A Combined Computational and Experimental Analysis of PLA and PCL Hybrid Nanocomposites 3D Printed Scaffolds for Bone Regeneration.

A combined computational and experimental study of 3D-printed scaffolds made from hybrid nanocomposite materials for potential applications in bone tissue engineering is presented. Polycaprolactone (PCL) and polylactic acid (PLA), enhanced with chitosan (CS) and multiwalled carbon nanotubes (MWCNTs), were investigated in respect of their mechanical characteristics and responses in fluidic environments. A novel scaffold geometry was designed, considering the requirements of cellular proliferation and mechanical properties.

Computational Fluid Dynamic Analysis of customised 3D-printed bone scaffolds with different architectures.

Through the recent years, tissue engineering has been proven as a solid substitute of autografts in the stimulation of bone tissue regeneration, through the development of three dimensional (3D) porous matrices, commonly known as scaffolds. In this work, we analysed two scaffold structures with 500μm pore size, by performing computational fluid dynamics simulations, to compare permeability, Wall Shear Stress (WSS), velocity and pressure distributions. Taking into account those parameters the geometry named as "PCL-50" was the best to anticipate showing a superior performance in supporting cell growth due to the improved flow characteristics in the scaffold.

A computational and experimental mechanical study of nanocomposites for 3D printed scaffolds with a new geometry.

We present a combined study of the mechanical properties of 3D printed scaffolds made by nanocomposite materials based on polycaprolactone (PCL). The geometry and dimensions of the three different systems is the same. Τhe porosity is 50% for all systems.

Adhesion strength and anti-tumor agents regulate vinculin of breast cancer cells.

The onset and progression of cancer are strongly associated with the dissipation of adhesion forces between cancer cells, thus facilitating their incessant attachment and detachment from the extracellular matrix (ECM) to move toward metastasis. During this process, cancer cells undergo mechanical stresses and respond to these stresses with membrane deformation while inducing protrusions to invade the surrounding tissues. Cellular response to mechanical forces is inherently related to the reorganization of the cytoskeleton, the dissipation of cell-cell junctions, and the adhesion to the surrounding ECM.

Comparison of the Weil and Triple Weil Osteotomies: A Clinical Retrospective Study.

Introduction: The Weil and triple Weil osteotomies are two widely used procedures in the surgical treatment of metatarsalgia. The aim of this comparative retrospective study was to evaluate the functional results and determine the complications of the two types of osteotomies in a series of patients who underwent surgery due to third rocker metatarsalgia.

Material And Methods: In this paper, 71 patients were included between September 2015 and October 2020.

Biomechanical Analysis of the Change of the Metatarsophalangeal Joint's Center of Rotation After Weil and Triple Weil Osteotomies: A Comparative Cadaveric Study.

Background The aim of the present biomechanical study on cadavers was to determine both the center of rotation of the metatarsophalangeal joints and the position of the tendons of the interosseous muscles after the Weil and triple Weil osteotomies, and to compare these parameters in order to clarify the pathogenesis of dorsal stiffness and floating toe. Materials and methods Seven fresh-frozen cadaveric feet were utilized. After completing the preparation of both the plantar and the dorsal surface, we performed the dissection of the entire second, third and fourth rays, and each ray was fixed to a wooden wall mounted on a movable frame.

The Role of Substrate Topography and Stiffness on MSC Cells Functions: Key Material Properties for Biomimetic Bone Tissue Engineering.

The hypothesis of the present research is that by altering the substrate topography and/or stiffness to make it biomimetic, we can modulate cells behavior. Substrates with similar surface chemistry and varying stiffnesses and topographies were prepared. Bulk PCL and CNTs-reinforced PCL composites were manufactured by solvent casting method and electrospinning and further processed to obtain tunable moduli of elasticity in the range of few MPa.

Engineering Breast Cancer Cells and hUMSCs Microenvironment in 2D and 3D Scaffolds: A Mechanical Study Approach of Stem Cells in Anticancer Therapy.

