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Polycaprolactone (PCL) is considered a potential biomaterial due to its good biocompatibility, but its slow degradability and insufficient mechanical properties limit its wide application in bone tissue engineering. Tetracalcium phosphate's (TTCP) good degradability and inherent high stiffness are expected to compensate for the aforementioned defects of PCL and endow it with good biological activity. This goal of this study was to obtain bioactive PCL composite scaffolds with tuneable degradation properties and good mechanical strength via selective laser sintering technology (SLS). Composite porous scaffolds with TTCP contents of 0%, 5%, 10%, 15%, 20%, and 25% were prepared, and the experimental results showed that the addition of TTCP significantly improved the mechanical properties of the scaffold. Notably, the tensile strength of the composite scaffold with 20% TTCP content reached 15.2 MPa, which was 2.9 times that of pure PCL, and the best flexural strength was found in the scaffold with 15% TTCP content (4.7 MPa). More importantly, the introduced TTCP not only achieved the effective pH regulation of the soaking solution and the promotion of biodegradation, but also provided the scaffold with good bioactivity and biocompatibility. [ABSTRACT FROM AUTHOR]

Abstract A newly designed hydroxyapatite-polyurethane (HA-PU) composite scaffold was prepared by polymerizing glyceride of castor oil (GCO) with isophorone diisocyanate (IPDI) and HA as fillers. The aim of this study was to determine the effect of HA fillers on the mechanical properties and osteogenesis capacity of the composite scaffolds. The physical and biological properties of the scaffold were evaluated by SEM observation, mechanical testing, cell culture and animal experiments. The results showed that HA fillers enhanced the mechanical properties of PU composite scaffolds such as compressive strength and elastic modulus. The mechanical properties of the scaffolds were seen to increase with increase in HA loading. The compressive strength of composite scaffold with 0 wt%, 20 wt%, 40 wt% of HA was 0.6 ± 0.1 MPa, 2.1 ± 0.1 MPa, and 4.6 ± 0.3 MPa, respectively. In vitro biodegradation studies of scaffolds were carried out. The results showed that all of the scaffolds were susceptible to cholesterol esterase (CE) -catalyzed degradation. HA-PU composite scaffolds exhibited a high affinity to osteoblastic cells and were good template for cell growth and proliferation. When implanted in bone defects of rats, PU scaffolds incorporated HA were biocompatible with the tissue host and had no immune rejection. Moreover, the higher the loading of HA in the composite scaffold, the better chances of osteogenesis. It confirmed that the prepared HA-PU composite scaffolds can be promising candidate for bone repair and bone tissue engineering. [ABSTRACT FROM AUTHOR]

