Fabrication of bioinspired grid-crimp micropatterns by melt electrospinning writing for bone-ligament interface study

Abstract Many strategies have been adopted to engineer bone-ligament interface, which is of great value to both the tissue regeneration and the mechanism understanding underlying interface regeneration. However, how to recapitulate the complexity and heterogeneity of the native bone-ligament interface including the structural, cellular and mechanical gradients is still challenging. In this work, a bioinspired grid-crimp micropattern fabricated by melt electrospinning writing (MEW) was proposed to mimic the native structure of bone-ligament interface. The printing strategy of crimped fiber micropattern was developed and the processing parameters were optimized, which were used to mimic the crimp structure of the collagen fibrils in ligament. The guidance effect of the crimp angle and fiber spacing on the orientation of fibroblasts was studied, and both of them showed different levels of cell alignment effect.. MEW grid micropatterns with different fiber spacings were fabricated as bone region. Both the alkaling phosphatase activity and calcium mineralization results demonstrated the higher osteoinductive ability of the MEW grid structures, especially for that with smaller fiber spacing. The combined grid-crimp micropatterns were applied for the co-culture of fibroblasts and osteoblasts. The results showed that more cells were observed to migrate into the in-between interface region for the pattern with smaller fiber spacing, suggested the faster migration speed of cells. Finally, a cylindrical triphasic scaffold was successfully generated by rolling the grid-crimp micropatterns up, showing both structural and mechanical similarity to the native bone-ligament interface. In summary, the proposed strategy is reliable to fabricate grid-crimp triphasic micropatterns with controllable structural parameters to mimic the native bone-to-ligament structure, and the generated 3D scaffold shows great potential for the further bone-ligament interface tissue engineering.

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Fibre pulsing during melt electrospinning writing

BioNanoMaterials ◽

10.1515/bnm-2015-0022 ◽

2016 ◽

Vol 17 (3-4) ◽

Cited By ~ 49

Author(s):

Gernot Hochleitner ◽

Almoatazbellah Youssef ◽

Andrei Hrynevich ◽

Jodie N. Haigh ◽

Tomasz Jungst ◽

...

Keyword(s):

Additive Manufacturing ◽

Processing Parameters ◽

Simple Approach ◽

Direct Writing ◽

Melt Electrospinning ◽

Printing Quality ◽

Constant Diameter ◽

Feeding Pressure ◽

The Stability ◽

Acceleration Voltage

AbstractAdditive manufacturing with electrohydrodynamic direct writing is a promising approach for the production of polymeric microscale objects. In this study we investigate the stability of one such process, melt electrospinning writing, to maintain accurate placement of the deposited fibre throughout the entire print. The influence of acceleration voltage and feeding pressure on the deposited poly(ε-caprolactone) fibre homogeneity is described, and how this affects the variable lag of the jet drawn by the collector movement. Three classes of diameter instabilities were observed that led to poor printing quality: (1) temporary pulsing, (2) continuous pulsing, and (3) regular long bead defects. No breakup of the electrified jet was observed for any of the experiments. A simple approach is presented for the melt electrospinning user to evaluate fibre writing integrity, and adjust the processing parameters accordingly to achieve reproducible and constant diameter fibres.

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A Novel Melt Electrospinning System for Studying Cell Substrate Interactions

Volume 2: Materials; Biomanufacturing; Properties, Applications and Systems; Sustainable Manufacturing ◽

10.1115/msec2015-9443 ◽

2015 ◽

Cited By ~ 4

Author(s):

Filippos Tourlomousis ◽

Azizbek Babakhanov ◽

Houzhu Ding ◽

Robert C. Chang

Keyword(s):

Electrospun Fiber ◽

Processing Parameters ◽

Electrospinning Process ◽

Melt Processing ◽

Complex Nature ◽

Melt Temperature ◽

Melt Electrospinning ◽

Culture Models ◽

Cellular Microenvironments

Controlling cell behavior has generated immense attention in the fields of tissue engineering and regenerative medicine. Particular emphasis has been given to the creation of 3D biomimetic cellular microenvironments that replicate the complex nature of the extracellular matrix (ECM). A key factor that has not been rigorously deconstructed using scalable, layered manufacturing approaches is the structural dimension or scale aspect of in vitro culture models. Melt electrospinning represents a bio-additive manufacturing process that has been relatively under-reported. Although complex in nature, the melt electrospinning process can furnish a 3D cell delivery format with physiologically relevant 3D structural cues. In the present work, poly-ε-caprolactone (PCL) has been chosen as the biomaterial substrate. Rheological studies that guide the design phase of the reported system have been performed for the entire PCL melt processing range, implicating the governing effect of the experimental melt temperature on the scale and the topography in the final processed material. Notable challenges that arise from the nature of the process with respect to the electrospun fiber stability and resolution have been overcome through the design of a novel heating element configuration. In this paper, a reliable biofabrication process with tunable processing of the fiber diameter and alignment is reported. Fundamental parametric studies utilizing the major processing parameters demonstrate the potential for the system to precisely fabricate 3D PCL scaffolds with microstructural features.

