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Biomechanical engineering

Roger W Nightingale, Cameron R Bass, Barry S Myers
BACKGROUND: Cervical bilateral facet dislocations are among the most devastating spine injuries in terms of likelihood of severe neurological sequelae. More than half of patients with tetraparesis had sustained some form of bilateral facet fracture dislocation. They can occur at any level of the sub-axial cervical spine, but predominate between C5 and C7. The mechanism of these injuries has long been thought to be forceful flexion of the chin towards the chest. This "hyperflexion" hypothesis comports well with intuition and it has become dogma in the clinical literature...
March 8, 2018: Clinical Biomechanics
Jaime L Bernstein, Benjamin P Cohen, Alexandra Lin, Alice Harper, Lawrence J Bonassar, Jason A Spector
PURPOSE: The significant shortcomings associated with current autologous reconstructive options for auricular deformities have inspired great interest in a tissue engineering solution. A major obstacle in the engineering of human auricular cartilage is the availability of sufficient autologous human chondrocytes. A clinically obtainable amount of auricular cartilage tissue (ie, 1 g) only yields approximately 10 million cells, where 25 times this amount is needed for the fabrication of a full-scale pediatric ear...
March 13, 2018: Annals of Plastic Surgery
Orestis G Andriotis, Sylvia Desissaire, Philipp J Thurner
Tissue hydration is well known to influence tissue mechanics and can be tuned via osmotic pressure. Collagen fibrils are nature's nanoscale building blocks to achieve biomechanical function in a broad range of biological tissues and across many species. Intrafibrillar covalent cross-links have long been thought to play pivotal role for collagen fibril elasticity, but predominantly at large, far from physiological, strains. Performing nanotensile experiments of collagen fibrils at varying hydration levels by adjusting osmotic pressure in situ during atomic force microscopy experiments, we show the power the intrafibrillar non-covalent interactions have for defining collagen fibril tensile elasticity at low fibril strains...
March 12, 2018: ACS Nano
Anne Caroline Oenning, Alexandre Rodrigues Freire, Ana Cláudia Rossi, Felippe Bevilacqua Prado, Paulo Henrique Ferreira Caria, Lourenço Correr-Sobrinho, Francisco Haiter-Neto
OBJECTIVES: Previous studies have suggested a relationship between resorption in second molars and pressure from the eruptive force of the third molar. The aim of this study was to simulate functional forces in a mandible model by means of finite element analysis and then assess the biomechanical response produced by impacted third molars on the roots of the second molar. MATERIALS AND METHODS: A cone beam computed tomography scan presenting an impacted mandibular third molar was segmented (Mimics V17 software)...
March 10, 2018: Clinical Oral Investigations
Iris Ribitsch, Christian Peham, Nicole Ade, Julia Dürr, Stephan Handschuh, Johannes Peter Schramel, Claus Vogl, Heike Walles, Monika Egerbacher, Florien Jenner
Meniscal pathologies are among the most common injuries of the femorotibial joint in both human and equine patients. Pathological forces and ensuing injuries of the cranial horn of the equine medial meniscus are considered analogous to those observed in the human posterior medial horn. Biomechanical properties of human menisci are site- and depth- specific. However, the influence of equine meniscus topography and composition on its biomechanical properties is yet unknown. A better understanding of equine meniscus composition and biomechanics could advance not only veterinary therapies for meniscus degeneration or injuries, but also further substantiate the horse as suitable translational animal model for (human) meniscus tissue engineering...
2018: PloS One
Lu Yin, Yingnan Wu, Zheng Yang, Vinitha Denslin, Xiafei Ren, Ching Ann Tee, Zhangxing Lai, Chwee Teck Lim, Jongyoon Han, Eng Hin Lee
Current clinical approaches for articular cartilage repair have not been able to restore the tissue with zonal architecture, and its biomechanical and functional properties. Mimicking the zonal organization of articular cartilage in neo-tissue by implanting zonal chondrocyte subpopulations in multilayer construct could enhance the functionality of the graft, engineering of stratified tissue has not yet been realized due to lack of efficient and specific zonal chondrocyte isolation protocol. We show that by using a spiral microchannel device, the superficial, middle and deep zone chondrocytes can be separated based on cell size, and enriched from full thickness porcine cartilage in a high-throughput, label-free manner...
March 1, 2018: Biomaterials
Tom Bongiorno, Jeremy Gura, Priyanka Talwar, Dwight Chambers, Katherine M Young, Dalia Arafat, Gonghao Wang, Emily L Jackson-Holmes, Peng Qiu, Todd C McDevitt, Todd Sulchek
The highly proliferative and pluripotent characteristics of embryonic stem cells engender great promise for tissue engineering and regenerative medicine, but the rapid identification and isolation of target cell phenotypes remains challenging. Therefore, the objectives of this study were to characterize cell mechanics as a function of differentiation and to employ differences in cell stiffness to select population subsets with distinct mechanical, morphological, and biological properties. Biomechanical analysis with atomic force microscopy revealed that embryonic stem cells stiffened within one day of differentiation induced by leukemia inhibitory factor removal, with a lagging but pronounced change from spherical to spindle-shaped cell morphology...
