Journal of Biomedical Materials Research - Part B Applied Biomaterials
1552-4973
1552-4981
Mỹ
Cơ quản chủ quản: John Wiley & Sons Inc. , WILEY
Lĩnh vực:
BiomaterialsBiomedical Engineering
Các bài báo tiêu biểu
Paraffin spheres as porogen to fabricate poly(L‐lactic acid) scaffolds with improved cytocompatibility for cartilage tissue engineering Abstract Three‐dimensional poly(L‐lactic acid) (PLLA) scaffolds with high porosity and pore size ranging from 150 to 700 μm were conveniently prepared with paraffin spheres used as porogen. PLLA/1,4‐dioxane solution containing a given amount of paraffin spheres was frozen at −25 °C to obtain a solidified mixture, followed with freeze drying and subsequent leaching with hexane to remove the 1,4‐dioxane and paraffin spheres, respectively. The fabricated PLLA scaffolds were highly porous with evenly distributed and interconnected pores. The microstructures of the PLLA scaffolds as a function of paraffin‐sphere size, paraffin‐sphere dosage, and PLLA concentration were characterized by confocal laser scanning microscopy (CLSM) and scanning‐electronic microscopy (SEM). To improve the cytocompatibility of the bioinert material, a hybrid PLLA scaffold containing Type I collagen was prepared by pressing the collagen solution into the scaffold under reduced pressure. The amounts of the collagen introduced in the scaffolds were detected by ninhydrin method. The distribution of the collagen in the scaffolds was studied with CLSM. Finally, in vitro cell culture was performed by injecting a chondrocyte suspension into the scaffolds. The results showed that the chondrocytes were more evenly distributed and more spread out in the collagen‐modified PLLA scaffolds than in the unmodified ones. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 67B: 610–617, 2003
Tập 67B Số 1 - Trang 610-617 - 2003
An innovative method to obtain porous PLLA scaffolds with highly spherical and interconnected pores Abstract Scaffolding is an essential issue in tissue engineering and scaffolds should answer certain essential criteria: biocompatibility, high porosity, and important pore interconnectivity to facilitate cell migration and fluid diffusion. In this work, a modified solvent casting‐particulate leaching out method is presented to produce scaffolds with spherical and interconnected pores. Sugar particles (200–300 μm and 300–500 μm) were poured through a horizontal Meker burner flame and collected below the flame. While crossing the high temperature zone, the particles melted and adopted a spherical shape. Spherical particles were compressed in plastic mold. Then, poly‐L ‐lactic acid solution was cast in the sugar assembly. After solvent evaporation, the sugar was removed by immersing the structure into distilled water for 3 days. The obtained scaffolds presented highly spherical interconnected pores, with interconnection pathways from 10 to 100 μm. Pore interconnection was obtained without any additional step. Compression tests were carried out to evaluate the scaffold mechanical performances. Moreover, rabbit bone marrow mesenchymal stem cells were found to adhere and to proliferate in vitro in the scaffold over 21 days. This technique produced scaffold with highly spherical and interconnected pores without the use of additional organic solvents to leach out the porogen. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Tập 86B Số 1 - Trang 9-17 - 2008
The use of collagen cross‐linking agents to enhance dentin bond strength Abstract Type I collagen is a major component of the hybrid layer, and improvement of its mechanical properties may be advantageous during bonding procedures. Objective: To investigate the effect of three different cross‐linking agents (Glutaraldehyde [GD], Grape seed extract [GSE], and Genipin [GE]) on the tensile bond strength (TBS) of resin‐dentin bonds. Materials and Methods: Sixty‐four sound human molars were collected and their occlusal surfaces were ground flat to expose dentin. Dentin surfaces were etched using a phosphoric acid and then teeth were randomly divided according to the dentin treatment: Control group (no treatment), 5% GD, 6.5% GSE, or 0.5% GE. Teeth were restored either with One Step Plus or Adper Single Bond Plus adhesive systems and resin composite. After 24 h, teeth were sectioned to produce a cross‐sectional surface area of 1.0 mm2 and tested for tensile bond strength. Data were statistically analyzed using ANOVA and Fisher's PLSD tests (p < 0.05). There was a statistically significant interaction between factors (treatment and adhesive p < 0.001). Treatment affected TBS (p < 0.0001), while no differences were observed between the adhesive systems (p = 0.6961). Conclusion: Chemical modification to the dentin matrix promoted by GD and GSE, but not GE, resulted in increased bond strength. The application of selective collagen cross‐linkers during adhesive restorative procedures may be a new approach to improve dentin bond strength properties. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Tập 91B Số 1 - Trang 419-424 - 2009
