Objective To observe the biocompatibility of the acellular corneal stroma materials prepared by three different methods. Methods Three different serial digestion methods were used to produce the acellular corneal stroma materials. The biocompatibility of the materials was investigated by the cell seeding and the materials were implanted into the rabbit corneal stroma layer. Results The cells in the materials 1 and 2 were not decellularized completely. The rabbit corneal fibroblasts died on the materials 1 and 2 after the cell seeding for 3-4 days. An obvious rejection could be observed after the implantation. The cells in material 3 were decellularized completely and the collagen fibers or elastic fibers were reserved integrally，showing a typical three-dimensional net work. The rabbit corneal fibroblasts could expand on the materials in vitro. No obvious rejection could be observed and the materials were gradually absorbed. Conclusion The acellular porcine cornea stroma materials prepared by trypsin-Dnase-Rnase are suitable for reconstruction of the tissue engineered cornea.
Objective To review the latest development in the research on the application of the electrostatic spinning technology in preparation of the nanometer high polymer scaffold. Methods The related articles published at home and abroad during the recent years were extensively reviewed and comprehensively analyzed. Results Micro/nano-structure and space topology on the surfaces of the scaffold materials, especially the weaving structure, were considered to have an important effect on the cell adhesion, proliferation, directional growth, and biological activation. The electrospun scaffold was reported to have a resemblance to the structure of the extracellular matrix and could be used as a promising scaffold for the tissue engineeringapplication. The electrospun scaffolds were applied to the cartilage, bone, blood vessel, heart, and nerve tissue engineering fields. Conclusion The nanostructured polymer scaffold can support the cell adhesion, proliferation, location, and differentiation，and this kind of scaffold has a considerable value in the tissue engineering field.
Objective To introduce the materials, preparative technique and endothel ial ization modification of scaffold. Methods The recent original articles about vascular tissue engineering were extensively reviewed and analyzed. Results The materials including natural materials, biodegradable polymers and composite materials were studied in the field of scaffold. The ways of casting, cell self-assembly, gel spinning and electrospinning were appl ied to prepare the scaffold of vascular tissue engineering. The modification of scaffold was one of the most important elements for vascular tissue engineering. Conclusion The recent researchs about scaffold of vascular tissue engineering focus on composite material and electrospinning, the modification of scaffold can improve the abil ity of adhesion to endothel ial cells.
Objective To observe the adhesion and prol iferation of late endothel ial progenitor cells (EPCs) planted on nanoporous PLLA scaffold in vitro and to provide a new approach that optimizes tissue engineered material. Methods Male and female New Zealand rabbits (weight 2.5-3.0 kg) were used. Isolated late EPCs from rabbit peri pheral blood were cultured. Electrostatic spinning technique was adopted to prepare misal igned nanofibers, al igned nanofibers and super-al igned nanofibers, and low temperature plasma technique was appl ied to prepare misal igned membrane, al igned membrane and super-al igned membrane. After being divided into group A (cells only), B (misal igned membrane), C (normal membrane), D (al igned membrane) and E (super-al igned membrane), the primary late EPCs (1 × 105/mL) werecultured on scaffolds and MTT method was used to detect cell prol iferation abil ity at 3, 5, 7, 9, 11, 13, 15 and 17 days afterculture. After being divided into group A (misal igned membrane), B (normal membrane), C (al igned membrane) and D (superal igned membrane), precipitation method was appl ied to detect cell adhesion rate at 4, 12 and 24 hours after compound culture, and the morphologic changes of cells were observed at 4, 24 and 72 hours after compound culture. Results Fiber diameters in nanofibrous PLLA scaffolds were 300-400 nm, with a porosity rate of above 90%. At 3, 5, 7, 9, 11, 13, 15 and 17 days after culture, A value of each group was increased with time and the cells in each group grew well, showing there was no significant difference between group A and group B at each time point (P gt; 0.05 ); during the period of 7-15 days after culture, the difference between groups C, D and E and groups A and B was significant (P lt; 0.05). At 4 hours after compound culture, the adhesion rate of group A was superior to that of groups B, C and D (P lt; 0.05); at 12 and 24 hours after compound culture, the adhesion rate of groups B, C and D was remarkably higher than that of group A (P lt; 0.05); significant difference was noted in each group between the time point of 4 hours and the time point of 12 and 24 hours after compound culture (P lt; 0.05), but no significant difference between 12 hours and 24 hours was detected (P gt; 0.05). Morphology observation demonstrated that cells grew well on the scaffolds, the cells in groups A and B grew sporadically and disorderly, while the cells in groups C and D attached and al igned along fiber and prol iferated, with an excretion of ECM. Group D was better at maintaining cell morphology. Conclusion Al igned and superal igned nanofibers of PLLA scaffold can promote the adhesion and prol iferation of seed cells on the scaffold and maintain good cell morphology, which is an appropriate candidate scaffold material for blood vessel tissue engineering. Late EPCs is an ideal cell source for blood vessel tissue engineering.
Objective To elucidate the latest research progress and application of tissue engineered meniscus. Methods The literature concerning the advance in tissue engineered meniscus was extensively reviewed, then closely-related issues including seed cells, scaffolds, and bioreactors were analyzed. Results With more and more attention being paid to meniscus tissue engineering, different approaches and strategies for seed cells, scaffolds, and bioreactors have contributed to the generation of meniscal constructs, which are capable of restoring meniscal lesions to some extent, but translating successes in basic science research to clinical application is still limited. Conclusion More research for the optimal combination of the appropriate cell source, the scaffold type, and the proper physical and chemical factors for the stimulation of cells differentiation into tissue with optimal phenotypes in tissue engineered meniscus is still in needed, but the overall future looks promising.