Although bone is regenerative, its regeneration capacity is limited. For bone defects beyond a critical size, further intervention is required. As an attractive strategy, bone tissue engineering (bone TE) has been widely investigated to repair bone defects. However, the rapid and effective bone regeneration of large non-healing defects is still a great challenge. Multifunctional scaffolds having osteoinductivity and osteoconductivity are desirable to fasten functional bone tissue regeneration. In the present study, biomimetic composite scaffolds of collagen and biphasic calcium phosphate nanoparticles (BCP NPs) with a controlled release of dexamethasone (DEX) and the controlled pore structures were prepared for bone TE. DEX was introduced in the BCP NPs during preparation of the BCP NPs and hybridized with collagen scaffolds, which pore structures were controlled by using pre-prepared ice particulates as a porogen material. The composite scaffolds had well controlled and interconnected pore structures, high mechanical strength and a sustained release of DEX. The composite scaffolds showed good biocompatibility and promoted osteogenic differentiation of hMSCs when used for three-dimensional culture of human bone marrow-derived mesenchymal stem cells. Subcutaneous implantation of the composite scaffolds at the dorsa of athymic nude mice demonstrated that they facilitated the ectopic bone tissue regeneration. The results indicated the DEX-loaded BCP NPs/collagen composite scaffolds had high potential for bone TE. Statement of Significance Scaffolds play a crucial role for regeneration of large bone defects. Biomimetic scaffolds having the same composition of natural bone and a controlled release of osteoinductive factors are desirable for promotion of bone regeneration. In this study, composite scaffolds of collagen and biphasic CaP nanoparticles (BCP NPs) with a controlled release nature of dexamethasone (DEX) were prepared and their porous structures were controlled by using ice particulates. In vitro cell culture and in vivo implantation experiments demonstrated the composite scaffolds exerted synergistic effects on the osteogenic differentiation of hMSCs and bone regeneration. The composite scaffolds also showed promotive effect on the formation of capillary blood vessels in the regenerated bone. This study is the first research to prepare DEX-loaded BCP NPs/collagen porous composite scaffolds. The superior performance of the composite scaffolds indicates the composite scaffolds should be useful for bone tissue engineering. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Mg-Zn-GO nano-composite scaffolds was fabricated successfully by using powder metallurgy method. • Mechanical strength of the Mg-Zn-GO nano-composite scaffolds was higher than the Mg-Zn scaffolds. • Corrosion resistance of the Mg-Zn-GO scaffolds was improved because of nano-graphene oxide existence in the Mg-Zn-GO scaffolds, and Mg(OH) 2 deposition on the scaffold surfaces. • MTT tests showed that the Mg-Zn-GO scaffolds are biocompatible. The aim of this study was to fabricate and evaluate magnesium-zinc-graphene oxide nanocomposite scaffolds for bone tissue engineering. For this reason, Mg-6Zn, Mg-6Zn-1GO, and Mg-6Zn-2GO scaffolds were fabricated by the powder metallurgy method. The porosity level and also the pore size of the scaffolds were evaluated by SEM which varied from 40 to 46% and 200 to 500 μm, respectively. The chemical composition and microstructure of the scaffolds were characterized by XRD and SEM equipped with EDS; the presence of Mg, Zn, C, and O elements in the structure of the scaffolds was shown. Also, the elemental map confirmed the existence of magnesium, zinc, carbon, and oxygen in the structure of the scaffold. The mechanical properties of the scaffolds were investigated by the compression test; the results showed that by the addition of graphene oxide to the structure, the compressive strength of the samples increased from 5 to 8 MPa. Electrochemical corrosion polarization tests were conducted to evaluate the corrosion resistance of the samples immersed in simulated body fluid (SBF). Furthermore, the biodegradability of the scaffolds was determined by immersion of the samples in phosphate-buffered saline (PBS). The results demonstrated that the polarization resistance value and the corrosion rate for different formulations including Mg-6Zn, Mg-6Zn-1GO, and Mg-6Zn-2GO were 41.58, 35.48, and 55.40 Ω.cm2 followed by 10.60, 14.83, and 9.06 mm.year−1, respectively. Based on the results, the Mg-6Zn-2GO formulation presented the best corrosion resistance among the samples were investigated, which confirmed the results of the immersion test. Moreover, the MTT assay proved that the extract of Mg-6Zn-2GO scaffolds was not cytotoxic in contact with L-929 cells which validated the studied scaffolds for bone tissue applications. [ABSTRACT FROM AUTHOR]

Electroactive biomaterials have been shown useful for the repair of injured peripheral nerve. While for conventional conductive conduits, outer electrical stimulation device is unavoidably employed to exert electrical signals, and their rigid microstructures are usually incompatible with neural cells. Herein, a soft carbon nanotubes@gelatin methacryloyl/poly(L -lactic acid) (CNTs@GelMA/PLLA) nerve tissue-engineering scaffold was fabricated, which provided an endogenous piezoelectric stimulation and conductive microenvironment. Based on amounts of in-vitro experiment data, such composite scaffold significantly improved adhesion and elongation of Schwann cells, and meanwhile promoted axonal outgrowth and neurites number of dorsal root ganglions. More interestingly, the scaffold was applied to a 10-mm sciatic nerve defect in rats and harvested at 12 weeks post-implantation. Immunohistochemical staining results indicated that our proposed graft significantly facilitated peripheral nerve regeneration by promoting myelination and axon outgrowth, meanwhile an enhanced motor functional recovery caused by the scaffold was also revealed due to the obviously-improved sciatic functional index and muscle weights. Overall, the soft, self-powered, and electroconductive CNTs@GelMA/PLLA scaffold is a promising candidate for the treatment of peripheral nerve injuries. • A soft, self-powered and conductive electrospun nerve scaffold with well-aligned structure is successfully fabricated. • The scaffold matches stiffness requirement of natural neural tissue perfectly. • The scaffold exhibits accelerated axonal growth, promoted remyelination regeneration, and improved nerve function recovery. [ABSTRACT FROM AUTHOR]

