Controlling cell adhesion and degradation of chitosan films by N-acetylation

Effects of different cross-linking conditions on the properties of genipin-cross-linked chitosan/collagen scaffolds for cartilage tissue engineering

A cross-linking reagent is required to improve mechanical strength and degradation properties of biopolymers for tissue engineering. To find the optimal preparative method, we prepared diverse genipin-cross-linked chitosan/collagen scaffolds using different genipin concentrations and various cross-linking temperatures and cross-linking times. The compressive strength increased with the increasing of genipin concentration from 0.1 to 1.0%, but when concentration exceeded 1.0%, the compressive strength decreased. Similarly, the compressive strength increased with the increasing of temperature from 4 to 20°C, but when temperature reached 37°C, the compressive strength decreased. Showing a different trend from the above two factors, the effect of cross-linking time on the compressive strength had a single increasing tendency. The other results also demonstrated that the pore size, degradation rate and swelling ratio changed significantly with different cross-linking conditions. Based on our study, 1.0% genipin concentration, 20°C cross-linking temperature and longer cross-linking time are recommended.

Construction of tissue engineered nerve grafts and their application in peripheral nerve regeneration

Surgical repair of severe peripheral nerve injuries represents not only a pressing medical need, but also a great clinical challenge. Autologous nerve grafting remains a golden standard for bridging an extended gap in transected nerves. The formidable limitations related to this approach, however, have evoked the development of tissue engineered nerve grafts as a promising alternative to autologous nerve grafts. A tissue engineered nerve graft is typically constructed through a combination of a neural scaffold and a variety of cellular and molecular components. The initial and basic structure of the neural scaffold that serves to provide mechanical guidance and optimal environment for nerve regeneration was a single hollow nerve guidance conduit. Later there have been several improvements to the basic structure, especially introduction of physical fillers into the lumen of a hollow nerve guidance conduit. Up to now, a diverse array of biomaterials, either of natural or of synthetic origin, together with well-defined fabrication techniques, has been employed to prepare neural scaffolds with different structures and properties. Meanwhile different types of support cells and/or growth factors have been incorporated into the neural scaffold, producing unique biochemical effects on nerve regeneration and function restoration. This review attempts to summarize different nerve grafts used for peripheral nerve repair, to highlight various basic components of tissue engineered nerve grafts in terms of their structures, features, and nerve regeneration-promoting actions, and finally to discuss current clinical applications and future perspectives of tissue engineered nerve grafts.

The effect of type II collagen coating of chitosan fibrous scaffolds on mesenchymal stem cell adhesion and chondrogenesis

The biocompatibility of chitosan and its similarity to glycosaminoglycans (GAG) make it attractive for cartilage tissue engineering. We have previously reported improved chondrogenesis but limited cell adhesion on chitosan scaffolds. Our objectives were to produce chitosan scaffolds coated with different densities of type II collagen and to evaluate the effect of this coating on mesenchymal stem cell (MSC) adhesion and chondrogenesis. Chitosan fibrous scaffolds were obtained by a wet spinning method and coated with type II collagen at two different densities. A polyglycolic acid mesh served as a reference group. The scaffolds were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and type II collagen content. Constructs were analyzed after MSCs seeding via live/dead assay, weight and DNA evaluations, SEM, and TEM. Constructs were cultured in chondrogenic medium for 21 days prior to quantitative analysis (weight, DNA, and GAG), SEM, TEM, histology, immunohistochemistry, and quantitative real time polymerase chain reaction. The cell attachment and distribution after seeding correlated with the density of type II collagen. The cell number, the matrix production, and the expression of genes specific for chondrogenesis were improved after culture in collagen coated chitosan constructs. These findings encourage the use of type II collagen for coating chitosan scaffolds to improve MSCs adhesion and chondrogenesis, and confirm the importance of biomimetic scaffolds for tissue engineering.

