Chitosan-based Scaffold Research Articles

Promising radiological outcome after repair of acetabular chondral defects by microfracture augmented with chitosan-based scaffold: mid-term T2 mapping evaluation.

Radiological evaluation of the repair tissue produced after arthroscopic treatment of acetabular chondral lesions associated with femoroacetabular impingement (FAI) by the chitosan-based scaffold. Patients of age 18-55years with clinical and radiological features of FAI and non-arthritic non-dysplastic hips were selected for arthroscopic treatment. Full-thickness acetabular chondral defects were filled with chitosan-based scaffold material after microfracture. T2 mapping was carried out for all patients after 24months using a 1.5-T machine. Nine regions of interest (ROIs) were localized from three consecutive sagittal slices including the area of repair. T2 relaxation times of ROIs in the repair area were compared with the corresponding posterior cartilage. Twenty-one patients, 17 men and 4 women, underwent arthroscopic treatment of full-thickness acetabular chondral defects with mean size of 3.6 ± 1cm2 (range 2-6cm2). Zone 2 was affected in all cases while zone 3 was involved in 13 cases. T2 relaxation values were collected from 189 ROIs for quantitative analysis. Within the peripheral repair area, the mean T2 value was 49.1 ± 7.2ms (ms), while ROIs of the central repair area had mean T2 values of 50.2 ± 7.1ms. Posterior cartilage showed mean T2 value of 46.2 ± 7.6ms CONCLUSION: Arthroscopic microfracture of large full-thickness acetabular chondral defects with chitosan-based scaffold produced a homogenous repair tissue similar to the corresponding native cartilage of the same joint on quantitative T2 mapping at mid-term follow-up. augmentation of the microfracture by chitosan-based scaffold is a promising modality for treatment of large full-thickness acetabular defects. IV.

Nanomaterials for Periodontal Tissue Engineering: Chitosan-Based Scaffolds. A Systematic Review.

Introduction. Several biomaterials are used in periodontal tissue engineering in order to obtain a three-dimensional scaffold, which could enhance the oral bone regeneration. These novel biomaterials, when placed in the affected area, activate a cascade of events, inducing regenerative cellular responses, and replacing the missing tissue. Natural and synthetic polymers can be used alone or in combination with other biomaterials, growth factors, and stem cells. Natural-based polymer chitosan is widely used in periodontal tissue engineering. It presents biodegradability, biocompatibility, and biological renewability properties. It is bacteriostatic and nontoxic and has hemostatic and mucoadhesive capacity. The aim of this systematic review is to obtain an updated overview of the utilization and effectiveness of chitosan-based scaffold (CS-bs) in the alveolar bone regeneration process. Materials and Methods. During database searching (using PubMed, Cochrane Library, and CINAHL), 72 items were found. The title, abstract, and full text of each study were carefully analyzed and only 22 articles were selected. Thirteen articles were excluded based on their title, five after reading the abstract, twenty-six after reading the full text, and six were not considered because of their publication date (prior to 2010). Quality assessment and data extraction were performed in the twelve included randomized controlled trials. Data concerning cell proliferation and viability (CPV), mineralization level (M), and alkaline phosphatase activity (ALPA) were recorded from each article Results. All the included trials tested CS-bs that were combined with other biomaterials (such as hydroxyapatite, alginate, polylactic-co-glycolic acid, polycaprolactone), growth factors (basic fibroblast growth factor, bone morphogenetic protein) and/or stem cells (periodontal ligament stem cells, human jaw bone marrow-derived mesenchymal stem cells). Values about the proliferation of cementoblasts (CB) and periodontal ligament cells (PDLCs), the activity of alkaline phosphatase, and the mineralization level determined by pure chitosan scaffolds resulted in lower than those caused by chitosan-based scaffolds combined with other molecules and biomaterials. Conclusions. A higher periodontal regenerative potential was recorded in the case of CS-based scaffolds combined with other polymeric biomaterials and bioceramics (bio compared to those provided by CS alone. Furthermore, literature demonstrated that the addition of growth factors and stem cells to CS-based scaffolds might improve the biological properties of chitosan.

Microwave-assisted synthesis and characterization of novel chitosan-based biomaterials for pelvic organ prolapse treatment.

