scholarly journals Inverse 3D Printing with Variations of the Strand Width of the Resulting Scaffolds for Bone Replacement

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1964
Author(s):  
Michael Seidenstuecker ◽  
Pia Schilling ◽  
Lucas Ritschl ◽  
Svenja Lange ◽  
Hagen Schmal ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Pore Size ◽  
Fused Deposition Modeling ◽  
Experimental Period ◽  
Fused Deposition ◽  
A Value ◽  
Significant Difference ◽  
Strand Spacing ◽  
Deposition Modeling ◽  
Good Biocompatibility

The objective of this study was to vary the wall thicknesses and pore sizes of inversely printed 3D molded bodies. Wall thicknesses were varied from 1500 to 2000 to 2500 µm. The pores had sizes of 500, 750 and 1000 µm. The sacrificial structures were fabricated from polylactide (PLA) using fused deposition modeling (FDM). To obtain the final bioceramic scaffolds, a water-based slurry was filled into the PLA molds. The PLA sacrificial molds were burned out at approximately 450 °C for 4 h. Subsequently, the samples were sintered at 1250 °C for at least 4 h. The scaffolds were mechanically characterized (native and after incubation in simulated body fluid (SBF) for 28 days). In addition, the biocompatibility was assessed by live/dead staining. The scaffolds with a strand spacing of 500 µm showed the highest compressive strength; there was no significant difference in compressive strength regardless of pore size. The specimens with 1000 µm pore size showed a significant dependence on strand width. Thus, the specimens (1000 µm pores) with 2500 µm wall thickness showed the highest compressive strength of 5.97 + 0.89 MPa. While the 1000(1500) showed a value of 2.90 + 0.67 MPa and the 1000(2000) of 3.49 + 1.16 MPa. As expected for beta-Tricalciumphosphate (β-TCP), very good biocompatibility was observed with increasing cell numbers over the experimental period.

scholarly journals Analysis of the Influencing Factors of FDM-Supported Positions for the Compressive Strength of Printing Components

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4008
Author(s):  
Zhengkai Feng ◽  
Heng Wang ◽  
Chuanjiang Wang ◽  
Xiujuan Sun ◽  
Shuai Zhang
Keyword(s):  
Compressive Strength ◽  
Stress Intensity ◽  
Influencing Factors ◽  
Fused Deposition Modeling ◽  
Experimental Results ◽  
Compression Tests ◽  
Suspended State ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Reference Experiment

Fused deposition modeling (FDM) has the advantage of being able to process complex workpieces with relatively simple operations. However, when processing complex components in a suspended state, it is necessary to add support parts to be processed and formed, which indicates an excessive dependence on support. The stress intensity of the supported positions of the printing components can be modified by changing the supporting model of the parts, their density, and their distance in relation to the Z direction in the FDM printing settings. The focus of the present work was to study the influences of these three modified factors on the stress intensity of the supporting position of the printing components. In this study, 99 sets of compression tests were carried out using a position of an FDM-supported part, and the experimental results were observed and analyzed with a 3D topographic imager. A reference experiment on the anti-pressure abilities of the printing components without support was also conducted. The experimental results clarify how the above factors can affect the anti-pressure abilities of the supporting positions of the printing components. According to the results, when the supporting density is 30% and the supporting distance in the Z direction is Z = 0.14, the compressive strength of the printing component is lowest. When the supporting density of the printing component is ≤30% and the supporting distance in the Z direction is Z ≥ 0.10, the compressive strength of printing without support is greater than that of the linear support model. Under the same conditions, the grid-support method offers the highest compressive strength.

scholarly journals Fabrication of Drug-Eluting Nano-Hydroxylapatite Filled Polycaprolactone Nanocomposites Using Solution-Extrusion 3D Printing Technique

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 318 ◽  
Author(s):  
Pang-Yun Chou ◽  
Ying-Chao Chou ◽  
Yu-Hsuan Lai ◽  
Yu-Ting Lin ◽  
Chia-Jung Lu ◽  
...  
Keyword(s):  
3D Printing ◽  
Fused Deposition Modeling ◽  
Three Dimensional ◽  
Fused Deposition ◽  
Drug Eluting ◽  
Deposition Modeling ◽  
3D Printed ◽  
Good Biocompatibility ◽  
3D Printing Technique ◽  
Moving Speed

