Physico-Mechanical Properties of HA/TCP Pellets and Their Three-Dimensional Biological Evaluation In Vitro

Engineered heart valve tissue (EHVT) has received much attention as a potential pediatric valve replacement therapy, offering prospective long-term functional improvements over current options. A significant gap in the literature exists, however, regarding estimating tissue mechanical properties from tissue-scaffold composites. Detailed three-dimensional structural information prior to implantation (in vitro) and after implantation in (in vivo) is needed for improved modeling of tissue properties. As such, a novel high-resolution imaging technique will be employed to obtain three-dimensional microstructural information. Analysis techniques will be used to fully quantify constituents of interest including scaffold, collagen, and cellular information and to develop appropriate two-dimensional sectioning sampling protocols. It is the intent of this work to guide modeling efforts to better elucidate EHVT tissue-specific mechanical properties.

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Improved Bioactivity of 3D Printed Porous Titanium Alloy Scaffold with Chitosan/Magnesium-Calcium Silicate Composite for Orthopaedic Applications

Materials ◽

10.3390/ma12020203 ◽

2019 ◽

Vol 12 (2) ◽

pp. 203 ◽

Cited By ~ 18

Author(s):

Chun-Hao Tsai ◽

Chih-Hung Hung ◽

Che-Nan Kuo ◽

Cheng-Yu Chen ◽

Yu-Ning Peng ◽

...

Keyword(s):

Mechanical Properties ◽

Calcium Silicate ◽

Cell Attachment ◽

Three Dimensional ◽

Bone Defects ◽

Metal Alloys ◽

Potential Candidate ◽

Natural Bone

Recently, cases of bone defects have been increasing incrementally. Thus, repair or replacement of bone defects is gradually becoming a huge problem for orthopaedic surgeons. Three-dimensional (3D) scaffolds have since emerged as a potential candidate for bone replacement, of which titanium (Ti) alloys are one of the most promising candidates among the metal alloys due to their low cytotoxicity and mechanical properties. However, bioactivity remains a problem for metal alloys, which can be enhanced using simple immersion techniques to coat bioactive compounds onto the surface of Ti–6Al–4V scaffolds. In our study, we fabricated magnesium-calcium silicate (Mg–CS) and chitosan (CH) compounds onto Ti–6Al–4V scaffolds. Characterization of these surface-modified scaffolds involved an assessment of physicochemical properties as well as mechanical testing. Adhesion, proliferation, and growth of human Wharton’s Jelly mesenchymal stem cells (WJMSCs) were assessed in vitro. In addition, the cell attachment morphology was examined using scanning electron microscopy to assess adhesion qualities. Osteogenic and mineralization assays were conducted to assess osteogenic expression. In conclusion, the Mg–CS/CH coated Ti–6Al–4V scaffolds were able to exhibit and retain pore sizes and their original morphologies and architectures, which significantly affected subsequent hard tissue regeneration. In addition, the surface was shown to be hydrophilic after modification and showed mechanical strength comparable to natural bone. Not only were our modified scaffolds able to match the mechanical properties of natural bone, it was also found that such modifications enhanced cellular behavior such as adhesion, proliferation, and differentiation, which led to enhanced osteogenesis and mineralization downstream. In vivo results indicated that Mg–CS/CH coated Ti–6Al–4V enhances the bone regeneration and ingrowth at the critical size bone defects of rabbits. These results indicated that the proposed Mg–CS/CH coated Ti–6Al–4V scaffolds exhibited a favorable, inducive micro-environment that could serve as a promising modification for future bone tissue engineering scaffolds.

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In Vitro Three Dimensional Imaging of Human Carotid Atherosclerotic Plaques Using Ultrasonography

ASME 2011 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2011-53463 ◽

2011 ◽

Author(s):

Renate W. Boekhoven ◽

Marcel C. M. Rutten ◽

Marc R. H. M. van Sambeek ◽

Frans N. van de Vosse

Keyword(s):

Mechanical Properties ◽

Carotid Artery ◽

Carotid Endarterectomy ◽

Early Stage ◽

Three Dimensional ◽

Atherosclerotic Plaques ◽

Unstable Plaques ◽

Human Carotid ◽

Selection Of

Ruptured atherosclerotic plaques in the carotid artery are the main cause of stroke (70–80%). To prevent it, carotid endarterectomy is the procedure of choice in patients with a recent symptomatic 70–99% stenosis. Today, the selection of candidates is based on stenosis size only. However, endarterectomy is beneficial for only 1 out of 6 patients [1], the patients with unstable plaques (Fig. 1). Knowledge of mechanical properties of different components in the atherosclerotic arteries is important, because it will allow the identification of plaque stability at an early stage.