Application of crosslinkers to dentin collagen enhances the ultimate tensile strength Abstract The stabilization of dentin collagen with biocompatible crosslinking agents may be of clinical importance to improve dentin bond strength. The present study aimed to evaluate the effect of three collagen crosslinking agents on the ultimate tensile strength (UTS) of undemineralized and demineralized dentin. Ten freshly extracted sound molars were sectioned into 0.5 × 0.5 mm2 thick beams. The beams were either demineralized or kept undemineralized. Then, specimens were subdivided into four groups according to treatments—PBS solution (control), 5% glutaraldehyde (GD), 0.5% proanthocyanidin PBS solution (PA), and 0.625% genipin PBS solution (GE). Specimens were kept in their respective solutions for either 4 or 40 h. To assess UTS, specimens were subjected to tensile forces at a crosshead speed of 1 mm/min. Statistical analysis was performed using two‐way ANOVA and Fisher's PLSD test (p < 0.05). Statistically significant increases in UTS were observed for demineralized dentin after PA and GE dentin treatment, when compared with those of the control group. Dentin treated with GD showed no statistically significant differences in UTS when compared with that the control. Undemineralized dentin revealed no significant differences as compared to that of the control, regardless of the collagen crosslinkers. The application of two naturally occurring crosslinkers, i.e., PA and GE, to dentin collagen significantly improves UTS, indicating its potential value in restorative dentistry. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Tập 80B Số 1 - Trang 268-272 - 2007
Micromechanical analysis of dentin/adhesive interface by the finite element method Abstract The interfacial microstructure and spatial distribution of the modulus of elasticity have a profound effect on load transfer at the dentin/adhesive (d/a) interface. The microstructure is influenced by the varying degree of demineralization of intertubular and peritubular dentin during etching as well as the depth of adhesive penetration into the hybrid layer. These factors lead not only to a unique microstructure in the vicinity of the dentinal tubules, but also to a mechanically graded hybrid layer. This article investigates the micromechanical stress distribution at a d/a interface with the use of finite element analysis (FEA). Such analysis is now feasible given the newly measured moduli of elasticity at micro‐ and nanoscales. The results indicate that the morphological and micromechanical properties of the d/a interface affects the stress field such that the fracture/failure is likely to initiate in the stress‐concentration zone of peritubular dentin next to the hybrid/exposed‐collagen layer. The results suggest that devising a full‐depth high modulus hybrid layer may considerably reduce the stress concentration zone and the magnitude of stress concentration in the peritubular dentin next to the hybrid/exposed‐collagen layer. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 56–65, 2004
Tập 70B Số 1 - Trang 56-65 - 2004
Nanoporous delivery system to treat osteomyelitis and regenerate bone: Gentamicin release kinetics and bactericidal effect Abstract Conventional treatment of osteomyelitis involves the repeated surgical removal of dead bone tissue coupled with repeated irrigation of the wound and prolonged systemic administration of antibiotics. Therapy of bone infections could easily last the rest of the patient's life because of the poor accessibility of the infection site by common systemically administered antibiotics. The objective of the present study is to develop a novel bone bioactive resorbable nanocomposite that can serve as a delivery system for antibiotics. We synthesized three different samples of porous bioactive resorbable silica–calcium phosphate nanocomposite (C3S1, C1S1, and C1S3) that has the ability to provide a sustained release of effective dose of gentamicin for 28 days. Porosity measurements showed that the average pore diameter of C3S1, C1S1, and C1S3 samples is 44.8, 54.4, and 70.9 nm, respectively. Moreover, the silica‐rich composite (C1S3) is characterized by a significantly higher surface area (155.8 m2 /g) than the silica‐poor samples (C3S1) (42.9 m2 /g). For all samples, the release profile study showed initial burst release followed by a sustained release of gentamicin. The released gentamicin has a strong inhibitory effect on Staphylococcus aureus bacteria. In addition FTIR analysis showed the formation of a biological apatite layer on the material surface after 24 h of immersion in simulated body fluid. Results of the study suggest that the silica–calcium phosphate nanocomposite can serve as a delivery vehicle for gentamicin to treat osteomyelitis and regenerate bone. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater
Tập 73B Số 2 - Trang 277-284 - 2005
<i>In vitro</i> assessment of electrospun polyamide‐6 scaffolds for esophageal tissue engineering Abstract Artificial tissue‐engineered grafts offer a potential alternative to autologous tissue grafts for patients, which can be traumatic. After decellularizing Papio hamadryas esophagus and studying the morphology and physical properties of the extracellular matrix (ECM), we generated electrospun polyamide‐6 based scaffolds to mimic it. The scaffolds supported a greater mechanical load than the native ECM and demonstrated similar 3D microstructure, with randomly aligned fibers, 90% porosity, 29 μm maximal pore size, and average fiber diameter of 2.87 ± 0.95 µm. Biocompatibility studies showed that human adipose‐ and bone marrow‐derived mesenchymal stromal cells (AD‐MSC and BMD‐MSC) adhered to the scaffold surface and showed some proliferation: scaffold cell coverage was 25% after 72 h of incubation when seeded with 1000 cells/mm2 ; cells elongated processes along the polyamide‐6, although they flattened 1.67–4 times less than on cell culture plastic. Human umbilical vein endothelial cells, however, showed poor adherence and proliferation. We thus provide in vitro evidence that polyamide‐6 scaffolds approximating the esophageal biomechanics and 3D topography of nonhuman primates may provide a biocompatible substrate for both AD‐MSC and BMD‐MSCs, supporting their adhesion and survival to some degree. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 253–268, 2019.
