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BACKGROUND: With the development of cartilage tissue engineering, affinity peptides have attracted some attention because of their special affinity to some key factors of cartilage tissue engineering. OBJECTIVE: To review the screening and identification of various affinity peptides and their application in cartilage tissue engineering. METHODS: The articles related to affinity peptides in CNKI, Wanfang, and PubMed were searched by computer from January 2000 to May 2020. “Affinity peptides, cartilage tissue engineering, mesenchymal stem cell, scaffold” in English and Chinese were used as key words. Finally, 66 articles were included for analysis. RESULTS AND CONCLUSION: Many polypeptides with specific amino acid sequence can bind with some cells, factors and molecules, and have affinity. According to different targets, they can be divided into cell affinity peptide, factor affinity peptide and extracellular matrix molecular affinity peptide. Affinity peptides have been used in cartilage tissue engineering through screening and identification to enhance the repair effect of tissue engineering by adhering fine cells, recruitment factors and molecules. In many strategies of biomimetic cartilage multilayer scaffolds, affinity peptides that interact with specific molecules play an important role in simulating the environment of normal cartilage. At the same time, with the development of cartilage tissue engineering technology, especially the application of computer-aided technology, it provides a new strategy for the use of affinity peptides. However, the residence time, degradation rate and degradation pathway of affinity peptides in vivo are relatively few, which need to be further understood.
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@#Presently, there is no specific federal legislation governing articular cartilage tissue engineering (ACTE) experimentation practices in Malaysia. However, there are related regulations and guidelines provided by government agencies to oversee and guide such practices. The rules and regulations provided in the documents have the essential aim of safeguarding public health through ensuring that non-clinical studies reach a certain quality, efficient and safe for human use. There are themes identified when scrutinising relevant documents which includes, the need for authorised personnel and the establishment of facilities in conducting such experiments, the aspect of cell-scaffold construct development, the use of human materials, the aspect of biosafety, animal care and use during the experiments, and considerations on the impact on the environment. The individual laboratory or facility shall adopt and adapt these standards as deemed appropriate by the ACTE researchers to ensure that non-clinical studies are conducted in a proper and ethical manner.
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The CRISPR/Cas9 system, consisting of Cas9 nuclease and single guide RNA (sgRNA), is an emerging gene editing technology that can perform gene reprogramming operations such as deletion, insertion, and point mutation on DNA sequences targeted by sgRNA. In addition, CRISPR/dCas9 (a mutant that loses Cas9 nuclease activity) still retains the ability of sgRNA to target DNA. The fusion of dCas9 protein with transcriptional activator (CRISPRa) can activate the expression of the target gene, and fusion transcriptional repressors (CRISPRi) can also be used to suppress target gene expression. Efficient delivery of the CRISPR/Cas9 system is one of the main problems limiting its wide clinical application. Viral vectors are widely used to efficiently deliver CRISPR/Cas9 elements, but non-viral vector research is more attractive in terms of safety, simplicity, and flexibility. In this review, we summarize the principles and research advances of CRISPR technology, including CRISPR/ Cas9 delivery vectors, delivery methods, and obstacles to the delivery, and review the progress of CRISPR-based research in bone and cartilage tissue engineering. Finally, the challenges and future applications of CRISPR technology in bone and cartilage tissue engineering are discussed.
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CRISPR-Cas Systems , Cartilage , Clustered Regularly Interspaced Short Palindromic Repeats , Tissue EngineeringABSTRACT
Cartilage tissue engineering, an effective way to repair cartilage defects, requires an ideal scaffold to promote the regeneration performance of stem cells. Cartilage extracellular matrix (CECM) can imitate the living environment of cartilage cells to the greatest extent. CECM not only exhibits good biocompatibility with chondrocytes and stem cells, which can meet the basic requirements of scaffolds, but also promotes chondrocytes to secrete matrix and induce stem cells to differentiate into chondrocytes; as such, this matrix is a better scaffold and has more advantages than existing ones. The promotion and induction effects could be related to various cartilage-related proteins inside. However, the practical application of this technique is hindered by problems, such as poor mechanical properties and insufficient cell penetration of CECM. Association with other materials can compensate for these inadequacies to a certain degree, and finding a combination mode with optimized performance is the application trend of CECM. This review focuses on research of CECM materials in cartilage tissue engineering.
