Organ Printing Research Articles

3D bioprinting using stem cells

Recent advances have allowed for three-dimensional (3D) printing technologies to be applied to biocompatible materials, cells and supporting components, creating a field of 3D bioprinting that holds great promise for artificial organ printing and regenerative medicine. At the same time, stem cells, such as human induced pluripotent stem cells, have driven a paradigm shift in tissue regeneration and the modeling of human disease, and represent an unlimited cell source for tissue regeneration and the study of human disease. The ability to reprogram patient-specific cells holds the promise of an enhanced understanding of disease mechanisms and phenotypic variability. 3D bioprinting has been successfully performed using multiple stem cell types of different lineages and potency. The type of 3D bioprinting employed ranged from microextrusion bioprinting, inkjet bioprinting, laser-assisted bioprinting, to newer technologies such as scaffold-free spheroid-based bioprinting. This review discusses the current advances, applications, limitations and future of 3D bioprinting using stem cells, by organ systems.

Current and emerging applications of 3D printing in medicine

Three-dimensional (3D) printing enables the production of anatomically matched and patient-specific devices and constructs with high tunability and complexity. It also allows on-demand fabrication with high productivity in a cost-effective manner. As a result, 3D printing has become a leading manufacturing technique in healthcare and medicine for a wide range of applications including dentistry, tissue engineering and regenerative medicine, engineered tissue models, medical devices, anatomical models and drug formulation. Today, 3D printing is widely adopted by the healthcare industry and academia. It provides commercially available medical products and a platform for emerging research areas including tissue and organ printing. In this review, our goal is to discuss the current and emerging applications of 3D printing in medicine. A brief summary on additive manufacturing technologies and available printable materials is also given. The technological and regulatory barriers that are slowing down the full implementation of 3D printing in the medical field are also discussed.

3D Integrated Tissue and Organ Printing System to Produce Human Body Parts with Structural Integrity

Tissue engineering and regenerative medicine strategies could offer new hope for patients with serious tissue injuries or end‐stage organ failure. Scientists are now applying the principles of cell transplantation, material science, and engineering to create biological substitutes that can restore and maintain normal function in diseased or injured tissues/organs. Among various three‐dimensional (3D) biofabrication technologies developed for the field of tissue engineering, 3D printing technology is one of the most attractive and powerful methods for use in constructing a structure that mimics native tissues, and thus many researchers are focusing on development of new printing technologies and applications. The hypothesis driving development of 3D bioprinting is that by precisely placing cells in relation to each other, an environment that encourages physiologically relevant cues both to and from these cells can be created, resulting in a tissue construct with functionality. Thus, we have developed 3D integrated tissue and organ printing (ITOP) system to allow construction of biological substitutes that mimic the structure and function of native tissues or organs. This system makes it possible to precisely place various cell types and biomaterials in a single 3D architecture. Our proof of concept experiments demonstrates the capabilities of our ITOP by fabricating structures of various tissue constructs of appropriate shape and size needed for clinical use. This novel organ printing system provides a leap forward in our ability to fabricate tissue constructs that could be used in translational applications.Support or Funding InformationThis work was supported, in part, by grants from the Armed Forces Institute of Regenerative Medicine (W81XWH‐08‐2‐0032), the Telemedicine and Advanced Technology Research Center at the US Army Medical Research and Material Command (W81XWH‐07‐1‐0718) and the Defense Threat Reduction Agency (N66001‐13‐C‐2027).

