scholarly journals 3D Printed Model of Extrahepatic Biliary Ducts for Biliary Stent Testing

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4788
Author(s):  
Joanna Thomas ◽  
Sagar Patel ◽  
Leia Troop ◽  
Robyn Guru ◽  
Nicholas Faist ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Computer Aided Design ◽  
Bile Ducts ◽  
Biliary Stent ◽  
Metal Stents ◽  
In Vitro Testing ◽  
Stent Deployment ◽  
3D Print ◽  
3D Printed

Several inflammatory conditions of the bile ducts cause strictures that prevent the drainage of bile into the gastrointestinal tract. Non-pharmacological treatments to re-establish bile flow include plastic or self-expanding metal stents (SEMs) that are inserted in the bile ducts during endoscopic retrograde cholangiopancreatography (ERCP) procedures. The focus of this study was to 3D print an anatomically accurate model of the extrahepatic bile ducts (EHBDs) with tissue-like mechanical properties to improve in vitro testing of stent prototypes. Following generation of an EHBD model via computer aided design (CAD), we tested the ability of Formlabs SLA 3D printers to precisely print the model with polymers selected based on the desired mechanical properties. We found the printers were reliable in printing the dimensionally accurate EHBD model with candidate polymers. Next, we evaluated the mechanical properties of Formlabs Elastic (FE), Flexible (FF), and Durable (FD) resins pre- and post-exposure to water, saline, or bile acid solution at 37 °C for up to one week. FE possessed the most bile duct-like mechanical properties based on its elastic moduli, percent elongations at break, and changes in mass under all liquid exposure conditions. EHBD models printed in FE sustained no functional damage during biliary stent deployment or when tube connectors were inserted, and provided a high level of visualization of deployed stents. These results demonstrate that our 3D printed EHBD model facilitates more realistic pre-clinical in vitro testing of biliary stent prototypes.

scholarly journals Fabrication of Polycaprolactone/Nano Hydroxyapatite (PCL/nHA) 3D Scaffold with Enhanced In Vitro Cell Response via Design for Additive Manufacturing (DfAM)

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1394
Author(s):  
Yong Sang Cho ◽  
So-Jung Gwak ◽  
Young-Sam Cho
Keyword(s):  
Mechanical Properties ◽  
Cell Response ◽  
Structural Characteristics ◽  
Structure Design ◽  
Compressive Modulus ◽  
Control Group ◽  
Design For Additive Manufacturing ◽  
3D Scaffold ◽  
3D Printed

In this study, we investigated the dual-pore kagome-structure design of a 3D-printed scaffold with enhanced in vitro cell response and compared the mechanical properties with 3D-printed scaffolds with conventional or offset patterns. The compressive modulus of the 3D-printed scaffold with the proposed design was found to resemble that of the 3D-printed scaffold with a conventional pattern at similar pore sizes despite higher porosity. Furthermore, the compressive modulus of the proposed scaffold surpassed that of the 3D-printed scaffold with conventional and offset patterns at similar porosities owing to the structural characteristics of the kagome structure. Regarding the in vitro cell response, cell adhesion, cell growth, and ALP concentration of the proposed scaffold for 14 days was superior to those of the control group scaffolds. Consequently, we found that the mechanical properties and in vitro cell response of the 3D-printed scaffold could be improved by kagome and dual-pore structures through DfAM. Moreover, we revealed that the dual-pore structure is effective for the in vitro cell response compared to the structures possessing conventional and offset patterns.

scholarly journals Effect of Selected Commercial Plasticizers on Mechanical, Thermal, and Morphological Properties of Poly(3-hydroxybutyrate)/Poly(lactic acid)/Plasticizer Biodegradable Blends for Three-Dimensional (3D) Print

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1893 ◽  
Author(s):  
Přemysl Menčík ◽  
Radek Přikryl ◽  
Ivana Stehnová ◽  
Veronika Melčová ◽  
Soňa Kontárová ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Thermal Properties ◽  
Three Dimensional ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Modulated Differential Scanning Calorimetry ◽  
3D Print ◽  
3D Printed ◽  
Biodegradable Blends

