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The poly lactic-co-glycolic acid (PLGA) bio-scaffold is a biodegradable scaffold commonly used for tissue repair. However, implanted PLGA scaffolds usually cause serious inflammatory responses around grafts. To improve PLGA scaffold-based tissue repair, it is important to control the PLGA-mediated inflammatory responses. Recent evidence indicated that PLGA induce dendritic cell (DC) maturation in vitro , which may initiate host immune responses. In the present study, we explored the modulatory effects of mesenchymal stem cells (MSC) on PLGA-induced DCs (PLGA-DC). We found that mouse MSCs inhibited PLGA-DC dendrite formation, as well as co-stimulatory molecule and pro-inflammatory factor expression. Functionally, MSC-educated PLGA-DCs promoted Th2 and regulatory T cell differentiation but suppressed Th1 and Th17 cell differentiation. Mechanistically, we determined that PLGA elicited DC maturation via inducing phosphorylation of p38/MAPK and ERK/MAPK pathway proteins in DCs. Moreover, MSCs suppressed PLGA-DCs by partially inactivating those pathways. Most importantly, we found that the MSCs were capable of suppressing DC maturation and immune function in vivo . Also, the proportion of mature DCs in the mice that received MSC-PLGA constructs greatly decreased compared with that of their PLGA-film implantation counterparts. Additionally, MSCs co-delivery increased regulatory T and Th2 cells but decreased the Th1 and Th17 cell numbers in the host spleens. Histological analysis showed that MSCs alleviated the inflammatory responses around the grafted PLGA scaffolds. In summary, our findings reveal a novel function for MSCs in suppressing PLGA-induced host inflammatory response and suggest that DCs are a new cellular target in improving PLGA scaffold-based tissue repair. [ABSTRACT FROM AUTHOR]

Abstract: The success of in vitro cartilage regeneration provides a promising approach for cartilage repair. However, the currently engineered cartilage in vitro is unsatisfactory for clinical application due to non-homogeneous structure, inadequate thickness, and poor mechanical property. It has been widely reported that orientation of scaffolds can promote cell migration and thus probably contributes to improving tissue regeneration. This study explored the impact of microtubular oriented scaffold on in vitro cartilage regeneration. Porcine articular chondrocytes were seeded into microtubule-oriented PLGA scaffolds and non-oriented scaffolds respectively. A long-term in vitro culture followed by a long-term in vivo implantation was performed to evaluate the influence of scaffold orientation on cartilage regeneration. The current results showed that the oriented scaffolds could efficiently promote cell migration towards the inner region of the constructs. After 12 weeks of in vitro culture, the chondrocyte-scaffold constructs in the oriented group formed thicker cartilage with more homogeneous structure, stronger mechanical property, and higher cartilage matrix content compared to the non-oriented group. Furthermore, the in vitro engineered cartilage based on oriented scaffolds showed better cartilage formation in terms of size, wet weight, and homogeneity after 12-week in vivo implantation in nude mice. These results indicated that the longitudinal microtubular orientation of scaffolds can efficiently improve the structure and function of in vitro engineered cartilage. [Copyright &y& Elsevier]