Fabrication of biodegradable nano test tubes by template synthesis

Aims: Recent publications have suggested that cylindrically shaped drug-delivery carriers have an advantage over carriers based on spherical particles in both blood circulation and cell internalization rates. For this reason, this article introduces a method to fabricate hollow, uniform, biodegradable chitosan nano test tubes for applications in drug delivery. Methods: A nanoporous alumina template membrane was used to fabricate hollow chitosan nano test tubes. The chitosan nano test tubes were crosslinked with a disulfide cleavable crosslinker before being removed from the alumina template membrane. We explored two mechanisms for degrading the chitosan nano test tubes – enzymatic degradation by lysozyme and cleavage of the disulfide bond in the crosslinking agent. Results: The template synthesis method resulted in the fabrication of uniform hollow chitosan nano test tubes whose dimensions were easily manipulated based on the dimensions of the pores in the alumina template membrane. The tubes were degraded upon exposure to either lysozyme or sulfhydryl-containing reducing reagents. Conclusion: These tubes have potential for drug-delivery applications. The fact that these tubes degrade upon exposure to a sulfhydryl-containing reducing agent allows for a mechanism for intercellular drug delivery as the tubes should degrade in the presence of intercellular glutathione.

Preparation and characterization of chitosan-heparin composite matrices for blood contacting tissue engineering

Chitosan has been widely used for biomaterial scaffolds in tissue engineering because of its good mechanical properties and cytocompatibility. However, the poor blood compatibility of chitosan has greatly limited its biomedical utilization, especially for blood contacting tissue engineering. In this study, we exploited a polymer blending procedure to heparinize the chitosan material under simple and mild conditions to improve its antithrombogenic property. By an optimized procedure, a macroscopically homogeneous chitosan-heparin (Chi-Hep) blended suspension was obtained, with which Chi-Hep composite films and porous scaffolds were fabricated. X-ray photoelectron spectroscopy and sulfur elemental analysis confirmed the successful immobilization of heparin in the composite matrices (i.e. films and porous scaffolds). Toluidine blue staining indicated that heparin was distributed homogeneously in the composite matrices. Only a small amount of heparin was released from the matrices during incubation in normal saline for 10 days. The composite matrices showed improved blood compatibility, as well as good mechanical properties and endothelial cell compatibility. These results suggest that the Chi-Hep composite matrices are promising candidates for blood contacting tissue engineering.

Effect of collagen II coating on mesenchymal stem cell adhesion on chitosan and on reacetylated chitosan fibrous scaffolds

The biocompatibility and biomimetic properties of chitosan make it attractive for tissue engineering but its use is limited by its cell adhesion properties. Our objectives were to produce and characterize chitosan and reacetylated-chitosan fibrous scaffolds coated with type II collagen and to evaluate the effect of these chemical modifications on mesenchymal stem cell (MSC) adhesion. Chitosan and reacetylated-chitosan scaffolds obtained by a wet spinning method were coated with type II collagen. Scaffolds were characterized prior to seeding with MSCs. The constructs were analyzed for cell binding kinetics, numbers, distribution and viability. Cell attachment and distribution were improved on chitosan coated with type II collagen. MSCs adhered less to reacetylated-chitosan and collagen coating did not improve MSCs attachment on those scaffolds. These findings are promising and encourage the evaluation of the differentiation of MSCs in collagen-coated chitosan scaffolds. However, the decreased cell adhesion on reacetylated chitosan scaffold seems difficult to overcome and will limit its use for tissue engineering.

