, revealing long-term drug-delivering potential. Antibacterial tests using survival assay against Gram-positive Staphylococcus aureus bacteria determined the effect of vancomycin release on reduction of infection risk. Almost no bacteria were survived on the coatings prepared from the EPD suspension containing ≥0.5g/l vancomycin. The developed chitosan-based composite coatings with bone bioactivity and long-term drug-delivery ability may be potentially useful for metallic implants to reduce infection risk.

Colloidal and Electrophoretic Behavior of Chitosan-Bioactive Glass Coating on Stainless Steel 316L

Colloidal and Electrophoretic Behavior of Chitosan-Bioactive Glass Coating on Stainless Steel 316L

Osteoinduction and Antiosteoporotic Performance of Hybrid Biomaterial Chitosan-Bioactive Glass Graft: Effects on Bone Remodeling

Osteoinductive and antiosteroporotic phenomena could be created by using synthetic biomaterials for applications in bone surgery. In the present study, CH-based bioactive glass (BG-CH) with 17 wt% chitosan was elaborated by a freeze-drying process. BG-CH was implanted in the muscle and in the femoral condyles of ovariectomised rats. Grafted tissues were carefully removed for physico-chemical and histological analysis. Several physic-chemical techniques (XRD, FT-IR, MEB, ICP-OES and NMR) were employed to highlight the effects of chitosan on the glass matrix before and after implantation. The results of the study show that despite the non-additional osteogenic cells or agents, BG-CH is endowed with an osteoinductive property. After 8 weeks, 13C NMR spectra showed the characteristic signals of γ-carbons of the hydroxyproline (71 ppm) abundant in collagen. γ-carboxyglutamate (55 ppm), which occurs in several other bone proteins like osteocalcin, indicating the BGCH degradation and the dominance of the bone tissue formation. Moreover, this study showed a rise in Ca and P ion concentrations in the implanted microenvironment, leading to the formation/deposition of Ca-P phases. Trace elements such as Zn and Fe were detected in the newly-formed bone and involved in the bone healing. The study highlights the suitability and the extensive applications of BG-CH composites and the clinically useful therapy in regenerative medicine.

O.137 Treatment of Frey's syndrome with Botulinum toxin

Composite coatings with bone-bioactivity and drug-eluting capacity are considered as promising materials for titanium bone implants. In this work, drug-eluting chitosan-bioactive glass coatings were fabricated by a single-step electrophoretic deposition technique. Drug-loading and -releasing capacity of the composite coatings were carried out using the vancomycin antibiotic. Uniform coatings with a thickness of ∼55 μm containing 23.7 wt% bioactive glass particles and various amounts of the antibiotic (380–630 μg/cm2) were produced. The coatings were bioactive in terms of apatite-forming ability in simulated body fluid and showed favorable cell adhesion and growth. In vitro biological tests also indicated that the composite coatings had better cellular affinity than pristine chitosan coatings. The in vitro elution kinetics of the composite coating revealed an initial burst release of around 40% of the drug within the first elution step of 1 h and following by a continuous eluting over 4 weeks, revealing long-term drug-delivering potential. Antibacterial tests using survival assay against Gram-positive Staphylococcus aureus bacteria determined the effect of vancomycin release on reduction of infection risk. Almost no bacteria were survived on the coatings prepared from the EPD suspension containing ≥0.5 g/l vancomycin. The developed chitosan-based composite coatings with bone bioactivity and long-term drug-delivery ability may be potentially useful for metallic implants to reduce infection risk.