Ligament flow during drop-on-demand inkjet printing of bioink containing living cells

Organ printing utilizes tissue spheroids or filaments as building blocks to fabricate three-dimensional (3D) functional tissues and organs based on a layer-by-layer manufacturing mechanism. These fabricated tissues and organs are envisioned as alternatives to replace the damaged human tissues and organs, which is emerging as a promising solution to solve the organ donor shortage problem being faced all over the world. Inkjetting, one of the key technologies in organ printing, has been widely developed because of its moderate fabrication cost, good process controllability, and scale-up potentials. There are several key steps towards inkjet-based organ printing: generation of droplets from bioink, fabrication of 3D cellular structures, and post-printing tissue fusion and maturation. The droplet formation process is the first step, affecting the overall feasibility of the envisioned organ printing technology. This paper focuses on the ligament flow of the droplet formation process during inkjet printing of bioink containing living cells and its corresponding effect on post-printing cell viability and cell distribution. It is found that (1) two types of ligament flow are observed: at 30 V (Type I), the ligament flow has two different directions at the locations near the nozzle orifice and the forming droplet; at 60 V (Type II), the ligament flow directions are the same at both locations; (2) compared to Type II, fewer cells are ejected into the primary droplets in Type I, because some cells move back into the nozzle driven by the ligament flow in the positive z direction; and (3) cell viability in both Type I and Type II is around 90% without a significant difference. The resulting knowledge will benefit precise control of printing dynamics during inkjet printing of viscoelastic bioink for 3D biofabrication applications.

Current Status and Challenges of Three-Dimensional Modeling and Printing of Tissues and Organs.

Current Status and Challenges of Three-Dimensional Modeling and Printing of Tissues and Organs.

3D Fabrication of Polymeric Scaffolds for Regenerative Therapy.

Recent advances in bioprinting technology have been used to precisely dispense cell-laden biomaterials for the construction of complex 3D functional living tissues or artificial organs. Organ printing and biofabrication provides great potential for the freeform fabrication of 3D living organs using cellular spheroids, biocomposite nanofibers, or bioinks as building blocks for regenerative therapy. Vascularization is often identified as a main technological barrier for building 3D organs in tissue engineering. 3D printing of living tissues starts with potential support of biomaterials to maintain structural integrity and degradation of certain time periods after printing of the scaffolds. Biofabrication is the production of complex living and nonliving biological products from raw materials such as cells, molecules, ECM, and biomaterials. Generally, two basic methods are used for the fabrication of scaffolds such as conventional/traditional fabrication processes and advance fabrication processes for engineering organs. A wide range of polymers and biomaterials are used for the fabrication of scaffolds in tissue engineering applications. 3D additive manufacturing is advancing day-by-day; however, there are various critical challenging factors used for fabricating 3D scaffolds. This review is aimed at understanding the various scaffold fabrication techniques, types of polymers and biomaterials used for the fabrication processes, various fields of applications, and different challenges faced in their fabrication of scaffolds in regenerative therapy.

Organ Printing With Life Cells: A Review

Human Organ Printing is one of the latest advancements in medical industry of today's world. With the help of current Bioprinting technology, it is possible to printed human organs directly with Bio-life cells. In the current world millions of dollars were spend in many research and educational institutes to eliminate the boundaries in organ printing. The goal of researchers is to replace a human organ with Bioprinted organ successfully. In process of organ printing various machines and materials are used across the globe. The most printed organs with this technology are liver, cartilage, skin, heart and bone tissues etc. Even though the approach may be differ from one to other but everyone is moving towards organ printing with life cells. In this some of them are very successful at their preclinical trials. Some of the major challenges in this technologies are printing organs with life (life time of printed organ), printing environment and post processing (like Autoclave) process. The advancements in this area clearly show that researchers are very near to the future, where replacement of human organ with printed organ is achievable. This paper majorly discusses on the current technologies in organ printing along with their applications, materials, case studies along with future advancements.

Multifunctional 3D printing of heterogeneous hydrogel structures.

Multimaterial additive manufacturing or three-dimensional (3D) printing of hydrogel structures provides the opportunity to engineer geometrically dependent functionalities. However, current fabrication methods are mostly limited to one type of material or only provide one type of functionality. In this paper, we report a novel method of multimaterial deposition of hydrogel structures based on an aspiration-on-demand protocol, in which the constitutive multimaterial segments of extruded filaments were first assembled in liquid state by sequential aspiration of inks into a glass capillary, followed by in situ gel formation. We printed different patterned objects with varying chemical, electrical, mechanical, and biological properties by tuning process and material related parameters, to demonstrate the abilities of this method in producing heterogeneous and multi-functional hydrogel structures. Our results show the potential of proposed method in producing heterogeneous objects with spatially controlled functionalities while preserving structural integrity at the switching interface between different segments. We anticipate that this method would introduce new opportunities in multimaterial additive manufacturing of hydrogels for diverse applications such as biosensors, flexible electronics, tissue engineering and organ printing.

