Roshan James

University of Connecticut, Storrs, Connecticut, United States

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Publications (26)63.5 Total impact

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    ABSTRACT: Electrospun nanofiber matrices have attracted a great deal of attention as matrices for skin repair and regeneration. The current manuscript reports the fabrication and characterization of a bioactive polycaprolactone (PCL) fiber matrix for its ability to deliver multiple factors. Bioactive PCL matrices were created by incorporating a model angiogenic factor and a model antibiotic drug. Chitosan coating on the fiber matrices significantly improved the ability to hold moisture and contributed to antibiotic activity. These fiber matrices have a modulus of 5.8 ± 1.3 MPa and matrices subjected to degradation over 4 weeks did not lose their tensile properties due to slow degradation rate. Chitosan coating avoided the initial burst release commonly associated with fiber matrices and only 60% of the encapsulated drug was released over a period of 15 days. Control PCL-chitosan matrices were able to reduce Staphylococcus aureus (S. aureus) growth both in static and dynamic condition as compared to formulations with 50 mg gentamicin. In general, all the fiber matrices were able to support fibroblast growth and maintained normal cell morphology. Such bioactive bandages may serve as versatile and less expensive alternatives for the treatment of complex wounds. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41879.
    Journal of Applied Polymer Science 04/2015; 132(16). DOI:10.1002/app.41879 · 1.64 Impact Factor
  • Roshan James, Cato T. Laurencin
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    ABSTRACT: Amputations of the upper extremity are severely debilitating, current treatments support very basic limb movement, and patients undergo extensive physiotherapy and psychological counseling. There is no prosthesis that allows the amputees near normal function. With increasing number of amputees due to injuries sustained in accidents, natural calamities, and international conflicts, there is a growing requirement for novel strategies and new discoveries. Advances have been made in technological, material, and in prosthesis integration where researchers are now exploring artificial prosthesis that integrate with the residual tissues and function based on signal impulses received from the residual nerves. Efforts are focused on challenging experts in different disciplines to integrate ideas and technologies to allow for the regeneration of injured tissues, recording on tissue signals and feedback to facilitate responsive movements and gradations of muscle force. A fully functional replacement and regenerative or integrated prosthesis will rely on interface of biological process with robotic systems to allow individual control of movement such as at the elbow, forearm, digits, and thumb in the upper extremity. Regenerative engineering focused on the regeneration of complex tissue and organ systems will be realized by the cross-fertilization of advances over the past 30 years in the fields of tissue engineering, nanotechnology, stem cell science, and developmental biology. The convergence of toolboxes crated within each discipline will allow interdisciplinary teams from engineering, science, and medicine to realize new strategies, mergers of disparate technologies, such as biophysics, smart bionics, and the healing power of the mind. Tackling the clinical challenges, interfacing the biological process with bionic technologies, engineering biological control of the electronic systems, and feedback will be the important goals in regenerative engineering over the next two decades.
    Rare Metals 02/2015; 34(3). DOI:10.1007/s12598-015-0446-0 · 0.81 Impact Factor
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    ABSTRACT: Conductive polymers have found extensive application in fuel cells, sensors and more recently as scaffolds for tissue and organ regeneration. Scaffolds that can transmit electrical impulses have been shown to be beneficial in regeneration of tissues like muscle and nerve that are electroactive in nature. Most cellular events and cell functions are regulated by ion movement, and their imbalance is the cause of several diseases. We report synthesis and characterization of sulfonated polymers of poly(methyl vinyl ether-alt-maleic anhydride) (PMVEMA), poly(ether ether ketone) (PEEK), poly(ether sulfone) (PES) and poly(phenylene oxide) (PPO) and evaluate their potential for tissue regeneration. The ionic conductive property stems from the presence of sulfonic groups on the polymer backbone. The structure of the polymer was confirmed using Fourier Transform Infrared Spectroscopy and membrane hydrophicity was determined by water contact angle measurement. The electrical conductivity of these sulfonated membranes was found to be 53.55, 35.39 and 29.51 mS/cm for SPPO, SPEEK and SPMVEMA, respectively. The conductivity was directly proportional to the sulfonic acid content on the polymer backbone. The ionic membranes namely SPPO, SPEEK and SPMVEMA demonstrated superior cell adhesion properties (~7–10 fold higher) than cells seeded onto tissue culture polystyrene. The sulfonated membranes exhibited static water contact angle in the range of 70–76°. The membranes supported the proliferation of human skin fibroblasts over 14 days in culture as evidenced by confocal and electron microscopy imaging. The ionic materials reported in this study may serve as scaffolds for a variety of tissue healing and drug delivery applications. Copyright © 2014 John Wiley & Sons, Ltd.