Pelvic organ disorders affect up to one in four women in the United States. The prevalence of pelvic organ prolapse (POP) is increasing with each year, particularly in the setting of prolonged life expectancy and an aging population. Current treatment approaches, including polypropylene monofilaments are associated with numerous painful and worrisome side-effects. Therefore, scientists are looking for new solutions. A promising alternative to the current treatment is tissue engineering, which can be utilized to re-create support to the vagina and pelvic organs. Tissue engineering requires the use of three-dimensional scaffolds, derived from biocompatible materials. Chitosan is a natural polymer, obtained from shellfish exoskeletons. It is known for its biodegradability, lack of cytotoxicity and non-pyrogenicity. Due to the presence of free hydroxyl and amino groups, it may undergo various modifications. In this paper, we describe a new type of chitosan-based biomaterials, which can be used as a new alternative scaffold that may provide support to prolapse organs. The chitosan scaffold was obtained under microwave radiation using multifunctional amino and organic acids. We discuss the scaffold's characteristics, with an emphasis on its chemical structure and morphology. Fourier transform infrared spectroscopy (FT-IR) analysis confirmed cross-linking processes with preservation of free amino groups. Moreover, mechanical durability, the stability and swelling ability of the scaffolds in a simulated body fluid were investigated. All of the prepared scaffolds demonstrated very good antioxidant activity and biodegradability. Importantly, the biocompatibility of chitosan scaffolds was examined on human vaginal VK2/E6E7 cell line. No evidence of toxicity was documented, and the cells maintained their presence on the studied materials. These results allude to the lack of toxicity of the scaffolds, and indicate that chitosan-based scaffold should be further investigated in in vivo studies as they may be a promising alternative treatment to pelvic organ prolapse.

Fabrication of Chitosan based-Scaffold as Potential Cornea Implant

Corneal damage is the second cause of blindness in the world due to limitation of high quality corneal from donor. This condition promote rapid development of biodegradable and biocompatible scaffold for corneal tissue because it can reduce the patient’s dependence on the cornea donor. The purpose of this research is to synthesize chitosan-based hydrogel scaffold with glutaraldehyde (GA) as crosslink agent and observe the influence of concentration chitosan and GA to transparency and mechanical properties of the scaffold. Scaffolds were prepared by solution casting combined with salt leaching method. Among all of chitosan-based scaffolds that have been prepared, sample with 6.7% of chitosan and 0.0% of GA possess the highest transparency (85%), while sample with 6.7% of chitosan and 0.3% of GA gave the highest Young’s modulus (3.09 MPa). However, sample with 6.7% of chitosan and 0.1% of GA might possess the highest potency as corneal tissue implant because of its transparency fulfill the minimum value of corneal tissue (80%) and its Young’s modulus (1.41 MPa) is higher than any chitosan-based scaffold with minimum transparency 80%.

A Composite Chitosan-Reinforced Scaffold Fails to Provide Osteochondral Regeneration.

Several biomaterials have recently been developed to address the challenge of osteochondral regeneration. Among these, chitosan holds promises both for cartilage and bone healing. The aim of this in vivo study was to evaluate the regeneration potential of a novel hybrid magnesium-doped hydroxyapatite (MgHA), collagen, chitosan-based scaffold, which was tested in a sheep model to ascertain its osteochondral regenerative potential, and in a rabbit model to further evaluate its ability to regenerate bone tissue. Macroscopic, microtomography, histology, histomorphometry, and immunohistochemical analysis were performed. In the sheep model, all analyses did not show significant differences compared to untreated defects (p > 0.05), with no evidence of cartilage and subchondral bone regeneration. In the rabbit model, this bone scaffold provided less ability to enhance tissue healing compared with a commercial bone scaffold. Moreover, persistence of scaffold material and absence of integration with connective tissue around the scaffolds were observed. These results raised some concerns about the osteochondral use of this chitosan composite scaffold, especially for the bone layer. Further studies are needed to explore the best formulation of chitosan-reinforced composites for osteochondral treatment.

Arthroscopic Treatment of Medial Femoral Knee Osteochondral Defect Using Subchondroplasty and Chitosan-Based Scaffold

Osteochondral defects of the knee are highly common, cause significant pain, and reduce function. Standard articular cartilage repair treatments include microfracture alone or in conjunction with subchondroplasty or CarGel (chitosan-based scaffold) application (Piramal Life Sciences). Combining such cartilage regenerative techniques with microfracture yields better long-term outcomes than microfracture alone. The purpose of this Technical Note was to describe the surgical technique of applying CarGel after subchondroplasty and microfracture to repair a medial femoral knee osteochondral defect.

