Biomedical subjects

Cato T Laurencin

Publications and source records attributed to Cato T Laurencin.

At least 19 recordsLinked to original sources

PubMed2007

A preliminary report on a novel electrospray technique for nanoparticle based biomedical implants coating: precision electrospraying.

The compatibility and biological efficacy of biomedical implants can be enhanced by coating their surface with appropriate agents. For predictable functioning of implants in situ, it is often desirable to obtain an extremely uniform coating thickness without effects on component dimensions or functions. Conventional coating techniques require rigorous processing conditions and often have limited adhesion and composition properties. In the present study, the authors report a novel precision electrospraying technique that allows both degradable and nondegradable coatings to be placed. Thin metallic slabs, springs, and biodegradable sintered microsphere scaffolds were coated with poly(lactide-co-glycolide) (PLAGA) using this technique. The effects of process parameters such as coating material concentration and applied voltage were studied using PLAGA and poly(ethylene glycol) coatings. Morphologies of coated surfaces were qualitatively characterized by scanning electron microscopy. Qualitative observations suggested that the coatings were composed of particles of various size/shape and agglomerates with different porous architectures. PLAGA coatings of uniform thickness were observed on all surfaces. Spherical nanoparticle poly(ethylene glycol) coatings (462-930 nm) were observed at all concentrations studied. This study found that the precision electrospraying technique is elegant, rapid, and reproducible with precise control over coating thickness (mum to mm) and is a useful alternative method for surface modification of biomedical implants.

Coated Materials, Biocompatible↗

PubMed2007

Nanobiomaterial applications in orthopedics.

Advancements in nanobiotechnology are revolutionizing our capability to understand biological intricacies and resolve biological and medical problems by developing subtle biomimetic techniques. Nanocomposites and nanostructured materials are believed to play a pivotal role in orthopedic research since bone itself is a typical example of a nanocomposite. This article reviews current strategies using nanobiomaterials to improve current orthopedic materials and examines their applications in bone tissue engineering. Preliminary investigations support the potential of nanobiomaterials in orthopedic applications; however, significant advancements are necessary to achieve clinical use. Overall, current trends in nanobiotechnology foreshadow a bright future through the use of nanobiomaterials in the orthopedic domain.

Biocompatible Materials↗

PubMed2006

Tissue engineering of the anterior cruciate ligament using a braid-twist scaffold design.

The anterior cruciate ligament (ACL) is the most commonly injured intra-articular ligament of the knee. The insufficient vascularization of this tissue prevents it from healing completely after extreme tearing or rupture, creating a need for ACL grafts for reconstruction. The limitations of existing grafts have motivated the investigation of tissue-engineered ACL grafts. A successful tissue-engineered graft must possess mechanical properties similar to the ACL; to date no commercially available synthetic graft has achieved this. To accomplish this goal we have combined the techniques of polymer fiber braiding and twisting to design a novel poly L-lactic acid (PLLA) braid-twist scaffold for ACL tissue engineering. The scaffold is designed to accurately mimic the biomechanical profile and mechanical properties of the ACL. In this study, braid-twist scaffolds were constructed and compared to braided scaffolds and twisted fiber scaffolds. The addition of fiber twisting to the braided scaffold resulted in a significant increase in the ultimate tensile strength, an increase in ultimate strain, and an increase in the length of the toe region in these constructs over scaffolds that were braided. Based on the findings of this study, the braid-twist scaffold studied was found to be a promising construct for tissue engineering of the ACL.

Anterior Cruciate Ligament↗

PubMed2006

Osteogenic differentiation of adipose-derived stromal cells treated with GDF-5 cultured on a novel three-dimensional sintered microsphere matrix.