    Polymers for Advanced Technologies 12/2014; 25(12). DOI:10.1002/pat.3385 · 1.96 Impact Factor
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    ABSTRACT: Polymers derived from plant (polysaccharides) and animal (proteins) kingdoms have been widely used for a variety of biomedical applications including drug delivery and tissue regeneration. These polymers due to their biochemical similarity with human extracellular matrix components are readily recognized and accepted by the body. Natural polymers inherit numerous advantages including natural abundance, relative ease of isolation, and room for chemical modification to meet varying technological needs. In addition, these polymers undergo enzymatic and/or hydrolytic degradation in biologic environments into non-toxic degradation byproducts. Polysaccharides (carbohydrates) are often isolated and purified from renewable sources including plants, animals, and microorganisms. Majority of these polymers are found in the extracellular matrix components of organisms and participate in inter and intracellular cell signaling and contribute to their growth. All these features offer polysaccharide-based biomaterials much desired biological recognition, biocompatibility, and bioactivity. In spite of many merits as biomaterials, these polysaccharides suffer from drawbacks including variations in material properties based on source, microbial contamination, uncontrolled water uptake, poor mechanical strength, and unpredictable degradation patterns. These inconsistencies have limited the usage of polysaccharides and biomedical application related technology development. Many of these polysaccharides have been chemically modified to achieve consistent physicochemical properties including mechanical stability, degradation, and bioactivity and processed into microparticles, hydrogels, and 3D porous structures for tissue regeneration applications. Presence of multiple functionalities on the polymer backbone allows easy structure modifications for the required application. The current article focuses on the application of polysaccharide-based materials in regenerative engineering and delivery. Copyright © 2014 John Wiley & Sons, Ltd.
    Polymers for Advanced Technologies 05/2014; 25(5). DOI:10.1002/pat.3266 · 1.96 Impact Factor
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    ABSTRACT: The electrospinning of chitosan remains challenging due to its rigid crystalline structure, insufficient viscosity and limited solubility in common organic solvents. This work presents a “smart” chitosan modification that allows electrospinning irrespective of molecular weight or deacetylation value and without blending with synthetic polymers. A novel derivative, namely 2-nitrobenzyl-chitosan (NB), at various molar compositions of chitosan:2-nitrobenzaldehyde (1:1 (NB-1), 1:0.5 (NB-2), 1:0.25 (NB-3)) was synthesized by the reaction between amino groups of chitosan and aldehyde groups of 2- nitrobenzaldehyde.
    Polymers for Advanced Technologies 05/2014; 25(5). DOI:10.1002/pat.3292 · 1.96 Impact Factor
  • Roshan James, Cato T. Laurencin
    MRS Online Proceeding Library 01/2014; 1687. DOI:10.1557/opl.2014.804
  • Roshan James, Cato T. Laurencin
    01/2014; 2014:1-12. DOI:10.1155/2014/123070
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    ABSTRACT: Current strategies to treat tissue or organ failure rely heavily on autografts and allografts. There has been some success; however, both approaches have limitations, including donor organ shortage, risk of disease transmission, and immune rejection. The future of regenerative medicine is the combination of advanced biomaterials, structures, and cues to guide stem cells to differentiate into the desired tissues. Strategies that recapitulate the complexity of the local tissue microenvironment and the stem cell niche play a crucial role in regulating cell self-renewal and differentiation. Biomaterials and scaffolds based on biomimicry of the native tissue will enable a convergence of concepts derived from advanced materials science, stem cell science, and developmental biology. Academic institutions take up the burden of implementing innovative initiatives through research grants provided by federal agencies and private foundations. Transitioning laboratory research into commercial reality requires a realization of the business opportunity, market share, prototyping, and market valued data sets. Funding initiatives by the National Science Foundation have helped to accelerate technology transfer in partnership with industries. Opportunities to partner with medical device companies and contract service providers must be leveraged to collectively prepare a business roadmap leading to a successful startup.