Preparation and Evaulation of Degradable Poly(lactic acid) Composite Dressings

Chitosan and sodium alginate are two prominent biomaterials because they have some unique properties such as good biocompatible and biodegradable. In this study, sodium alginate was as swelling and moisture retention layer; Chitosan was antibacterial layer.Polylactic acid (PLA) blended in different weight ratios with low melting point polylactic acid (LMPLA) to fabricate nonwoven fabric which reinforced by needle punching and hot pressing. Afterward, chitosan/ sodium alginate compound solution were treated by UV light in order to form cross-linking. Then chitosan/ sodium alginate compound solution coated on the PLA nonwoven fabric to make PLA composite dressings. The mechanical properties of chitosan/ sodium alginate membrane and dressing were measured. The optimum parameters of chitosan/sodium alginate composite membrane was treated by UV light for five minutes and the volume ratio of chitosan (3 wt %) and sodium alginate (1 wt %) solution was 8:2. After we coated chitosan/sodium alginate solution on PLA nonwoven fabric, the Tensile strength, and tear strength were upgraded by 80 % and 98 %; its air permeability and flexibility length, however, dropped by 18 % and 60 %, respectively.

The use of immobilized neurotrophins to support neuron survival and guide nerve fiber growth in compartmentalized chambers

We answered two major questions: (1) does retrograde signaling involve retrograde transport of nerve growth factor (NGF); and (2) is a gradient of immobilized NGF sufficient to promote and guide local axonal growth? To answer these questions, we developed a technique that resulted in stably immobilized NGF and combined this with compartmented chambers. NGF was photochemically-immobilized on a chitosan surface either in the cell body (CB) compartment, distal axon (DA) compartment, or both. Neuron survival and axon outgrowth were found to be insignificantly different from positive controls where soluble NGF was present. When NGF was immobilized on chitosan surfaces in the DA compartment, and in the absence of soluble NGF, neuron survival was observed, likely due to the retrograde signal of the activated TrkA receptor and NGF-induced signals, but not the retrograde signal of NGF itself. Axons were guided towards the higher end of the step concentration gradient of NGF that was photoimmobilized on the chitosan surface in the DA compartment by laser confocal patterning, demonstrating axonal guidance. These studies provide better insight into NGF signaling mechanisms which are important to both understanding developmental disorders and degenerative diseases of the nervous system, as well as improving design strategies to promote nerve regeneration after injury.

Chitosan film containing poly(D,L-lactic-co-glycolic acid) nanoparticles: a platform for localized dual-drug release

PURPOSE

To characterize and evaluate chitosan film containing PLGA nanoparticles (NPs) as a platform for localized dual-drug release.

METHODS

Fluorescent Paclitaxel (FPTX), a hydrophobic drug, was incorporated into PLGA NPs. FPTX-loaded PLGA NPs and Carboxyfluorescein (CF), a hydrophilic model drug, were embedded into chitosan films. Release of CF and NPs from chitosan and release of FPTX from PLGA NPs were monitored by fluorescence. The stability of the platform was observed through SEM and dynamic light scattering (DLS).

RESULTS

Chitosan films containing CF and FPTX-loaded PLGA NPs showed a biphasic release profile. In the first phase, 78% of CF and 34% of NPs were released within few days. In the second phase, the release was slower, showing an additional release of 22% of CF and 18% of NPs after 3 weeks. SEM images and DLS measurements showed that NP release depends on film degradation rate. FPTX-loaded PLGA NPs showed the release of 19.8% of total drug in 2 days, and no additional release was detected in the next 26 days.

CONCLUSIONS

The ability of chitosan film containing PLGA NPs to coat gold surface and to incorporate and release two different drugs of different hydrophilicity make it a promising platform for localized dual-drug release.

Biomaterial design strategies for the treatment of spinal cord injuries

The highly debilitating nature of spinal cord injuries has provided much inspiration for the design of novel biomaterials that can stimulate cellular regeneration and functional recovery. Many experts agree that the greatest hope for treatment of spinal cord injuries will involve a combinatorial approach that integrates biomaterial scaffolds, cell transplantation, and molecule delivery. This manuscript presents a comprehensive review of biomaterial-scaffold design strategies currently being applied to the development of nerve guidance channels and hydrogels that more effectively stimulate spinal cord tissue regeneration. To enhance the regenerative capacity of these two scaffold types, researchers are focusing on optimizing the mechanical properties, cell-adhesivity, biodegradability, electrical activity, and topography of synthetic and natural materials, and are developing mechanisms to use these scaffolds to deliver cells and biomolecules. Developing scaffolds that address several of these key design parameters will lead to more successful therapies for the regeneration of spinal cord tissue.