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Fabrication of High-Strength and Porous Hybrid Scaffolds Based on Nano-Hydroxyapatite and Human-Like Collagen for Bone Tissue Regeneration

Polymers ◽

10.3390/polym12010061 ◽

2020 ◽

Vol 12 (1) ◽

pp. 61 ◽

Cited By ~ 6

Author(s):

Yannan Liu ◽

Juan Gu ◽

Daidi Fan

Keyword(s):

Mechanical Properties ◽

Enzymatic Hydrolysis ◽

Bone Tissue ◽

Tissue Regeneration ◽

Bone Repair ◽

Three Dimensional ◽

High Strength ◽

Biological Properties ◽

Bone Tissue Regeneration

A novel, three-dimensional, porous, human-like collagen (HLC)/nano-hydroxyapatite (n-HA) scaffold cross-linked by 1,2,7,8-diepoxyoctane (DEO) was successfully fabricated, which showed excellent mechanical and superior biological properties for bone tissue regeneration in this study. The physicochemical characterizations of different n-HA/HLC/DEO (nHD) scaffolds were investigated by determining the morphology, compression stress, elastic modulus, Young’s modulus and enzymatic hydrolysis behavior in vitro. The results demonstrated that nHD-2 and nHD-3 scaffolds showed superior mechanical properties and resistance to enzymatic hydrolysis compared to nHD-1 scaffolds. The cell viability, live cell staining and cell adhesion analysis results demonstrated that nHD-2 scaffolds exhibited low cytotoxicity and excellent cytocompatibility compared with nHD-1 and nHD-3 scaffolds. Furthermore, subcutaneous injections of nHD-2 scaffolds in rabbits produced superior anti-biodegradation effects and histocompatibility compared with injections of nHD-1 and nHD-3 scaffolds after 1, 2 and 4 weeks. In addition, the repair of bone defects in rabbits demonstrated that nHD-2 scaffolds presented an improved ability for guided bone regeneration and reconstruction compared to commercially available bone scaffold composite hydroxyapatite/collagen (HC). Collectively, the results show that nHD-2 scaffolds show promise for application in bone tissue engineering due to their excellent mechanical properties, anti-biodegradation, anti-biodegradation, biocompatibility and bone repair effects.

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The mechanical properties of kinesin-1: a holistic approach

Biochemical Society Transactions ◽

10.1042/bst20110768 ◽

2012 ◽

Vol 40 (2) ◽

pp. 438-443 ◽

Cited By ~ 10

Author(s):

George M. Jeppesen ◽

J.K. Heinrich Hoerber

Keyword(s):

Mechanical Properties ◽

Atp Hydrolysis ◽

Optical Trap ◽

Three Dimensional ◽

In Vitro Study ◽

Holistic Approach ◽

Weakly Coupled ◽

Kinesin Molecule ◽

Mechanochemical Cycle

During the last 25 years, a vast amount of research has gone into understanding the mechanochemical cycle of kinesin-1 and similar processive motor proteins. An experimental method that has been widely used to this effect is the in vitro study of kinesin-1 molecules moving along microtubules while pulling a bead, the position of which is monitored optically while trapped in a laser focus. Analysing results from such experiments, in which thermally excited water molecules are violently buffeting the system components, can be quite difficult. At low loads, the effect of the mechanical properties of the entire molecule must be taken into account, as stalk compliance means the bead position recorded is only weakly coupled to the movement of the motor domains, the sites of ATP hydrolysis and microtubule binding. In the present review, findings on the mechanical and functional properties of the various domains of full-length kinesin-1 molecules are summarized and a computer model is presented that uses this information to simulate the motion of a bead carried by a kinesin molecule along a microtubule, with and without a weak optical trap present. A video sequence made from individual steps of the simulation gives a three-dimensional visual insight into these types of experiment at the molecular level.

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Extrusion Printed Graphene/Polycaprolactone/Composites for Tissue Engineering

Materials Science Forum ◽

10.4028/www.scientific.net/msf.773-774.496 ◽

2013 ◽

Vol 773-774 ◽

pp. 496-502 ◽

Cited By ~ 12

Author(s):

Sepidar Sayyar ◽

Rhys Cornock ◽

Eoin Murray ◽

Stephen Beirne ◽

David L. Officer ◽

...