    01/2014; 16. DOI:10.3727/194982414X14138187301579
  • Cato T. Laurencin, Roshan James
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    ABSTRACT: Regenerative engineering was conceptualized by bridging the lessons learned in developmental biology and stem cell science with biomaterial constructs and engineering principles to ultimately generate de novo tissue. We seek to incorporate our understanding of natural tissue development to design tissue-inducing biomaterials, structures and composites than can stimulate the regeneration of complex tissues, organs, and organ systems through location-specific topographies and physico-chemical cues incorporated into a continuous phase. This combination of classical top-down tissue engineering approach with bottom-up strategies used in regenerative biology represents a new multidisciplinary paradigm. Advanced surface topographies and material scales are used to control cell fate and the consequent regenerative capacity.Musculoskeletal tissues are critical to the normal functioning of an individual and following damage or degeneration they show extremely limited endogenous regenerative capacity. The increasing demand for biologically compatible donor tissue and organ transplants far outstrips the availability leading to an acute shortage. We have developed several biomimetic structures using various biomaterial platforms to combine optimal mechanical properties, porosity, bioactivity, and functionality to effect repair and regeneration of hard tissues such as bone, and soft tissues such as ligament and tendon. Starting with simple structures, we have developed composite and multi-scale systems that very closely mimic the native tissue architecture and material composition. Ultimately, we aim to modulate the regenerative potential, including proliferation, phenotype maturation, matrix production, and apoptosis through cell-scaffold and host –scaffold interactions developing complex tissues and organ systems.
    MRS Online Proceeding Library 01/2014; 1621. DOI:10.1557/opl.2014.4
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    ABSTRACT: ABSTRACTA novel polymer poly(caprolactone triol succinate) (PPCLSu) was synthesized from monomers polycaprolactone triol and succinic acid by direct polycondensation. The tensile strength of PPCLSu was found to be 0.33 ± 0.03 MPa with an elongation of 47.8 ± 1.9%. These elastomers lost about 7% of their original mass in an in vitro degradation study conducted in phosphate‐buffered saline (PBS) at 37°C up to 10 weeks. Three‐dimensional (3D) porous scaffolds were created by a porogen‐leaching method and these constructs were evaluated for primary rat osteoblast (PRO) proliferation and phenotype development in vitro. This elastomer promoted primary rat osteoblast adhesion, proliferation and increased expression of alkaline phosphatase, an early marker of osteoblastic phenotype. These preliminary results suggest that PPCLSu may be a good candidate material for scaffolding applications in tissue regeneration. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3770–3777, 2013
    Journal of Applied Polymer Science 12/2013; 130(5). DOI:10.1002/app.39633 · 1.64 Impact Factor
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    ABSTRACT: Electrospun nanofiber matrices have been produced using natural and synthetic polymers for a variety of biomedical applications. However, electrospinning of water-soluble polymers still remains as a major challenge. Polysaccharides are difficult to spin and often mixed with other synthetic polymers to produce electrospun nanofiber matrices. Chitosan, the deacetylated form of chitin, is reported to be a biocompatible, biodegradable, antimicrobial and non-toxic polysaccharide and thus used for a variety of biomedical applications including tissue engineering, drug delivery device and wound healing. Chitosan electrospinning remains challenging due to limited solubility and a rigid crystalline structure which does not allow sufficient polymer concentrations required for successful fiber formation by electrospinning. Here we present a novel and “smart” chitosan modification methodology that allows direct electrospinning