Subacute Transplantation of Native and Genetically Engineered Neural Progenitors Seeded on Microsphere Scaffolds Promote Repair and Functional Recovery After Traumatic Brain Injury.

There is intense interest and effort toward regenerating the brain after severe injury. Stem cell transplantation after insult to the central nervous system has been regarded as the most promising approach for repair; however, engrafting cells alone might not be sufficient for effective regeneration. In this study, we have compared neural progenitors (NPs) from the fetal ventricular zone (VZ), the postnatal subventricular zone, and an immortalized radial glia (RG) cell line engineered to conditionally secrete the trophic factor insulin-like growth factor 1 (IGF-1). Upon differentiation in vitro, the VZ cells were able to generate a greater number of neurons than subventricular zone cells. Furthermore, differentiated VZ cells generated pyramidal neurons. In vitro, doxycycline-driven secretion of IGF-1 strongly promoted neuronal differentiation of cells with hippocampal, interneuron and cortical specificity. Accordingly, VZ and engineered RG-IGF-1-hemagglutinin (HA) cells were selected for subsequent in vivo experiments. To increase cell survival, we delivered the NPs attached to a multifunctional chitosan-based scaffold. The microspheres containing adherent NPs were injected subacutely into the lesion cavity of adult rat brains that had sustained controlled cortical impact injury. At 2 weeks posttransplantation, the exogenously introduced cells showed a reduction in stem cell or progenitor markers and acquired mature neuronal and glial markers. In beam walking tests assessing sensorimotor recovery, transplanted RG cells secreting IGF-1 contributed significantly to functional improvement while native VZ or RG cells did not promote significant recovery. Altogether, these results support the therapeutic potential of chitosan-based multifunctional microsphere scaffolds seeded with genetically modified NPs expressing IGF-1 to promote repair and functional recovery after traumatic brain injuries.

Arthroscopic Repair of Acetabular Cartilage Lesions by Chitosan-Based Scaffold: Clinical Evaluation at Minimum 2 Years Follow-up

To evaluate the functional outcome of using chitosan-based material in our patients after 2years of follow-up. Nonarthritic nondysplastic femoroacetabular impingement patients with an acetabular chondral lesion, 18 to 55years of age, were included for arthroscopic repair between May 2013 and July 2015. Full-thickness chondral defects ≥2cm2 were filled with chitosan-based implant after microfractures. Follow-up consisted of alpha angle assessment and clinical outcome in the form of the Non Arthritic Hip Score (NAHS), International Hip Outcome Tool 33 (iHOT33), Hip Outcome Score of Activities of Daily Living (HOS-ADL), and Hip Outcome Score of Sports Specific Scale (HOS-SSS). Twenty-three patients were included. The mean follow-up was 38.4 ± 7.0months (range, 24-50months). The mean defect size was 3.5 ± 1.0cm2, principally involving zone 2 and to a lesser extent in zones 1 and 3. Using femoroplasty, the alpha angle was corrected from a mean 70.5 ± 6.3° to 44.3 ± 4.9° (P= .00001). Significant improvement occurred comparing the preoperative to the first-year postoperative patient-reported outcomes: P= .00001 for the NAHS, P= .00004 for the iHOT33, P= .00005 for the HOS-ADL, and P= .0002 for the HOS-SSS. No statistically significant change has been observed in the patient-reported outcomes obtained at the endpoint when compared with the first-year values (P= .13 for the NAHS, P= .21 for the HOS-ADL, and P= .29 for the HOS-SSS), except for the iHOT33, which showed further significant improvement (P= .02). Up to 91% of the patients met or exceeded the minimal clinically important difference. One patient needed total hip arthroplasty. Perineal hypoesthesia occurred in 3 patients, who recovered within 2 to 6weeks, and 1 patient needed a prolonged physiotherapy program for postoperative muscular stiffness. The arthroscopic combined treatment of microfractures and chitosan-based scaffold has maintained satisfactory clinical outcomes in 91% of the patients with s large (≥2cm2) full-thickness acetabular chondral defect associated with femoroacetabular impingement at a mean follow-up of 38.4months. The study could not definitely draw any conclusion regarding the safety of chitosan-based material for use in the hip joint. Level IV, case series.