Polycaprolactone/nano-hydroxylapatite (PCL/nHA) nanocomposites have found use in tissue engineering and drug delivery owing to their good biocompatibility with these types of applications in addition to their mechanical characteristics. Three-dimensional (3D) printing of PCL/nHA nanocomposites persists as a defiance mostly because of the lack of commercial filaments for the conventional fused deposition modeling (FDM) method. In addition, as the composites are prepared using FDM for the purpose of delivering pharmaceuticals, thermal energy can destroy the embedded drugs and biomolecules. In this report, we investigated 3D printing of PCL/nHA using a lab-developed solution-extrusion printer, which consists of an extrusion feeder, a syringe with a dispensing nozzle, a collection table, and a command port. The effects of distinct printing variables on the mechanical properties of nanocomposites were investigated. Drug-eluting nanocomposite screws were also prepared using solution-extrusion 3D printing. The empirical outcomes suggest that the tensile properties of the 3D-printed PCL/nHA nanocomposites increased with the PCL/nHA-to-dichloromethane (DCM) ratio, fill density, and print orientation but decreased with an increase in the moving speed of the dispensing tip. Furthermore, printed drug-eluting PCL/nHA screws eluted high levels of antimicrobial vancomycin and ceftazidime over a 14-day period. Solution-extrusion 3D printing demonstrated excellent capabilities for fabricating drug-loaded implants for various medical applications.

scholarly journals Inversely 3D-Printed β-TCP Scaffolds for Bone Replacement

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3417 ◽  
Author(s):  
Michael Seidenstuecker ◽  
Svenja Lange ◽  
Steffen Esslinger ◽  
Sergio H. Latorre ◽  
Rumen Krastev ◽  
...  
Keyword(s):  
Lactate Dehydrogenase ◽  
Simulated Body Fluid ◽  
Pore Structure ◽  
Body Fluid ◽  
Fused Deposition Modeling ◽  
Lactate Dehydrogenase Activity ◽  
Fused Deposition ◽  
Bone Replacement ◽  
Strand Spacing ◽  
Deposition Modeling

The aim of this study was to predefine the pore structure of β-tricalcium phosphate (β-TCP) scaffolds with different macro pore sizes (500, 750, and 1000 µm), to characterize β-TCP scaffolds, and to investigate the growth behavior of cells within these scaffolds. The lead structures for directional bone growth (sacrificial structures) were produced from polylactide (PLA) using the fused deposition modeling techniques. The molds were then filled with β-TCP slurry and sintered at 1250 °C, whereby the lead structures (voids) were burnt out. The scaffolds were mechanically characterized (native and after incubation in simulated body fluid (SBF) for 28 d). In addition, biocompatibility was investigated by live/dead, cell proliferation and lactate dehydrogenase assays. The scaffolds with a strand spacing of 500 µm showed the highest compressive strength, both untreated (3.4 ± 0.2 MPa) and treated with simulated body fluid (2.8 ± 0.2 MPa). The simulated body fluid reduced the stability of the samples to 82% (500), 62% (750) and 56% (1000). The strand spacing and the powder properties of the samples were decisive factors for stability. The fact that β-TCP is a biocompatible material is confirmed by the experiments. No lactate dehydrogenase activity of the cells was measured, which means that no cytotoxicity of the material could be detected. In addition, the proliferation rate of all three sizes increased steadily over the test days until saturation. The cells were largely adhered to or within the scaffolds and did not migrate through the scaffolds to the bottom of the cell culture plate. The cells showed increased growth, not only on the outer surface (e.g., 500: 36 ± 33 vital cells/mm² after three days, 180 ± 33 cells/mm² after seven days, and 308 ± 69 cells/mm² after 10 days), but also on the inner surface of the samples (e.g., 750: 49 ± 17 vital cells/mm² after three days, 200 ± 84 cells/mm² after seven days, and 218 ± 99 living cells/mm² after 10 days). This means that the inverse 3D printing method is very suitable for the presetting of the pore structure and for the ingrowth of the cells. The experiments on which this work is based have shown that the fused deposition modeling process with subsequent slip casting and sintering is well suited for the production of scaffolds for bone replacement.

scholarly journals Design of Scaffold with Controlled internal Architecture using Fused Deposition Modeling (FDM)

2019 ◽  
Vol 9 (1) ◽  
pp. 2764-2768
Keyword(s):  
Tissue Engineering ◽  
Compressive Strength ◽  
Pore Size ◽  
Fused Deposition Modeling ◽  
Tool Path ◽  
Slice Thickness ◽  
Manufacturing Method ◽  
Fused Deposition ◽  
Scaffold Structure ◽  
Internal Architecture