of high molecular weight chitosan at very high concentrations. In brief, to facilitate chitosan electrospinning a new 2-nitrobenzyl-chitosan derivative was synthesized and electrospun nanofibers were produced by dissolving the derivative in trifluoroacetic acid (TFA) solvent. In this derivative, 2-nitrobenzyl aldehyde is used as a photolytic removal group to block the amino groups of chitosan and subsequently reduce its structural rigidity. Subsequently, the electrospun nanofiber matrices produced by 2-nitrobenzyl-chitosan was exposed to UV light to produce pure chitosan nanofiber matrix. Electrospinning parameters were optimized to produce defect-free cylindrical nanofibers at 15% (wt/v) chitosan solution concentration and 1 kV/cm electrical potential. In this work we report on electrospinning of three different 2-Nitrobenzyl-chitosan compositions namely 1:1, 1:0.5, and 1:0.25 and evaluating chitosan matrices for scaffold properties and cell compatibility. The mechanism of photolysis to obtain neat chitosan from 2-Nitrobenzyl-chitosan followed by UV exposure was confirmed by FTIR analysis. The morphology of the electrospun fibers, pore structure, and fiber diameter was examined using scanning electron microscopy. Biocompatibility was evaluated by measuring cell proliferation and metabolic activity of MC3T3 cells seeded onto the nanofiber scaffolds.The samples were screened for antimicrobial activity by disc diffusion method using B. subtilis as gram positive, E. coli as gram negative, C. albicans as yeast and A. niger as fungi. The results showed that the samples have a strong inhibitory activity against all pathogenic microorganisms used.
    MRS Fall meeting & Exhibit, Boston, USA; 12/2013
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    ABSTRACT: Repair and regeneration of human tissues and organs using biomaterials, cells and/or growth factors is the ultimate goal of tissue engineers. One of the grand challenges in this field is to closely mimic the structures and properties of native tissues. Regenerative engineering-the convergence of tissue engineering with advanced materials science, stem cell science, and developmental biology-represents the next valuable tool to overcome the challenges. This article reviews the recent progress in developing advanced chitosan structures using various fabrication techniques. These chitosan structures, together with stem cells and functional biomolecules, may provide a robust platform to gain insight into cell-biomaterial interactions and may function as excellent artificial extracellular matrices to regenerate complex human tissues and biological systems.
    Acta biomaterialia 07/2013; DOI:10.1016/j.actbio.2013.07.003 · 5.68 Impact Factor
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    ABSTRACT: Scaffold based bone tissue engineering (BTE) has made great progress in regenerating lost bone tissue. Materials of natural and synthetic origin have been used for scaffold fabrication. Scaffolds derived from natural polymers offer greater bioactivity and biocompatibility with mammalian tissues to favor tissue healing, due to their similarity to native extracellular matrix (ECM) components. Often it is a challenge to fabricate natural polymer based scaffolds for BTE applications without compromising their bioactivity, while maintaining adequate mechanical properties. In this work, we report the fabrication and characterization of cellulose and collagen based micro-nano structured scaffolds using human osteoblasts (HOB) for BTE applications. These porous micro-nano structured scaffolds (average pore diameter 190 +/- 10 microm) exhibited mechanical properties in the mid range of human trabecular bone (compressive modulus 266.75 +/- 33.22 MPa and strength 12.15 3 +/- 2.23 MPa). These scaffolds supported the greater adhesion and phenotype maintenance of cultured HOB as reflected by higher levels of osteogenic enzyme alkaline phosphatase and mineral deposition compared to control polyester micro-nano structured scaffolds of identical pore properties. These natural polymer based micro-nano structured scaffolds may serve as alternatives to polyester based scaffolds for BTE applications.