BACKGROUND CONTEXT: It is well known that under the proper conditions multipotential bone marrow stromal cells are capable of osteogenic differentiation. Recently studies have demonstrated that an analogous subpopulation of cells exist within adipose tissue. Although early studies characterizing these adipose-derived stromal (ADS) cells in culture exist, investigations exploring the characteristics and viability of these cells cultured on a three-dimensional sintered microsphere matrix are absent. PURPOSE: To characterize and investigate the viability of ADS cells cultured on bioengineered three-dimensional sintered microsphere matrices (SMM). STUDY DESIGN: Basic science, laboratory study. PATIENT SAMPLE: Sixty SMM total. Six underwent examination by scanning electron microscopy, 18 for cellular viability, 18 for biochemical assay, and 18 for evaluation by gene expression. OUTCOME MEASURES: The SMM were examined under scanning electron microscopy to evaluate for adherence, migration, and proliferation at 7, 14, and 28 days. Cellular viability was assessed using colorimetric assay for mitochondrial dehydrogenases activity in viable cells (MTS [3-(4,5-dimethylthiazol-2-yl)5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] assay) at each corresponding time point. Osteoblastic differentiation was determined using biochemical assays for alkaline phosphatase activity and gene expression for alkaline phosphatase (ALP), osteocalcin (OC), and core binding factor alpha-1 (Cbfa1). METHODS: Multipotential ADS cells from adult Sprague Dawley rats were isolated and maintained in media. Sintered microsphere matrices of poly(lactide-co-glycolide) [85:15] were prepared using solvent evaporation technique followed by mechanical sieving and fabricated by heating in metal molds. ADS cells were then seeded on the SMM and cultured in media with growth and differentiation factor-5 (GDF-5). Treated samples and controls were evaluated at 7, 14, and 28 days. Statistical significance was set at p<.05. RESULTS: Multipotential ADS cells were capable of being isolated from adipose tissue. Scanning electron microscopy evaluation revealed cells adherent to the scaffold surface in a monolayer by 7 days. Cytoplasmic extensions were seen linking the cells on adjacent microspheres. Migration and proliferation resulting in extension of the cellular elements into the scaffold was apparent by 14 days. MTS confirmed cell viability within the scaffold throughout the 28-day study. Osteoblastic differentiation was confirmed using biochemical assays for alkaline phosphatase activity and gene expression for ALP, OC, and Cbfa1. CONCLUSIONS: This is the first study to investigate the fate of ADS seeded on a three-dimensional sintered microsphere matrix. The results of this study confirm that ADS cells, when treated with GDF-5, are not only capable of adhering to the bioengineered scaffold, but also remain viable and demonstrated the ability to migrate, proliferate, and subsequently undergo osteogenic differentiation under the conditions described. These early findings support the concept that ADS cells cultured on a SMM may serve as a viable alternative to more traditional methods of bone graft materials.

Adipose Tissue↗

PubMed2006

Fibroblast growth factor 2 induced proliferation in osteoblasts and bone marrow stromal cells: a whole cell model.

Fibroblast growth factor 2 (FGF2) can enhance the proliferative capacity of bone and bone marrow stromal cells; however, the mechanisms behind this effect are not well described. We present a whole-cell kinetic model relating receptor-mediated binding, internalization, and processing of FGF2 to osteoblastic proliferative response. Focusing on one of the potential signaling complex stoichiometries, we utilized experimentally measured and modeled estimated rate constants to predict in vitro proliferation and distinguish between potential binding orders. We found that piecewise assemblage of a ternary signaling complex may occur in several ways depending on the local binding environment. Using experimental data of endocytosed FGF2 as a constraint, we have also shown evidence of potential multistep processes involved in heparan-sulfate proteoglycans-bound FGF2 release, internalization, and fragment formation in conjunction with the normal metabolism of the proteoglycan.

Animals↗

PubMed2006

Bone tissue engineering by gene delivery.

Recombinant human bone morphogenetic protein-2 and -7 were recently granted United States Food and Drug Administration approval for select clinical applications in bone repair. While significant progress has been made in the delivery of recombinant osteogenic factor to promote bone healing, the short half-life and instability of the protein requires the delivery of milligram quantities of factor or multiple dosages. The potential of gene therapy for bone regeneration is the delivery of physiological levels of therapeutic protein using natural cellular mechanisms. Experimental investigations have demonstrated this approach uses lower dosages of factor to yield bone healing equivalent to that achieved via the administration of recombinant factor or use of bone grafts. The current states of gene delivery for bone tissue engineering applications and challenges to be met are presented in this review. Over the past couple of years, studies have continued to examine the delivery of the osteogenic factor bone morphogenetic protein using gene therapies. The importance of angiogenesis to bone formation has prompted the development of vascular endothelial growth factor gene expression systems for bone regeneration. Viral vectors, in combination with allograft bone, have been investigated to improve existing surgical care. Newly constructed vectors with reduced immunogenicity and regulated gene expression systems provide a greater degree of control over the timing and level of gene expression. Several advances have allowed bone tissue engineering by gene delivery to advance beyond serving as a potential treatment for isolated bone defects and fractures to a gene therapy approach for the treatment of genetic based bone diseases, such as osteogenesis imperfecta.