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Cartilage , Cell Biology , Chondrocytes , Extracellular Matrix , Tissue Engineering , Tissue ScaffoldsABSTRACT
OBJECTIVE@#This study aimed to optimize the preparation of carboxymethyl chitosan/sodium alginate (CMCS/OSA) compound hydrogels. This study also aimed to investigate the applicability of the hydrogels in cartilage tissue engi-neering.@*METHODS@#Three groups of CMCS/OSA composite hydrogels with amino-to-aldehyde ratios of 2∶1, 1∶1 and 1∶2 were prepared. The microstructure, physical properties, and cell biocompatibility of the three groups of CMCS/OSA com-posite hydrogels were evaluated. Samples were subjected to scanning electron microscopy, rheological test, adhesion tension test, swelling rate test, and cell experiments to identify the CMCS/OSA composite hydrogel with the cross-linking degree that can meet the requirements for scaffolds in cartilage tissue engineering.@*RESULTS@#The experimental results showed that the CMCS/OSA hydrogel with a amine-to-aldhyde ratio of 1∶1 had good porosity, suitable gelling time, strong adhesive force, stable swelling rate, and good cellular biocompatibility.@*CONCLUSIONS@#The CMCS/OSA compound hydrogel prepared with a 1∶1 ratio of amino and aldehyde groups has potential applications in cartilage tissue engineering.
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Alginates , Cartilage , Chitosan , Hydrogels , Tissue EngineeringABSTRACT
BACKGROUND: Cartilage tissue engineering (CTE) aims to obtain a structure mimicking native cartilage tissue through the combination of relevant cells, three-dimensional scaffolds, and extraneous signals. Implantation of ‘matured’ constructs is thus expected to provide solution for treating large injury of articular cartilage. Type I collagen is widely used as scaffolds for CTE products undergoing clinical trial, owing to its ubiquitous biocompatibility and vast clinical approval. However, the long-term performance of pure type I collagen scaffolds would suffer from its limited chondrogenic capacity and inferior mechanical properties. This paper aims to provide insights necessary for advancing type I collagen scaffolds in the CTE applications. METHODS: Initially, the interactions of type I/II collagen with CTE-relevant cells [i.e., articular chondrocytes (ACs) and mesenchymal stem cells (MSCs)] are discussed. Next, the physical features and chemical composition of the scaffolds crucial to support chondrogenic activities of AC and MSC are highlighted. Attempts to optimize the collagen scaffolds by blending with natural/synthetic polymers are described. Hybrid strategy in which collagen and structural polymers are combined in non-blending manner is detailed. RESULTS: Type I collagen is sufficient to support cellular activities of ACs and MSCs; however it shows limited chondrogenic performance than type II collagen. Nonetheless, type I collagen is the clinically feasible option since type II collagen shows arthritogenic potency. Physical features of scaffolds such as internal structure, pore size, stiffness, etc. are shown to be crucial in influencing the differentiation fate and secreting extracellular matrixes from ACs and MSCs. Collagen can be blended with native or synthetic polymer to improve the mechanical and bioactivities of final composites. However, the versatility of blending strategy is limited due to denaturation of type I collagen at harsh processing condition. Hybrid strategy is successful in maximizing bioactivity of collagen scaffolds and mechanical robustness of structural polymer. CONCLUSION: Considering the previous improvements of physical and compositional properties of collagen scaffolds and recent manufacturing developments of structural polymer, it is concluded that hybrid strategy is a promising approach to advance further collagen-based scaffolds in CTE.
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Cartilage , Cartilage, Articular , Chondrocytes , Collagen Type I , Collagen Type II , Collagen , Extracellular Matrix , Mesenchymal Stem Cells , Polymers , Tissue EngineeringABSTRACT
Objective: To review the progress of cell sheet technology and its application in bone and cartilage engineering.
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Results: The scaffolds in 3 groups were all showed a cross-linked and pore interconnected with pore size of 400-500 μm, porosity of 56%, and fiber orientation of 0°/90°. For dopamine modification, the scaffolds in groups B and C were dark brown while in group A was white. Similarly, water static contact angle was from 76° of group A to 0° of groups B and C. After cultured for 24 hours, the cell adhesion rate of groups A, B, and C was 34.3%±3.5%, 48.3%±1.5%, and 57.4%±2.5% respectively, showing significant differences between groups ( P<0.05). Live/Dead staining showed good cell activity of cells in 3 groups. MTT test showed that hBMSCs proliferated well in 3 groups and the absorbance ( A) value was increased with time. The A value in group C was significantly higher than that in groups B and A, and in group B than in group A after cultured for 4, 7, 14, and 21 days, all showing significant differences ( P<0.05). The mRNA relative expression of collagen type Ⅱ and Aggrecan increased gradually with time in 3 groups. The mRNA relative expression of collagen type Ⅱafter cultured for 7, 14, and 21 days, and the mRNA relative expression of Aggrecan after cultured for 14 and 21 days in group C were significantly higher than those in groups A and B, and in group B than in group A, all showing significant differences ( P<0.05).