Abstract: The bladder is an organ susceptible to a variety of congenital anomalies, injuries and disorders. To address the clinical limitations of existing scaffolds, we fabricated a novel scaffold that can be applied to morphological and functional bladder reconstruction. As a first step to prove the benefit of the scaffold, intensive in vitro and in vivo analyses were conducted. The novel composite scaffold was fabricated using polycaprolactone/Pluronic F127 (PCL/F127) and variable proportions (1, 3, 5 and 10wt.%) of porcine acellular bladder submucosa matrix (BSM). Physicochemical properties and biocompatibilities of the scaffolds were characterized. For cell-mediated analysis, upper-urinary-tract-derived urine stem cells were used. Observations of tensile strength, modulus, porosity, cell adhesion, viability and proliferation characteristics of scaffolds indicated that the optimum proportion of BSM in the composite scaffolds was 3 or 5wt.%. Based on comparison of 3 and 5wt.% BSM/PCL/F127 scaffolds with respect to degradability, hydrophilicity, surface properties and functional group presence, the 3wt.% BSM was chosen for in vivo studies. 8weeks after kidney-subcapsular implantation of the 3wt.% BSM/PCL/F127 scaffold, cells remained attached to the surface and there was no evidence of teratomas. A BSM content of 3wt.% was the optimum proportion for fabrication of the neo scaffold. We predict that the 3wt.% BSM/PCL/F127 composite scaffold could act as an ideal matrix after cystectomy based on its favorable physicochemical properties and biocompatibilities. [Copyright &y& Elsevier]

Hydrogels, based on natural polymers, are gaining attention as possible cell scaffolding materials for the regeneration of a variety of tissues. In this work, gelatin (Gel) and hyaluronic acid (HA) were used to fabricate novel scaffold materials using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide as a cross-linker. The degradation behaviours of Gel/HA scaffolds in phosphate buffered saline (PBS) and PBS solution containing lysozyme were investigated respectively. The biological properties including haemolytic activity and acute systemic toxicity were also studied. The results showed that the scaffold had an interconnected pore structure with an average pore size of about 100-500 μm. The degradation of Gel/HA scaffolds in PBS solution containing lysozyme was faster than that in PBS solution. The haemolytic ratio of 0·340-0·781% indicated that the Gel/HA scaffolds have a good blood compatibility. The acute systemic toxicity test showed that Gel/HA extracts have no acute systemic toxicity. [ABSTRACT FROM AUTHOR]

Abstract: In this study, a two-part bone tissue engineering scaffold was investigated. The scaffold consists of a solid poly(propylene fumarate) (PPF) intramedullary rod for mechanical support surrounded by a porous PPF sleeve for osseointegration and delivery of poly(dl-lactic-co-glycolic acid) (PLGA) microspheres with adsorbed recombinant human bone morphogenetic protein-2 (rhBMP-2). Scaffolds were implanted into critical size rat segmental femoral defects with internal fixation for 12weeks. Bone formation was assessed throughout the study via radiography, and following euthanasia, via microcomputed tomography and histology. Mechanical stabilization was evaluated further via torsional testing. Experimental implant groups included the PPF rod alone and the rod with a porous PPF sleeve containing PLGA microspheres with 0, 2 or 8μg of rhBMP-2 adsorbed onto their surface. Results showed that presence of the scaffold increased mechanical stabilization of the defect, as evidenced by the increased torsional stiffness of the femurs by the presence of a rod compared to the empty defect. Although the presence of a rod decreased bone formation, the presence of a sleeve combined with a low or high dose of rhBMP-2 increased the torsional stiffness to 2.06±0.63 and 1.68±0.56N·mm, respectively, from 0.56±0.24N·mm for the rod alone. The results indicate that, while scaffolds may provide structural support to regenerating tissues and increase their mechanical properties, the presence of scaffolds within defects may hinder overall bone formation if they interfere with cellular processes. [Copyright &y& Elsevier]