2018: PloS One
Nasser K Awad, Haitao Niu, Usman Ali, Yosry S Morsi, Tong Lin
Small-diameter blood vessels (SDBVs) are still a challenging task to prepare due to the occurrence of thrombosis formation, intimal hyperplasia, and aneurysmal dilation. Electrospinning technique, as a promising tissue engineering approach, can fabricate polymer fibrous scaffolds that satisfy requirements on the construction of extracellular matrix (ECM) of native blood vessel and promote the adhesion, proliferation, and growth of cells. In this review, we summarize the polymers that are deployed for the fabrication of SDBVs and classify them into three categories, synthetic polymers, natural polymers, and hybrid polymers...
March 6, 2018: Membranes
Agnieszka A Ksiazek, Laura Frese, Petra E Dijkman, Bart Sanders, Sarah E Motta, Benedikt Weber, Simon P Hoerstrup
Data on in vitro engineered "off the shelf" matrices support the concept of endogenous cellular repopulation driving the graft's remodeling via immune-mediated response. This seems important to further accelerate the cell reconstitution and may play a crucial role when mononuclear cells are used. Nevertheless, studies on decellularized xenogeneic grafts showed only limited host cell repopulation post-implantation. This study aims at a systematic comparison of reseeding methods (dripping, injection, bathing in a cell suspension and combined puncturing-dripping method) to define the most efficient technique enhancing recellularization of tissue engineered vascular matrices (patches, vessels, small diameter and standard size valves) prior implantation...
March 2, 2018: Acta Biomaterialia
Nathan Cho, Shadi E Razipour, Megan L McCain
Cardiac fibroblasts and their activated derivatives, myofibroblasts, play a critical role in wound healing after myocardial injury and often contribute to long-term pathological outcomes, such as excessive fibrosis. Thus, defining the microenvironmental factors that regulate the phenotype of cardiac fibroblasts and myofibroblasts could lead to new therapeutic strategies. Both chemical and biomechanical cues have previously been shown to induce myofibroblast differentiation in many organs and species. For example, transforming growth factor beta 1, a cytokine secreted by neutrophils, and rigid extracellular matrix environments have both been shown to promote differentiation...
January 1, 2018: Experimental Biology and Medicine
Udi Sarig, Hadar Sarig, Aleksander Gora, Muthu Kumar Krishnamoorthi, Gigi Chi Ting Au-Yeung, Elio de-Berardinis, Su Yin Chaw, Priyadarshini Mhaisalkar, Hanumakumar Bogireddi, Seeram Ramakrishna, Freddy Yin Chiang Boey, Subbu S Venkatraman, Marcelle Machluf
Tissue development, regeneration, or de-novo tissue engineering in-vitro, are based on reciprocal cell-niche interactions. Early tissue formation mechanisms, however, remain largely unknown given complex in-vivo multifactoriality, and limited tools to effectively characterize and correlate specific micro-scaled bio-mechanical interplay. We developed a unique model system, based on decellularized porcine cardiac extracellular matrices (pcECMs)-as representative natural soft-tissue biomaterial-to study a spectrum of common cell-niche interactions...
March 2, 2018: Scientific Reports
Anton G Kutikhin, Maxim Yu Sinitsky, Arseniy E Yuzhalin, Elena A Velikanova
Among applicable high-throughput techniques in cardiovascular biology, whole-transcriptome sequencing is of particular use. By utilizing RNA that is isolated from virtually all cells and tissues, the entire transcriptome can be evaluated. In comparison with other high-throughput approaches, RNA sequencing is characterized by a relatively low-cost and large data output, which permits a comprehensive analysis of spatiotemporal variation in the gene expression profile. Both shear stress and cyclic strain exert hemodynamic force upon the arterial endothelium and are considered to be crucial determinants of endothelial physiology...
February 21, 2018: High Throughput
Li-Ming Zhao, Dong-Mu Tian, Yue Wei, Jun-Hui Zhang, Zheng-Lin Di, Zhi-Yong He, Yong-Cheng Hu
OBJECTIVE: To study the biomechanical properties of a novel modular intercalary prosthesis for humeral diaphyseal segmental defect reconstruction, to establish valid finite element humerus and prosthesis models, and to analyze the biomechanical differences in modular intercalary prostheses with or without plate fixation. METHODS: Three groups were set up to compare the performance of the prosthesis: intact humerus, humerus-prosthesis and humerus-prosthesis-plate...