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Objective: To observe the feasibility of acellular cartilage extracellular matrix (ACECM) oriented scaffold combined with chondrocytes to construct tissue engineered cartilage.
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Objective: To investigate the effect of cartilage tissue engineering scaffold PVA/ι-CA on the biological behavior of the ATDC-5 cells,and to evaluate its feasibility on constructing tissue engineering cartilage. Methods:The polyvinyl alcohol (PVA)and carrageenan were used to make the composite scaffold material PVA/ι-CA according to a certain proportion by physical blending technology and repeated freezing thawing method,and the porosity and pore size of PVA/ι-CA were detected.The ATDC-5 cells were seeded into the composite scaffold and its growth was observed; the expressions of collagen type Ⅱ in the ATDC-5 cells were tested by immunohistochemical staining and immunofluorescence staining; the morphology of the ATDC-5 cells was confirmed by Toluidine blue staining.The growth and secretion of extracellular matrix of the ATDC-5 cells were observed under scanning electron microscope (SEM);the proliferative rates of ATDC-5 cells in composite scaffold materials in negative control group (added with DMEM culture media)and experimental group (added with DMEM contain scaffold)were determined by MTT assay.The composite scaffolds were implanted subcutaneously in the SD rats.The histocompatibility and vascularization in vivo of the composite scaffolds were evaluated.Results:The average porosity of cartilage tissue engineering scaffold PVA/ι-CA was (86.88±3.88)%,and the average pore size was 20-40 μm.The HE staining results showed that the ATDC-5 cells grew well with the polygon and plumpness morphology. All the samples were stained positive for collagen type Ⅱ by immunohistochemistry and immunofluorescence staining,which verified the normal phenotype of chondrocytes on the scaffolds. All the sample were stained positive for toluidine blue staining,which verified ECM deposition of the ATDC-5 cells on the scaffolds.The number of the positive cells was significantly increased with the prolongation of time.After cultured for 7 d,few of the ATDC-5 cells presented polygonal;after cultured for 14 d,the ATDC-5 cells distributed more densely,and contacted with each other on the scaffold;after cultured for 21 - 28 d,the ATDC-5 cells filled the interconnected pores of the scaffolds,synthesizing a significant amount of neo-formed ECM.The proliferation of ATDC-5 cells in PVA/ι-CA grew fast during 7-14 d,and it became slow during 21-28 d;the difference was not statistically significant compared with control group (P >0.05).The subcutaneous implantation results showed the inflammatory reactions were slight at the early stage and eviated gradually,there was an increasing angiogenesis at the late stage,and the degradation and absorption of the meterial were slight.Conclusion:PVA/ι-CA composite material will be an ideal material for the cartilage tissue engineering.
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In this paper we report the differentiating properties of platelet-rich plasma releasates (PRPr) on human chondrocytes within elastomeric polycaprolactone triol–citrate (PCLT–CA) porous scaffold. Human-derived chondrocyte cellular content of glycosaminoglycans (GAGs) and total collagen were determined after seeding into PCLT–CA scaffold enriched with PRPr cells. Immunostaining and real time PCR was applied to evaluate the expression levels of chondrogenic and extracellular gene markers. Seeding of chondrocytes into PCLT–CA scaffold enriched with PRPr showed significant increase in total collagen and GAGs production compared with chondrocytes grown within control scaffold without PRPr cells. The mRNA levels of collagen II and SOX9 increased significantly while the upregulation in Cartilage Oligomeric Matrix Protein (COMP) expression was statistically insignificant. We also report the reduction of the expression levels of collagen I and III in chondrocytes as a consequence of proximity to PRPr cells within the scaffold. Interestingly, the pre-loading of PRPr caused an increase of expression levels of following extracellular matrix (ECM) proteins: fibronectin, laminin and integrin β over the period of 3 days. Overall, our results introduce the PCLT–CA elastomeric scaffold as a new system for cartilage tissue engineering. The method of PRPr cells loading prior to chondrocyte culture could be considered as a potential environment for cartilage tissue engineering as the differentiation and ECM formation is enhanced significantly.