Keyword(s):

Mechanical Properties ◽

Tissue Engineering ◽

Three Dimensional ◽

Promising Material ◽

Additive Fabrication ◽

Printing System ◽

Good Biocompatibility ◽

Covalently Linked ◽

Extrusion Printing

In this work fibres and complex three-dimensional scaffolds of a covalently linked graphene-polycaprolactone composite were successfully extruded and printed using a melt extrusion printing system. Fibres with varying diameters and morphologies, as well as complex scaffolds were fabricated using an additive fabrication approach and were characterized. It was found that the addition of graphene improves the mechanical properties of the fibres by over 50% and in vitro cytotoxicity tests showed good biocompatibility indicating a promising material for tissue engineering applications.

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Fabrication andIn VitroEvaluation of Nanosized Hydroxyapatite/Chitosan-Based Tissue Engineering Scaffolds

Journal of Nanomaterials ◽

10.1155/2014/194680 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 13

Author(s):

Tao Sun ◽

Tareef Hayat Khan ◽

Naznin Sultana

Keyword(s):

Tissue Engineering ◽

Composite Scaffold ◽

Three Dimensional ◽

Biological Evaluation ◽

Mouse Fibroblast ◽

Tissue Engineering Scaffolds ◽

Composite Scaffolds ◽

Thermally Induced ◽

Chitosan Composite

Composite scaffolds based on biodegradable natural polymer and osteoconductive hydroxyapatite (HA) nanoparticles can be promising for a variety of tissue engineering (TE) applications. This study addressed the fabrication of three-dimensional (3D) porous composite scaffolds composed of HA and chitosan fabricated via thermally induced phase separation and freeze-drying technique. The scaffolds produced were subsequently characterized in terms of microstructure, porosity, and mechanical property.In vitrodegradation andin vitrobiological evaluation were also investigated. The scaffolds were highly porous and had interconnected pore structures. The pore sizes ranged from several microns to a few hundred microns. The incorporated HA nanoparticles were well mixed and physically coexisted with chitosan in composite scaffold structures. The addition of 10% (w/w) HA nanoparticles to chitosan enhanced the compressive mechanical properties of composite scaffold compared to pure chitosan scaffold.In vitrodegradation results in phosphate buffered saline (PBS) showed slower uptake properties of composite scaffolds. Moreover, the scaffolds showed positive response to mouse fibroblast L929 cells attachment. Overall, the findings suggest that HA/chitosan composite scaffolds could be suitable for TE applications.

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The Emerging Role of Decellularized Plant-Based Scaffolds as a New Biomaterial

International Journal of Molecular Sciences ◽

10.3390/ijms222212347 ◽

2021 ◽

Vol 22 (22) ◽

pp. 12347

Author(s):

Ashlee F. Harris ◽

Jerome Lacombe ◽

Frederic Zenhausern

Keyword(s):

Mechanical Properties ◽

Fruits And Vegetables ◽

Low Cost ◽

Three Dimensional ◽

Structural Features ◽

Cellular Models ◽

Current State ◽

Wide Range ◽

Future Challenges

The decellularization of plant-based biomaterials to generate tissue-engineered substitutes or in vitro cellular models has significantly increased in recent years. These vegetal tissues can be sourced from plant leaves and stems or fruits and vegetables, making them a low-cost, accessible, and sustainable resource from which to generate three-dimensional scaffolds. Each construct is distinct, representing a wide range of architectural and mechanical properties as well as innate vasculature networks. Based on the rapid rise in interest, this review aims to detail the current state of the art and presents the future challenges and perspectives of these unique biomaterials. First, we consider the different existing decellularization techniques, including chemical, detergent-free, enzymatic, and supercritical fluid approaches that are used to generate such scaffolds and examine how these protocols can be selected based on plant cellularity. We next examine strategies for cell seeding onto the plant-derived constructs and the importance of the different functionalization methods used to assist in cell adhesion and promote cell viability. Finally, we discuss how their structural features, such as inherent vasculature, porosity, morphology, and mechanical properties (i.e., stiffness, elasticity, etc.) position plant-based scaffolds as a unique biomaterial and drive their use for specific downstream applications. The main challenges in the field are presented throughout the discussion, and future directions are proposed to help improve the development and use of vegetal constructs in biomedical research.

