3D Printing of Layered Gradient Pore Structure of Brain-like Tissue

The pathological research and drug development of brain diseases require appropriate brain models. Given the complex, layered structure of the cerebral cortex, as well as the constraints on the medical ethics and the inaccuracy of animal models, it is necessary to construct a brain-like model in vitro. In this study, we designed and built integrated three-dimensional (3D) printing equipment for cell printing/culture, which can guarantee cell viability in the printing process and provide the equipment foundation for manufacturing the layered structures with gradient distribution of pore size. Based on this printing equipment, to achieve the purpose of printing the layered structures with multiple materials, we conducted research on the performance of bio-inks with different compositions and optimized the printing process. By extruding and stacking materials, we can print the layered structure with the uniform distribution of cells and the gradient distribution of pore sizes. Finally, we can accurately print a structure with 30 layers. The line width (resolution) of the printed monolayer structure was about 478 μm, the forming accuracy can reach 97.24%, and the viability of cells in the printed structure is as high as 94.5%.

Download Full-text

Recent Cell Printing Systems for Tissue Engineering

International Journal of Bioprinting ◽

10.18063/ijb.2017.01.004 ◽

2017 ◽

Vol 3 (1) ◽

Cited By ~ 25

Author(s):

Hyeongjin Lee ◽

YoungWon Koo ◽

Miji Yeo ◽

SuHon Kim ◽

Geun Hyung Kim

Keyword(s):

Tissue Engineering ◽

Growth Factors ◽

3D Printing ◽

Cell Damage ◽

Three Dimensional ◽

Human Tissues ◽

Printing Process ◽

Cell Printing ◽

3D Space ◽

Printing Ink

Three-dimensional (3D) printing in tissue engineering has been studied for the bio mimicry of the structures of human tissues and organs. Now it is being applied to 3D cell printing, which can position cells and biomaterials, such as growth factors, at desired positions in the 3D space. However, there are some challenges of 3D cell printing, such as cell damage during the printing process and the inability to produce a porous 3D shape owing to the embedding of cells in the hydrogel-based printing ink, which should be biocompatible, biodegradable, and non-toxic, etc. Therefore, researchers have been studying ways to balance or enhance the post-print cell viability and the print-ability of 3D cell printing technologies by accommodating several mechanical, electrical, and chemical based systems. In this mini-review, several common 3D cell printing methods and their modified applications are introduced for overcoming deficiencies of the cell printing process.

Download Full-text

Laser-based 3D cell printing for tissue engineering

BioNanoMaterials ◽

10.1515/bnm-2014-0005 ◽

2014 ◽

Vol 15 (3-4) ◽

Cited By ~ 6

Author(s):

Lothar Koch ◽

Andrea Deiwick ◽

Boris Chichkov

Keyword(s):

Tissue Engineering ◽

3D Printing ◽

Three Dimensional ◽

Living Cells ◽

Cell Printing ◽

Printing Technique ◽

Cell Patterns ◽

Printing Techniques

AbstractCurrently, different 3D printing techniques are investigated for printing biomaterials and living cells. An ambitious aim is the printing of fully functional tissue or organs. Furthermore, for manifold applications in biomedical research and in testing of pharmaceuticals or cosmetics, printed tissue could be a new method, partly substituting test animals. Here we describe a laser-based printing technique applied for the arrangement of vital cells in two and three-dimensional patterns and for tissue engineering. First printed tissue, tested in vitro and in vivo, and printing of cell patterns for investigating cell-cell interactions are presented.

Download Full-text

Three-dimensionally printed polycaprolactone/multicomponent bioactive glass scaffolds for potential application in bone tissue engineering

Biomedical glasses ◽

10.1515/bglass-2020-0006 ◽

2020 ◽

Vol 6 (1) ◽

pp. 57-69

Author(s):

Amirhosein Fathi ◽

Farzad Kermani ◽

Aliasghar Behnamghader ◽

Sara Banijamali ◽

Masoud Mozafari ◽

...