Perspectives on Additive Manufacturing

Additive manufacturing (AM) has skyrocketed in visibility commercially and in the public sector. This article describes the development of this field from early layered manufacturing approaches of photosculpture, topography, and material deposition. Certain precursors to modern AM processes are also briefly described. The growth of the field over the last 30 years is presented. Included is the standard delineation of AM technologies into seven broad categories. The economics of AM part generation is considered, and the impacts of the economics on application sectors are described. On the basis of current trends, the future outlook will include a convergence of AM fabricators, mass-produced AM fabricators, enabling of topology optimization designs, and specialization in the AM legal arena. Long-term developments with huge impact are organ printing and volume-based printing.

3D bioprinting technology for regenerative medicine applications

 Alternative strategies that overcome existing organ transplantation methods are of increasing importance because of ongoing demands and lack of adequate organ donors. Recent improvements in tissue engineering techniques offer improved solutions to this problem and will influence engineering and medicinal applications. Tissue engineering employs the synergy of cells, growth factors and scaffolds besides others with the aim to mimic the native extracellular matrix for tissue regeneration. Three-dimensional (3D) bioprinting has been explored to create organs for transplantation, medical implants, prosthetics, in vitro models and 3D tissue models for drug testing. In addition, it is emerging as a powerful technology to provide patients with severe disease conditions with personalized treatments. Challenges in tissue engineering include the development of 3D scaffolds that closely resemble native tissues. In this review, existing printing methods such as extrusion-based, robotic dispensing, cellular inkjet, laser-assisted printing and integrated tissue organ printing (ITOP) are examined. Also, natural and synthetic polymers and their blends as well as peptides that are exploited as bioinks are discussed with emphasis on regenerative medicine applications. Furthermore, applications of 3D bioprinting in regenerative medicine, evolving strategies and future perspectives are summarized.

Granular gel support-enabled extrusion of three-dimensional alginate and cellular structures

Freeform fabrication of soft structures has been of great interest in recent years. In particular, it is viewed as a critical step toward the grand vision of organ printing—the on-demand design and fabrication of three-dimensional (3D) human organ constructs for implantation and regenerative medicine. The objective of this study is to develop a novel granular gel support material-enabled, two-step gelation-based ‘printing-then-gelation’ approach to fabricate 3D alginate structures using filament extrusion. Specifically, a granular Carbopol microgel bath holds the ungelled alginate structure being extruded, avoiding the instantaneous gelation of each printed layer as well as resultant surface tension-induced nozzle clogging. Since Carbopol microgels react with multivalent cations, which are needed for alginate crosslinking, gelatin is introduced as a sacrificial material to make an alginate and gelatin bioink for extrusion, which gels thermally (step-one gelation) to initially stabilize the printed structure for removal from Carbopol. Then gelatin is melted and diffused away while alginate is ionically crosslinked in a 37 °C calcium chloride bath (step-two gelation), resulting in an alginate structure. The proposed ‘printing-then-gelation’ approach works for alginate structure fabrication, and it is also applicable for the printing of cellular constructs and other similar homogeneous soft structures using a two-step or even multi-step approach. The main conclusions are: (1) 0.8% (w/v) Carbopol bath with a neutral pH value may be most suitable for soft structure printing; (2) it is most effective to use a 0.9% (w/v) NaCl solution to facilitate the removal of residual Carbopol; and (3) alginate structures fabricated using the proposed approach demonstrate better mechanical properties than those fabricated using the conventional ‘gelation-while-printing’ approach.