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Effect of Sequential Electrospinning And Co-Electrospinning On Morphological And Fluid Mechanical Wall Properties of Polycaprolactone And Bovine Gelatin Scaffolds, For Potential Use In Small Diameter Vascular Grafts

10.21203/rs.3.rs-680589/v1 ◽

2021 ◽

Author(s):

Yuliet Montoya ◽

José Cardenas ◽

John Bustamante ◽

Raúl Valencia

Keyword(s):

Mechanical Properties ◽

Vascular Grafts ◽

Three Dimensional ◽

Small Diameter ◽

Porous Wall ◽

Experimental Tests ◽

Cellular Transport ◽

Functional Requirements ◽

Bovine Gelatin

Abstract Background: Nowadays, the engineering vascular grafts with a diameter less than 6 mm by means of electrospinning, is an attracted alternative technique to create different three-dimensional microenvironments with appropriate physicochemical properties to promote the nutrient transport and to enable the bioactivity, dynamic growth and differentiation of cells. Although the performance of a well-designed porous wall is key for these functional requirements maintaining the mechanical function, yet predicting the flow rate and cellular transport are still not widely understood and many questions remain open about new configurations of wall can be used for modifying the conventional electrospun samples. The aim of the present study was to evaluate the effect of fabrication techniques on scaffolds composed of bovine gelatin and polycaprolactone (PCL) developed by sequential electrospinning and co-electrospinning, on the morphology and fluid-mechanical properties of the porous wall. Methodology: For this purpose, small diameter tubular structures were manufactured and experimental tests were performed to characterize the crystallinity, morphology, wettability, permeability, degradability, and mechanical properties. Some samples were cross-linked with Glutaraldehyde (GA) to improve the stability of the gelatin fiber. In addition, it was analyzed how the characteristics of the scaffold favored the levels of cell adhesion and proliferation in an in vitro model of T3T fibroblasts in incubation periods of 24, 48 and 72h. Results: It was found that in terms of the morphology of tubular scaffolds, the co-electrospun samples had a better alignment with higher values of fiber diameters and apparent pore area than the sequential samples. The static permeability was more significant in the sequential scaffolds and the hydrophilic was higher in the co-electrospun samples. Therefore, the gelatin mass losses were less in the co-electrospun samples, which promote cellular functions. In terms of mechanical properties, no significant differences were observed for different types of samples. Conclusion: This research concluded that the tubular scaffolds generated by sequential and co-electrospinning with modification in the microarchitecture could be used as a vascular graft, as they have better permeability and wettability, interconnected pores, and a circumferential tensile strength similar to native vessel compared to the commercial graft analyzed.

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Biocomposites conductive scaffold based on PEDOT:PSS/nHA/chitosan/PCL: Fabrication and characterization

Malaysian Journal of Fundamental and Applied Sciences ◽

10.11113/mjfas.v15n2.1201 ◽

2019 ◽

Vol 15 (2) ◽

pp. 146-149

Author(s):

Alireza Lari ◽

Naznin Sultana ◽

Chin Fhong Soon

Keyword(s):

Mechanical Properties ◽

Contact Angle ◽

Composite Scaffold ◽

Biological Evaluation ◽

Sem Analysis ◽

Human Skin Fibroblast ◽

Fabrication Technique ◽

Pore Sizes ◽

Material Component

Biomaterial-based scaffolds with suitable characteristics are highly desired in tissue engineering (TE) application. Biocomposites based on polymer and ceramics increase the chance for modulating the properties of scaffold. In recent years, researchers have considered conductive polymers to be used in TE application, due to their conductivity. This property has a good impact on tissue regeneration. A suitable design for bone substitute that consists of considerations such as material component, fabrication technique and mechanical properties. The previous studies on PEDOT:PSS/nHA/CS showed high wettability rate but low mechanical properties. Polycaprolactone (PCL) is a biodegradable and biocompatible polymer with a low wettability. The incorporation of PCL inside biocomposite can lead to the decrement in wettability and increment in mechanical property. In addition, this paper would examine the feasibility of blending of PCL and chitosan to fabricate PEDOT:PSS/nHA/CS composite scaffold. The fabrication technique of freezing/ lyophilization was used in this study. The scaffolds were characterized morphologically using scanning electron microscopy (SEM). Wettability was studied using a contact angle instrument. The attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR) spectra interpreted the presence of polymeric ingredients within composite scaffold. Conductivity of the scaffolds was measured using a Digital Multimeter. In-vitro biological evaluation of the scaffolds was studied using human skin Fibroblast (HSF) cell line. The morphological study of biocomposite PEDOT:PSS/nHA/CS/PCL scaffold revealed random pore sizes and 66% porosity. Contact angle of the scaffold was increased and the swelling property and pore sizes were decreased after blending of PCL polymer. The viability of HSF cells on biocomposite PEDOT:PSS/nHA/CS/PCL scaffold was 85%. After 7 days, SEM analysis revealed the presence of cells on the surface of scaffold. In conclusion, the results suggested that PEDOT:PSS/nHA/CS/PCL biocomposite scaffold was non-toxic to cells and has suitable properties.

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