February 2018: Orthopaedic Surgery
Max J H Witjes, Rutger H Schepers, Joep Kraeima
PURPOSE OF REVIEW: This review describes the advances in 3D virtual planning for mandibular and maxillary reconstruction surgical defects with full prosthetic rehabilitation. The primary purpose is to provide an overview of various techniques that apply 3D technology safely in primary and secondary reconstructive cases of patients suffering from head and neck cancer. RECENT FINDINGS: Methods have been developed to overcome the problem of control over the margin during surgery while the crucial decision with regard to resection margin and planning of osteotomies were predetermined by virtual planning...
February 20, 2018: Current Opinion in Otolaryngology & Head and Neck Surgery
Mamatha M Pillai, J Gopinathan, R Senthil Kumar, G Sathish Kumar, S Shanthakumari, K Santosh Sahanand, Amitava Bhattacharyya, R Selvakumar
Tissue engineered constructs with rapid restoration of mechanical and biological properties remains a challenge, emphasizing the need to develop novel scaffolds. Here we present a multi-component composite 3D scaffold structure with biomimetic reinforcement and biomolecule functionalization for meniscus tissue engineering. The scaffold structure was developed using 3:1 silk fibroin (SF) and polyvinyl alcohol (PVA). Autoclaved eggshell membrane (AESM) powder (1-3%w/v) was used as reinforcement to enhance biomechanical properties...
February 20, 2018: Journal of Biomedical Materials Research. Part A
Zhan Wang, Sang Jin Lee, Heng-Jie Cheng, James J Yoo, Anthony Atala
Bioengineering of a functional cardiac tissue composed of primary cardiomyocytes has great potential for myocardial regeneration and in vitro tissue modeling. However, its applications remain limited because the cardiac tissue is a highly organized structure with unique physiologic, biomechanical, and electrical properties. In this study, we undertook a proof-of-concept study to develop a contractile cardiac tissue with cellular organization, uniformity, and scalability by using three-dimensional (3D) bioprinting strategy...
February 13, 2018: Acta Biomaterialia
Alexander Blanke, Manuel Pinheiro, Peter J Watson, Michael J Fagan
Insect head shapes are remarkably variable but the influences of these changes on biomechanical performance are unclear. Among "basal" winged insects, such as dragonflies, mayflies, earwigs, and stoneflies, some of the most prominent anatomical changes are the general mouthpart orientation, eye size and the connection of the endoskeleton to the head. Here, we assess these variations as well as differing ridge and sclerite configurations using modern engineering methods including multibody dynamics modelling and finite element analysis in order to quantify and compare the influence of anatomical changes on strain in particular head regions and the whole head...
February 14, 2018: Journal of Evolutionary Biology
Janani Radhakrishnan, Amrutha Manigandan, Prabu Chinnaswamy, Anuradha Subramanian, Swaminathan Sethuraman
Fabrication of anisotropic osteochondral-mimetic scaffold with mineralized subchondral zone and gradient interface remains challenging. We have developed an injectable semi-interpenetrating network hydrogel construct with chondroitin sulfate nanoparticles (ChS-NPs) and nanohydroxyapatite (nHA) (∼30-90 nm) in chondral and subchondral hydrogel zones respectively. Mineralized subchondral hydrogel exhibited significantly higher osteoblast proliferation and alkaline phosphatase activity (p < 0.05). Osteochondral hydrogel exhibited interconnected porous structure and spatial variation with gradient interface of nHA and ChS-NPs...
February 3, 2018: Biomaterials
D Bigoni, N Bordignon, A Piccolroaz, S Stupkiewicz
Lubricated sliding contact between soft solids is an interesting topic in biomechanics and for the design of small-scale engineering devices. As a model of this mechanical set-up, two elastic nonlinear solids are considered jointed through a frictionless and bilateral surface, so that continuity of the normal component of the Cauchy traction holds across the surface, but the tangential component is null. Moreover, the displacement can develop only in a way that the bodies in contact do neither detach, nor overlap...
January 2018: Proceedings. Mathematical, Physical, and Engineering Sciences
Fatemeh Ajalloueian, Greg Lemon, Jöns Hilborn, Ioannis S Chronakis, Magdalena Fossum
The urinary bladder is a complex organ with the primary functions of storing urine under low and stable pressure and micturition. Many clinical conditions can cause poor bladder compliance, reduced capacity, and incontinence, requiring bladder augmentation or use of regenerative techniques and scaffolds. To replicate an organ that is under frequent mechanical loading and unloading, special attention towards fulfilling its biomechanical requirements is necessary. Several biological and synthetic scaffolds are available, with various characteristics that qualify them for use in bladder regeneration in vitro and in vivo, including in the treatment of clinical conditions...
February 13, 2018: Nature Reviews. Urology
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