Abstract: Aseptic loosening is a major cause of failure of total hip arthroplasty (THA). Macrophage apoptosis in interface membrane has been proved to play an important role in the pathogenesis of aseptic loosening. The purpose of current study was to identify the apoptotic mechanism of macrophages in the interface membrane of aseptic loosening. We collected periprosthetic interface membrane from 23 patients undergoing the revision operations for aseptic loosening of hip joint prostheses. To serve as the control group, samples of capsule were collected from 18 patients undergoing the primary hip arthroplasties for osteoarthritis (OA). The ultrastructure of interface membrane was examined by transmission electron microscopy (TEM), and in situ apoptotic macrophage identification was performed by TUNEL staining. Furthermore, using immunohistochemical methods we investigated the expression of some apoptosis-related markers such as inducible nitric oxide synthase (iNOS), peroxynitrite (ONOO−), cleaved caspase-3/4/8/9, cytochrome c, glucose regulated protein 78 (GRP78), and growth arrest and DNA damage-inducible gene 153 (GADD153) in macrophages. These markers were regarded as apoptotic inducers or specific indicators of different apoptotic pathways such as death receptor pathway, mitochondrial pathway and endoplasmic reticulum (ER) stress pathway. TEM showed that a great deal of wear debris was phagocytosed by macrophages, which displayed morphological changes characteristic of apoptosis. The results of TUNEL staining demonstrated that there were more apoptotic macrophages in interface membrane. The expression levels of iNOS, ONOO−, cleaved caspase-3/4/8/9, cytochrome c, GRP78 and GADD153 in macrophages in interface membrane were significantly higher than those in the control samples (p < 0.05). Our results suggest that death receptor pathway, mitochondria/cytochrosome c caspase-dependent pathway and ER stress pathway are involved in the process of macrophage apoptosis. A therapeutic target to modulate the apoptotic pathways in macrophages may be a strategy to prevent and treat aseptic loosening. [Copyright &y& Elsevier]

Abstract: Different approaches towards making 3-dimensional (3-D) bioengineered tooth for future replacement therapy have been developed including scaffold-based tooth regeneration. However, selection of optimal scaffold for future clinical application remains a challenge. In the present study, we tested biocompatibility of four different types of 3-D scaffolds for tooth-tissue regeneration, including a pure poly(lactide-co-glycolide) (PLGA) (70/30, mol/mol) scaffold and three types of calcium phosphate contained composites scaffolds that were 50 wt% of PLGA combined with 50 wt% of hydroxyapatite (HA), tricalcium phosphate (TCP) or calcium carbonate hydroxyapatite (CDHA) respectively. These scaffolds were fabricated by the particle leaching in combination with phase separation technology. Surface modification of these scaffolds was further performed by an ammonia plasma treatment and anchorage of collagen technology. Effect of composition of the composite scaffolds on proliferation of human dental pulp stem cells (DPSCs) was accessed using in vitro MTT assay and in vivo BrdU labeling. Differentiation capability of the DPSCs in the scaffolds was analyzed by measurement of the levels of calcified tissue formation and ALP activity. Our results showed that while the calcium phosphate contained compound is able to support regeneration of tooth tissue effectively, the PLGA/TCP scaffold is more appropriate for the proliferation and differentiation of DPSCs. Furthermore, seeding of dissociated 4-dpn rat tooth bud cells on the PLGA/TCP scaffold generated dentin- and pulp-like tissues. Our results demonstrate that the PLGA/TCP scaffold is superior to the other three scaffolds for tooth-tissue regeneration, especially for dentin formation. [Copyright &y& Elsevier]

Abstract: Although Sox9 is essential for chondrogenic differentiation and matrix production, its application in cartilage tissue engineering has been rarely reported. In this study, the chondrogenic effect of Sox9 on bone marrow mesenchymal stem cells (BMSCs) in vitro and its application in articular cartilage repair in vivo were evaluated. Rabbit BMSCs were transduced with adenoviral vector containing Sox9. Toluidine blue, safranin O staining and real-time PCR were performed to check chondrogenic differentiation. The results showed that Sox9 could induce chondrogenesis of BMSCs both in monolayer and on PGA scaffold effectively. The rabbit model with full-thickness cartilage defects was established and then repaired by PGA scaffold and rabbit BMSCs with or without Sox9 transduction. HE, safranin O staining and immunohistochemistry were used to assess the repair of defects by the complex. Better repair, including more newly-formed cartilage tissue and hyaline cartilage-specific extracellular matrix and greater expression of several chondrogenesis marker genes were observed in PGA scaffold and BMSCs with Sox9 transduction, compared to that without transduction. Our findings defined the important role of Sox9 in the repair of cartilage defects in vivo and provided evidence that Sox9 had the potential and advantage in the application of tissue engineering. [Copyright &y& Elsevier]

