The Impact of Melt Electrowritten Scaffold Design on Porosity Determined by X-Ray Microtomography

Youssef, Almoatazbellah; Hrynevich, Andrei; Fladeland, Logan; Balles, Andreas; Groll, Jürgen; Dalton, Paul D.; Zabler, Simon

doi:10.1089/ten.tec.2018.0373

Cited by 42 publications

(47 citation statements)

References 49 publications

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“…[ 17 ] Depending on the laydown pattern and inter‐fiber spacing, MEW scaffolds with different porosities and pore designs such as regular squares, dodecagon, triangular/hexagon, and octagon can be fabricated. [ 18 ] The fabrication of MEW structures with an increased build height might be applicable for in vitro systems. The current maximum thickness of fabricated MEW scaffolds is 7 mm.…”

Section: Figurementioning

confidence: 99%

Melt Electrowritten In Vitro Radial Device to Study Cell Growth and Migration

et al. 2020

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of these scenarios. [1] Migration is influenced by chemotactic, topographical, and mechanotransductive cues from the extracellular matrix. [2] Moreover, cell migration in the context of cancer metastasis is a complex and important factor for understanding tumor progression. [3] The most aggressive form of a primary brain tumor is glioblastoma multiforme (GBM) which are highly invasive heterogenous tumors with a very low survival rate. [4] Surgical resection and chemo-or radiotherapy is commonly used for patient treatment, however, tumor recurrence is very frequent. Importantly, GBM cells invade and migrate along white matter tracts and brain blood vessels which promote tumor dissemination. [5] Hence, it is critical to understand the basic process of tumor migration and progression in order to develop new therapeutic drugs and treatment regimens. While therapeutic approaches that minimize GBM migration are logical, another approach focuses on guiding these cells away from the tumor into biomaterial reservoirs with the goal to reduce tumor size. [6] This diversional approach is based on the placement of a tube filled with a matrix and oriented substrate that provides topographical guidance cues at the tumor site. This results in the attraction and guidance of migration of GBM cells into the tube, effectively reducing overall tumor size. Therefore, in line with this study and the fact that GBM cells have an affinity for white brain matter and blood vessels, it is important to develop new 3D in vitro cell culture models to determine the optimal matrix composition that drives GBM migration. Novel research methods and tools provide an opportunity to study cell migration during cancer metastasis [7] where loss of cell adhesion from the primary tumor along with increased cell motility and invasion occurs. There is evidence from 3D microfluidic devices and microchips that matrix stiffness influences the migratory and invasive capabilities of tumor cells through the structure characteristics. [8] There have been significant advances to understand the process of cell migration using in vitro models, which are cost effective and easier to use compared to in vivo studies. With existing in vitro assays, cell migration conditions are welldefined with many based on the traditional 2D cell culture methods. [9] While simple to use, they are challenged to recapitulate the 3D in vivo microenvironment.

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Section: Figurementioning

confidence: 99%

Melt Electrowritten In Vitro Radial Device to Study Cell Growth and Migration

et al. 2020

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“…In this study, we hypothesized that smaller-pore scaffolds provided more adhesion support to the cells, thereby improving cell adhesion, while larger pores provided more space for cells to proliferate, thereby avoiding premature contact inhibition (Woodfield et al, 2005). To verify this, we used melt electrowritten (MEW) printing scaffolds (Hrynevich et al, 2018;Brennan et al, 2019;Youssef et al, 2019). Although humans have large-sized tissues and organs, the size of the smallest functional units of the tissues and organs is often in the micrometer range, potentially giving rise to challenges associated with conducting related research.…”

Section: Introductionmentioning

confidence: 99%

Effect of Pore Size on Cell Behavior Using Melt Electrowritten Scaffolds

Han

Lian

et al. 2021

Front. Bioeng. Biotechnol.

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Tissue engineering technology has made major advances with respect to the repair of injured tissues, for which scaffolds and cells are key factors. However, there are still some issues with respect to the relationship between scaffold and cell growth parameters, especially that between the pore size and cells. In this study, we prepared scaffolds with different pore sizes by melt electrowritten (MEW) and used bone marrow mensenchymal stem cells (BMSCs), chondrocytes (CCs), and tendon stem cells (TCs) to study the effect of the scaffold pore size on cell adhesion, proliferation, and differentiation. It was evident that different cells demonstrated different adhesion and proliferation rates on the scaffold. Furthermore, different cell types showed differential preferences for scaffold pore sizes, as evidenced by variations in cell viability. The pore size also affected the differentiation and gene expression pattern of cells. Among the tested cells, BMSCs exhibited the greatest viability on the 200-μm-pore-size scaffold, CCs on the 200- and 100-μm scaffold, and TCs on the 300-μm scaffold. The scaffolds with 100- and 200-μm pore sizes induced a significantly higher proliferation, chondrogenic gene expression, and cartilage-like matrix deposition after in vitro culture relative to the scaffolds with smaller or large pore sizes (especially 50 and 400 μm). Taken together, these results show that the architecture of 10 layers of MEW scaffolds for different tissues should be different and that the pore size is critical for the development of advanced tissue engineering strategies for tissue repair.

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“…determined the thickness distribution for designs with a 90° or 45° fiber orientation, a fiber diameter of 10 µm and a fiber spacing of 250 µm, but with 10 or 12 layers, respectively. [ 52 ] The average thicknesses determined were between 50 and 60 µm, thus significantly less than an approximated maximum thickness of 100 or 120 µm. Taking into account these corrections of the thicknesses, the determination of the bending stiffnesses could be further refined in future.…”

Section: Discussionmentioning

confidence: 90%

Biomimetic Tympanic Membrane Replacement Made by Melt Electrowriting

Witzleben

Stoppe

Ahlfeld

et al. 2021

Adv Healthcare Materials

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The tympanic membrane (TM) transfers sound waves from the air into mechanical motion for the ossicular chain. This requires a high sensitivity to small dynamic pressure changes and resistance to large quasi-static pressure differences. The TM achieves this by providing a layered structure of about 100µm in thickness, a low flexural stiffness, and a high tensile strength. Chronically infected middle ears require reconstruction of a large area of the TM. However, current clinical treatment can cause a reduction in hearing. With the novel additive manufacturing technique of melt electrowriting (MEW), it is for the first time possible to fabricate highly organized and biodegradable membranes within the dimensions of the TM. Scaffold designs of various fiber composition are analyzed mechanically and acoustically. It can be demonstrated that by customizing fiber orientation, fiber diameter, and number of layers the desired properties of the TM can be met. An applied thin collagen layer seals the micropores of the MEW-printed membrane while keeping the favorable mechanical and acoustical characteristics. The determined properties are beneficial for implantation, closely match those of the human TM, and support the growth of a neo-epithelial layer. This proves the possibilities to create a biomimimetic TM replacement using MEW. IntroductionDefects of the tympanic membrane (TM) have many causes, ranging from injuries to chronic otitis media (COM). In the

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The Impact of Melt Electrowritten Scaffold Design on Porosity Determined by X-Ray Microtomography

Cited by 42 publications

References 49 publications

Melt Electrowritten In Vitro Radial Device to Study Cell Growth and Migration

Melt Electrowritten In Vitro Radial Device to Study Cell Growth and Migration

Effect of Pore Size on Cell Behavior Using Melt Electrowritten Scaffolds

Biomimetic Tympanic Membrane Replacement Made by Melt Electrowriting

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