Tập 107 Số 2 - Trang 253-268 - 2019
A multilayer scaffold design with spatial arrangement of cells to modulate esophageal tissue growth Abstract Esophageal diseases may require resectioning of the damaged portion. The current standard of care requires the replacement of the esophagus with the stomach or the intestine. Such procedures have high rates of mortality and morbidity; therefore, the use of alternative conduits is needed. A tissue engineering approach that allows for the regeneration of esophageal tissues would have significant clinical application. A cell‐seeded synthetic scaffold could replace the resected part of the esophagus and elicit tissue regrowth. In order to ideally recreate a functioning esophagus, its two crucial tissue layers should be induced: an epithelium on the luminal surface and a muscle layer on the exterior surface. To create a bioengineered esophagus with both tissue layers, a multilayer (ML) tubular scaffold design was considered. Luminal and exterior layers were electrospun with broad pore size to promote penetration and proliferation of mesenchymal stem cells on the lumen and smooth muscle cells on the external. These two layers would be separated by a thin layer with substantially narrower pore size intended to act as a barrier for the two cell types. This ML scaffold design was achieved via electrospinning by tuning the solution and the process parameters. Analysis of the scaffold demonstrated that this tuning enabled the production of three integrated layers with distinguishable microstructures and good mechanical integrity. In vitro validation was conducted on the separated unilayer components of the ML scaffold. The resultant proof‐of‐concept ML scaffold design could possibly support the spatial arrangement of cells needed to promote esophageal tissue regeneration. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 324–331, 2019.
Tập 107 Số 2 - Trang 324-331 - 2019
Self‐production of oxygen system CaO<sub>2</sub>/MnO<sub>2</sub>@PDA‐MB for the photodynamic therapy research and switch‐control tumor cell imaging Abstract Photodynamic therapy (PDT) holds promise in biochemical study and tumor treatment. A novel multifunctional nanosystem CaO2 /MnO2 @polydopamine (PDA)‐methylene blue (MB) nanosheet (CMP‐MB) was designed. CaO2 nanoparticles were encapsulated by MnO2 nanosheet, and then PDA was coated on the surface of CaO2 /MnO2 nanosheets, which could adsorb photosensitizer MB through hydrophobic interaction or π‐π stacking. In this nanosystem, CaO2 /MnO2 had the ability of self‐production of oxygen, which solved the problem of tumor hypoxia largely. Moreover, it is worth mentioning that the fluorescence of MB was suppressed by MnO2 , while its emission was triggered in the simulated tumor microenvironment. Therefore, CMP‐MB nanosheet could be used to switch‐control cell imaging potentially. 3‐(4,5‐dimethyl‐thiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide testing and Live/Dead assay confirmed CMP‐MB nanosheet had fewer side effects without illumination while it destroyed Hela cell with the illumination of light. Vitro cell experiment demonstrated CMP‐MB nanosheet could achieve tumor microenvironment responsive imaging and inhibit tumor cell growth under illumination effectively. Therefore, the system has great potential for PDT application and switch‐control tumor cell imaging. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2544–2552, 2018.
Tập 106 Số 7 - Trang 2544-2552 - 2018
Three‐dimensional printing of porous ceramic scaffolds for bone tissue engineering Abstract This article reports a new process chain for custom‐made three‐dimensional (3D) porous ceramic scaffolds for bone replacement with fully interconnected channel network for the repair of osseous defects from trauma or disease. Rapid prototyping and especially 3D printing is well suited to generate complex‐shaped porous ceramic matrices directly from powder materials. Anatomical information obtained from a patient can be used to design the implant for a target defect. In the 3D printing technique, a box filled with ceramic powder is printed with a polymer‐based binder solution layer by layer. Powder is bonded in wetted regions. Unglued powder can be removed and a ceramic green body remains. We use a modified hydroxyapatite (HA) powder for the fabrication of 3D printed scaffolds due to the safety of HA as biocompatible implantable material and efficacy for bone regeneration. The printed ceramic green bodies are consolidated at a temperature of 1250°C in a high temperature furnace in ambient air. The polymeric binder is pyrolysed during sintering. The resulting scaffolds can be used in tissue engineering of bone implants using patient‐derived cells that are seeded onto the scaffolds.This article describes the process chain, beginning from data preparation to 3D printing tests and finally sintering of the scaffold. Prototypes were successfully manufactured and characterized. It was demonstrated that it is possible to manufacture parts with inner channels with a dimension down to 450 μm and wall structures with a thickness down to 330 μm. The mechanical strength of dense test parts is up to 22 MPa. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
Tập 74B Số 2 - Trang 782-788 - 2005