The development of a ε-polycaprolactone (PCL) scaffold for CNS repair

Potential treatment strategies for the repair of spinal cord injury (SCI) currently favour a combinatorial approach incorporating several factors, including exogenous cell transplantation and biocompatible scaffolds. The use of scaffolds for bridging the gap at the injury site is very appealing although there has been little investigation into CNS neural cell interaction and survival on such scaffolds before implantation. Previously we demonstrated that aligned micro-grooves 12.5-25 µm wide on ε-polycaprolactone (PCL) promoted aligned neurite orientation and supported myelination. In this study we identify the appropriate substrate and its topographical features required for the design of a 3D scaffold intended for transplantation in SCI. Using an established myelinating culture system of dissociated spinal cord cells, recapitulating many of the features of the intact spinal cord, we demonstrate that astrocytes plated on the topography secrete soluble factors(s) that delay oligodendrocyte differentiation but do not prevent myelination. However, as myelination does occur after a further 10-12 days in culture this does not prevent the use of PCL as a scaffold material as part of a combined strategy for the repair of SCI

Optimizing interfacial features to regulate neural progenitor cells using polyelectrolyte multilayers and brain derived neurotrophic factor

The development of biomaterials with controllable interfacial features which have the capability to instruct cellular behavior are required to produce functional scaffolds for the treatment of spinal cord injury (SCI). Here, poly-ɛ-caprolactone surfaces were biofunctionalized via layer-by-layer (LbL) deposition. The polyelectrolytes employed in this LbL technique were heparin and poly-L-lysine (PLL), the latter being chosen to improve cell adhesion and the subsequent cellular function of in vitrocultured neural progenitor cells. Material characterization results confirmed the deposition of well structured multilayers. Cell culture studies revealed significant differences in the cellular response to these adhesive/nonadhesive (PLL/heparin) polyelectrolyte multilayer (PEM)surfaces, with neurite outgrowth being significantly promoted on the PLL terminating layers. In addition, brain derived neurotrophic factor (BDNF) was adsorbed onto the LbL surfaces. This combined chemical and biological effect was then characterized in terms of neurite length along with the full length/truncated isoform 1 tyrosine kinase receptor (TrkB-FL/TrkB-T1) and growth associated protein-43 mRNA levels. Here, the authors report the differential effect of adsorbed and soluble BDNF of different concentrations. Adsorbed BDNF promoted neurite outgrowth and led to elevated, sustained TrkB mRNA levels. These findings highlight the potential of PEM biofunctionalized surfaces with integrated chemical and neurotrophin supportive cues to overcome SCI inhibitory environments and to promote regeneration

A comparison of polarized and non-polarized human endometrial monolayer culture systems on murine embryo development

BACKGROUND: Co-culture of embryos with various somatic cells has been suggested as a promising approach to improve embryo development. Despite numerous reports regarding the beneficial effects of epithelial cells from the female genital tract on embryo development in a co-culture system, little is known about the effect of these cells when being cultured under a polarized condition on embryo growth. Our study evaluated the effects of in vitro polarized cells on pre-embryo development. METHODS: Human endometrial tissue was obtained from uterine specimens excised at total hysterectomy performed for benign indications. Epithelial cells were promptly isolated and cultured either on extra-cellular matrix gel (ECM-Gel) coated millipore filter inserts (polarized) or plastic surfaces (non-polarized). The epithelial nature of the cells cultured on plastic was confirmed through immunohistochemistry, and polarization of cells cultured on ECM-Gel was evaluated by transmission electron microscopy (TEM). One or two-cell stage embryos of a superovulated NMRI mouse were then flushed and placed in culture with either polarized or non-polarized cells and medium alone. Development rates were determined for all embryos daily and statistically compared. At the end of the cultivation period, trophectoderm (TE) and inner cell mass (ICM) of expanded blastocysts from each group were examined microscopically. RESULTS: Endometrial epithelial cells cultured on ECM-Gel had a highly polarized columnar shape as opposed to the flattened shape of the cells cultured on a plastic surface. The two-cell embryos cultured on a polarized monolayer had a higher developmental rate than those from the non-polarized cells. There was no statistically significant difference; still, the blastocysts from the polarized monolayer, in comparison with the non-polarized group, had a significantly higher mean cell number. The development of one-cell embryos in the polarized and non-polarized groups showed no statistically significant difference. CONCLUSION: Polarized cells could improve in vitro embryo development from the two-cell stage more in terms of quality (increasing blastocyst cellularity) than in terms of developmental rate