A Review of 3D Printing Techniques and the Future in Biofabrication of Bioprinted Tissue.

3D printing has been around in the art, micro-engineering, and manufacturing worlds for decades. Similarly, research for traditionally engineered skin tissue has been in the works since the 1990s. As of recent years, the medical field also began to take advantage of the untapped potential of 3D printing for the biofabrication of tissue. To do so, researchers created a set of goals for fabricated tissues based on the characteristics of natural human tissues and organs. Fabricated tissue was then measured against this set of standards. Researchers were interested in not only creating tissue that functioned like natural tissues but in creating techniques for 3D printing that would print tissues quickly, efficiently, and ultimately result in the ability to mass produce fabricated tissues. Three promising methods of 3D printing emerged from their research: thermal inkjet printing with bioink, direct-write bioprinting, and organ printing using tissue spheroids. This review will discuss all three printing techniques, as well as their advantages, disadvantages, and the possibility of future advancements in the field of tissue fabrication.

Developments of 3D Printing Microfluidics and Applications in Chemistry and Biology: a Review

AbstractThree‐dimensional (3D) printing, also called additive manufacturing (AM) or rapid prototyping (RP), is a layer by layer manufacturing method and now has been widely used in many areas such as organ printing, aerospace and industrial design. Now 3D printed microfluidics attract more and more interests for its rapid printing in the lab. In this review, we focused on the advances of 3D printed microfluidic chips especially the use in the chemistry and biology (vascularization and organs on chips). Based on the brief review of different 3D printing methods, we discussed how to choose the suitable 3D printing methods to print the desired microfluidics. We predict that microfluidics will be evolved from 2D chips to 3D cubes, printed hydrogel‐based microfluidics will be reported and widely used, sensors & actuators could be integrated in the microfluidics during printing, and rapid assembling chips with printed microfluidic modules will be popular in the near future.

Three-dimensional printing of biological matters

Three-dimensional (3D) printing of human tissues and organ has been an exciting research topic in the past three decades. However, existing technological and biological challenges still require a significant amount of research. The present review highlights these challenges and discusses their potential solutions such as mapping and converting a human organ onto a 3D virtual design, synchronizing the virtual design with the printing hardware. Moreover, the paper discusses in details recent advances in formulating bio-inks and challenges in tissue construction with or without scaffold. Next, the paper reviews fusion processes effecting vascular cells and tissues. Finally, the paper deliberates the feasibility of organ printing with state-of-the-art technologies.

Olten Meeting 2015 – Antibiotics and Bioprinting – for a better life

The ever lurking danger of antibiotic resistance and the potential of bioprinting are on everyone's lips. But where do we stand in the battle against antibiotic-resistant pathogens? And what are the opportunities for biotech in the 3D printing of biological tissues and organs through the layering of living cells? At the Olten Meeting 2015 scientists and entrepreneurs met to throw light on the current situation.

3D Printing of Organs for Transplantation: Where Are We and Where Are We Heading?

In the field of transplantation, the demand for organs continues to increase and has far outpaced the supply. This ever-growing unmet need for organs calls for innovative solutions in order to save more lives. The development of new technologies in the field of biomedical engineering might be able to provide some solutions. With the advent of 3D bioprinting, the potential development of tissues or organ grafts from autologous cells might be within the reach in the near future. Based on the technology and platform used for regular 3D printing, 3D bioprinters have the ability to create biologically functional tissues by dispensing layer after layer of bioink and biogel that if left to mature with the proper environment will produce a functional tissue copy with normal metabolic activity. In the present day, 3D-bioprinted bladders, tracheal grafts, bone, and cartilage have proven to be functional after development and implantation in animal models and humans. Promising ongoing projects in different institutions around the world are focused on the development of 3D-bioprinted organs such as the livers and kidneys with integrated vasculature, in order for the tissue to be able to thrive once it has been transplanted. This review focuses on the background, the present, and the future of 3D bioprinting and its potential role in transplantation.