Effect of inorganic and organic bioactive signals decoration on the biological performance of chitosan scaffolds for bone tissue engineering.

The present work is focused on the design of a bioactive chitosan-based scaffold functionalized with organic and inorganic signals to provide the biochemical cues for promoting stem cell osteogenic commitment. The first approach is based on the use of a sequence of 20 amino acids corresponding to a 68-87 sequence in knuckle epitope of BMP-2 that was coupled covalently to the carboxyl group of chitosan scaffold. Meanwhile, the second approach is based on the biomimetic treatment, which allows the formation of hydroxyapatite nuclei on the scaffold surface. Both scaffolds bioactivated with organic and inorganic signals induce higher expression of an early marker of osteogenic differentiation (ALP) than the neat scaffolds after 3 days of cell culture. However, scaffolds decorated with BMP-mimicking peptide show higher values of ALP than the biomineralized one. Nevertheless, the biomineralized scaffolds showed better cellular behaviour than neat scaffolds, demonstrating the good effect of hydroxyapatite deposits on hMSC osteogenic differentiation. At long incubation time no significant difference among the biomineralized and BMP-activated scaffolds was observed. Furthermore, the highest level of Osteocalcin expression (OCN) was observed for scaffold with BMP2 mimic-peptide at day 21. The overall results showed that the presence of bioactive signals on the scaffold surface allows an osteoinductive effect on hMSC in a basal medium, making the modified chitosan scaffolds a promising candidate for bone tissue regeneration.

Investigation of the mechanical properties and degradability of a modified chitosan-based scaffold

The aim of this research is to evaluate the mechanical properties and degradation behavior of the chitosan/hydroxyapatite/ferrite nanocomposites in the ringer solution. The initial materials, including chitosan and hydroxyapatite, were developed from shrimp shells and bovine cortical bone, respectively. Ferrite was also synthesized through wet-chemical method using FeCl2.4H2O and FeCl3.6H2O as precursors. The obtained results showed that the samples containing chitosan with a lesser deacetylation degree (73.5%) possess higher bending strength when compared to the samples with a higher deacetylation degree (82.5%). The samples with higher amounts of chitosan remain healthier and have a lesser weight loss percentage than the samples with more hydroxyapatite. The samples with the ratio of chitosan:hydroxyapatite (6:4) have displayed the smallest amount of degradation. Additionally, the samples with lower ratio of chitosan:hydroxyapatite (4:6) (the sample labeled as B) have demonstrated significantly higher fracture toughness (regarding to compression stress-strain curves) than other samples. Finally, it is concluded that chitosan/hydroxyapatite/ferrite nanocomposite with 6 g chitosan, 4 g hydroxyapatite, 0.5 g FeCl2.4H2O, and 1 g FeCl3.6H2O (the sample labeled as F) is selected as the optimal sample of this research, with regards to both of the mechanical properties and degradation behavior results.

P.3.d.053 - Antipsychotic-induced hyperprolactinemia in a sample of psychotic patients

Currently, there is no widely accepted technique to efficiently and reproducibly grow stem and progenitor cells in vitro. Stem cells require contact with extracellular matrices as well as signals from growth factors to proliferate and to retain their stemness. We have shown a novel tissue culture platform (StemTrix cultureware) that transforms standard tissue culture plasticware into a multi-functional chitosan-based scaffold that supports the expansion of neural stem cells. The StemTrix scaffold is comprised of chitosan with immobilized heparin which in turn tethers heparin-binding growth factors. The scaffold is also coated with an adhesive ECM protein. Here we demonstrate that fibronectin or the RGD peptide contained in fibronectin are equally effective in promoting the adhesion, viability and growth of rat and human neural stem cells. When FGF-2 and heparin-binding EGF are tethered to the StemTrix cultureware neural stem cells grow ∼3 times faster and remain in a more primitive state as determined by both Western Blot and gene expression analyses. Another important feature of this new culture platform is that the NSCs remain in a primitive and proliferative state for 4 days without refreshing the culture medium or providing new growth factors, which represents a 20-fold extension of FGF-2’s biological activity vs when it is freely soluble in the medium. To test the utility of this scaffold for propagating other types of stem cells and progenitors we tethered platelet-derived growth factor (PDGF) and FGF-2 alone and in combination to the scaffold and tested the efficacy of this platform to maintain primary oligodendrocyte progenitors or the CG-4 cell line in a primitive state. Oligodendrocyte progenitors plated onto this multifunctional film proliferated for at least 3 days without providing soluble growth factors while inhibiting the expression of the differentiation marker myelin-basic protein. Oligodendrocyte progenitors proliferated 3 times more rapidly than cells maintained on fibronectin-coated culture substrates in culture medium supplemented with soluble FGF-2 and PDGF. Finally, we show that StemTrix cultureware can be produced using clinical grade components, providing users with a fully defined platform suitable for clinical use that maintains stem cells or progenitors in a more uniform and primitive state.