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Humans , Blood Platelets , Cartilage Oligomeric Matrix Protein , Cartilage , Chondrocytes , Collagen , Elastomers , Extracellular Matrix , Fibronectins , Glycosaminoglycans , Laminin , Methods , Phenotype , Platelet-Rich Plasma , Real-Time Polymerase Chain Reaction , RNA, Messenger , Tissue Engineering , Up-RegulationABSTRACT
For successful tissue engineering of articular cartilage, a scaffold with mechanical properties that match those of natural cartilage as closely as possible is needed. In the present study, we prepared a fibrous silk fibroin (SF)/poly(L-lactic acid) (PLLA) scaffold via electrospinning and investigated the morphological, mechanical, and degradation properties of the scaffolds fabricated using different electrospinning conditions, including collection distance, working voltage, and the SF:PLLA mass ratio. In addition, in vitro cell-scaffold interactions were evaluated in terms of chondrocyte adhesion to the scaffolds as well as the cytotoxicity and cytocompatibility of the scaffolds. The optimum electrospinning conditions for generating a fibrous SF/PLLA scaffold with the best surface morphology (ordered alignment and suitable diameter) and tensile strength (~1.5 MPa) were a collection distance of 20 cm, a working voltage of 15 kV, and a SF:PLLA mass ratio of S50P50. The degradation rate of the SF/PLLA scaffolds was found to be determined by the SF:PLLA mass ratio, and it could be increased by reducing the PLLA proportion. Furthermore, chondrocytes spread well on the fibrous SF/PLLA scaffolds and secreted extracellular matrix, indicating good adhesion to the scaffold. The cytotoxicity of SF/PLLA scaffold extract to chondrocytes over 24 and 48 h in culture was low, indicating that the SF/PLLA scaffolds are biocompatible. Chondrocytes grew well on the SF/PLLA scaffold after 1, 3, 5, and 7 days of direct contact, indicating the good cytocompatibility of the scaffold. These results demonstrate that the fibrous SF/PLLA scaffold represents a promising composite material for use in cartilage tissue engineering.
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Cartilage , Cartilage, Articular , Chondrocytes , Extracellular Matrix , Fibroins , In Vitro Techniques , Silk , Tensile Strength , Tissue EngineeringABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of electronspun PLGA/HAp/Zein scaffolds on the repair of cartilage defects.</p><p><b>METHODS</b>The PLGA/HAp/Zein composite scaffolds were fabricated by electrospinning method. The physiochemical properties and biocompatibility of the scaffolds were separately characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), and fourier transform infrared spectroscopy (FTIR), human umbilical cord mesenchymal stem cells (hUC-MSCs) culture and animal experiments.</p><p><b>RESULTS</b>The prepared PLGA/HAp/Zein scaffolds showed fibrous structure with homogenous distribution. hUC-MSCs could attach to and grow well on PLGA/HAp/Zein scaffolds, and there was no significant difference between cell proliferation on scaffolds and that without scaffolds (P>0.05). The PLGA/HAp/Zein scaffolds possessed excellent ability to promote in vivo cartilage formation. Moreover, there was a large amount of immature chondrocytes and matrix with cartilage lacuna on PLGA/HAp/Zein scaffolds.</p><p><b>CONCLUSION</b>The data suggest that the PLGA/HAp/Zein scaffolds possess good biocompatibility, which are anticipated to be potentially applied in cartilage tissue engineering and reconstruction.</p>
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Animals , Female , Humans , Male , Young Adult , Biocompatible Materials , Bone Development , Physiology , Cartilage , Cells, Cultured , Durapatite , Chemistry , Lactic Acid , Chemistry , Mesenchymal Stem Cells , Physiology , Polyglycolic Acid , Chemistry , Regeneration , Physiology , Tissue Scaffolds , Chemistry , Zein , ChemistryABSTRACT
BACKGROUND:Polyvinyl alcohol is a biocompatible and biodegradable polymer. It is widely used in clinical areas because of its water-soluble, film forming, emulsification, adhesiveness, tasteless, and nontoxic. OBJECTIVE:To review the applications of polyvinyl alcohol and its composite materials in bone, cartilage, skin, vessels and other tissue engineering scaffolds. METHODS:A computer-based online search of CNKI database from January 2000 to December 2011, PubMed database and Elsevier (ScienceDirect) database from January 1980 to December 2012, was performed by the first author with key words of“poly(vinyl alcohol), composite material, tissue engineering scaffold”both in Chinese and English. Literatures concerning polyvinyl alcohol and its composite materials in bone, cartilage, skin, vessels and other tissue engineering scaffolds were included, and repetitive research was excluded. RESULTS AND CONCLUSION:Although there are not enough strength, complications and other shortcomings in vivo, due to its good biocompatibility and biodegradable properties, polyvinyl alcohol and its composite materials have made great progress in tissue engineering applications from the laboratory to the pre-clinical research. But its long-term effects need further research. It wil be a main research aim of scaffold materials in the future to improve the interaction of cel s with the scaffold materials by surface modification, to prepare biomimetic materials by cel microenvironment simulation, to improve the hydrophilicity, the adhesion of cel s, and cel differentiation and proliferation, to bionic the structure and function of the natural extracel ular matrix by building three-dimensional porous structure and control ing the release of cel growth factors, to meet the need of tissue regeneration by congruity or harmony of degradation and mechanical strength.