    Journal of Biomedical Nanotechnology 04/2013; 9(4):719-31. DOI:10.1166/jbn.2013.1574 · 7.58 Impact Factor
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    ABSTRACT: Tissue engineering aims to repair, restore, and regenerate lost or damaged tissues by using biomaterials, cells, mechanical forces and factors (chemical and biological) alone or in combination. Growth factors are routinely used in the tissue engineering approach to expedite the process of regeneration. The growth factor approach has been hampered by several complications including high dose requirements, lower half-life, protein instability, higher costs and undesired side effects. Recently a variety of alternative small molecules of both natural and synthetic origin have been explored as alternatives to growth factors for tissue regeneration applications. Small molecules are simple biochemical components that elicit certain cellular responses through signaling cascades. Small molecules present a viable alternative to biological factors. Small molecule strategies can reduce various side effects, maintain bioactivity in a biological environment and minimize cost issues associated with complex biological growth factors. This manuscript focuses on three-osteoinductive small molecules, namely melatonin, resveratrol (from natural sources) and purmorphamine (synthetically designed) as inducers of bone formation and osteogenic differentiation of stem cells. Efforts have been made to summarize possible biological pathways involved in the action of each of these drugs. Melatonin is known to affect Mitogen Activated Protein (MAP) kinase, Bone morphogenic protein (BMP) and canonical wnt signaling. Resveratrol is known to activate cascades involving Int mammalian homologue of drosophila wingless protein (Wnt) and NAD-dependent deacetylase sirtuin-1 (Sirt1). Purmorphamine is a Hedgehog (Hh) pathway agonist as it acts on Smoothened (Smo) receptors. These mechanisms and the way they are affected by the respective small molecules will also be discussed in the manuscript.
    Current pharmaceutical design 02/2013; DOI:10.2174/1381612811319190008 · 3.29 Impact Factor
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    ABSTRACT: Poly[(ethyl alanato)(1)(p-methyl phenoxy)(1)] phosphazene (PNEA-mPh) was used to modify the surface of electrospun poly(ε-caprolactone) (PCL) nanofiber matrices having an average fiber diameter of 3000 ± 1700 nm for the purpose of tendon tissue engineering and augmentation. This study reports the effect of polyphosphazene surface functionalization on human mesenchymal stem cell (hMSC) adhesion, cell-construct infiltration, proliferation and tendon differentiation, as well as long term cellular construct mechanical properties. PCL fiber matrices functionalized with PNEA-mPh acquired a rougher surface morphology and led to enhanced cell adhesion as well as superior cell-construct infiltration when compared to smooth PCL fiber matrices. Long-term in vitro hMSC cultures on both fiber matrices were able to produce clinically relevant moduli. Both fibrous constructs expressed scleraxis, an early tendon differentiation marker, and a bimodal peak in expression of the late tendon differentiation marker tenomodulin, a pattern that was not observed in PCL thin film controls. Functionalized matrices achieved a more prominent tenogenic differentiation, possessing greater tenomodulin expression and superior phenotypic maturity according to the ratio of collagen I to collagen III expression. These findings indicate that PNEA-mPh functionalization is an efficient method for improving cell interactions with electrospun PCL matrices for the purpose of tendon repair.