Cell biomechanics plays a major role as a promising biomarker for early cancer diagnosis and prognosis. In the present study, alterations in modulus of elasticity, cell membrane roughness, and migratory potential of MCF-7 (ER+) and SKBR-3 (HER2+) cancer cells were elucidated prior to and post treatment with conditioned medium from human umbilical mesenchymal stem cells (hUMSCs-CM) during static and dynamic cell culture. Moreover, the therapeutic potency of hUMSCs-CM on cancer cell's viability, migratory potential, and F-actin quantified intensity was addressed in 2D surfaces and 3D scaffolds.

Recent Advancements in 3D Printing and Bioprinting Methods for Cardiovascular Tissue Engineering.

Recent decades have seen a plethora of regenerating new tissues in order to treat a multitude of cardiovascular diseases. Autografts, xenografts and bioengineered extracellular matrices have been employed in this endeavor. However, current limitations of xenografts and exogenous scaffolds to acquire sustainable cell viability, anti-inflammatory and non-cytotoxic effects with anti-thrombogenic properties underline the requirement for alternative bioengineered scaffolds.

Gradient 3D Printed PLA Scaffolds on Biomedical Titanium: Mechanical Evaluation and Biocompatibility.

The goal of the present investigation was to find a solution to crucial engineering aspects related to the elaboration of multi-layered tissue-biomimicking composites. 3D printing technology was used to manufacture single-layered and gradient multi-layered 3D porous scaffolds made of poly-lactic acid (PLA). The scaffolds manufacturing process was optimized after adjusting key printing parameters.

Combined Optimized Effect of a Highly Self-Organized Nanosubstrate and an Electric Field on Osteoblast Bone Cells Activity.

The effect of an electric field within specific intensity limits on the activity of human cells has been previously investigated. However, there are a considerable number of factors that influence the in vitro development of cell populations. In biocompatibility studies, the nature of the substrate and its topography are decisive in osteoblasts bone cells development.

Human trichinellosis caused by in Greece, and literature review.

Trichinellosis is a cosmopolitan zoonotic parasitic disease caused by the nematodes of the genus Trichinella, through the consumption of raw or semi-raw infected meat from swine, horses and wild animals. This disease has been sporadically reported in Greece since 1946. The aim of the present study was to describe a trichinellosis case in a patient hospitalized in northern Greece, in 2017.

Recellularization potential of small diameter vascular grafts derived from human umbilical artery.

Background: The primary therapeutic strategy in cardiovascular disease is the coronary artery bypass surgery, which in- volves the use of small diameter vascular grafts (<6 mm). Human umbilical arteries could be used as a source for the development of these grafts.

Objective: The aim of this study was the decellularization of human umbilical arteries and the evaluation of their re- cellularization potential.

Modeling of the interaction between osteoblasts and biocompatible substrates as a function of adhesion strength.

A goal of current implantology research is to design devices that induce controlled, guided, and rapid healing. Nanoscale structured substrates [e.g.

Acoustoelasticity in cancellous bone.

Strain-dependence of ultrasound speed in cancellous bone was determined by applying a range of uniaxial compressive strains in the elasticity region, in a single direction, parallel or perpendicular to the propagating wave. Compressive strain modulated the ultrasound speed significantly. The decrease of ultrasound speed was found to change linearly as a function of strain.

Apolipoprotein A-1 regulates osteoblast and lipoblast precursor cells in mice.

Imbalances in lipid metabolism affect bone homeostasis, altering bone mass and quality. A link between bone mass and high-density lipoprotein (HDL) has been proposed. Indeed, it has been recently shown that absence of the HDL receptor scavenger receptor class B type I (SR-B1) causes dense bone mediated by increased adrenocorticotropic hormone (ACTH).

Multiwalled carbon nanotubes enhance human bone marrow mesenchymal stem cells' spreading but delay their proliferation in the direction of differentiation acceleration.

Investigating the ability of films of pristine (purified, without any functionalization) multiwalled carbon nanotubes (MWCNTs) to influence human bone marrow mesenchymal stem cells' (hBMSCs) proliferation, morphology, and differentiation into osteoblasts, we concluded to the following: A. MWCNTs delay the proliferation of hBMSCs but increase their differentiation. The enhancement of the differentiation markers could be a result of decreased proliferation and maturation of the extracellular matrix B.

MWCNTs enhance hBMSCs spreading but delay their proliferation in the direction of differentiation acceleration.