Keyword(s):

Tissue Engineering ◽

3D Printing ◽

Bone Tissue Engineering ◽

Bone Tissue ◽

Three Dimensional ◽

Layer By Layer ◽

Composite Scaffolds ◽

3D Printed ◽

Co Doped

AbstractOver the last years, three-dimensional (3D) printing has been successfully applied to produce suitable substitutes for treating bone defects. In this work, 3D printed composite scaffolds of polycaprolactone (PCL) and strontium (Sr)- and cobalt (Co)-doped multi-component melt-derived bioactive glasses (BGs) were prepared for bone tissue engineering strategies. For this purpose, 30% of as-prepared BG particles (size <38 μm) were incorporated into PCL, and then the obtained composite mix was introduced into a 3D printing machine to fabricate layer-by-layer porous structures with the size of 12 × 12 × 2 mm3.The scaffolds were fully characterized through a series of physico-chemical and biological assays. Adding the BGs to PCL led to an improvement in the compressive strength of the fabricated scaffolds and increased their hydrophilicity. Furthermore, the PCL/BG scaffolds showed apatite-forming ability (i.e., bioactivity behavior) after being immersed in simulated body fluid (SBF). The in vitro cellular examinations revealed the cytocompatibility of the scaffolds and confirmed them as suitable substrates for the adhesion and proliferation of MG-63 osteosarcoma cells. In conclusion, 3D printed composite scaffolds made of PCL and Sr- and Co-doped BGs might be potentially-beneficial bone replacements, and the achieved results motivate further research on these materials.

Download Full-text

Application of 3D printed model for planning the endoscopic endonasal transsphenoidal surgery

Scientific Reports ◽

10.1038/s41598-021-84779-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Xing Huang ◽

Ni Fan ◽

Hai-jun Wang ◽

Yan Zhou ◽

Xudong Li ◽

...

Keyword(s):

3D Printing ◽

Skull Base ◽

Transsphenoidal Surgery ◽

Three Dimensional ◽

Spatial Relationship ◽

Cranial Computed Tomography ◽

Imaging Data ◽

Endoscopic Endonasal ◽

Endoscopic Endonasal Transsphenoidal Surgery

AbstractThe application of 3D printing in planning endoscopic endonasal transsphenoidal surgery is illustrated based on the analysis of patients with intracranial skull base diseases who received treatment in our department. Cranial computed tomography/magnetic resonance imaging data are attained preoperatively, and three-dimensional reconstruction is performed using MIMICS (Materialise, Leuven, Belgium). Models of intracranial skull base diseases are printed using a 3D printer before surgery. The models clearly demonstrate the morphologies of the intracranial skull base diseases and the spatial relationship with adjacent large vessels and bones. The printing time of each model is 12.52–15.32 h, and the cost ranges from 900 to 1500 RMB. The operative approach was planned in vitro, and patients recovered postoperatively well without severe complications or death. In a questionnaire about the application of 3D printing, experienced neurosurgeons achieved scores of 7.8–8.8 out of 10, while unexperienced neurosurgeons achieved scores of 9.2–9.8. Resection of intracranial skull base lesions is demonstrated to be well assisted by 3D printing technique, which has great potential in disclosing adjacent anatomical relationships and providing the required help to clinical doctors in preoperative planning.

Download Full-text

On the Simulation of 3D Printing Process by a Novel Meshless Analysis Procedure

Journal of Mechanics ◽

10.1017/jmech.2019.28 ◽

2020 ◽

Vol 36 (3) ◽

pp. 285-294

Author(s):

Ying Mao ◽

Wen-Hwa Chen ◽

Ming-Hisao Lee

Keyword(s):

3D Printing ◽

Thermal Deformation ◽

Solid Phase ◽

Slenderness Ratio ◽

Three Dimensional ◽

Analysis Procedure ◽

Integration Scheme ◽

Practical Implementation ◽

Printing Process ◽

Equivalent Layer

ABSTRACTTo evaluate the thermal deformation induced by 3D Printing (Three Dimensional Printing) process, a novel meshless analysis procedure is established. To account for the heat transfer and solidification effects of each printing layer from liquid to solid phase transition, the layer temperature is measured by the implanted thermocouples. Based on the temperature variation measured, the printing layer temperature can be averaged and considered as uniform for thermal analysis. In addition, as observed by the deformation of the printed target through experiment, only linear thermal elastic analysis is performed.A rigorous algorithm for simulating the 3D Printing process is presented herein. Since the interpolation functions are no longer polynomials, a simple integration scheme using uniform integration points is applied to calculate the global stiffness matrix. Thus, the density and location of the integration points can be easily adjusted to fulfill the required accuracy. Further, for practical implementation, the simulation is also carried out by the concept of equivalent layer.Demonstrative cases of printing a rectangular PLA (Polylactic Acid) brick are tackled to prove the accuracy and efficiency of the proposed meshless analysis procedure. The effects of layer thickness, equivalent layer and slenderness ratio on the thermal deformation of the printed brick are also investigated.