Animals↗

PubMed2006

In vivo biodegradability and biocompatibility evaluation of novel alanine ester based polyphosphazenes in a rat model.

Amino acid ester substituted polyphosphazenes are attractive candidates for various biomedical applications because of their biocompatibility, controllable hydrolytic degradation rates, and nontoxic degradation products. In this study, the biocompatibility of three L-alanine ethyl ester functionalized polyphosphazenes was evaluated in a subcutaneous rat model. The polymers used in the study were poly[bis(ethylalanato)phosphazene] (PNEA), poly[(50% ethylalanato) (50% methylphenoxy) phosphazene] (PNEA(50)mPh(50)), and poly[(50% ethylalanato)(50% phenyl phenoxy) phosphazene] (PNEA(50)PhPh(50)). Polymer disks of diameter 7.5 mm were prepared by a solvent evaporation technique and were implanted subcutaneously in rats. After 2, 4, and 12 weeks, the polymer along with the surrounding tissues were excised, prepared, and viewed by light microscopy to evaluate the tissue responses of the implanted polymers. The tissue responses were classified as minimal, mild, or moderate, based on a biocompatibility scheme developed in our laboratory. Minimal inflammation was characterized by the presence of few neutrophils, erythrocytes, and lymphocytes; mild response was characterized by the predominant presence of macrophages, fibroblasts, or giant cells; and moderate inflammation was characterized by the abundance of macrophages, giant cells, and by the presence of tissue exudates. The in vivo degradation profiles of the polymers at various time points were evaluated by gel permeation chromatography (GPC). PNEA and PNEA(50)mPh(50) matrices elicited varying levels of tissue responses during the 12-week implantation period. At 2 weeks both polymers evoked a moderate response, and by 12 weeks the response was found to be mild. However, PNEA(50)PhPh(50) elicited a mild response at the end of 2 weeks and demonstrated a further decreased inflammatory response after 12 weeks. The in vivo degradation of the polymers was followed by determining the molecular weights of the explanted polymer disks. PNEA and PNEA(50)mPh(50) disks showed significant decrease in molecular weight after 2 weeks of implantation. The molecular weights of PNEA and PNEA(50)mPh(50) residues could not be determined by GPC after 12 weeks of implantation because of almost complete degradation. On the other hand the in vivo degradation of PNEA(50)PhPh(50) was found to be slow, with a 63% loss in molecular weight in 12 weeks. Furthermore, this polymer maintained its shape and structure during the entire study. Thus, these polymers demonstrated excellent tissue compatibility and in vivo biodegradability and can be potential candidates for various biomedical applications.

Absorbable Implants↗

PubMed2006

In vitro evaluation of chitosan/poly(lactic acid-glycolic acid) sintered microsphere scaffolds for bone tissue engineering.

A three-dimensional (3-D) scaffold is one of the major components in many tissue engineering approaches. We developed novel 3-D chitosan/poly(lactic acid-glycolic acid) (PLAGA) composite porous scaffolds by sintering together composite chitosan/PLAGA microspheres for bone tissue engineering applications. Pore sizes, pore volume, and mechanical properties of the scaffolds can be manipulated by controlling fabrication parameters, including sintering temperature and sintering time. The sintered microsphere scaffolds had a total pore volume between 28% and 37% with median pore size in the range 170-200microm. The compressive modulus and compressive strength of the scaffolds are in the range of trabecular bone making them suitable as scaffolds for load-bearing bone tissue engineering. In addition, MC3T3-E1 osteoblast-like cells proliferated well on the composite scaffolds as compared to PLAGA scaffolds. It was also shown that the presence of chitosan on microsphere surfaces increased the alkaline phosphatase activity of the cells cultured on the composite scaffolds and up-regulated gene expression of alkaline phosphatase, osteopontin, and bone sialoprotein.

3T3 Cells↗

PubMed2006

Structural and nanoindentation studies of stem cell-based tissue-engineered bone.