Abstract: This work developed a multimodal imaging system by co-encapsulating superparamagnetic iron oxides (IOs) and quantum dots (QDs) in the nanoparticles of poly (lactic acid) - d-α-tocopheryl polyethylene glycol 1000 succinate (PLA-TPGS) for concurrent imaging of the magnetic resonance imaging (MRI) and the fluorescence imaging to combine their advantages and to overcome their disadvantages as well as to promote a sustained and controlled imaging with passive targeting effects to the diseased cells. The QDs and IOs-loaded PLA-TPGS NPs were prepared by a modified nanoprecipitation method, which were then characterized for their size and size distribution, zeta potential and the imaging agent encapsulation efficiency. The transmission electron microscopy (TEM) images showed direct evidence for the well-dispersed distribution of the QDs and IOs within the PLA-TPGS NPs. The cellular uptake and the cytotoxicity of the PLA-TPGS NPs formulation of QDs and IOs were investigated in vitro with MCF-7 breast cancer cells, which were conducted in close comparison with the free QDs and IOs at the same agent dose. The Xenograft model was also conducted for biodistribution of the QDs and IOs-loaded PLA-TPGS NPs among the various organs, which showed greatly enhanced tumor imaging due to the passively targeting effects of the NPs to the tumor. Images of tumors were acquired in vivo by a 7T MRI scanner. Further ex vivo images of the tumors were obtained by confocal laser scanning microscopy. Such a multimodal imaging system shows great advantages of both contrast agents making the resultant probe highly sensitive with good depth penetration, which confirms the diagnosis obtained from each individual imaging. With therapeutics co-encapsulation and ligand conjugation, such nanoparticles system can realize a multi-functional system for medical diagnosis and treatment. [Copyright &y& Elsevier]

Abstract: Tissue engineering using scaffold not only should have biodegradability and a certain 3D structure, but also its morphology structure should be mimetic to that of the repaired natural tissue. So to manufacture the scaffold with a biomimetic structure as the natural tissues is important. In this research, highly porous poly(l-lactic acid) (PLLA) and poly(l-lactic-co-glycolic acid) (PLGA) scaffolds with microtubules orientation structure were designed and fabricated by using dioxane as solvent and an improved thermal-induced phase separation (TIPS) technique. All the factors which will affect solvent crystallization and microtubules orientation structure of the scaffold, such as the type of the solvent and polymer, concentration of the polymer solution, and temperature-gradient of the system have been studied carefully. So the porosity, diameter, tubular morphology and orientation of the microtubules could be controlled by adjusting the concentration of the polymer solution and temperature-gradient of the system. The scaffold with diameter of microtubules from 40 to 240μm and high porosity up to 96% could be obtained by adjusting temperature-gradient during the TIPS process. By increasing concentration of the polymer solution the regularity of the microtubular scaffold has been improved and the thickness of wall of the microtubules has been increased as well. In vitro cell culture results show that after the scaffolds have been improved by the ammonia plasma treatment and then collagen anchorage method, the human transparent cartilage cells H144, could be seeded deeply into the microtubules orientation-structured scaffolds and grew well there. [Copyright &y& Elsevier]

Films made of poly (3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate- co-3-hydroxyhexanoate) (PHBHHx) consisting of 5%, 12% and 20% hydroxyhexanoate (HHx), respectively, were evaluated for biomedical application in comparison with poly (l-Lactide) (PLA). With the increase of HHx content in PHBHHx, the polymer surface properties changed accordingly. P(HB-co-20%-HHx) had the smoothest surface while PHB surface was most hydrophilic among the evaluated PHB and all the PHBHHx. All PHBHHx also showed strong protein affinity and biocompatibility. It was found that fibroblast and osteoblast had different responses to these polymers: fibroblast cells favored P(HB-co-20%-HHx), yet osteoblast cells preferred P(HB-co-12%-HHx). PHB and all PHBHHx appeared to have better biocompatibility for fibroblast and osteoblast compared with PLA. Polymers possessing diferent surface properties may help meet different cellular requirements. Combined with their good mechanical properties for elongation and adjustable biocompatibility, PHBHHx may meet the needs of growth requirements of different tissues and cells. [Copyright &y& Elsevier]