Tethered growth factors on biocompatible scaffolds improve stemness of cultured rat and human neural stem cells and growth of oligodendrocyte progenitors.

Currently, there is no widely accepted technique to efficiently and reproducibly grow stem and progenitor cells in vitro. Stem cells require contact with extracellular matrices as well as signals from growth factors to proliferate and to retain their stemness. We have shown a novel tissue culture platform (StemTrix cultureware) that transforms standard tissue culture plasticware into a multi-functional chitosan-based scaffold that supports the expansion of neural stem cells. The StemTrix scaffold is comprised of chitosan with immobilized heparin which in turn tethers heparin-binding growth factors. The scaffold is also coated with an adhesive ECM protein. Here we demonstrate that fibronectin or the RGD peptide contained in fibronectin are equally effective in promoting the adhesion, viability and growth of rat and human neural stem cells. When FGF-2 and heparin-binding EGF are tethered to the StemTrix cultureware neural stem cells grow ∼3 times faster and remain in a more primitive state as determined by both Western Blot and gene expression analyses. Another important feature of this new culture platform is that the NSCs remain in a primitive and proliferative state for 4days without refreshing the culture medium or providing new growth factors, which represents a 20-fold extension of FGF-2's biological activity vs when it is freely soluble in the medium. To test the utility of this scaffold for propagating other types of stem cells and progenitors we tethered platelet-derived growth factor (PDGF) and FGF-2 alone and in combination to the scaffold and tested the efficacy of this platform to maintain primary oligodendrocyte progenitors or the CG-4 cell line in a primitive state. Oligodendrocyte progenitors plated onto this multifunctional film proliferated for at least 3days without providing soluble growth factors while inhibiting the expression of the differentiation marker myelin-basic protein. Oligodendrocyte progenitors proliferated 3 times more rapidly than cells maintained on fibronectin-coated culture substrates in culture medium supplemented with soluble FGF-2 and PDGF. Finally, we show that StemTrix cultureware can be produced using clinical grade components, providing users with a fully defined platform suitable for clinical use that maintains stem cells or progenitors in a more uniform and primitive state.

Results of arthroscopic treatment of chondral delamination in femoroacetabular impingement with bone marrow stimulation and BST-CarGel®.

Objectives: The purpose of this study is to show the preliminary results of using chitosan-based scaffold (BST-CarGel®) with microfracture for treatment of acetabular chondral delamination associated with femoroacetabular impingement. Methods: A prospective study was performed on 13 hips. Patients were selected in the age group between 18 and 50 years. Patients with delamination of acetabular cartilage associated with femoroacetabular impingement received arthroscopic debridement and microfracture technique. Then cases with defect > 2 cm2 were considered for the application of BST-CarGel® and included in the study. Also, reattachment of the torn labrum and resection of the cam deformity were performed according to the case. For evaluation of the functional outcome, the patients had completed the hip outcome score (HOS) pre- and post-operatively. For evaluation of the regeneration of the cartilage, delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) was used and the percentage of defect filling and type of cartilage studied. Results: Patients had a mean age of 41 years, with moderate to high level of activity (mean Tegner scale 7). The mean size of the chondral defect after debridement was 3.7 cm2. The mean HOS for daily live activities has been improved from 64.4 to 87.4 and for sports subscale from 35.2 to 75.2, which is statistically highly significant. All patients had > 90% of filling of chondral defect. Conclusion: The use of BST-CarGel® with microfracture for treatment of acetabular chondral delamination associated with femoroacetabular impingement can improve the functional outcome at two years, with a complete restoration of the cartilage defect in magnetic resonance images (MRI) with specific cartilage sequences.

