Stem Cell Production With A 3D Bioprinter
Dr. Utkan Demirci from Harvard University produced a print with droplet containing human embryonic stem cells by 3D bioprinter.
Stating that they can control the droplet size and cell number during printing with the methods they use, Assoc. Dr. Demirci said that this study will break new ground in the treatment of problems encountered in stem cell production and organ transplantation. Turkish scientists continue to achieve worldwide success. Having made a name for himself with his studies, Assoc. Dr. Utkan Demirci is getting ready to break new ground. Many attempts have been made to develop the use of stem cells in medicine. Continuing his studies on the use of human embryonic stem cells in 3D printing for the first time and speaking to Esra Öz from Med-Index, Demirci gave the following information about the study:
It is possible to print cells as droplets with a 3D printer. When you hang these droplets, it’s called the so-called “hanging drop method”. Then the cells begin to merge and divide with each other and form the 3D cluster. This is where the name 3D comes from. We made bionic stem cells with this advanced technique that we introduced in the field of bioprinting before.
In this droplet printing containing human embryonic stem cells, the size of the droplets and the number of cells that will go to these droplets can be controlled, and really well-controlled cells are printed on the surface. Your ability to control the number and size of cells allows you to create reproducible embryonic stem cell fusion. Thanks to this automated system, 3D structures are obtained and these images can be repeated in the same size and volume on top of each other. This point is important because if you’re looking for a scientific answer it’s important to be controlled so that our experiments aren’t affected by size or human factors.
3D Bioprinting Technique
Three-dimensional (3d) printing is defined as the material output of a three-dimensional model.
This material output is the result of the successive stacking of two-dimensional layers.
3D printing is considered different from traditional processing techniques that rely on cutting and drilling and removing material.
A 3d printer is a type of industrial robot that produces computer-controlled three-dimensional material output. 3d printing technology are used in various fields such as industrial design (car), engineering, architecture (home), military, medical sector (orthotics, prosthetics), biotechnology (human tissue equivalents), fashion (shoes, clothes), food (cakes, meat) and many other fields. The printing process with this technology is based on the use of basic techniques such as fused deposition modeling (FDM), inkjet material deposition, sintering (SLS – selective laser sintering, DLMS – direct laser metal sintering), selective laser melting (SLM), laminated object fabrication (LOM). is performed.
Biomimicry aims to produce biological structures that have the same characteristics as the real biological structure by examining the nature and functionality of cells.
Biomimicry aims to produce biological structures that have the same characteristics as the real biological structure by examining the nature and functionality of cells. Autonomic assembly aims to provide the same structural features, cell localization and tissue functionality as the real biological structure by examining the interactions of cells with each other. The term mini-tissue, in association with the above two strategies, refers to tissue or organs obtained by combining small functional building blocks. The bioprinting process consists of six main topics: imaging, design, material, cell, bioprinting and application.
In the imaging step, complex architectural information to be used in computer-aided design and mathematical modeling of biological structures is obtained by using medical imaging devices.
Raw data obtained with imaging devices are converted into 3D digital (CAD/CAM) drawings using a computer-aided software package.
In the design step, the appropriate design approach or combinations of these approaches are determined for the target tissue planned to be produced. 3D digital drawings processed according to design approaches are prepared for bioprinting and sliced into two-dimensional successive layers of certain thicknesses.
Synthetic and natural polymers and the extracellular medium (ECM) are commonly used in the material step. The cell source used in the cell step may be allogeneic or autologous. These components are integrated into inkjet, microextrusion or laser-assisted bioprinters. In the bioprinting step, selected materials and cell sources are used together with inkjet, microextrusion and laser-assisted printing technologies developed specifically for the target tissue to form living structures. In the application step, some tissues may require a period of maturation in the bioreactor before transplantation. These tissues can alternatively be used in in-vitro (lab environment) applications.
Tissues that have completed the maturation period are analyzed and suitability for the target tissue is determined. Mainly used bio printing technologies; are inkjet, microextrusion and laser assisted printing systems. In inkjet printers, the print head is heated electrically and pulses of air pressure are generated in the head that cause dripping. Sound printers use pulses of piezoelectric or ultrasound pressure. Microextrusion printers use pneumatic or mechanical systems for extrusion. In laser-assisted printers, a pulse is generated using a laser focused on the absorbent surface. The cells are pushed towards a collecting surface located at the bottom by this pressure. Microextrusion printing technology is the most commonly used and most cost-effective printing technology. This printing technology is usually realized by temperature-controlled material delivery and extrusion, which can move in 3 dimensions along the X, Y and Z axes. Some bioprinters have multiple printheads that allow to print different cell type. Printers using microextrusion technology perform robot-controlled material extrusion. In microextrusion technology, extrusion is carried out with pneumatic or mechanical (piston or shaft) systems. Mechanical systems perform a healthier extrusion than pneumatic systems. The reason for this is that this event is realized by gas pressure in pneumatic systems, and by a piston or shaft in mechanical systems. While pneumatic systems are large and easily applicable, mechanical systems have a smaller, sensitive and complex structure.
Microextrusion technology can be used with many biocompatible materials that have fluid properties and are known in the literature.