The collagen-chitosan composite scaffolds were fabricated by lyophilization technique, which were structurally modified by laminin (LN) protein, and their physical performance characteristics were determinated. Neural stem cells (NSCs) obtained from the fetal mouse hippocampus were cultured in the collagen-chitosan composite scaffolds and the biocompatibility was studied. The comparative results of different scaffolds with the parameters of aperture, porosity, water absorption and degradation rate show that the volume ratio of 7 : 3 is more suitable for cell culture in vitro and the inoculation rate of NSCs is markedly improved in LN-treated scaffolds. Through the observation of laser scanning confocal microscope (LSCM) and scanning electron microscopy (SEM), NSCs within collagen-chitosan composite scaffolds present good growth, proliferation and differentiation. These results provide a scientific experimental basis not only for further NSCs clinical transplantation applications, but also for the drug screening and mechanism research on the treatment of diseases of the nervous system. [ABSTRACT FROM AUTHOR]

In this study, novel porous composite scaffolds for bone tissue engineering and drug delivery system were prepared from nanohydroxyapatite, biodegradable Ca crosslinked sodium alginate (SA) and polyvinyl alcohol (PVA) by the method of coprecipitation. The properties of the composite were characterised by the means of burning test, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, mechanical test and cell experiment. The results show that the nanohydroxyapatite component could disperse uniformly in SA-PVA copolymer matrix. Excellent miscibility existed among the three phases and inter- or intrahydrogen bonding could be formed among the three phases. The entrance of PVA matrix in the composite enhanced the mechanical properties of the composite scaffold. The scaffold exhibited highly porous structure with a pore size of 50-250 μm and porosity up to 75%. When the porous scaffold contained 50% PVA, its compressive strength reached 8·29 MPa. Preliminary cell experiment testified that the composite scaffold was no cytotoxicity. This triphasic composite scaffold shows good prospects for bone tissue engineering and controlled drug delivery system. [ABSTRACT FROM AUTHOR]

Summary: For many years, bone graft substitutes have been used to reconstruct bone defects in orthopedic and dental fields. However, synthetic bone substitutes such as hydroxyapatite or β-tricalcium phosphate have no osteoinductive or osteogenic abilities. Bone tissue engineering has also been promoted as an alternative approach to regenerating bone tissue. To succeed in bone tissue engineering, osteoconductive scaffolding biomaterials should provide a suitable environment for osteogenic cells and provide local controlled release of osteogenic growth factors. In addition, the scaffold for the bone graft substitute should biodegrade to replace the newly formed bone. Recent advances in bone tissue engineering have allowed the creation of composite scaffolds with tailored functional properties. This review focuses on composite scaffolds that consist of synthetic ceramics and natural polymers as drug delivery carriers for alveolar bone tissue engineering. [Copyright &y& Elsevier]

Abstract: Previous studies have demonstrated the potential of fibrin as a cell carrier for cardiovascular tissue engineering applications. Unfortunately, fibrin exhibits poor mechanical properties. One method of addressing this issue is to incorporate a textile in fibrin to provide structural support. However, it is first necessary to develop a deeper understanding of the effect of the textile on cell response. In this study, the cytotoxicity of a polylactic acid (PLA) warp-knit textile was assessed with human coronary artery smooth muscle cells (HCASMC). Subsequently, quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) was employed to examine the gene expression of HCASMC embedded in fibrin with and without the textile. Five genes were examined over a 3-week period: smooth muscle α-actin (SMαΑ), myosin heavy chain 11 smooth muscle (SM1/SM2), calponin, myosin heavy chain 10 non-muscle (SMemb) and collagen. Additionally, a microarray analysis was performed to examine a wider range of genes. The knitting process did not adversely affect the cell response; there was no dramatic change in cell number or metabolic rate compared to the negative control. After 3 weeks, there was no significant difference in gene expression, except for a slight decrease of 10% in SMemb in the fibrin with textile. After 3 weeks, there were no obvious cytotoxic effects observed as a result of the knitting process and the gene expression profile did not appear to be altered in the presence of the mesh in the fibrin gel. [Copyright &y& Elsevier]