Effects of a Bioactive Scaffold Containing a Sustained Transforming Growth Factor-β1–releasing Nanoparticle System on the Migration and Differentiation of Stem Cells from the Apical Papilla

IntroductionThis 2-part study hypothesized that a bioactive scaffold containing a sustained transforming growth factor (TGF)-β1–releasing nanoparticle system will promote migration and enhance differentiation of stem cells from the apical papilla (SCAP). The study aimed to develop and characterize a novel modified chitosan-based scaffold containing TGF-β1–releasing chitosan nanoparticles (TGF-β1-CSnp) to enhance migration and differentiation of SCAP. MethodsPart I concerns the synthesis and characterization of a carboxymethyl chitosan–based scaffold and TGF-β1-CSnp. Part II examines the effect of sustained TGF-β1 release from scaffold containing TGF-β1-CSnp on odontogenic differentiation of SCAP. ResultsThe scaffold demonstrated properties conducive to cellular activities. The incorporation of TGF-β1 in CSnp allowed sustained release of TGF-β1, facilitating delivery of a critical concentration of TGF-β1 at the opportune time. TGF-β1 bioactivity was maintained for up to 4 weeks. SCAP showed greater viability, migration, and biomineralization in the presence of TGF-β1-CSnp than in the presence of free TGF-β1. SCAP cultured in TGF-β1-CSnp + scaffold showed significantly higher dentin matrix protein-1 and dentin sialophosphoprotein signals compared with free TGF-β1 + scaffold or CSnp + scaffold. ConclusionsThese experiments highlighted the potential of a carboxymethyl chitosan–based scaffold with growth factor releasing nanoparticles to promote migration and differentiation of SCAP. The results of this study may have direct application to improve current endodontic regenerative protocols.

Optimization, characterization, and efficacy evaluation of 2% chitosan scaffold for tissue engineering and wound healing.

Objective:To develop a chitosan-based scaffold and carry out a complete comprehensive study encompassing optimization of exact chitosan strength, product characterization, toxicity evaluation, in vitro validation in cell culture experiments, and finally in vivo efficacy in animal excision wound model.Materials and Methods:Developed chitosan scaffolds (CSs) were optimized for tissue engineering and wound healing efficacy by means of microstructure, toxicity, and biocompatibility evaluation.Results:Scanning electron microscope (SEM) studies revealed that porosity of CS decreased with increase in chitosan concentration. Chemical stability and integrity of scaffolds were confirmed by Fourier transform infrared studies. Highest swelling percentage (SP) of 500% was observed in 2%, while lowest (200%) was observed in 1% CS. Reabsorption and noncytotoxic property of optimized scaffold were established by enzymatic degradation and MTT assay. Enzymatic degradation suggested 20–45% of weight loss (WL) within 14 days of incubation. Cytotoxicity analysis showed that scaffolds were noncytotoxic against normal human dermal fibroblast human dermal fibroblast cell lines. Significant cellular adherence over the scaffold surface with normal cellular morphology was confirmed using SEM analysis. In vivo efficacy evaluation was carried out by means of reduction in wound size on Sprague-Dawley rats. Sprague-Dawley rats treated with optimized scaffold showed ~ 100% wound healing in comparison to ~80% healing in betadine-treated animals within 14 days. Histological examination depicted advance re-epithelization with better organization of collagen bundle in wound area treated with 2% CS in comparison to conventional treatment or no treatment.Conclusion:This study, thus, reveals that 2% CSs were found to have a great potential in wound healing.

Tri-layered chitosan scaffold as a potential skin substitute

A tri-layered chitosan-based scaffold was successfully made to replicate the striation of a full-thickness skin more accurately than a single- or bi-layered scaffold, which needed weeks of co-culturing of fibroblasts and keratinocytes to achieve similar striation. Chitosan solution was freeze-dried and made into porous disks. Chitosan or chitosan–pectin in acetic acid solution was electrospun onto the chitosan disk to form a nanofibrous layer and a thin film. Examinations based on scanning electron spectroscopy showed that the scaffold was composed of a porous layer (2 mm) to simulate the dermis, a thin film (25–45 μm) to mimic the basement membrane, and a layer of nanofibers (100–200 μm) to serve as the protective epidermis. The tensile strength and modulus of the composite scaffold were significantly higher than those of the chitosan disk (p < 0.01). The composite was able to quickly absorb water and stayed intact throughout the course of the 14-day cell culture tests. The fibroblast cells seeded on both sides of the scaffolds were able to proliferate and stayed separated by the thin film.