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Effects of Process Parameters on Structure and Properties of Melt-Blown Poly(Lactic Acid) Nonwovens for Skin Regeneration

Journal of Functional Biomaterials ◽

10.3390/jfb12010016 ◽

2021 ◽

Vol 12 (1) ◽

pp. 16

Author(s):

Ewa Dzierzkowska ◽

Anna Scisłowska-Czarnecka ◽

Marcin Kudzin ◽

Maciej Boguń ◽

Piotr Szatkowski ◽

...

Keyword(s):

Air Temperature ◽

Process Parameters ◽

Cellular Response ◽

3D Structure ◽

Three Dimensional ◽

Nonwoven Material ◽

Processing Parameters ◽

Skin Regeneration ◽

Poly Lactic Acid ◽

3D Scaffold

Skin regeneration requires a three-dimensional (3D) scaffold for cell adhesion, growth and proliferation. A type of the scaffold offering a 3D structure is a nonwoven material produced via a melt-blown technique. Process parameters of this technique can be adapted to improve the cellular response. Polylactic acid (PLA) was used to produce a nonwoven scaffold by a melt-blown technique. The key process parameters, i.e., the head and air temperature, were changed in the range from 180–270 °C to obtain eight different materials (MB1–MB8). The relationships between the process parameters, morphology, porosity, thermal properties and the cellular response were explored in this study. The mean fiber diameters ranged from 3 to 120 µm. The average material roughness values were between 47 and 160 µm, whereas the pore diameters ranged from 5 to 400 µm. The calorimetry thermograms revealed a correlation between the temperature parameters and crystallization. The response of keratinocytes and macrophages exhibited a higher cell viability on thicker fibers. The cell-scaffold interaction was observed via SEM after 7 days. This result proved that the features of melt-blown nonwoven scaffolds depended on the processing parameters, such as head temperature and air temperature. Thanks to examinations, the most suitable scaffolds for skin tissue regeneration were selected.

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Penetration of urea-formaldehyde adhesives in wood tissue, part I: Radial penetration of UF adhesives into beech

Glasnik Sumarskog fakulteta ◽

10.2298/gsf0898039g ◽

2008 ◽

pp. 39-48 ◽

Cited By ~ 4

Author(s):

Ivana Gavrilovic-Grmusa ◽

Jovan Miljkovic ◽

Milanka Djiporovic-Momcilovic ◽

Gordana Radosevic

Keyword(s):

Urea Formaldehyde ◽

Beech Wood ◽

Processing Parameters ◽

Hydraulic Press ◽

Wood Industry ◽

Cross Sectional ◽

Wood Tissue ◽

Adhesive Penetration ◽

Sectional Surface ◽

Different Levels

Adhesive penetration plays an important role in wood adhesion, since wood is a porous material. The degree of penetration mostly depends on the wood factors, resin type and formulation and processing parameters. Tangentially cut 5 mm thick beech wood (Fagus moesiaca) plies, 100 mm long (parallel to grain) and 30 mm wide, were prepared for this study. The urea-formaldehyde (UF) adhesive was applied to the surface of one ply. Two plies were assembled into sample so that the grains of two plies were parallel. Samples were pressed in a hydraulic press at 120?C and 0,7 MPa for 15 min. Microtome test-specimens were cut of each sample. 20 ?m thick microtomes were cut by sliding microtome apparatus, exposing a bondline with a cross-sectional surface. The lack of more exhausting research on the penetration of urea-formaldehyde adhesives in wood is evident. Since ureaformaldehyde (UF) glue resins were the most important type of adhesives in the wood industry in the last 60 years (Dunky, 2000), the objective of this research was microscopic detection of UF adhesive penetration in wood tissue. Four types of UF resins with different levels of polycondensation were used in this research. Safranin was added in resins, since epi-fluorescence microscope was used in this research for measuring the adhesive penetration.

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Influence of electrohydrodynamic jetting parameters on the morphology of PCL scaffolds

International Journal of Bioprinting ◽

10.18063/ijb.2017.01.009 ◽

2017 ◽

Vol 3 (1) ◽

Cited By ~ 18

Author(s):

Hang Liu ◽

Sanjairaj Vijayavenkataraman ◽

Dandan Wang ◽

Linzhi Jing ◽

Jie Sun ◽

...