Use of chitosan conduit combined with bone marrow mesenchymal stem cells for promoting peripheral nerve regeneration

Many studies have been dedicated to the development of scaffolds for improving post-traumatic nerve regeneration. The goal of this study was to develop and test chitosan conduit to use in peripheral nerve reconstruction, either alone or combined with bone marrow mesenchymal stem cells (BMSCs). In this study, the roles of the degree of deacetylation (DD) and molecular weight of chitosan on some biological properties of chitosan films, including hydrophilicity, degradation and BMSCs affinity were investigated. The molecular weight of Chitosans used are 5 x 10(4) Da, 2 x 10(5) Da, 5 x 10(5) Da, 1 x 10(6) Da, the deacetylation degrees are 85, 95%, respectively. The affinity of eight kinds of Chitosans to the BMSCs was assessed by MTT assay, the contact angle and the degradation time of the materials in vivo were also measured. Chitosans with the molecular weight of 1 x 10(6) Da and DD of 95% can significantly promote the survival and outgrowth of cells, which have better hydrophilicity and can remain integrity even after 8 to 16 weeks, all of above meet the requirement of nerve engineering. The BMSCs we transplanted can differentiate into neural stem cells in vivo, and the materials we selected combined with BMSCs can bridge 8-mm-long neural gap better resulting from the differentiation effects of the BMSCs.

Biomaterials for neural-tissue engineering — Chitosan supports the survival, migration, and differentiation of adult-derived neural stem and progenitor cells

Neural precursor cells (NPCs or stem and progenitor cells) are promising in transplantation strategies to treat an injury to the central nervous system, such as a spinal cord injury (SCI), because of their ability to differentiate into neurons and glia. Transplantation studies to date have met with limited success for a number of reasons, including poor cell survival. One way to encourage cell survival in injured tissue is to provide the cells with a scaffold to enhance their survival, their integration, and potentially their differentiation into appropriate cell types. Towards this end, four amine-functionalized hydrogels were screened in vitro for adult murine NPC viability, migration, and differentiation: chitosan, poly(oligoethylene oxide dimethacrylate-co-2-amino ethyl methacrylate), blends of poly(oligoethylene oxide dimethacrylate-co-2-amino ethyl methacrylate), and poly(vinyl alcohol), and poly(glycerol dimethacrylate-co-2-amino ethyl methacrylate). The greatest cell viability was found on chitosan at all times examined, Chitosan had the greatest surface amine content and the lowest equilibrium water content, which likely contributed to the greater NPC viability observed over three weeks in culture. Only chitosan supported survival of multipotent stem cells and the differentiation of the progenitors into neurons, astrocytes, and oligodendrocytes. Plating intact NPC colonies revealed greater cell migration on chitosan relative to the other hydrogels. Importantly, long term cultures on chitosan showed no significant difference in total cell counts over time, suggesting no net cell growth. Together, these findings reveal chitosan as a promising material for the delivery of adult NPC cell-based therapies.

The safety of chitosan as a pharmaceutical excipient

Interest in use of the polysaccharide chitosan as a pharmaceutical excipient by different dose routes and for a number of applications is not new but it still does not appear to be present in any marketed drugs. Including a novel excipient in a new drug formulation requires a number of safety considerations. Review of the published literature showed that chitosan has low oral toxicity and local tolerance potential supporting use in non-parenteral formulations. Prior human oral exposure has occurred through use of chitosan dietary supplements and food additive, medical device and cosmetic applications. Although systemic exposure to parent chitosan may be limited (due to digestion in the gastrointestinal tract), any that is absorbed will likely undergo enzyme degradation to naturally occurring glucosamine, and N-acetylglucosamine, its copolymers, which are excreted or used in the amino sugar pool. Chitosan has local biological activity in the form of haemostatic action and, together with its ability to activate macrophages and cause cytokine stimulation (which has resulted in interest in medical device and wound healing applications), may result in a more careful assessment of its safety as a parenteral excipient.