Abstract: In order to effectively and uniformly immobilize basic fibroblast growth factor (bFGF) to thick PLGA scaffold, the heparin-conjugated PLGA (H-PLGA) was synthesized at the first by reaction between heparin and a low molecular weight PLGA. Then heparin-containing PLGA (H-PLGA/PLGA) scaffold was fabricated by blending the H-PLGA with a high molecular weight PLGA. Finally, bFGF was immobilized on the H-PLGA/PLGA scaffold mainly by static electricity action between them. The effect of H-PLGA content on bFGF binding efficiency of the H-PLGA/PLGA scaffolds was investigated. It was found that bFGF binding efficiency increased with increasing H-PLGA content. The bound bFGF can release in vitro slowly from the H-PLGA/PLGA scaffolds and last over two weeks. The released bFGF has still preserved its bioactivity. The attachment and growth of mouse 3T3 fibroblasts on the H-PLGA/PLGA scaffolds were better than that on the PLGA scaffold, however bFGF immobilized H-PLGA/PLGA scaffolds showed much better cell affinity. Therefore, the method to use the H-PLGA/PLGA scaffold for immobilizing bFGF is not only effective for slow delivering bFGF with bioactivity, but also can be used for fabricating thick scaffold where bFGF could be combined and uniformly distributed. [Copyright &y& Elsevier]

Abstract: In this study, immobilization of rhBMP-2 on polylactone-type polymer scaffolds via plasma treatment was investigated. To introduce proper functional groups on the surface of poly(lactide-co-glycolide) (PLGA) matrix, PLGA films were treated under different atmospheres, such as oxygen, ammonia and carbon dioxide, respectively, and then incubated in rhBMP-2 solution of de-ionized water. The effect of various plasma-treated PLGA films on binding rhBMP-2 was investigated and compared. It was found that PLGA binding ability to rhBMP-2 was enhanced by carbon dioxide and oxygen plasma treatment, and the binding ability of the oxygen plasma-treated PLGA (OT-PLGA) to rhBMP-2 was the strongest after oxygen plasma treating for 10min under a power of 50W. The changes of surface chemistry and surface topography of PLGA matrix induced by oxygen plasma treatment played main roles in improving the PLGA binding ability to rhBMP-2. The stability of rhBMP-2 bound on OT-PLGA film was determined under a dynamic condition by a Parallel Plate Flow Chamber. The result showed that the rhBMP-2 had been immobilized on the OT-PLGA film. Mouse OCT-1 osteoblast-like cell as a model cell was cultured on the rhBMP-2 bound OT-PLGA (OT-PLGA/BMP) in vitro, which showed that the bound rhBMP-2 via oxygen plasma treatment was bioactive. Depending on hydrophilicity and rich polar O-containing groups of the OT-PLGA scaffold, different amount of rhBMP-2 could be evenly immobilized on the surface of the OT-PLGA scaffold. The immobilized rhBMP-2 had stimulated differentiation of OCT-1 cell and accelerated process of mineralization of OCT-1 cell in the scaffold. It revealed the rhBMP-2 immobilized PLGA scaffold had good cell affinity. [Copyright &y& Elsevier]