Chitosan-based scaffold modified with D-(+) raffinose for cartilage repair: an in vivo study.

BackgroundOsteochondral defects significantly affect patients’ quality of life and represent challenging tissue lesions, because of the poor regenerative capacity of cartilage. Tissue engineering has long sought to promote cartilage repair, by employing artificial scaffolds to enhance cell capacity to deposit new cartilage. An ideal biomaterial should closely mimic the natural environment of the tissue, to promote scaffold colonization, cell differentiation and the maintenance of a differentiated cellular phenotype. The present study evaluated chitosan scaffolds enriched with D-(+) raffinose in osteochondral defects in rabbits. Cartilage defects were created in distal femurs, both on the condyle and on the trochlea, and were left untreated or received a chitosan scaffold. The animals were sacrificed after 2 or 4 weeks, and samples were analysed microscopically.ResultsThe retrieved implants were surrounded by a fibrous capsule and contained a noticeable inflammatory infiltrate. No hyaline cartilage was formed in the defects. Although defect closure reached approximately 100% in the control group after 4 weeks, defects did not completely heal when filled with chitosan. In these samples, the lesion contained granulation tissue at 2 weeks, which was then replaced by fibrous connective tissue by week 4. Noteworthy, chitosan never appeared to be integrated in the surrounding cartilage.ConclusionsIn conclusion, the present study highlights the limits of D-(+) raffinose-enriched chitosan for cartilage regeneration and offers useful information for further development of this material for tissue repair.Electronic supplementary materialThe online version of this article (doi:10.1186/s12952-014-0021-5) contains supplementary material, which is available to authorized users.

Cardiac Effects of Glucagon-Like Peptide 1 with Chitosan-Based Scaffold after Inducing Myocardial Infarction in Dogs

Aims: Glucagon-like peptide 1 (GLP-1) is one of the new choices in the management of diabetes mellitus because of its glucose regulatory effects. GLP-1 receptors are expressed not only in islet cells, kidney, lung, brain, and gastrointestinal tract, but also in the heart. The cardiac effects of GLP-1 play a major role in the choice to use this treatment, considering the expression of GLP-1 receptors in heart. Degradation by dipeptidyl peptidase-IV (DPPIV) makes GLP-1’s half-life very short. In this study, the cardiac effects of GLP-1 with chitosan-based scaffold as well as the tissue changes after induction of myocardial infarction in canines were evaluated. Method: Twelve canines of a similar breed and weight were included in this study. They were categorized into three groups: A case group treated with GLP-1 based on a chitosan scaffold, a group given chitosan with normal saline, and a control group given normal saline alone. Every four weeks after induction of infarction, the troponin-I serum level, regional wall motion abnormality (RWMA), angiogenesis, and microscopic and macroscopic tissue changes were analyzed. Results: Angiogenesis and infarcted area thickness (which is inversely related to the subsequent risk of pseudoaneurysm development) were significantly higher in the case group compared with the other two groups (p value<0.05). Our case group recorded lower scores of RWMA compared with other canines (p value=0.02). Conclusion: This investigation revealed that the new compound (GLP-1+chitosan) not only lengthens the releasing duration of GLP-1 but also has cardioprotective effects after myocardial infarction.

Composite of Decellular Adipose Tissue with Chitosan-Based Scaffold for Tissue Engineering with Adipose-Derived Stem Cells

Composite of Decellular Adipose Tissue with Chitosan-Based Scaffold for Tissue Engineering with Adipose-Derived Stem Cells

Conducting scaffolds for liver tissue engineering

It is known that there is a correlation between a cell membrane potential and the proliferation of the cell. The high proliferation capacity of liver cells can also be attributed to its specific cell membrane potential as liver cell is recognized as one of the most depolarized of all differentiated cells. We hypothesized that this phenomenon can be emphasized by growing liver cells in conducting scaffolds that can increase the electrical communication among the cells. In this article, using tissue engineering techniques, we grew hepatocyte cells in scaffolds with various compositions. It was found that the scaffolds containing conducting polymer of poly (3,4-ethylenedioxythiophene) (PEDOT) provide the best condition for attachment and proliferation of the cells. More specifically, the blend of hyaluronan, PEDOT, and collagen (I) as dopants in gelatin-chitosan-based scaffold presented the best cell/scaffold interactions for regeneration of liver cells.