Current tissue engineering and novel therapeutic approaches to axonal regeneration following spinal cord injury using polymer scaffolds

This review highlights current tissue engineering and novel therapeutic approaches to axonal regeneration following spinal cord injury. The concept of developing 3-dimensional polymer scaffolds for placement into a spinal cord transection model has recently been more extensively explored as a solution for restoring neurologic function after injury. Given the patient morbidity associated with respiratory compromise, the discrete tracts in the spinal cord conveying innervation for breathing represent an important and achievable therapeutic target. The aim is to derive new neuronal tissue from the surrounding, healthy cord that will be guided by the polymer implant through the injured area to make functional reconnections. A variety of naturally derived and synthetic biomaterial polymers have been developed for placement in the injured spinal cord. Axonal growth is supported by inherent properties of the selected polymer, the architecture of the scaffold, permissive microstructures such as pores, grooves or polymer fibres, and surface modifications to provide improved adherence and growth directionality. Structural support of axonal regeneration is combined with integrated polymeric and cellular delivery systems for therapeutic drugs and for neurotrophic molecules to regionalize growth of specific nerve populations.

Aligned and random nanofibrous substrate for the in vitro culture of Schwann cells for neural tissue engineering

The current challenge in peripheral nerve tissue engineering is to produce an implantable scaffold capable of bridging long nerve gaps that will produce results similar to autograft without requiring the harvest of autologous donor tissue. Aligned and random polycaprolactone/gelatin (PCL/gelatin) nanofibrous scaffolds were fabricated for the in vitro culture of Schwann cells that assist in directing the growth of regenerating axons in nerve tissue engineering. The average fiber diameter attained by electrospinning of polymer blend (PCL/gelatin) ranged from 232+/-194 to 160+/-86nm with high porosity (90%). Blending PCL with gelatin resulted in increased hydrophilicity of nanofibrous scaffolds and yielded better mechanical properties, approaching those of PCL nanofibers. The biocompatibility of fabricated nanofibers was assessed for culturing and proliferation of Schwann cells by MTS assay. The results of the MTS assay and scanning electron microscopy confirmed that aligned and random PCL/gelatin nanofibrous scaffolds are suitable substrates for Schwann cell growth as compared to PCL nanofibrous scaffolds for neural tissue engineering.

Forever Young: How to Control the Elongation, Differentiation, and Proliferation of Cells Using Nanotechnology

Within the emerging field of stem cells there is a need for an environment that can regulate cell activity, to slow down differentiation or proliferation, in vitro or in vivo while remaining invisible to the immune system. By creating a nanoenvironment surrounding PC12 cells, Schwann cells, and neural precursor cells (NPCs), we were able to control the proliferation, elongation, differentiation, and maturation in vitro. We extended the method, using self-assembling nanofiber scaffold (SAPNS), to living animals with implants in the brain and spinal cord. Here we show that when cells are placed in a defined system we can delay their proliferation, differentiation, and maturation depending on the density of the cell population, density of the matrix, and the local environment. A combination of SAPNS and young cells can be implanted into the central nervous system (CNS), eliminating the need for immunosuppressants.