Keyword(s):

Cell Culture ◽

Cell Attachment ◽

3D Cell Culture ◽

Solution Concentration ◽

Processing Parameters ◽

Optical Microscope ◽

3D Scaffold ◽

Sem Images ◽

Scaffold Fabrication ◽

Fibre Characteristics

One of the important constituents in tissue engineering is scaffold, which provides structural support and suitable microenvironment for the cell attachment, growth and proliferation. To fabricate micro/nano structures for soft tissue repair and three-dimensional (3D) cell culture, the key is to improve fibre-based scaffold fabrication. Electrohydrodynamic (EHD) jetting is capable of producing and orientating submicron fibres for 3D scaffold fabrication. In this work, an EHD-jetting system was developed to explore the relationship between vital processing parameters and fibre characteristics. In this study, polycaprolactone (PCL) solution prepared by dissolving PCL pellets in acetic acid was used to fabricate the scaffolds. The influence of voltage, motorized stage speed, solution feed rate, and solution concentration on fibre characteristics and scaffold pattern were studied. Morphology of the EHD-jetted PCL fibres and scaffolds were analysed using optical microscope images and scanning electron microscope (SEM) images. Multi-layer scaffolds with the varied coiled pattern were fabricated and analysed. Cell attachment and proliferation have to be investigated in the future by further cell culture studies on these multi-layer coiled scaffolds.

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A New Method for Precision of a Serpentine Snake-Like Robot

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.232.377 ◽

2012 ◽

Vol 232 ◽

pp. 377-382 ◽

Cited By ~ 1

Author(s):

Siavash Sarrafan ◽

Alireza Akbarzadeh

Keyword(s):

Structural Parameters ◽

Positional Error ◽

Control Parameters ◽

Arc Length ◽

Gait Control ◽

Snake Robot ◽

Geometrical Error ◽

Input Parameters ◽

Winding Angle ◽

Different Levels

In this paper, a planar snake-like robot travelling in serpentine locomotion is considered. A method is presented where structural and gait control parameters are used to obtain the minimum snake-robot positional error, geometrical error. Two structural parameters, length and mass of each link as well as two control parameters, initial winding angle (α0) and arc length (s) are considered. Each of the four input parameters is examined at five different levels. The method uses Taguchi experimental techniques and analyzes effects of uncertainties by means of adding noise to the robot parameters. Significance of the input parameters is also determined using Analysis of Variance.

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Influence of different levels and sources of resistant starch on faecal quality of dogs of various body sizes

British Journal Of Nutrition ◽

10.1017/s0007114511003345 ◽

2011 ◽

Vol 106 (S1) ◽

pp. S211-S215 ◽

Cited By ~ 6

Author(s):

Raphaël Goudez ◽

Mickael Weber ◽

Vincent Biourge ◽

Patrick Nguyen

Keyword(s):

Resistant Starch ◽

Potato Starch ◽

Processing Parameters ◽

Bacterial Fermentation ◽

Ileal Digestibility ◽

Body Sizes ◽

High Amylose ◽

Faecal Score ◽

Different Levels

In dry-extruded canine diets, starch ileal digestibility varies with the starch source, amount and processing parameters. Starch that escapes duodeno-ileal digestion can affect faecal quality by stimulating colonic bacterial fermentation. The aim of the present study was to assess the effect of various resistant starch (RS) sources and levels on the faecal score of dogs of different breeds and sizes. A total of twenty-one healthy adult female dogs (body weight ranging 5·0–30·6 kg) were used. The maintenance diet for the dogs was supplemented with increasing amounts of RS from two sources: high-amylose starch from maize (to 2·5, 4·3 and 7·4 % RS) and raw potato starch (to 7·4 and 11·4 % RS). Each level of RS was tested over a 7 d period followed by a 7 d washout period. Faecal scores were evaluated by one person using a scale ranging from 1 (for hard and dry faeces) to 5 (for liquid stools). Faeces were considered ‘optimal’ at scores of 2·5–3·0, ‘acceptable’ at scores of 3·0–3·75 and ‘unacceptable’ at scores >3·75. Small dogs showed very little sensitivity to RS based on the faecal score, while large dogs were quite responsive to RS supplementation. These results suggest that small dogs are poor models for assessing the effect of starch sources on ileal digestibility. They also indicate that a low RS content (strongly affected by source and processing) is an important factor for ensuring an optimal faecal score in large breed dogs.

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Optimization for Morphology of Grinding Layer on Textured Laser Cladding Grinding Tool

10.21203/rs.3.rs-1046543/v1 ◽

2021 ◽

Author(s):

Xufeng Zhao ◽

Changhe Li ◽

Tianbiao Yu

Keyword(s):

Laser Cladding ◽

High Speed ◽

Laser Scanning ◽

Structural Parameters ◽

Scanning Speed ◽

Processing Parameters ◽

Width Ratio ◽

Structure Parameters ◽

Grinding Tool ◽

Cladding Layers

Abstract In order to improving the grinding performance of laser cladding textured grinding tool (LCTGT) under high speed grinding process, the topography shape (height, width and height/width ratio) of laser cladding grinding layers on LCTGT were designed with RSM (response surface method) through optimizing laser cladding processing parameters and laser cladding layers structure parameters that based on Archimedes helix coefficients. The LCTGTs were produced with optimized laser cladding parameters and structural parameters for laser cladding grinding layers. The results showed that laser cladding parameters of 397W of laser power, 3.56 mm/s of the laser scanning speed and 0.91 r/min of powder feeding rate and structure parameters of laser cladding layers of 6-10-10 can meet requirement.

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