Stem cell-based gene therapy and tissue engineering have been shown to be an efficient method for the regeneration of critical-sized bone defects. Despite being an area of active research over the last decade, no knowledge of the intrinsic ultrastructural and nanomechanical properties of such bone tissue exists. In this study, we report the nanomechanical properties of engineered bone tissue derived from genetically modified mesenchymal stem cells (MSCs) overexpressing the rhBMP2 gene, grown in vivo in the thigh muscle of immunocompetent mice for 4 weeks, compared to femoral bone adjacent to the transplantation site. The two types of bone had similar mineral contents (61 and 65 wt% for engineered and femoral bone, respectively), overall microstructures showing lacunae and canaliculi (both measured by back-scattered electron microscopy), chemical compositions (measured by energy dispersive X-ray analysis), and nanoscale topographical morphologies (measured by tapping-mode atomic force microscopy imaging or TMAFM). Nanoindentation experiments revealed that the small length scale mechanical properties were statistically different with the femoral bone (indented parallel to the bone long axis) being stiffer and harder (apparent elastic modulus, E approximately 27.3+/-10.5 GPa and hardness, H approximately 1.0+/-0.7G Pa) than the genetically engineered bone (E approximately 19.8+/-5.6 GPa, H approximately 0.9+/-0.4G Pa). TMAFM imaging showed clear residual indents characteristic of viscoelastic plastic deformation for both types of bone. However, fine differences in the residual indent area (smaller for the engineered bone), pile up (smaller for the engineered bone), and fracture mechanisms (microcracks for the engineered bone) were observed with the genetically engineered bone behaving more brittle than the femoral control.

Biomechanical Phenomena↗

PubMed2006

Human osteoblast cells: isolation, characterization, and growth on polymers for musculoskeletal tissue engineering.

We performed a detailed examination of the isolation, characterization, and growth of human osteoblast cells derived from trabecular bone. We further examined the morphology, phenotypic gene expression, mineralization,and growth of these human osteoblasts on polyester polymers used for musculoskeletal tissue engineering. Polylactic-co-glycolic acid [PLAGA (85:15, 50:50, 75:25)], and poly-lactic acid (L-PLA, D,L-PLA) were examined. The osteoblastic expression of key phenotypic markers osteocalcin, alkaline phosphatase, collagen, and bone sialoprotein at 4 and 8 weeks was examined. Reverse transcription-polymerase chain reaction studies revealed that trabecular-derived osteoblasts were positive for all markers evaluated with higher levels expressed over long-term culture. These cells also revealed mineralization and maturation as evidenced by energy dispersive X-ray analysis and scanning electron microscopy. Growth studies on PLAGA at 50:50,75:25, and 85:15 ratios and PLA in the L and DL isoforms revealed that human osteoblasts actively grew, with significantly higher cell numbers attached to scaffolds composed of PLAGA 50:50 in the short term and PLAGA 85:15 in the long term compared with PLA (p < 0.05). We believe human cell adhesion among these polymeric materials may be dependent on differences in cellular integrin expression and extracellular matrix protein elaboration.

Biocompatible Materials↗

PubMed2006

Evaluation of the anterior cruciate ligament, medial collateral ligament, achilles tendon and patellar tendon as cell sources for tissue-engineered ligament.

This study investigated four different connective tissue cell types to determine which cell type should be the source for seeding a tissue-engineered anterior cruciate ligament (ACL) replacement. Cells derived from the ACL, medial collateral ligament (MCL), achilles tendon (AT), and patellar tendon (PT) of New Zealand White rabbits were isolated and cultured. Each cell type was cultured in vitro after seeding on three-dimensional (3-D) braided polymer scaffolds and on tissue culture polystyrene that served as a control. Samples were evaluated and compared for their morphology, proliferation, and gene expression of fibronectin, type I and type III collagen. Scanning electron microscopy (SEM) photomicrographs verified cell attachment of all four types of connective tissue fibroblasts to the scaffolds. Preliminary results comparing proliferation indicate that cells obtained from the PT and AT have the fastest proliferation. Whereas gene expression of the phenotypic markers measured using real-time reverse transcription polymerase chain reaction (RT-PCR) indicates ACL cells have the highest gene expression for the matrix markers. This leads to the question of which cell type should be the cell source for tissue-engineering of ligament, the highly proliferating cells or the differentiated matrix producing cells. This study would suggest that ACL differentiated matrix producing cells are the most suitable cells for further study and development of a tissue-engineered ligament.

Achilles Tendon↗

PubMed2006

Synthesis, characterization, and osteocompatibility evaluation of novel alanine-based polyphosphazenes.