Download Full-text

Evaluation of the 3D Printing Accuracy of a Dental Model According to Its Internal Structure and Cross-Arch Plate Design: An In Vitro Study

Materials ◽

10.3390/ma13235433 ◽

2020 ◽

Vol 13 (23) ◽

pp. 5433

Author(s):

Seung-Ho Shin ◽

Jung-Hwa Lim ◽

You-Jung Kang ◽

Jee-Hwan Kim ◽

June-Sung Shim ◽

...

Keyword(s):

3D Printing ◽

Internal Structure ◽

Three Dimensional ◽

In Vitro Study ◽

Thick Shell ◽

Plate Design ◽

Dental Model ◽

3D Printed ◽

Modeling Data

The amount of photopolymer material consumed during the three-dimensional (3D) printing of a dental model varies with the volume and internal structure of the modeling data. This study analyzed how the internal structure and the presence of a cross-arch plate influence the accuracy of a 3D printed dental model. The model was designed with a U-shaped arch and the palate removed (Group U) or a cross-arch plate attached to the palate area (Group P), and the internal structure was divided into five types. The trueness and precision were analyzed for accuracy comparisons of the 3D printed models. Two-way ANOVA of the trueness revealed that the accuracy was 135.2 ± 26.3 µm (mean ± SD) in Group U and 85.6 ± 13.1 µm in Group P. Regarding the internal structure, the accuracy was 143.1 ± 46.8 µm in the 1.5 mm-thick shell group, which improved to 111.1 ± 31.9 µm and 106.7 ± 26.3 µm in the roughly filled and fully filled models, respectively. The precision was 70.3 ± 19.1 µm in Group U and 65.0 ± 8.8 µm in Group P. The results of this study suggest that a cross-arch plate is necessary for the accurate production of a model using 3D printing regardless of its internal structure. In Group U, the error during the printing process was higher for the hollowed models.

Download Full-text

A Heuristic Scaling Strategy for Multi-Robot Cooperative Three-Dimensional Printing

Journal of Computing and Information Science in Engineering ◽

10.1115/1.4045143 ◽

2020 ◽

Vol 20 (4) ◽

Author(s):

Laxmi Poudel ◽

Chandler Blair ◽

Jace McPherson ◽

Zhenghui Sha ◽

Wenchao Zhou

Keyword(s):

3D Printing ◽

Fused Deposition Modeling ◽

Three Dimensional ◽

Evaluation Framework ◽

Geometric Constraints ◽

Mathematical Representation ◽

Printing Process ◽

Fused Deposition ◽

3D Printers ◽

Printing Time

Abstract While three-dimensional (3D) printing has been making significant strides over the past decades, it still trails behind mainstream manufacturing due to its lack of scalability in both print size and print speed. Cooperative 3D printing (C3DP) is an emerging technology that holds the promise to mitigate both of these issues by having a swarm of printhead-carrying mobile robots working together to finish a single print job cooperatively. In our previous work, we have developed a chunk-based printing strategy to enable the cooperative 3D printing with two fused deposition modeling (FDM) mobile 3D printers, which allows each of them to print one chunk at a time without interfering with the other and the printed part. In this paper, we present a novel method in discretizing the continuous 3D printing process, where the desired part is discretized into chunks, resulting in multi-stage 3D printing process. In addition, the key contribution of this study is the first working scaling strategy for cooperative 3D printing based on simple heuristics, called scalable parallel arrays of robots for 3DP (SPAR3), which enables many mobile 3D printers to work together to reduce the total printing time for large prints. In order to evaluate the performance of the printing strategy, a framework is developed based on directed dependency tree (DDT), which provides a mathematical and graphical description of dependency relationships and sequence of printing tasks. The graph-based framework can be used to estimate the total print time for a given print strategy. Along with the time evaluation metric, the developed framework provides us with a mathematical representation of geometric constraints that are temporospatially dynamic and need to be satisfied in order to achieve collision-free printing for any C3DP strategy. The DDT-based evaluation framework is then used to evaluate the proposed SPAR3 strategy. The results validate the SPAR3 as a collision-free strategy that can significantly shorten the printing time (about 11 times faster with 16 robots for the demonstrated examples) in comparison with the traditional 3D printing with single printhead.

