Journal International Journal of Bioprinting-
International Journal of Bioprinting, Volume 5; doi:10.18063/ijb.v5i1.153
Abstract:Biofabrication is an emerging multidisciplinary field that makes a revolutionary impact on the researches on life science, biomedical engineering, and both basic and clinical medicine, has progressed tremendously over the past few years. Recently, there has been a big boom in three-dimensional (3D) printing or additive manufacturing (AM) research worldwide, and there is a significant increase not only in the number of researchers turning their attention to AM but also publications demonstrating the potential applications of 3D printing techniques in multiple fields. Biofabrication and bioprinting hold great promise for the innovation of engineering-based organ replacing medicine. In this mini review, various challenges in the field of tissue engineering are focused from the point of view of the biofabrication - strategies to bridge the gap between organ shortage and mission of medical innovation research seek to achieve organ-specific treatments or regenerative therapies. Four major challenges are discussed including (i) challenge of producing organs by AM, (ii) digitalization of tissue engineering and regenerative medicine, (iii) rapid production of organs beyond the biological natural course, and (iv) extracorporeal organ engineering.
International Journal of Bioprinting, Volume 5; doi:10.18063/ijb.v5i1.178
Abstract:Optical tissue phantoms enable to mimic the optical properties of biological tissues for biomedical device calibration, new equipment validation, and clinical training for the detection, and treatment of diseases. Unfortunately, current methods for their development present some problems, such as a lack of repeatability in their optical properties. Where the use of three-dimensional (3D) printing or 3D bioprinting could address these issues. This paper aims to evaluate the use of this technology in the development of optical tissue phantoms. A competitive technology intelligence methodology was applied by analyzing Scopus, Web of Science, and patents from January 1, 2000, to July 31, 2018. The main trends regarding methods, materials, and uses, as well as predominant countries, institutions, and journals, were determined. The results revealed that, while 3D printing is already employed (in total, 108 scientific papers and 18 patent families were identified), 3D bioprinting is not yet applied for optical tissue phantoms. Nevertheless, it is expected to have significant growth. This research gives biomedical scientists a new window of opportunity for exploring the use of 3D bioprinting in a new area that may support testing of new equipment and development of techniques for the diagnosis and treatment of diseases.
International Journal of Bioprinting, Volume 5; doi:10.18063/ijb.v5i1.184
International Journal of Bioprinting, Volume 5; doi:10.18063/ijb.v5i1.166
Abstract:The purpose of this paper is to review the mechanisms of electrohydrodynamic (EHD) phenomenon. From this review, researchers and students can learn principles and development history of EHD. Significant progress has been identified in research and development of EHD high-resolution deposition as a direct additive manufacturing method, and more effort will be driven to this direction soon. An introduction is given about current trend of additive manufacturing and advantages of EHD inkjet printing. Both theoretical models and experiment approaches about the formation of cone, development of cone-jet transition and stability of jet are presented. The formation of a stable cone-jet is the key factor for precision EHD printing which will be discussed. Different scaling laws can be used to predict the diameter of jet and emitted current in different parametrical ranges. The information available in this review builds a bridge between EHD phenomenon and three-dimensional high-resolution inkjet printing.
International Journal of Bioprinting, Volume 5; doi:10.18063/ijb.v5i1.172
Abstract:This paper mainly reviews the designs of electrohydrodynamic (EHD) inkjet printing machine and related applications. The review introduces the features of EHD printing and its possible research directions. Significant progress has been identified in research and development of EHD high-resolution printing as a direct additive manufacturing method, and more effort will be driven to this direction soon. An introduction is given about current trend of additive manufacturing and advantages of EHD inkjet printing. Designs of EHD printing platform and applications of different technologies are discussed. Currently, EHD jet printing is in its infancy stage with several inherent problems to be overcome, such as low yielding rate and limitation of stand-off height. Some potential modifications are proposed to improve printing performance. EHD high-resolution printing has already been applied to precision components for electronics and biotechnology applications. This paper gives a review about the latest research regarding EHD used for high-resolution inkjet printing. A starting base is given to help researchers and students to get a quick overview on the recent development of EHD printing technology.