Promising System for Selecting Healthy In Vitro–Fertilized Embryos in Cattle

Conventionally, in vitro–fertilized (IVF) bovine embryos are morphologically evaluated at the time of embryo transfer to select those that are likely to establish a pregnancy. This method is, however, subjective and results in unreliable selection. Here we describe a novel selection system for IVF bovine blastocysts for transfer that traces the development of individual embryos with time-lapse cinematography in our developed microwell culture dish and analyzes embryonic metabolism. The system can noninvasively identify prognostic factors that reflect not only blastocyst qualities detected with histological, cytogenetic, and molecular analysis but also viability after transfer. By assessing a combination of identified prognostic factors—(i) timing of the first cleavage; (ii) number of blastomeres at the end of the first cleavage; (iii) presence or absence of multiple fragments at the end of the first cleavage; (iv) number of blastomeres at the onset of lag-phase, which results in temporary developmental arrest during the fourth or fifth cell cycle; and (v) oxygen consumption at the blastocyst stage—pregnancy success could be accurately predicted (78.9%). The conventional method or individual prognostic factors could not accurately predict pregnancy. No newborn calves showed neonatal overgrowth or death. Our results demonstrate that these five predictors and our system could provide objective and reliable selection of healthy IVF bovine embryos

Biomaterials: a basic introduction

Part IBiomaterials ScienceBiomaterials Science and EngineeringLearning ObjectivesMaterials Science and EngineeringMultilevels of Structure and Categorization of MaterialsFour Categories of MaterialsDefinitions of Biomaterials, Biomedical Materials, and Biological MaterialsBiocompatibilityChapter HighlightsActivitiesSimple Questions in ClassProblems and ExercisesBibliographyToxicity and CorrosionLearning ObjectivesElements in the BodyBiological Roles and Toxicities of Trace ElementsSelection of Metallic Elements in Medical-Grade AlloysCorrosion of MetalsEnvironment inside the BodyMinimization of Toxicity of Metal ImplantsChapter HighlightsLaboratory Practice 1Simple Questions in ClassProblems and ExercisesAdvanced Topic: Biological Roles of Alloying ElementsBibliographyMechanical Properties of BiomaterialsLearning ObjectivesRole of Implant BiomaterialsMechanical Properties of General ImportanceHardnessElasticity: Resilience and StrechabilityMechanical Properties Terms Used in the Medical CommunityFailureEssential Mechanical Properties of Orthopedic Implant BiomaterialsChapter HighlightsActivitiesSimple Questions in ClassProblems and ExercisesBibliographyMetallic Biomaterials in Orthopedic ImplantsLearning ObjectivesDevelopment of Metallic BiomaterialsStainless SteelsCobalt-Based AlloysTitanium AlloysComparison of Stainless Steels, Cobalt, and Titanium AlloysSummary and RemarksChapter HighlightsActivitiesSimple Questions in ClassProblems and ExercisesBibliographyMetallic Biomaterials: Miscellaneous OthersLearning ObjectivesDental MaterialsNiTi Shape-Memory AlloysOther Clinically Applied Metallic MaterialsNew Metallic Materials: Magnesium AlloysChapter HighlightsLaboratory Practice 2Simple Questions in ClassProblems and ExercisesBibliographyBioinert CeramicsLearning ObjectivesOverview of BioceramicsInert Bioceramics: Al2O3Inert Bioceramics: ZrO2Two Types of JointsSummary and Remarks on Al2O3 and ZrO2Dental CeramicsChapter HighlightsActivitiesSimple Questions in ClassProblems and ExercisesAdvanced Topic: Total Joint ReplacementBibliographyBioactive and Bioresorbable CeramicsLearning ObjectivesOverview of Surface Bioactive and Bulk Degradable CeramicsCalcium Phosphates and HydroxyapatiteBioactive GlassesBioactive Glass-CeramicsBone-Bonding MechanismsBiodegradable CeramicsChapter HighlightsLaboratory Practice 3Simple Questions in ClassProblems and ExercisesAdvanced Topic: Bioceramic Scaffolds for Bone Tissue EngineeringBibliographyPolymeric Biomaterials: FundamentalsLearning ObjectivesBasic Concepts on PolymersOverview of Polymeric BiomaterialsChapter HighlightsActivitiesSimple Questions