Carbon nanotubes for organ regeneration: An electrifying performance

Summary Tissue regeneration research is advancing rapidly, thanks to the innovation potential of stem cells and nanomaterials. In particular, carbon nanotubes (CNTs) have shown an unmatched performance in conductive tissue regeneration. When grown in contact with CNTs, conducting cells become “electrified”, i.e., electrically more active, mature, and better interconnected. The challenges inherent in translating these concepts into 3D printing of whole organs for biomedical use are being addressed worldwide.

Influence of Cell Printing on Biological Characters of Chondrocytes

Objective To establish a two-dimensional biological printing technique of chondrocytes and compare the difference of related biological characters between printed chondrocytes and unprinted cells so as to control the cell transfer process and keep cell viability after printing. Methods Primary chondrocytes were obtained from human mature and fetal cartilage tissues and then were regularly sub-cultured to harvest cells at passage 2 (P2), which were adjusted to the single cell suspension at a density of 1×10(6)/mL. The experiment was divided into 2 groups: experimental group P2 chondrocytes were transferred by rapid prototype biological printer (driving voltage value 50 V, interval in x-axis 300 μm, interval in y-axis 1500 μm). Afterwards Live/Dead viability Kit and flow cytometry were respectively adopted to detect cell viability; CCK-8 Kit was adopted to detect cell proliferation viability; immunocytochemistry, immunofluorescence and RT-PCR was employed to identify related markers of chondrocytes; control group steps were the same as the printing group except that cell suspension received no printing. Results Fluorescence microscopy and flow cytometry analyses showed that there was no significant difference between experimental group and control group in terms of cell viability. After 7-day in vitro culture, control group exhibited higher O.D values than experimental group from 2nd day to 7th day but there was no distinct difference between these two groups (P>0.05). Inverted microscope observation demonstrated that the morphology of these two groups had no significant difference either. Similarly, Immunocytochemistry, immunofluorescence and RT-PCR assays also showed that there was no significant difference in the protein and gene expression of type II collagen and aggrecan between these two groups (P>0.05). Conclusion Cell printing has no distinctly negative effect on cell vitality, proliferation and phenotype of chondrocytes. Biological printing technique may provide a novel approach for realizing the oriented, quantificational and regular distribution of chondrocytes in a two-dimensional plane and lay the foundation for the construction of three-dimensional cell printing or even organ printing system.

Electrohydrodynamic printing: a potential tool for high-resolution hydrogel/cell patterning

ABSTRACTElectrohydrodynamic printing has gained increasing attentions to fabricate micro/nanoscale patterns in a controlled and cost-effective manner. However, most of the existing studies focus on printing tiny dried fibres, which limits its applications in high-resolution cell printing. Here we investigated the feasibility of using electrohydrodynamic printing to pattern microscale liquid filaments. Process parameters like stage moving speed and substrate resistance were optimised to stably print polyvinyl alcohol (PVA) liquid lines with the smallest line width of 37.4 μm. Complex patterns like XJTU logo with constant or variable line width were successfully printed by dynamically adjusting the moving speed. Fluorescent microparticles, with a similar diameter to living cells, were patterned in a one-by-one manner along with the PVA filaments. It is envisioned that the presented electrohydrodynamic printing method could be potentially used to high-resolution hydrogel/cell patterning for the studies of microscale cell–cell interactions or organ printing.

Three-dimensional Printing Technology in Surgery

Background: Three-dimensional printing has become an increasingly widespread technology, becoming more accessible to individuals, small businesses and organisations. It represents the ability to manufacture objects of various substrate material using computer aided 3D plans. This article aims to explore the various uses of this technology in medicine and surgery including future directions and applications Method: A generalised review of past and current articles was performed exploring the known uses of three-dimensional printing in medicine and surgery. Results: Broadly, the applications include; education for health professionals and patients, surgical planning and decisionmaking, custom prostheses, tissue scaffolds, and customised surgical instrument manufacturing. Future directions include bionic prostheses, live tissue grafts, and whole organ printing.