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Objective To investigate the effect of IGF-1 on the TGF-β3 induced chondrogenesis of MSCs encapsulated in alginate beads and its application in cartilage tissue engineering.Methods MSC chondrogenesis in alginate beads was induced by TGF-β3 and/or IGF-1.Collagen type Ⅱ,aggrecan and Sox-9 expression was evaluated by immunostaining,RT-PCR and Western blot,respectively.Scanning electron microscope and laser confocal microscope were used to observe the differentiated chondrocytes when cultured on the chitosan-based scaffold.Results TGF-β3 with IGF-1 induced MSCs in alginate beads to express the higher level of collagen type Ⅱ,aggrecan and Sox-9 than any other growth factor alone (P＜0.05).The correlation coefficient between Sox9 and collagen type Ⅱ or aggrecan was 0.95 and 0.91,respectively.The chitosan-based scaffold supported the cell's adhesion,migration and proliferation.Conlusion IGF-1 enhances the TGF-β3-induced MSC chondrogenesis via upregulating Sox9 expression.The chitosan-based scaffold is biocompatible with the differentiated chondrocytes.
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Cartilage is one of the earliest reconstructed tissues used in tissue engineering. Due to the lack of appropriate seeding cells, cartilage tissue engineering is, however, relatively lagged behind. With the emergence of stem cell research, adipose stem cells(ASCs) are introduced as seeding cells into tissue engineering for possessing many advantages such as wide spreading, large amount of cells available and easy to obtain. However, the outcome of tissue engineered cartilage construction by ASCs is not as ideal as that by bone marrow stem cells (BMSCs) yet. Low efficiency of ASC chondrogenesis is considered the major cause. This review summarizes the purification of adipose-derived cells, maintenance of sternness and optimization of ehondrogenie induction, which play vital roles in improving ASC s chondrogenesis.
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Objective To investigate the protective mechanism of hyaluronic acid (HA) antagonistic to nitmprusside sodium (SNP) on the tissue engineering cartilage. Methods Alginate culture for two weeks was used to recover phenotype of dedifferentiated chondrocytes. Differentiation state of chondrecytes was analyzed by immunostaining. The growth of alginate-recovered chondrocytes on the chitosan-based scaffold was observed by scanning electron microscope. After cultured for 3 weeks, this tissue engineering cartilage was treated with SNP in the absence or presence of HA combined with specific β1 integrin blocking antibody collagen type Ⅱ and aggreean were detected by RT-PCR and Western blot. Results Collagen type Ⅱ expression in dedifferentiated chondrocytes was significantly enhanced by alginate bead culture. The chitosan-based scaffold supported cell adhesion, proliferation and migration. A dose-dependent inhibitory effect on the expression of collagen type Ⅱ and aggrecan was observed when tissue engineering cartilage was treated with SNP alone. HA significantly promoted collagen type Ⅱ, and aggrecan expression antagonistic to low concentrations of SNP (p<0.05). However, the specific β1,integrin blocking antibody abrogated the effects of HA. Conclusion Alginate culture recovers the phenotype of dedifferentiated chondrocytes. HA abrogats the inhibitory effect of SNP via β1 integrin signal pathway to protect tissue engineering cartilage.
