scholarly journals 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

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.

scholarly journals 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

2021 ◽  
Vol 25 (1) ◽  
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 3T3 fibroblasts in incubation periods of 24, 48 and 72 h. 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.

Small diameter electrospun silk fibroin vascular grafts: Mechanical properties, in vitro biodegradability, and in vivo biocompatibility

2015 ◽  
Vol 54 ◽  
pp. 101-111 ◽  
Author(s):  
Valentina Catto ◽  
Silvia Farè ◽  
Irene Cattaneo ◽  
Marina Figliuzzi ◽  
Antonio Alessandrino ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Silk Fibroin ◽  
Vascular Grafts ◽  
Small Diameter

scholarly journals Comparative Evaluation on Impacts of Fibronectin, Heparin–Chitosan, and Albumin Coating of Bacterial Nanocellulose Small-Diameter Vascular Grafts on Endothelialization In Vitro

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1952
Author(s):  
Max Wacker ◽  
Jan Riedel ◽  
Heike Walles ◽  
Maximilian Scherner ◽  
George Awad ◽  
...  
Keyword(s):  
Low Density Lipoprotein ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Density Lipoprotein ◽  
Human Albumin ◽  
Water Soluble ◽  
Bacterial Nanocellulose ◽  
Functionally Impaired ◽  
Small Diameter Vascular Grafts

In this study, we contrast the impacts of surface coating bacterial nanocellulose small-diameter vascular grafts (BNC-SDVGs) with human albumin, fibronectin, or heparin–chitosan upon endothelialization with human saphenous vein endothelial cells (VEC) or endothelial progenitor cells (EPC) in vitro. In one scenario, coated grafts were cut into 2D circular patches for static colonization of a defined inner surface area; in another scenario, they were mounted on a customized bioreactor and subsequently perfused for cell seeding. We evaluated the colonization by emerging metabolic activity and the preservation of endothelial functionality by water soluble tetrazolium salts (WST-1), acetylated low-density lipoprotein (AcLDL) uptake assays, and immune fluorescence staining. Uncoated BNC scaffolds served as controls. The fibronectin coating significantly promoted adhesion and growth of VECs and EPCs, while albumin only promoted adhesion of VECs, but here, the cells were functionally impaired as indicated by missing AcLDL uptake. The heparin–chitosan coating led to significantly improved adhesion of EPCs, but not VECs. In summary, both fibronectin and heparin–chitosan coatings could beneficially impact the endothelialization of BNC-SDVGs and might therefore represent promising approaches to help improve the longevity and reduce the thrombogenicity of BNC-SDVGs in the future.

scholarly journals Review: Tissue Engineering of Small-Diameter Vascular Grafts and Their In Vivo Evaluation in Large Animals and Humans

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 713
Author(s):  
Shu Fang ◽  
Ditte Gry Ellman ◽  
Ditte Caroline Andersen
Keyword(s):  
Animal Models ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Large Animal ◽  
Large Animal Models ◽  
Graft Outcome ◽  
Limited Success ◽  
Large Animals

To date, a wide range of materials, from synthetic to natural or a mixture of these, has been explored, modified, and examined as small-diameter tissue-engineered vascular grafts (SD-TEVGs) for tissue regeneration either in vitro or in vivo. However, very limited success has been achieved due to mechanical failure, thrombogenicity or intimal hyperplasia, and improvements of the SD-TEVG design are thus required. Here, in vivo studies investigating novel and relative long (10 times of the inner diameter) SD-TEVGs in large animal models and humans are identified and discussed, with emphasis on graft outcome based on model- and graft-related conditions. Only a few types of synthetic polymer-based SD-TEVGs have been evaluated in large-animal models and reflect limited success. However, some polymers, such as polycaprolactone (PCL), show favorable biocompatibility and potential to be further modified and improved in the form of hybrid grafts. Natural polymer- and cell-secreted extracellular matrix (ECM)-based SD-TEVGs tested in large animals still fail due to a weak strength or thrombogenicity. Similarly, native ECM-based SD-TEVGs and in-vitro-developed hybrid SD-TEVGs that contain xenogeneic molecules or matrix seem related to a harmful graft outcome. In contrast, allogeneic native ECM-based SD-TEVGs, in-vitro-developed hybrid SD-TEVGs with allogeneic banked human cells or isolated autologous stem cells, and in-body tissue architecture (IBTA)-based SD-TEVGs seem to be promising for the future, since they are suitable in dimension, mechanical strength, biocompatibility, and availability.

Three-Dimensional High Resolution Scaffold Fiber Architecture and Morphology in Tissue Engineered Heart Valve Tissue

2010 ◽  
Author(s):  
Chad E. Eckert ◽  
Brandon T. Mikulis ◽  
Dane Gerneke ◽  
Danielle Gottlieb ◽  
Bruce Smaill ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Resolution ◽  
Heart Valve ◽  
Structural Information ◽  
Three Dimensional ◽  
Tissue Scaffold ◽  
Valve Tissue ◽  
Sampling Protocols ◽  
Heart Valve Tissue

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.

Bioengineering silk into blood vessels

2021 ◽  
Author(s):  
Yuen Ting Lam ◽  
Richard P. Tan ◽  
Praveesuda L. Michael ◽  
Kieran Lau ◽  
Nianji Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Inflammatory Responses ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Biological Response ◽  
Endothelial Cell Layer ◽  
Significant Research ◽  
Rising Incidence ◽  
Highly Hydrophobic ◽  
Synthetic Grafts

The rising incidence of cardiovascular disease has increased the demand for small diameter (<6 mm) synthetic vascular grafts for use in bypass surgery. Clinically available synthetic grafts (polyethylene terephthalate and expanded polytetrafluorethylene) are incredibly strong, but also highly hydrophobic and inelastic, leading to high rates of failure when used for small diameter bypass. The poor clinical outcomes of commercial synthetic grafts in this setting have driven significant research in search of new materials that retain favourable mechanical properties but offer improved biocompatibility. Over the last several decades, silk fibroin derived from Bombyx mori silkworms has emerged as a promising biomaterial for use in vascular applications. Progress has been driven by advances in silk manufacturing practices which have allowed unprecedented control over silk strength, architecture, and the ensuing biological response. Silk can now be manufactured to mimic the mechanical properties of native arteries, rapidly recover the native endothelial cell layer lining vessels, and direct positive vascular remodelling through the regulation of local inflammatory responses. This review summarises the advances in silk purification, processing and functionalisation which have allowed the production of robust vascular grafts with promise for future clinical application.

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

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 203 ◽  
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.

scholarly journals In vitro hemo- and cytocompatibility of bacterial nanocelluose small diameter vascular grafts: Impact of fabrication and surface characteristics.

PLoS ONE ◽  
2020 ◽  
Vol 15 (6) ◽  
pp. e0235168 ◽  
Author(s):  
Max Wacker ◽  
Viktoria Kießwetter ◽  
Ingo Slottosch ◽  
George Awad ◽  
Adnana Paunel-Görgülü ◽  
...  
Keyword(s):  
Vascular Grafts ◽  
Small Diameter ◽  
Surface Characteristics ◽  
Small Diameter Vascular Grafts

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

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.

Sign in / Sign up

Export Citation Format

Share Document