Abstract: In this study, a kind of microtubular orientation-structured blood vessel mimicking natural structure was fabricated with poly(lactide-co-glycolide)(70/30) (PLGA(70/30)) solutions in 1,4-dioxane by an improved thermal-induced phase separation (TIPS) technique. The effect of main factors of the TIPS technique, such as environmental temperature, temperature gradient and concentration of the polymer solution on the structure and morphology of formed vessel scaffold was investigated. It was observed that the outer-wall of the scaffold became thick obviously and the microtubules neighboring the outer-wall became disordered with environmental temperature increasing. The diameter of microtubules of vessel scaffolds reduced with temperature gradient increasing or concentration of the polymer solution increasing. By controlling parameters of the TIPS, the scaffolds with various morphologies could be manufactured, which had different diameters of microtubules. On the other hand, inner-diameter and outer-diameter of the vessel scaffolds could be controlled by adjusting size of the polyethylene mould. Cell affinity of the scaffolds was tested in vitro by using A10 cell as model cells. Results showed that the cells grew well in the vessel scaffolds which were modified by ammonia plasma treatment and then anchored with collagen. The cells could array along the direction of the microtubules. [Copyright &y& Elsevier]

Abstract: Surface characteristics greatly influence attachment and growth of cells on biomaterials. Although polylactone-type biodegradable polymers have been widely used as scaffold materials for tissue engineering, lack of cell recognition sites, poor hydrophilicity and low surface energy lead to a bad cell affinity of the polymers, which limit the usage of polymers as scaffolds in tissue engineering. In the present study, surface of poly (l-lactide-co-glycolide) (PLGA) was modified by a method of combining oxygen plasma treatment with anchorage of cationized gelatin. Modification effect of the method was compared with other methods of oxygen plasma treatment, cationized gelatin or gelatin coating and combining oxygen plasma treatment with anchorage of gelatin. The change of surface property was compared by contact angles, surface energy, X-ray photoelectron spectra (XPS), attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM) measurement. The optimum oxygen pretreatment time determined by surface energy was 10min when the power was 50W and the oxygen pressure was 20Pa. Analysis of the stability of gelatin and cationized gelatin anchored on PLGA by XPS, ATR-FTIR, contact angles and surface energy measurement indicated the cationized gelatin was more stable than gelatin. The result using mouse NIH 3T3 fibroblasts as model cells to evaluate cell affinity in vitro showed the cationized gelatin-anchored PLGA (OCG-PLGA) was more favorable for cell attachment and growth than oxygen plasma treated PLGA (O-PLGA) and gelatin-anchored PLGA (OG-PLGA). Moreover cell affinity of OCG-PLGA could match that of collagen-anchored PLGA (AC-PLGA). So the surface modification method combining oxygen plasma treatment with anchorage of cationized gelatin provides a universally effective way to enhance cell affinity of polylactone-type biodegradable polymers. [Copyright &y& Elsevier]

Abstract: In this study, biodegradable poly(lactide-co-glycolide) (PLGA) (70/30) films and scaffolds were first treated with oxygen plasma and then incubated in a modified simulated body fluid 1.5SBF0 to prepare a bone-like apatite layer. The formation of the apatite and its influence on osteoblast-like cells growth were investigated. It was found that the bone-like apatite formability of PLGA(70/30) was enhanced by plasma pretreatment. The changes of surface chemistry and surface topography induced by oxygen plasma treatment were both effective for apatite formation. The apatite formability increased with increasing plasma-treating time. Under a treating condition of 20W for 30min, oxygen plasma treatment could penetrate into the inner scaffold. After 6 days incubation, the apatite formed in plasma-treated scaffold was better distributed than in untreated scaffold, and the weight and mechanical strength of the plasma-treated scaffold were both enhanced. Compared with PLGA(70/30), the apatite layer formed on oxygen plasma-treated PLGA(70/30) surface enhanced adhesion and proliferation of OCT-1 osteoblast-like cell, but had no significant effect on cell''s ALP activity at day 7. A prolonged investigation is being in process to further verify the bone-like apatite effects on osteogenic differentiation. [Copyright &y& Elsevier]