In bone tissue engineering, scaffolds play a vital role in regeneration of tissue. It acts as a template for cell interaction and formation of extracellular matrix to provide structural support to newly formed bone tissues. The scaffold design and manufacturing with additive manufacturing method are still challenging. The parameters of scaffold structure are pore size, pore interconnectivity, porosity, and surface area to volume ratio, strength and stiffness of the material. Among these, porosity is directly influencing stiffness and strength of the structure. Higher porosity can accommodate more number of tissues and interconnected pore allow uniform distribution of cells in the scaffold structure. The objective of this work is to develop scaffold structures with controlled internal architecture using FDM and evaluate the percentage variation in compressive strength and structural modulus of scaffold structures. The internal architecture is controlled by porosity and pore size of scaffold with custom defined tool path of FDM system in pre-processing software. In this work, using the custom defined tool path with minimum slice thickness, the scaffold developed are found with maximum porosity of 82.7% and compressive strength varied from 1.76 MPa to 9.34 MPa and structural modulus of scaffold varied from 52.2 MPa to 212.MPa. These results showed that FDM process is suitable for tissue engineering applications. The material used in this study is ABS, which is biocompatible.

scholarly journals Optimizing process parameters to improve the compressive strength of FDM products (Fused Deposition Modeling)

2017 ◽  
Vol 20 (K5) ◽  
pp. 37-43
Author(s):  
Nghi Huu Huynh ◽  
Ton Minh Tran ◽  
Tho Huu Nguyen ◽  
Ha Thi Thu Thai
Keyword(s):  
Compressive Strength ◽  
3D Printing ◽  
Process Parameters ◽  
Fused Deposition Modeling ◽  
Industrial Revolution ◽  
Optimum Process ◽  
Modeling Technology ◽  
Fused Deposition ◽  
Raster Angle ◽  
Deposition Modeling

Nowadays, 3D Printing Technology, also known as AM - Additive Manufacturing plays an important role in the 4.0 industrial revolution. In 3D printing technologies, FDM (Fused Deposition Modeling) technology is the most popular technology. In general, the quality of AM products and FDM depend on the process parameters. The article addressed the issue of optimizing process parameters to improve the compressive strength of the product. The parameters are considered as the fill pattern, fill density, number of contours, layer thickness and raster angle. The experimental design based on the Taguchi method is employed to identify the optimum process parameters. In addition, ANOVA is also utilized to evaluate the effect of each parameter on the compressive strength of the product.

Biodegradable 3D Printed Polymer Microneedles for Transdermal Drug Delivery

2018 ◽  
Author(s):  
Michael A. Luzuriaga ◽  
Danielle R. Berry ◽  
John C. Reagan ◽  
Ronald A. Smaldone ◽  
Jeremiah J. Gassensmith
Keyword(s):  
Drug Delivery ◽  
3D Printing ◽  
Transdermal Drug Delivery ◽  
Fused Deposition Modeling ◽  
Fused Deposition ◽  
Modeling Software ◽  
Deposition Modeling ◽  
3D Printed ◽  
Microfabrication Technique ◽  
Mechanical Strengths

Biodegradable polymer microneedle (MN) arrays are an emerging class of transdermal drug delivery devices that promise a painless and sanitary alternative to syringes; however, prototyping bespoke needle architectures is expensive and requires production of new master templates. Here, we present a new microfabrication technique for MNs using fused deposition modeling (FDM) 3D printing using polylactic acid, an FDA approved, renewable, biodegradable, thermoplastic material. We show how this natural degradability can be exploited to overcome a key challenge of FDM 3D printing, in particular the low resolution of these printers. We improved the feature size of the printed parts significantly by developing a post fabrication chemical etching protocol, which allowed us to access tip sizes as small as 1 μm. With 3D modeling software, various MN shapes were designed and printed rapidly with custom needle density, length, and shape. Scanning electron microscopy confirmed that our method resulted in needle tip sizes in the range of 1 – 55 µm, which could successfully penetrate and break off into porcine skin. We have also shown that these MNs have comparable mechanical strengths to currently fabricated MNs and we further demonstrated how the swellability of PLA can be exploited to load small molecule drugs and how its degradability in skin can release those small molecules over time.

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