Investigating the ability of films of pristine multiwalled nanotubes (MWCNTs) to influence human mesenchymal stem cells' proliferation, morphology, and differentiation into osteoblasts, we concluded to the following: A. MWCNTs delay the proliferation of hBMS cells but increase their differentiation. The enhancement of the differentiation markers could be a result of decreased proliferation and maturation of the extracellular matrix B.

Towards a solution of the wires' slippage problem of the Ilizarov external fixator.

Clinical experience has indicated that many complications during treatment with the Ilizarov method, and mainly tract infection, are related to decreased wire tension. The aim of this work was to evaluate biomechanically a novel wire tensioning and clamping system that will minimise or even diminish the reduction of the wire pretension during treatment. The proposed approach is based on threading of the wire end in a sufficient length.

Mechanoresponses of human primary osteoblasts grown on carbon nanotubes.

Bone mechanotransduction is strongly influenced by the biomaterial properties. A good understanding of these mechanosensory mechanisms in bone has the potential to provide new strategies in the highly evolving field of bone tissue engineering. The aim of the present investigation was to study the interactive effects of local mechanical stimuli on multiwalled carbon nanotubes (MWCNTs)/osteoblast interface, using an in vitro model that allows the study of cell growth, attachment and differentiation.

Body composition in young patients with galactose metabolic disorders: a preliminary report.

Aim: Body composition evaluation in patients with galactosemia and its variants.

Methods: The body composition of young subjects with galactose metabolic disorders was analyzed with dual X-ray absorptiometry. The subjects were divided into the classic galactosemia (CG; n=14) group and the group with other galactose metabolic disorders (OGMD, e.

Carbon nanotubes reinforced chitosan films: mechanical properties and cell response of a novel biomaterial for cardiovascular tissue engineering.

Carbon nanotubes have been proposed as fillers to reinforce polymeric biomaterials for the strengthening of their structural integrity to achieve better biomechanical properties. In this study, a new polymeric composite material was introduced by incorporating various low concentrations of multiwalled carbon nanotubes (MWCNTs) into chitosan (CS), aiming at achieving a novel composite biomaterial with superior mechanical and biological properties compared to neat CS, in order to be used in cardiovascular tissue engineering applications. Both mechanical and biological characteristics in contact with the two relevant cell types (endothelial cells and vascular myofibroblasts) were studied.

Cellular function and adhesion mechanisms of human bone marrow mesenchymal stem cells on multi-walled carbon nanotubes.

Multiwalled carbon nanotubes (MWCNTs) are considered to be excellent reinforcements for biorelated applications, but, before being incorporated into biomedical devices, their biocompatibility need to be investigated thoroughly. We investigated the ability of films of pristine MWCNTs to influence human mesenchymal stem cells' proliferation, morphology, and differentiation into osteoblasts. Moreover, the selective integrin subunit expression and the adhesion mechanism to the substrate were evaluated on the basis of adherent cell number and adhesion strength, following the treatment of cells with blocking antibodies to a series of integrin subunits.

On the biocompatibility between TiO2 nanotubes layer and human osteoblasts.

Titanium and its alloys are the most popular biomaterials replacing hard tissues in implant surgeries. Clinicians are generally pleased by titanium mechanical properties and non-toxicity performances; on the other hand, there have been reported several cases of titanium implantation failure, phenomenon explained sometimes as "non adherence of human tissue to the metallic surface." Yet, researchers reported that titanium surfaces are favorable for osteoblasts adhesion.

Detachment strength of human osteoblasts cultured on hydroxyapatite with various surface roughness. Contribution of integrin subunits.

Hydroxyapatite (HA) has been widely used as a bone substitute in dental, maxillofacial and orthopaedic surgery and as osteoconductive bone substitute or precoating of pedicle screws and cages in spine surgery. The aim of the present study was to investigate the osteoblastic adhesion strength on HA substrata with different surface topography and biochemistry (pre-adsorption of fibronectin) after blocking of specific integrin subunits with monoclonal antibodies. Stoichiometric HA was prepared by precipitation followed by ageing and characterized by SEM, EDX, powder XRD, Raman spectroscopy, TGA, and specific surface area analysis.