This paper explores the influence of selected commercial plasticizers structure, which are based on esters of citric acid, on mechanical and thermal properties of Poly(3-hydroxybutyrate)/Poly(lactic acid)/Plasticizer biodegradable blends. These plasticizers were first tested with respect to their miscibility with Poly(3-hydroxybutyrate)/Poly(lactic acid) (PHB/PLA) blends using a kneading machine. PHB/PLA/plasticizer blends in the weight ratio (wt %) of 60/25/15 were then prepared by single screw and corotating meshing twin screw extruders in the form of filament for further three-dimensional (3D) printing. Mechanical, thermal properties, and shape stability (warping effect) of 3D printed products can be improved just by the addition of appropriate plasticizer to polymeric blend. The goal was to create new types of eco-friendly PHB/PLA/plasticizers blends and to highly improve the poor mechanical properties of neat PHB/PLA blends (with majority of PHB) by adding appropriate plasticizer. Mechanical properties of plasticized blends were then determined by the tensile test of 3D printed test samples (dogbones), as well as filaments. Measured elongation at break rapidly enhanced from 21% for neat non-plasticized PHB/PLA blends (reference) to 328% for best plasticized blends in the form of filament, and from 5% (reference) to 187% for plasticized blends in the form of printed dogbones. The plasticizing effect on blends was confirmed by Modulated Differential Scanning Calorimetry. The study of morphology was performed by the Scanning Electron Microscopy. Significant problem of plasticized blends used to be also plasticizer migration, therefore the diffusion of plasticizers from the blends after 15 days of exposition to 110 °C in the drying oven was investigated as their measured weight loss. Almost all of the used plasticizers showed meaningful positive softening effects, but the diffusion of plasticizers at 110 °C exposition was quite extensive. The determination of the degree of disintegration of selected plasticized blend when exposed to a laboratory-scale composting environment was executed to roughly check the “biodegradability”.

scholarly journals Radiopaque Chitosan Ducts Fabricated by Extrusion-Based 3D Printing to Promote Healing After Pancreaticoenterostomy

2021 ◽  
Vol 9 ◽  
Author(s):  
Maoen Pan ◽  
Chaoqian Zhao ◽  
Zeya Xu ◽  
Yuanyuan Yang ◽  
Tianhong Teng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Pancreatic Duct ◽  
Silicone Rubber ◽  
The Body ◽  
Molecular Weights ◽  
Pancreatic Duct Stent ◽  
3D Printed

Long-term placement of non-degradable silicone rubber pancreatic duct stents in the body is likely to cause inflammation and injury. Therefore, it is necessary to develop degradable and biocompatible stents to replace silicone rubber tubes as pancreatic duct stents. The purpose of our research was to verify the feasibility and biological safety of extrusion-based 3D printed radiopaque chitosan (CS) ducts for pancreaticojejunostomy. Chitosan-barium sulfate (CS-Ba) ducts with different molecular weights (low-, medium-, and high-molecular weight CS-Ba: LCS-Ba, MCS-Ba, and HCS-Ba, respectively) were soaked in vitro in simulated pancreatic juice (SPJ) (pH 8.0) with or without pancreatin for 16 weeks. Changes in their weight, water absorption rate and mechanical properties were tested regularly. The biocompatibility, degradation and radiopaque performance were verified by in vivo and in vitro experiments. The results showed that CS-Ba ducts prepared by this method had regular compact structures and good molding effects. In addition, the lower the molecular weight of the CS-Ba ducts was, the faster the degradation rate was. Extrusion-based 3D-printed CS-Ba ducts have mechanical properties that match those of soft tissue, good biocompatibility and radioopacity. In vitro studies have also shown that CS-Ba ducts can promote the growth of fibroblasts. These stents have great potential for use in pancreatic duct stent applications in the future.

scholarly journals The Effects of Combined Infill Patterns on Mechanical Properties in FDM Process

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2792
Author(s):  
Mohammadreza Lalegani Dezaki ◽  
Mohd Khairol Anuar Mohd Ariffin
Keyword(s):  
Mechanical Properties ◽  
Computer Aided Design ◽  
Fused Deposition Modeling ◽  
Strength Analysis ◽  
Element Analysis ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
3D Printed ◽  
Complex Features ◽  
Aided Design

Fused deposition modeling (FDM) is commonly used to print different products with highly complex features. Process parameters for FDM are divided into controllable or uncontrollable parameters. The most critical ones are built orientation, layer thickness, infill pattern, infill density, and nozzle diameter. This study investigates the effects of combined infill patterns in 3D printed products. Five patterns (solid, honeycomb, wiggle, grid, and rectilinear) were combined in samples to analyze their effects on mechanical properties for tensile strength analysis. Polylactic acid (PLA) samples were printed in different build orientations through two directions: flat and on-edge. The limitation was that the software and machine could not combine the infill patterns. Thus, the patterns were designed and assembled in computer aided design (CAD) software. Finite element analysis (FEA) was used to determine the patterns’ features and results showed honeycomb and grid have the highest strength while their weights were lighter compared to solid. Moreover, 0° samples in both flat and on-edge direction had the strongest layer adhesion and the best quality. In contrast, perpendicular samples like 60° and 75° showed poor adhesion and were the weakest specimens in both flat and on-edge, respectively. In brief, by increasing the build orientation, the strength decreases in this study.

scholarly journals Comparison of the Accuracy of Three-Dimensional Printed Casts, Digital, and Conventional Casts: An In Vitro Study