This study deals with the synthesis and in vitro osteocompatibility evaluation of two novel alanine-containing biodegradable ester polyphosphazenes as candidates to form self-setting composites with hydroxyapatite (HAp) precursors. The two novel biodegradable polyphosphazenes synthesized were poly[(ethyl alanato)1.0(ethyl oxybenzoate)1.0 phosphazene] (PN-EA/EOB) and poly[(ethyl alanato)1.0(propyl oxybenzoate)1.0 phosphazene] (PN-EA/POB). The polymers were characterized by multinuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), and gel permeation chromatography (GPC). Biodegradability and percentage water absorption of the polymers were evaluated by following the mass change in phosphate buffer (pH 7.4) at 37 degrees C. PN-EA/POB underwent faster degradation and showed higher water absorption compared to PN-EA/EOB. Both polymers became insoluble in common organic solvents following hydrolysis presumably due to crosslinking reactions accompanying the degradation process. Osteoblast cell adhesion and proliferation on PN-EA/EOB and PN-EA/POB was followed by scanning electron microscopy (SEM) and by using a biochemical assay. Both PN-EA/EOB and PN-EA/POB supported the adhesion and proliferation of primary rat osteoblast cells in vitro. Furthermore, the enzymatic activity of the osteoblast cells cultured on the polymers was confirmed by the alkaline phosphatase activity. Thus, these biodegradable amino-acid-based polyphosphazenes are promising new materials for forming self-setting bone cements.

Alanine↗

PubMed2006

Polymers as biomaterials for tissue engineering and controlled drug delivery.

The advent of biodegradable polymers has significantly influenced the development and rapid growth of various technologies in modern medicine. Biodegradable polymers are mainly used where the transient existence of materials is required and they find applications as sutures, scaffolds for tissue regeneration, tissue adhesives, hemostats, and transient barriers for tissue adhesion, as well as drug delivery systems. Each of these applications demands materials with unique physical, chemical, biological, and biomechanical properties to provide efficient therapy. Consequently, a wide range of degradable polymers, both natural and synthetic, have been investigated for these applications. Furthermore, recent advances in molecular and cellular biology, coupled with the development of novel biotechnological drugs, necessitate the modification of existing polymers or synthesis of novel polymers for specific applications. This review highlights various biodegradable polymeric materials currently investigated for use in two key medical applications: drug delivery and tissue engineering.

Biocompatible Materials↗

PubMed2006

Effect of side group chemistry on the properties of biodegradable L-alanine cosubstituted polyphosphazenes.

Biodegradable polyphosphazenes have been investigated for a variety of applications, such as controlled drug delivery matrixes, tissue-engineering scaffolds, membranes, and bone-type composites. In this study we have evaluated the effect of side group chemistry on the properties of biodegradable phosphazene polymers that contain ethyl alanato side groups together with ethyl glycinato, p-methylphenoxy, or p-phenylphenoxy side groups. The polymers were synthesized by a macromolecular substitution route. The molecular weights of aryloxy/amino acid ester cosubstituted polymers were much higher than the amino acid ester substituted polyphosphazenes described earlier. Polymer properties, such as glass transition temperature, hydrolytic degradation, surface wettability, tensile strength, and modulus of elasticity varied over a wide range following changes to the type of co-substituents on the polymer backbone. The glass transition temperatures varied from -10 to 35 degrees C and increased with the bulkiness of the side groups. Polymer films in phosphate buffer saline solution showed molecular weight declines ranging from 58% to >80% and mass loss ranging from 4% to 90% over a period of 7 weeks. Water contact angles for polymer films varied from 63 degrees to 107 degrees , with the highest angles for the alanine ethyl ester and p-phenylphenoxy cosubstituted polyphosphazene. The tensile strengths were in the range of 2.4-7.6 MPa and the modulus of elasticity was in the range of 31.4-455.9 MPa. Thus, in this study we have demonstrated the tunability of biodegradable polyphosphazenes to suit a range of biomedical applications.

Alanine↗

PubMed2006

The ABJS Nicolas Andry Award: Tissue engineering of bone and ligament: a 15-year perspective.