    Biomedical Materials 06/2012; 7(4):045016. DOI:10.1088/1748-6041/7/4/045016 · 2.92 Impact Factor
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    ABSTRACT: Electrospun polycaprolactone nanofiber matrices surface functionalized with poly[(ethyl alanato), (p-methyl phenoxy),] phosphazene were fabricated for the purpose of soft skeletal tissue regeneration. This preliminary study reports the effect of fiber diameter and polyphosphazene surface functionalization on significant scaffold properties such as morphology, surface hydrophilicity, porosity, tensile properties, human mesenchymal stem cell adhesion and proliferation. Six fiber matrices comprised of average fiber diameters in the range of 400-500, 900-1000, 1400-1500, 1900-2000, 2900-3000 and 3900-4000 nm were considered for primary evaluation. After achieving the greatest proliferation while maintaining moderate tensile modulus, matrices in the diameter range of 2900-3000 nm were selected to examine the effect of coating with 1%, 2% and 3% (weight/volume) polyphosphazene solutions. Polyphosphazene functionalization resulted in rougher surfaces that correlated with coating solution concentration. Analytical techniques such as energy dispersive X-ray analysis, Fourier transform infrared spectroscopy, elemental analysis, differential scanning calorimetry, water contact angle goniometry and confocal microscopy confirmed the presence of polyphosphazene and its distribution on the functionalized fiber matrices. Functionalization achieved through 2% polymer solutions did not affect average pore diameter, tensile modulus, suture retention strength or cell proliferation compared to PCL controls. Surface polyphosphazene functionalization significantly improved the matrix hydrophilicity evidenced through decreased water contact angle of PCL matrices from 130 degrees to 97 degrees. Further, enhanced total protein synthesis by cells during in vitro culture was seen on 2% PPHOS functionalized matrices over controls. Improving PCL matrix hydrophilicity via proposed surface functionalization may be an efficient method to improve cell-PCL matrix interactions.
    Journal of Biomedical Nanotechnology 02/2012; 8(1):107-24. DOI:10.1166/jbn.2012.1368 · 7.58 Impact Factor
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    ABSTRACT: Successful regeneration necessitates the development of three-dimensional (3-D) tissue-inducing scaffolds that mimic the hierarchical architecture of native tissue extracellular matrix (ECM). Cells in nature recognize and interact with the surface topography they are exposed to via ECM proteins. The interaction of cells with nanotopographical features such as pores, ridges, groves, fibers, nodes, and their combinations has proven to be an important signaling modality in controlling cellular processes. Integrating nanotopographical cues is especially important in engineering complex tissues that have multiple cell types and require precisely defined cell-cell and cell-matrix interactions on the nanoscale. Thus, in a regenerative engineering approach, nanoscale materials/scaffolds play a paramount role in controlling cell fate and the consequent regenerative capacity. Advances in nanotechnology have generated a new toolbox for the fabrication of tissue-specific nanostructured scaffolds. For example, biodegradable polymers such as polyesters, polyphosphazenes, polymer blends and composites can be electrospun into ECM-mimicking matrices composed of nanofibers, which provide high surface area for cell attachment, growth, and differentiation. This review provides the fundamental guidelines for the design and development of nanostructured scaffolds for the regeneration of various tissue types in human upper and lower extremities such as skin, ligament, tendon, and bone. Examples focusing on the collective work of our laboratory in those areas are discussed to demonstrate the regenerative efficacy of this approach. Furthermore, preliminary strategies and significant challenges to integrate these individual tissues into one complex organ through regenerative engineering-based integrated graft systems are also discussed.
    IEEE transactions on nanobioscience 01/2012; 11(1):3-14. DOI:10.1109/TNB.2011.2179554 · 1.77 Impact Factor
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    ABSTRACT: This manuscript focuses on bone repair/regeneration using tissue engineering strategies, and highlights nanobiotechnology developments leading to novel nanocomposite systems. About 6.5 million fractures occur annually in USA, and about 550,000 of these individual cases required the application of a bone graft. Autogenous and allogenous bone have been most widely used for bone graft based therapies; however, there are significant problems such as donor shortage and risk of infection. Alternatives using synthetic and natural biomaterials have been developed, and some are commercially available for clinical applications requiring bone grafts. However, it remains a great challenge to design an ideal synthetic graft that very closely mimics the bone tissue structurally, and can modulate the desired function in osteoblast and progenitor cell populations. Nanobiomaterials, specifically nanocomposites composed of hydroxyapatite (HA) and/or collagen are extremely promising graft substitutes. The biocomposites can be fabricated to mimic the material composition of native bone tissue, and additionally, when using nano-HA (reduced grain size), one mimics the structural arrangement of native bone. A good understanding of bone biology and structure is critical to development of bone mimicking graft substitutes. HA and collagen exhibit excellent osteoconductive properties which can further modulate the regenerative/healing process following fracture injury. Combining with other polymeric biomaterials will reinforce the mechanical properties thus making the novel nano-HA based composites comparable to human bone. We report on recent studies using nanocomposites that have been fabricated as particles and nanofibers for regeneration of segmental bone defects. The research in nanocomposites, highlight a pivotal role in the future development of an ideal orthopaedic implant device, however further significant advancements are necessary to achieve clinical use.