Objective To investigate the cellular compatibil ity of polyvinyl alcohol (PVA)/wild antheraea pernyisilk fibroin (WSF), and to explore the feasibil ity for tendon tissue engineering scaffold in vitro. Methods The solutions of WSF (11%), PVA (11%), and PVA/WSF (11%) were prepared with 98% formic acid (mass fraction) at a mass ratio of 9 : 1. The electrospinning membranes of WSF, PVA, and PVA/WSF were prepared by electrostatic spinning apparatus. The morphologies of scaffolds were evaluated using scanning electronic microscope (SEM). The tendon cells were isolated from tail tendon of 3-dayold Sprague Dawley rats in vitro. The experiment was performed using the 3rd generation cells. The tendon cells (1 × 106/mL) were cocultured with PVA and PVA/WSF electrospinning film, respectively, and MTT test was used to assess the cell adhesion rate 4, 12 hours after coculture. The tendon cells were cultured in PVA and PVA/WSF extraction medium of different concentration (1, 1/2, and 1/4), respectively; and the absorbance (A) values were detected at 1, 3, 5, and 7 days to evaluate the cytotoxicity. The composite of tendon cells and the PVA or PVA/WSF scaffold were observed by HE staining at 7 days and characterized by SEM at 1,3, 5, and 7 days. Results The solution of WSF could not be used to electrospin; and the solution of PVA and PVA/WSF could be electrospun. After coculture of tendon and PVA or PVA/WSF electrospinning membranes, the cell adhesion rates were 26.9% ±0.4% and 87.0% ± 1.0%, respectively for 4 hours, showing significant difference (t=100.400, P=0.000); the cell adhesion rates were 35.2% ± 0.6% and 110.0% ± 1.7%, respectively for 12 hours, showing significant difference (t=42.500, P=0.000). The cytotoxicity of PVA/WSF was less significantly than that of PVA (P lt; 0.05) and significant difference was observed between 1/2 PVA and 1/4PVA (P lt; 0.05). HE staining and SEM images showed that the tendon cells could adhere to PVA and PVA/WSF scaffolds, but that the cells grew better in PVA/WSF scaffold than in PVA scaffold in vitro. Conclusion PVA/WSF electrospinning membrane scaffold has good cell compatibility, and it is expected to be an ideal scaffold of tendon tissue engineering.
Objective To review the recent progress of the researches in the field of cartilage tissue engineering, and to discuss the challenges in construction of tissue engineered cartilage. Methods Literature related with cartilage tissue engineering was reviewed and analyzed. Results Some techniques have been appl ied in cl inical. As far as the seeding cells, induced pluripotent stem cells have attracted much more attention. Current strategies of scaffold designing are trying to imitate both component and structure of natural extracellular matrix. Cartilage regeneration through the autologous cell homing technique el iminate the transplantation of exotic cells and has become the hot topic. Conclusion Successful treatment of the damaged cartilage using tissue engineering method will depend on the advances of stem cell technology development, biomimetic scaffolds fabrication and proper appl ication of growth factors.
Objective To introduce the research advances of scaffold materials of intervertebral disc tissue engineering. Methods The recent original articlesabout the scaffolds in intervertebral disc tissue engineering were extensively reviewed. Results At present, agarose, alginate gel, collagentype Ⅰ, PLA, PGAare still major scaffold materials for intervertebral disc tissue engineering because of their good biocompatibility. Conclusion It is one of the popular studies on current intervertebral disc tissue engineering to explore the ideal scaffold materials.
Objective To establish a scaffold model from heterogeneoussmall blood vessels. Methods Caudal arteries from 34 Wistar rats( average length 12.08±1.69 cm) were made into acellular blood vessel scaffolds. Some scaffoldswere observed by electron microscope, and others were transplanted to the cut ends of ear central arteries of male Japanese big ear white rabbits. Results Average external diameter was 0.74±0.08 mm in proximal, and 0.55±0.08 mm in distal end of rat caudal arteries. The small blood vessel scaffolds had shin wall whichwas white and soft, composed of fibrous tissues without cells. On the intima surface the fibrous tissues were arrayed densely in a grid-like pattern. After transplantation, the blood flow was reserved, and kept flowing freely in 24 hours. The pulsation of the transplanted artery was accessible and no blood leakage wasfound.Conclusion The natural scaffolds are composed of fibrous tissues, and can sustain the artery pulse pressure for 24 hours. It is better to suture the blood vessels by sleeve anastomosis.
ObjectiveTo review the properties of bio-derived hydrogels and their application and research progress in tissue engineering. MethodsThe literature concerning the biol-derived hydrogels was extensively reviewed and analyzed. ResultsBio-derived hydrogels can be divided into single-component hydrogels (collagen,hyaluronic acid,chitosan,alginate,silk fibroin,etc.) and multi-component hydrogels[Matrigel,the extract of extracellular matrix (ECM),and decellularized ECM].They have favorable biocompatibility and bioactivity because they are mostly extracted from the ECM of biological tissue.Among them,hydrogels derived from decellularized ECM,whose composition and structure are more in line with the requirements of bionics,have incomparable advantages and prospects.This kind of scaffold is the closest to the natural environment of the cell growth. ConclusionBio-derived hydrogels have been widely used in tissue engineering research.Although there still exist many problems,such as the poor mechanical properties,rapid degradation,the immunogenicity or safety,vascularization,sterilization methods,and so on,with the deep-going study of optimization mechanism,desirable bio-derived hydrogels could be obtained,and thus be applied to clinical application.