in ClassProblems and ExercisesAdvanced Topic: Polymers and Polymer Scaffolds for Soft Tissue EngineeringBibliographyBioinert PolymersLearning ObjectivesPolyolefinPoly(Ethylene Terephthalate)Acrylate PolymerFluorocarbon PolymersSiliconePolyurethaneChapter HighlightsActivitiesSimple Questions in ClassProblems and ExercisesAdvanced Topic: Properties and Applications of Polyurethane as BiomaterialsBibliographyBioresorbable PolymersLearning ObjectivesBiodegradation of PolymersPolyesters: PGA, PLA, and PCLPolyesters: PHAElastomeric Polyester: Poly(Polyol Sebacate)Polyether: Poly(Ethylene Glycol)PolyamideSurface-Erodible PolymersBiological PolymersChapter HighlightsSimple Questions in ClassProblems and ExercisesLaboratory Practice 4Advanced Topic: Natural Polymers: Resilin, Silk, and GlutenBibliographyComposite BiomaterialsLearning ObjectivesOverview of CompositesNatural Composites: BoneDental CompositesArtificial BoneChapter HighlightsLaboratory Practice 5Simple Questions in ClassProblems and ExercisesAdvanced Topic: Development of Artificial Bone: Composites and ScaffoldsBibliographyPart IIMedical ScienceMedicine and Medical ScienceLearning ObjectivesMedicine and Medical ScienceMedical Science versus Materials ScienceLearning Goals of Part IIChapter HighlightsActivityBibliographyImage LinksSimple Questions in ClassProblems and ExercisesHuman Anatomy And Diseases I: Integumentary, Skeletal, Muscular, Nervous, and Endocrine SystemsLearning ObjectivesIntegumentary SystemSkeletal SystemMuscular SystemNervous SystemEndocrine SystemChapter HighlightsActivitiesSimple Questions in ClassProblems and ExercisesAdvanced Topic: Biomaterial Challenges in Bone Tissue EngineeringBibliographyHuman Anatomy And Diseases II: Cardiovascular SystemLearning ObjectivesAnatomy and Functions of the Cardiovascular SystemCardiovascular DiseaseCardiac Performance: P-V LoopCurrent Therapies for Heart DiseaseAlternative Treatments and Application of BiomaterialsArtificial Blood VesselsChapter HighlightsActivitiesSimple Questions in ClassProblems and ExercisesBibliographyHuman Anatomy And Diseases III: Respiratory, Lymphatic, Digestive, Urinary, and Reproductive SystemsLearning ObjectivesRespiratory SystemLymphatic SystemDigestive SystemUrinary SystemReproductive SystemChapter HighlightsActivitiesSimple Questions in ClassProblems and ExercisesBibliographyCells and BiomoleculesLearning ObjectivesIntroductionCell Biochemistry and BiosynthesisCell StructureTransport across Plasma MembranesCell ProliferationCell Differentiation and Stem CellsChapter HighlightsActivitiesAdvanced Topic: Cell Therapy to Treat Cardiac DiseaseStrategies to Address Immune Rejection in CellsSummary of Cell-Based Therapies and Their LimitationsSimple Questions in ClassProblems and ExercisesBibliographyHistology and Tissue Properties I: Epithelial, Neuronal, and Muscle TissueLearning ObjectivesIntroductionEpitheliumMuscular TissueNervous TissueChapter HighlightsActivitiesAdvanced Topic: Properties of Proteins in Mammalian TissuesSimple Questions in ClassProblems and ExercisesBibliographyHistology and Tissue Properties II: Connective TissuesLearning ObjectivesOverview of Connective TissuesTypes of Connective TissueConnective Tissue Proper (Skin, Tendon, Ligament)Mechanical Properties of Structural ProteinsCartilageBoneChapter HighlightsLaboratory Practice 6Simple Questions in ClassProblems and ExercisesBibliographyImmune System and Body Responses to BiomaterialsLearning ObjectivesImmune SystemTissue Response to InjuriesBody Response to ImplantsChapter HighlightsActivitiesSimple Questions in ClassProblems and ExercisesBibliographyEvaluation of BiomaterialsLearning ObjectivesOverview of Biomaterials EvaluationStandardsToxicological EvaluationCytotoxicity TestingEvaluation in AnimalsChapter HighlightsLaboratory Practice 7Case Study: Evaluation of Heart Patch in RatsSimple Questions in ClassProblems and ExercisesBibliographyRegulation of Medical DevicesLearning ObjectivesRegulations versus StandardsMedical DevicesPreclinical TestingClinical TrialsDevelopment of Medical Devices and Possible Career OpportunitiesChapter HighlightsActivitiesSimple Questions in ClassProblems and ExercisesBibliographyIndex