Gene expression profile on chitosan/rhBMP-2 films: A novel osteoinductive coating for implantable materials

This study focusses on the gene expression profile related to a new rhBMP-2 carrier material, chitosan film. This film could be suitable for use as an osteoinductive coating of commercially available titanium implants. The developed material was characterized, biocompatibility was tested and the cellular response was extensively characterized by transcriptional expression studies. Finally, in vivo studies were carried out to confirm the osteoinductivity of the developed coating. Results show good material properties for cell adhesion and proliferation. Presented data show cellular differentiation to the osteoblastic phenotype due to rhBMP-2, with a 90% common transcriptional response between the control rhBMP-2 treatment and the developed chitosan/rhBMP-2 film. The growing surface also had an influence on the observed cellular response and was quantified as 7% of the total. These results indicate that both the growth factor and the material induce a cell response, but this is mainly driven by the osteoinductor factor. In vivo, new bone formation and early vascularization was observed around chitosan/rhBMP-2 coated titanium pieces implanted in mouse muscle. In contrast, control implants did not induce this reaction. This work, therefore, shows both in vitro and in vivo that chitosan/rhBMP-2 film is a promising osteoinductive coating for titanium implantable materials.

Preparation, Cytotoxicity and Degradability of Chitosan-Based Thermosensitive Hydrogels as Drug Delivery System

A new thermosensitive hydrogel had been prepared that could be transformed into gel at 37 °C from chitosan and a mixture of α- and β-glycerophosphate (αβ-GP). The appearance of hydrogel was compact and corrugated. There was little granule in the appearance of gel loaded with adriamycin and the granules might be crystals of the added model drug. In vitro cytotoxicity of the hydrogel was tested by the MTT method using mouse embryonic fibroblasts (MEF). MEF cultured with leachates of CS-αβ-GP were investigated and the relative growth rate (RGR) was calculated and the cytotoxicity was graded by generally accepted standard. The study of in vitro degradation of CS-αβ-GP hydrogels included hydrolysis and degradation by lysozyme. The CS-αβ-GP thermosensitive hydrogel was degradable in vitro and the degradation rate was faster in lysozyme solution than that in the medium of PBS. So the CS-αβ-GP system had good cell biocompatibility and biodegradability which provided possibilities and foundations for the further research.

Fibronectin-mediated endothelialisation of chitosan porous matrices

Chitosan (Ch) porous matrices were investigated regarding their ability to be colonized by human microvascular endothelial cells (HPMEC-ST1.6R cell line) and macrovascular endothelial cells namely HUVECs. Specifically we assessed if previous incubation of Ch in a fibronectin (FN) solution was effective in promoting endothelial cell (EC) adhesion to Ch matrices with different degrees of acetylation (DAs). Upon FN physiadsorption, marked differences were found between the two DAs investigated, namely DA 4% and 15%. While cell adhesion was impaired on Ch with DA 15%, ECs were able to not only adhere to Ch with DA 4%, but also to spread and colonize the scaffolds, with retention of the EC phenotype and angiogenic potential. To explain the observed differences between the two DAs, protein adsorption studies using (125)I-FN and immunofluorescent labelling of FN cell-binding domains were carried out. In agreement with the higher cell numbers found, scaffolds with DA 4% revealed a higher number of exposed FN cell-binding domains as well as greater ability to adsorb FN and to retain and exchange adsorbed FN in the presence of competitive proteins. These findings suggest that the DA is a key parameter modulating EC adhesion to FN-coated Ch by influencing the adsorbed protein layer.

Branched chitosans II: Effects of branching on degradation, protein adsorption and cell growth properties

The demand for biodegradable implant materials has fueled interest in chitosan as a biomaterial. In previous work, branched chitosans were synthesized and structurally characterized. In this study the biological properties of branched chitosans were explored. Branched chitosans were synthesized by grafting low molecular weight chitosan chains (1.6, 16 and 80 kDa) to high molecular weight (600 kDa) linear chitosans via reductive amination. Films of the branched materials were evaluated with regard to: lysozyme-mediated degradation; protein adsorption; cell adhesion and proliferation. Branched chitosan with a 1.6 kDa branch length exhibited higher degradation rates than either linear or higher branch length materials. Branched chitosans also exhibited reduced adsorption of bovine serum albumin that was more pronounced with thicker films. Branched chitosans supported proliferation of rat endothelial cells, but growth rates were significantly lower than on linear chitosan. The results of this study demonstrate that control of many aspects of chitosan's physical and biological properties can be achieved by changes in molecular architecture.