2020 ◽  
Vol 14 (02) ◽  
pp. 189-193 ◽  
Author(s):  
Passent Aly ◽  
Cherif Mohsen
Keyword(s):  
Treatment Planning ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
In Vitro Study ◽  
Vitro Study ◽  
The Other ◽  
Intraoral Scanner ◽  
Linear Measurements ◽  
3D Printed

Abstract Objectives The integration of computer-aided design and manufacturing technologies in diagnosis, treatment planning, and fabrication of prosthetic restoration is changing the way in which prosthodontic treatment is provided to patients. The aim of this study was to compare the accuracy of three-dimensional (3D) printed casts produced from the intraoral scanner using stereolithographic (SLA) 3D printing technique, their digital replicas, and conventional stone casts. Materials and Methods In this in vitro study, a typodont of maxillary and mandibular arches with full dentate ivory teeth was used as a reference cast. The typodont was digitized using Trios 3Shape intraoral scanner to create digital casts. The digital files were converted into 3D printed physical casts using a prototyping machine that utilizes the stereolithography printing technology and photocurable polymer as printing material. Linear measurements (mesiodistal and occlusocervical) and interarch measurements (intercanine and intermolar) were made for digital and prototyped models and were compared with the original stone casts. The reference teeth were canines, first premolars and second premolars in the maxillary and mandibular arches on the right and left sides. The measurements on printed and conventional casts were done by digital caliper while on digital casts; Geomagic Qualify software was used. Statistical Analysis One-way analysis of variance (ANOVA) was used to compare measurements among groups. Results Digital casts showed significantly higher error than the other two groups in all linear and interarch measurements. The mean errors of the digital cast in occlusocervical (OC) and mesiodistal (MD) measurements (0.016 and 0.006, respectively) were higher compared with those in the other two groups (OC, 0.004 and 0.007 and MD, 0.003 and 0.005 [p < 0.0001 and p = 0.02, respectively]). Also, digital mean error in intermolar width (IMW) and intercanine width (ICW) (0.142 and 0.113, respectively) were greater than the other two groups (IMW, 0.019 and 0.008 and ICW, 0.021 and 0.011 [p < 0.0001]). However, the errors were within the acceptable clinical range. Conclusion The 3D printed casts may be considered as a substitute for stone casts with clinically acceptable accuracy that can be used in diagnosis, treatment planning, and fabrication of prosthetic restorations.

scholarly journals Fabrication and In Vitro Evaluation of 3D Printed Porous Polyetherimide Scaffolds for Bone Tissue Engineering

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Xiongfeng Tang ◽  
Yanguo Qin ◽  
Xinyu Xu ◽  
Deming Guo ◽  
Wenli Ye ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Cell Proliferation ◽  
Cell Adhesion ◽  
3D Printing ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Porous Scaffold ◽  
3D Printed

For bone tissue engineering, the porous scaffold should provide a biocompatible environment for cell adhesion, proliferation, and differentiation and match the mechanical properties of native bone tissue. In this work, we fabricated porous polyetherimide (PEI) scaffolds using a three-dimensional (3D) printing system, and the pore size was set as 800 μm. The morphology of 3D PEI scaffolds was characterized by the scanning electron microscope. To investigate the mechanical properties of the 3D PEI scaffold, the compressive mechanical test was performed via an electronic universal testing system. For the in vitro cell experiment, bone marrow stromal cells (BMSCs) were cultured on the surface of the 3D PEI scaffold and PEI slice, and cytotoxicity, cell adhesion, and cell proliferation were detected to verify their biocompatibility. Besides, the alkaline phosphatase staining and Alizarin Red staining were performed on the BMSCs of different samples to evaluate the osteogenic differentiation. Through these studies, we found that the 3D PEI scaffold showed an interconnected porous structure, which was consistent with the design. The elastic modulus of the 3D PEI scaffold (941.33 ± 65.26 MPa) falls in the range of modulus for the native cancellous bone. Moreover, the cell proliferation and morphology on the 3D PEI scaffold were better than those on the PEI slice, which revealed that the porous scaffold has good biocompatibility and that no toxic substances were produced during the progress of high-temperature 3D printing. The osteogenic differentiation level of the 3D PEI scaffold and PEI slice was equal and ordinary. All of these results suggest the 3D printed PEI scaffold would be a potential strategy for bone tissue engineering.

scholarly journals Development of Custom Wall-Less Cardiovascular Flow Phantoms with Tissue-Mimicking Gel