A series of chitosan–gelatin composite films was prepared by varying the ratio of constituents. FT-IR and X-ray analysis showed good compatibility between these two biopolymers. Differential scanning calorimetry (DSC) analysis indicated that the water take-up of chitosan film increased when blended with gelatin. Composite film exhibited a lower Young''s modulus and a higher percentage of elongation-at-break compared with chitosan film, especially in wet state. All composite films were hydrophilic materials with water contact angles ranging from 55° to 65°. The results obtained from ELISA indicated the adsorption amount of fibronectin on composite films was much higher than on chitosan film. PC12 cells culture was used to evaluate the nerve cell affinity of materials. The cells cultured on the composite film with 60 wt% gelatin differentiated more rapidly and extended longer neurites than on chitosan film. The results suggest that the soft and elastic complex of chitosan and gelatin, which has better nerve cell affinity compared to chitosan, is a promising candidate biomaterial for nerve regeneration. [Copyright &y& Elsevier]

Bone tuberculosis (TB) is one of the most common extrapulmonary TB. Effective integration of chemotherapy and bone regeneration is an optimal solution for bone TB therapy. Herein, we produce a composite scaffold drug delivery system fabricated with an isoniazid conjugated star poly(lactide-co-glycolide) (PLGA-INH 4 ) and β -TCP. The cytological assay indicated the composite system possesses good biocompatibility. The in vitro and in vivo drug release evaluations showed that the composite system can intactly release the pristine INH and maintain effective INH concentration in a controlled manner for more than 100 days, and achieve high localized drug concentration and low systemic drug concentration. The rabbit radius repair experiment testified the scaffold has good bone regeneration capacity. Our work demonstrate the composite system can simultaneously achieve localized long-term drug controlled release and bone regeneration, which provides a promising route for improved bone TB treatment. [ABSTRACT FROM AUTHOR]

Abstract: Bone defects are common in elderly patients suffering from osteoporosis. Current methods of bone defect treatment for osteoporosis are not always satisfactory. In this study, we demonstrated that bone marrow mesenchymal stem cells (MSCs) harvested from goats with long-term estrogen deficiencies exhibited a lower proliferation rate and decreased osteogenic capacity, which are critical obstacles for bone defect repair in the elderly. However, by combining autologous enriched bone marrow mesenchymal stem cells with porous β-TCP, we successfully repaired critical-sized bone defects in the medial femoral condyle of the osteoporotic goats. Both micro-CT images and histomorphometry analysis illustrated improved bone formation following the enriched MSC therapy. Thus, we proposed autologous enriched bone marrow mesenchymal stem cells as a quick, safe therapeutic strategy to treat osteoporotic bone defects. [Copyright &y& Elsevier]

Abstract: We developed a natural, acellular, 3-D interconnected porous scaffold derived from cartilage extracellular matrix (ECM). Human cartilage was physically shattered, then decellularized sequentially with use of hypotonic buffer, TritonX-100, and a nuclease solution and made into a suspension. The scaffold was fabricated by simple freeze-drying and cross-linking techniques. On histology, scaffolds showed most of the ECM components after removal of the cell fragments, and scanning electron microscopy revealed a 3-D interconnected porous structure. Cellular viability assay revealed no cytotoxic effects. In vitro study showed that the novel scaffold could provide a suitable 3-D environment to support the adheration, proliferation and differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) to chondrocytes in culture with chondrogenic medium after 21 days. Chondrogenically induced BMSCs labeled with fluorescent dye PKH26 were then grown on scaffolds and implanted subcutaneously into nude mice. Four weeks later, cartilage-like tissue formed, with positive staining for Safranin O, tuoluidine blue and collagen II. Cells in the samples seemed to confirm that they originated from the labeled BMSCs, as confirmed by in vivo fluorescent imaging and immunofluorescence examination. In conclusion, the cartilage ECM-derived porous scaffold shows potential as biomaterial for cartilage tissue engineering, and PKH26 fluorescent labeling and in vivo fluorescent imaging can be useful for cell tracking and analyzing cell-scaffold constructs in vivo. [Copyright &y& Elsevier]