    12/2011; 5(4). DOI:10.1007/s11706-011-0151-3
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    ABSTRACT: This study was designed to examine the cellular and molecular response of tendon fibroblasts to growth/differentiation factor-5 (GDF-5). Rat Achilles tendon fibroblasts (ATFs) were treated in culture with varying concentrations of GDF-5 (0-1000 ng/ml) over varying periods of time (0-12 days). Cell proliferation, evaluated through use of a standard MTT colorimetric assay, confirmed that GDF-5 stimulates ATF proliferation in a concentration- and time-dependent fashion. Temporal and concentration analysis revealed that GDF-5 increases total DNA, glycosaminoglycan (GAG), and hydroxyproline (HYP) content. Ratios of HYP/DNA and GAG/DNA increased with increasing concentrations of GDF-5 (0-1000 ng/ml). Expression of the following 12 extracellular matrix (ECM) and cell-adhesion-related genes was assessed using real-time reverse transcriptase polymerase chain reaction (RT-PCR): collagen I (col I), collagen III (col III), matrix metalloproteinases (MMP)-3 and -13, aggrecan, tissue inhibitor of matrix metalloproteinase (TIMP)-2, syndecan-4, N-cadherin, tenascin-C, biglycan, versican, and decorin. RT-PCR data revealed an increase in the expression of col I, col III, MMP-3, MMP-13, TIMP-2, syndecan-4, N-cadherin, tenascin-C, and aggrecan genes by day 6. A statistically significant decrease in TIMP-2 and MMP-13 was observed on day 12. Decorin expression was depressed at all time points in cells treated with GDF-5. There was no significant change in biglycan expression in ATFs supplemented with GDF-5. These findings suggest that GDF-5 induces cellular proliferation and ECM synthesis as well as expression of ECM and cell-adhesion-related genes in ATFs. This study further defines the influence of GDF-5 on rat ATFs through its action on the expression of genes that are associated with tendon ECM.
    Connective tissue research 08/2011; 52(4):353-64. DOI:10.3109/03008207.2010.534208 · 1.98 Impact Factor
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    ABSTRACT: Tendon injuries range from acute traumatic ruptures and lacerations to chronic overuse injuries, such as tendinosis. Even with improved nonsurgical, surgical, and rehabilitation techniques, outcomes following tendon repair are inconsistent. Primary repair remains the standard of care. However, repaired tendon tissue rarely achieves functionality equal to that of the preinjured state. Poor results have been linked to alterations in cellular organization within the tendon that occur at the time of injury and throughout the early stages of healing. Enhanced understanding of the biology of tendon healing is needed to improve management and outcomes. The use of growth factors and mesenchymal stem cells and the development of biocompatible scaffolds could result in enhanced tendon healing and regeneration. Recent advances in tendon bioengineering may lead to improved management following tendon injury.
    The Journal of the American Academy of Orthopaedic Surgeons 03/2011; 19(3):134-42. · 2.40 Impact Factor

Publication Stats

496 Citations
63.50 Total Impact Points

Institutions

  • 2012–2015
    • University of Connecticut
      • Department of Orthopaedic Surgery
      Storrs, Connecticut, United States
  • 2013
    • UConn Health Center
      • Department of Orthopaedic Surgery
      Farmington, Connecticut, United States
  • 2008–2012
    • University of Virginia
      • • Department of Orthopaedic Surgery
      • • Department of Biomedical Engineering
      Charlottesville, Virginia, United States