2021 ◽  
Author(s):  
Megan E. Laughlin ◽  
Sam E. Stephens ◽  
Jamie A. Hestekin ◽  
Morten O. Jensen
Keyword(s):  
Mechanical Properties ◽  
Continuous Flow ◽  
Cardiac Tissue ◽  
Flow Imaging ◽  
Straight Channel ◽  
Young’S Moduli ◽  
Flow Phantom ◽  
Cardiovascular Flow ◽  
3D Printed

Abstract Purpose Flow phantoms are used in experimental settings to aid in the simulation of blood flow. Custom geometries are available, but current phantom materials present issues with degradability and/or mimicking the mechanical properties of human tissue. In this study, a method of fabricating custom wall-less flow phantoms from a tissue-mimicking gel using 3D printed inserts is developed. Methods A 3D blood vessel geometry example of a bifurcated artery model was 3D printed in polyvinyl alcohol, embedded in tissue-mimicking gel, and subsequently dissolved to create a phantom. Uniaxial compression testing was performed to determine the Young’s moduli of the five gel types. Angle-independent, ultrasound-based imaging modalities, Vector Flow Imaging (VFI) and Blood Speckle Imaging (BSI), were utilized for flow visualization of a straight channel phantom. Results A wall-less phantom of the bifurcated artery was fabricated with minimal bubbles and continuous flow demonstrated. Additionally, flow was visualized through a straight channel phantom by VFI and BSI. The available gel types are suitable for mimicking a variety of tissue types, including cardiac tissue and blood vessels. Conclusion Custom, tissue-mimicking flow phantoms can be fabricated using the developed methodology and have potential for use in a variety of applications, including ultrasound-based imaging methods. This is the first reported use of BSI with an in vitro flow phantom.

scholarly journals Evaluation of Biodegradable PVA-Based 3D Printed Carriers during Dissolution

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1350
Author(s):  
Bálint Basa ◽  
Géza Jakab ◽  
Nikolett Kállai-Szabó ◽  
Bence Borbás ◽  
Viktor Fülöp ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Pharmaceutical Manufacturing ◽  
In Vitro Dissolution ◽  
Uv Spectrophotometry ◽  
Test Results ◽  
Computer Design ◽  
3D Printed ◽  
Aided Design ◽  
Kinetics Of

The presence of additive manufacturing, especially 3D printing, has the potential to revolutionize pharmaceutical manufacturing owing to the distinctive capabilities of personalized pharmaceutical manufacturing. This study’s aim was to examine the behavior of commonly used polyvinyl alcohol (PVA) under in vitro dissolution conditions. Polylactic acid (PLA) was also used as a comparator. The carriers were designed and fabricated using computer-aided design (CAD). After printing the containers, the behavior of PVA under in vitro simulated biorelevant conditions was monitored by gravimetry and dynamic light scattering (DLS) methods. The results show that in all the dissolution media PVA carriers were dissolved; the particle size was under 300 nm. However, the dissolution rate was different in various dissolution media. In addition to studying the PVA, as drug delivery carriers, the kinetics of drug release were investigated. These dissolution test results accompanied with UV spectrophotometry tracking indirectly determine the possibilities for modifying the output of quality by computer design.

scholarly journals Breaking the Third Wall: Implementing 3D-Printing Technics to Expand the Complexity and Abilities of Multi-Organ-on-a-Chip Devices

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 627
Author(s):  
Yoel Goldstein ◽  
Sarah Spitz ◽  
Keren Turjeman ◽  
Florian Selinger ◽  
Yechezkel Barenholz ◽  
...  
Keyword(s):  
Cell Culture ◽  
Cfd Simulation ◽  
Cost Effective ◽  
In Vitro Models ◽  
3D Print ◽  
Biological Compatibility ◽  
3D Printed ◽  
Organ On A Chip

The understanding that systemic context and tissue crosstalk are essential keys for bridging the gap between in vitro models and in vivo conditions led to a growing effort in the last decade to develop advanced multi-organ-on-a-chip devices. However, many of the proposed devices have failed to implement the means to allow for conditions tailored to each organ individually, a crucial aspect in cell functionality. Here, we present two 3D-print-based fabrication methods for a generic multi-organ-on-a-chip device: One with a PDMS microfluidic core unit and one based on 3D-printed units. The device was designed for culturing different tissues in separate compartments by integrating individual pairs of inlets and outlets, thus enabling tissue-specific perfusion rates that facilitate the generation of individual tissue-adapted perfusion profiles. The device allowed tissue crosstalk using microchannel configuration and permeable membranes used as barriers between individual cell culture compartments. Computational fluid dynamics (CFD) simulation confirmed the capability to generate significant differences in shear stress between the two individual culture compartments, each with a selective shear force. In addition, we provide preliminary findings that indicate the feasibility for biological compatibility for cell culture and long-term incubation in 3D-printed wells. Finally, we offer a cost-effective, accessible protocol enabling the design and fabrication of advanced multi-organ-on-a-chip devices.

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