Download Full-text

A Collaborative and Ubiquitous System for Fabricating Dental Parts Using 3D Printing Technologies

Healthcare ◽

10.3390/healthcare7030103 ◽

2019 ◽

Vol 7 (3) ◽

pp. 103 ◽

Cited By ~ 10

Author(s):

Wang ◽

Chen ◽

Lin

Keyword(s):

3D Printing ◽

Three Dimensional ◽

Mixed Integer ◽

Printing Process ◽

Planning Optimization ◽

Integer Quadratic Programming ◽

Ubiquitous System ◽

Independent Decision ◽

Mixed Integer Quadratic Programming ◽

And Control

Three-dimensional (3D) printing has great potential for establishing a ubiquitous service in the medical industry. However, the planning, optimization, and control of a ubiquitous 3D printing network have not been sufficiently discussed. Therefore, this study established a collaborative and ubiquitous system for making dental parts using 3D printing. The collaborative and ubiquitous system split an order for the 3D printing facilities to fulfill the order collaboratively and forms a delivery plan to pick up the 3D objects. To optimize the performance of the two tasks, a mixed-integer linear programming (MILP) model and a mixed-integer quadratic programming (MIQP) model are proposed, respectively. In addition, slack information is derived and provided to each 3D printing facility so that it can determine the feasibility of resuming the same 3D printing process locally from the beginning without violating the optimality of the original printing and delivery plan. Further, more slack is gained by considering the chain effect between two successive 3D printing facilities. The effectiveness of the collaborative and ubiquitous system was validated using a regional experiment in Taichung City, Taiwan. Compared with two existing methods, the collaborative and ubiquitous 3D printing network reduced the manufacturing lead time by 45% on average. Furthermore, with the slack information, a 3D printing facility could make an independent decision about the feasibility of resuming the same 3D printing process locally from the beginning.

Download Full-text

New Materials for 3D-Printing Based on Polycaprolactone with Gum Rosin and Beeswax as Additives

Polymers ◽

10.3390/polym12020334 ◽

2020 ◽

Vol 12 (2) ◽

pp. 334 ◽

Cited By ~ 4

Author(s):

Cristina Pavon ◽

Miguel Aldas ◽

Juan López-Martínez ◽

Santiago Ferrándiz

Keyword(s):

Tensile Strength ◽

3D Printing ◽

Mechanical Characterization ◽

Three Dimensional ◽

New Materials ◽

Elongation At Break ◽

Printing Process ◽

Gum Rosin ◽

The Matrix ◽

Natural Additives

In this work, different materials for three-dimensional (3D)-printing were studied, which based on polycaprolactone with two natural additives, gum rosin, and beeswax. During the 3D-printing process, the bed and extrusion temperatures of each formulation were established. After, the obtained materials were characterized by mechanical, thermal, and structural properties. The results showed that the formulation with containing polycaprolactone with a mixture of gum rosin and beeswax as additive behaved better during the 3D-printing process. Moreover, the miscibility and compatibility between the additives and the matrix were concluded through the thermal assessment. The mechanical characterization established that the addition of the mixture of gum rosin and beeswax provides greater tensile strength than those additives separately, facilitating 3D-printing. In contrast, the addition of beeswax increased the ductility of the material, which makes the 3D-printing processing difficult. Despite the fact that both natural additives had a plasticizing effect, the formulations containing gum rosin showed greater elongation at break. Finally, Fourier-Transform Infrared Spectroscopy assessment deduced that polycaprolactone interacts with the functional groups of the additives.

Download Full-text