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In vitro construction technology is a key approach to industrialization and clinic application of engineered cartilage. However, it is very difficult to acquire a functional engineered cartilage with the present technology. Bioreactors can simulate the cartilage microenvironment in vivo and are expected to make up the shortcoming of the present technology. Current bioreactors in use are designed according to fluid shear pressure, hydrostatic pressure and/or direct compression, all of which can promote the development and mature of cartilage in vivo. Due to the failure to achieve ideal results by a single-purpose bioreactor, it will become a development direction in future to design and produce a compound bioreactor. This article reviewed the advances in the bioreactor for cartilage tissue engineering.
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PURPOSE: The scaffold is essential for cartilage tissue engineering. Collagen, chitosan, or glycosaminoglycan( GAG) has separately been proposed as in vitro scaffolds. However, the influence of collagen:chitosanchondroitin sulfate(Col:Chi-CS) composites on cell behavior has not yet been thoroughly examined. Therefore, the aim of this study is to develop a novel Col:Chi-CS blended scaffold that binds covalently with CS for cartilage tissue engineering. MATERIALS AND METHODS: The behavior of rabbit chondrocytes seeded in vitro into collagen/chitosan/GAG scaffolds with different chitosan contents (collagen:chitosan ratios of 20:1, 5:1, and 1.25:1) was investigated. The porous scaffolds containing collagen and chitosan were fabricated by using a freeze drying technique and crosslinked using 1-ethyl-3-(3-dimethyl aminopropyl)carbodiimide(EDC) in the presence of CS. The physicochemical/ mechanical properties of scaffolds were determined by analyzing scanning electron microscopy, compression modulus, immobilized GAG content, and water-binding capacity. Rabbit chondrocytes seeded onto these scaffolds were cultured for 1, 3, 7, and 14 days. The cell proliferation rate was evaluated with 3H-thymidine uptake and total GAG content assay was done via DMB assay using ELISA method. For the histological assessment of extracellular matrix, staining with safranin-O/fast green and immunohistochemistry were used. RESULTS: Scanning electron microscope(SEM) views of the scaffolds showed that all three had interconnected pores of mean diameter 164, 353, and 567 micrometer at collagen:chitosan ratios of 20:1, 5:1, and 1.25:1. GAG was covalently bound onto these scaffolds at 6.4%(w/w) in all three cases, i.e., regardless of chitosan content. However, increased chitosan content resulted in enhanced mechanical properties and increased pore size. Biochemical analysis of these scaffolds showed that proliferation rate and GAG synthesis increased with time, and this became most significant in the collagen:chitosan(20:1)-CS scaffold on day 14. The histology of the cell-seeded constructs showed a significantly higher percentage of cells with spherical morphology, which is specific to mature chondrocyte, especially in the collagen:chitosan(20:1)-CS scaffold at each time point. This finding was consistent with the observation that the pericellular matrix was stained positive for proteoglycans and type II collagen on day 14. CONCLUSION: The novel collagen:chitosan(20:1)-CS scaffold seems to be a useful carrier material for cartilage tissue engineering.
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Cartilage , Cell Proliferation , Chitosan , Chondrocytes , Chondrogenesis , Collagen , Collagen Type II , Enzyme-Linked Immunosorbent Assay , Extracellular Matrix , Freeze Drying , Immunohistochemistry , Microscopy, Electron, Scanning , Proteoglycans , Tissue EngineeringABSTRACT
Clinical application of the cartilage formed by tissue engineering is of no practical use due to the failure of long-term structural integrity maintenance. One of the important factors for integrity maintenance is the biomaterial for a scaffold. The purpose of this study is to evaluate the difference between polylactic-co-glycolic acids (PLGA) and chitosan as scaffolds. Human auricular chondrocytes were isolated, cultured, and seeded on the scaffolds, which were implanted in the back of nude mice. Eight animals were sacrificed at 4, 8, 12, 16, and 24 weeks after implantation respectively. In gross examination and histological findings, the volume of chondrocyte-PLGA complexes was decreased rapidly. The volume of chondrocyte-chitosan complexes was well maintained with a slow decrease rate. The expression of type II collagen protein detected by immunohistochemistry and western blots became weaker with time in the chondrocyte-PLGA complexes. However, the expression in the chondrocyte-chitosan complexes was strong for the whole period. Collagen type II gene expressions using RT-PCR showed a similar pattern. In conclusion, these results suggest that chitosan is a superior scaffold in cartilage tissue engineering in terms of structural integrity maintenance. It is expected that chitosan scaffold may become one of the most useful scaffolds for cartilage tissue engineering.