Musculoskeletal repair is a major challenge for orthopaedic surgeons. The burden of repair is compounded by supply constraints and morbidity associated with autograft and allograft tissue. We report 15 years of research regarding tissue engineering and biological substitutes for bone and ligaments. Our approach has focused on biomaterial selection, scaffold development, cell selection, cell/material interaction, and growth factor delivery. We have extensively tested poly(ester), poly(anhydride), poly(phosphazene) derivatives, and composite materials using biocompatibility, degradation, and mechanical analyses for bone and ligament tissue engineering. We have developed novel three-dimensional matrices with a pore structure and mechanical properties similar to native tissue. We also have reported on the attachment, growth, proliferation, and differentiation of cells cultured on several scaffolds. Through extensive molecular analysis, in vitro culture condition analysis, and in vivo evaluation, our findings provide new methods of bone tissue regeneration using three-dimensional tissue engineered scaffolds, bioactive bone cement composite materials, and three-dimensional tissue engineered scaffolds for ligament regeneration.

Animals↗

PubMed2005

Demineralized bone matrix gelatin as scaffold for osteochondral tissue engineering.

To develop a single-unit osteochondral tissue with demineralized bone matrix gelatin (BMG), rabbit chondrocytes were cultured on demineralized bone matrix gelatin for 6 weeks. The engineered osteochondral tissue was characterized with histology, immunolocalization, TEM, SEM, biochemical assay, and gene expression analysis. About 1.3mm viable neo-cartilage was produced on demineralized BMG. RT-PCR, immunohistochemistry, TEM, biochemical assay, and histology revealed hyaline-like cartilage with zonal layers, intense type II collagen expression, and abundant proteoglycan content formed upon BMG compared with normal cartilage. But hydroxyproline content and type I collagen gene and protein expressions were significantly lower. We consider engineering cartilage tissue with chondrocytes cultured on allogenic demineralized BMG is a good approach for osteochondral tissue engineering.

Animals↗

PubMed2005

Anterior cruciate ligament regeneration using braided biodegradable scaffolds: in vitro optimization studies.

The anterior cruciate ligament (ACL) is the most commonly injured intra-articular ligament of the knee, and limitations in existing reconstruction grafts have prompted an interest in tissue engineered solutions. Previously, we reported on a tissue-engineered ACL scaffold fabricated using a novel, three-dimensional braiding technology. A critical factor in determining cellular response to such a graft is material selection. The objective of this in vitro study was to optimize the braided scaffold, focusing on material composition and the identification of an appropriate polymer. The selection criteria are based on cellular response, construct degradation, and the associated mechanical properties. Three compositions of poly-alpha-hydroxyester fibers, namely polyglycolic acid (PGA), poly-L-lactic acid (PLLA), and polylactic-co-glycolic acid 82:18 (PLAGA) were examined. The effects of polymer composition on scaffold mechanical properties and degradation were evaluated in physiologically relevant solutions. Prior to culturing with primary rabbit ACL cells, scaffolds were pre-coated with fibronectin (Fn, PGA-Fn, PLAGA-Fn, PLLA-Fn), an important protein which is upregulated during ligament healing. Cell attachment and growth were examined as a function of time and polymer composition. While PGA scaffolds measured the highest tensile strength followed by PLLA and PLAGA, its rapid degradation in vitro resulted in matrix disruption and cell death over time. PLLA-based scaffolds maintained their structural integrity and exhibited superior mechanical properties over time. The response of ACL cells was found to be dependent on polymer composition, with the highest cell number measured on PLLA-Fn scaffolds. Surface modification of polymer scaffolds with Fn improved cell attachment efficiency and effected the long-term matrix production by ACL cells on PLLA and PLAGA scaffolds. Therefore based on the overall cellular response and its temporal mechanical and degradation properties in vitro, the PLLA braided scaffold pre-coated with Fn was found to be the most suitable substrate for ACL tissue engineering.

Absorbable Implants↗

PubMed2005

Fiber-based tissue-engineered scaffold for ligament replacement: design considerations and in vitro evaluation.

The anterior cruciate ligament (ACL) is the major intraarticular ligamentous structure of the knee, which functions as a joint stabilizer. It is the most commonly injured ligament of the knee, with over 150,000 ACL surgeries performed annually in the United States. Due to limitations associated with current grafts for ACL reconstruction, there is a significant demand for alternative graft systems. We report here the development of a biodegradable, tissue-engineered ACL graft. Several design parameters including construct architecture, porosity, degradability, and cell source were examined. This graft system is based on polymeric fibers of polylactide-co-glycolide 10:90, and it was fabricated using a novel, three-dimensional braiding technology. The resultant micro-porous scaffold exhibited optimal pore diameters (175-233 microm) for ligament tissue ingrowth, and initial mechanical properties of the construct approximate those of the native ligament.

Absorbable Implants↗