Influence of the degree of acetylation on the enzymatic degradation and in vitro biological properties of trimethylated chitosans

Chitosan derivatives such as N,N,N-trimethylated chitosan (TMC) are currently being investigated for the delivery of drugs, vaccines and genes. However, the influence of the extent of N-acetylation of these polymers on their enzymatic degradability and biological properties is unknown. In this study, TMCs with a degree of acetylation (DA) ranging from 11 to 55% were synthesized by using a three-step method. First, chitosan was partially re-acetylated using acetic anhydride followed by quantitative dimethylation using formaldehyde and sodium borohydrate. Then, in presence of an excess amount of iodomethane, TMC was synthesized. The TMCs obtained by this method showed neither detectable O-methylation nor loss in acetyl groups ((1)H NMR) and a slight increase in molecular weight (GPC) with increasing degree of substitution, implying that no chain scission occurred during synthesis. The extent of lysozyme-catalyzed degradation of TMC, and that of its precursors chitosan and dimethyl chitosan, was highly dependent on the DA and polymers with the highest DA showed the largest decrease in molecular weight. On Caco-2 cells, TMCs with a high DA ( approximately 50%), a DQ of around 44% and with or without O-methylated groups, were not able to open tight junctions in the trans-epithelial electrical resistance (TEER) assay, in contrast with TMCs (both O-methylated and O-methyl free; concentration 2.5mg/ml) with a similar DQ but a lower DA which were able to reduce the TEER with 30 and 70%, respectively. Additionally, TMCs with a high DA ( approximately 50%) demonstrated no cell toxicity (MTT, LDH release) up to a concentration of 10mg/ml.

Assessment of the suitability of chitosan/polybutylene succinate scaffolds seeded with mouse mesenchymal progenitor cells for a cartilage tissue engineering approach

In this work, scaffolds derived from a new biomaterial originated from the combination of a natural material and a synthetic material were tested for assessing their suitability for cartilage tissue engineering applications. In order to obtain a better outcome result in terms of scaffolds' overall properties, different blends of natural and synthetic materials were created. Chitosan and polybutylene succinate (C-PBS) 50/50 (wt%) were melt blended using a twin-screw extruder and processed into 5 x 5 x 5 mm scaffolds by compression moulding with salt leaching. Micro-computed tomography analysis calculated an average of 66.29% porosity and 92.78% interconnectivity degree for the presented scaffolds. The salt particles used ranged in size between 63 and 125 mum, retrieving an average pore size of 251.28 mum. Regarding the mechanical properties, the compressive modulus was of 1.73 +/- 0.4 MPa (E(sec) 1%). Cytotoxicity evaluation revealed that the leachables released by the developed porous structures were not harmful to the cells and hence were noncytotoxic. Direct contact assays were carried out using a mouse bone marrow-derived mesenchymal progenitor cell line (BMC9). Cells were seeded at a density of 5 x 10(5) cells/scaffold and allowed to grow for periods up to 3 weeks under chondrogenic differentiating conditions. Scanning electron microscopy analysis revealed that the cells were able to proliferate and colonize the scaffold structure, and MTS test demonstrated cell viability during the time of the experiment. Finally, Western blot performed for collagen type II, a natural cartilage extracellular matrix component, showed that this protein was being expressed by the end of 3 weeks, which seems to indicate that the BMC9 cells were being differentiated toward the chondrogenic pathway. These results indicate the adequacy of these newly developed C-PBS scaffolds for supporting cell growth and differentiation toward the chondrogenic pathway, suggesting that they should be considered for further studies in the cartilage tissue engineering field.