International Journal of Bioprinting, Volume 5; doi:10.18063/ijb.v5i1.170
Abstract:Science and technology (S&T) on three-dimensional (3D) bioprinting is growing at an increasingly accelerated pace; one major challenge represents how to develop new solutions for frequent oral diseases such as periodontal problems and loss of alveolar bone. 3D bioprinting is expected to revolutionize the health industry in the upcoming years. In dentistry, this technology can become a significant contributor. This study applies a Competitive Technology Intelligence methodology to uncover the main S&T drivers in this domain. Looking at a 6-year period from 2012 to 2018 an analysis of scientific and technology production was made. Three principal S&T drivers were identified: Scaffolds development, analysis of natural and synthetic materials, and the study of scaffold characteristics. Innovative hybrid and multiphasic scaffolds are being developed to regenerate periodontal tissue and alveolar bone by combining them with stem cells from the pulp or periodontal ligament. To improve scaffolds performance, biodegradable synthetic polymers are often used in combination with bioceramics. The characteristics of scaffolds such as fiber orientation, porosity, and geometry, were also investigated. This research contributes to people interested in bringing innovative solutions to the health industry, particularly by applying state-of-the-art technologies such as 3D bioprinting, in this case for dental tissues and dental bone diseases.
International Journal of Bioprinting, Volume 5; doi:10.18063/ijb.v5i1.164
Abstract:Electrohydrodynamic printing (EHDP) is able to precisely manipulate the position, size, and morphology of micro-/nano-fibers and fabricate high-resolution scaffolds using viscous biopolymer solutions. However, less attention has been paid to the influence of EHDP jet characteristics and key process parameters on deposited fiber patterns. To ensure the printing quality, it is very necessary to establish the relationship between the cone shapes and the stability of scaffold fabrication process. In this work, we used a digital microscopic imaging technique to monitor EHDP cones during printing, with subsequent image processing algorithms to extract related features, and a recognition algorithm to determine the suitability of Taylor cones for EHDP scaffold fabrication. Based on the experimental data, it has been concluded that the images of EHDP cone modes and the extracted features (centroid, jet diameter) are affected by their process parameters such as nozzle-substrate distance, the applied voltage, and stage moving speed. A convolutional neural network is then developed to classify these EHDP cone modes with the consideration of training time consumption and testing accuracy. A control algorithm will be developed to regulate the process parameters at the next stage for effective scaffold fabrication.
International Journal of Bioprinting, Volume 5; doi:10.18063/ijb.v5i1.167
Abstract:The overarching principle of three-dimensional (3D) bioprinting is the placing of cells or cell clusters in the 3D space to generate a cohesive tissue microarchitecture that comes close to in vivo characteristics. To achieve this goal, several technical solutions are available, generating considerable combinatorial bandwidth: (i) Support structures are generated first, and cells are seeded subsequently; (ii) alternatively, cells are delivered in a printing medium, so-called “bioink,” that contains them during the printing process and ensures shape fidelity of the generated structure; and (iii) a “scaffold-free” version of bioprinting, where only cells are used and the extracellular matrix is produced by the cells themselves, also recently entered a phase of accelerated development and successful applications. However, the scaffold-free approaches may still benefit from secondary incorporation of scaffolding materials, thus expanding their versatility. Reversibly, the bioink-based bioprinting could also be improved by adopting some of the principles and practices of scaffold-free biofabrication. Collectively, we anticipate that combinations of these complementary methods in a “hybrid” approach, rather than their development in separate technological niches, will largely increase their efficiency and applicability in tissue engineering.
International Journal of Bioprinting, Volume 5; doi:10.18063/ijb.v5i1.163
Abstract:Bioactive glasses have recently gained attention in tissue engineering and three-dimensional (3D) bioprinting because of their ability to enhance angiogenesis. Some challenges for developing biological tissues with bioactive glasses include incorporation of glass particles and achieving a 3D architecture mimicking natural tissues. In this study, we investigate the fabrication of scaffolds with a polymer/bioactive glass composite using near-field electrospinning (NFES). An overall controlled 3D scaffold with pores, containing random fibers, is created and aimed to provide superior cell proliferation. Highly angiogenic borate bioactive glass (13-93B3) in 20 wt.% is added to polycaprolactone (PCL) to fabricate scaffolds using the NFES technique. Scaffolds measuring 5 mm × 5 mm × 0.2 mm3 in overall dimensions were seeded with human adipose-derived mesenchymal stem cells to investigate the cell viability. The cell viability on PCL and PCL+glass scaffolds fabricated using NFES technique and 3D printing is compared and discussed. The results indicated higher cell proliferation on 3D biomimetic scaffolds fabricated by NFES technique
International Journal of Bioprinting, Volume 5; doi:10.18063/ijb.v5i1.148
Abstract:Additive manufacturing (AM) can obtain not only customized external shape but also porous internal structure for scaffolds, both of which are of great importance for repairing large segmental bone defects. The scaffold fabrication process generally involves scaffold design, AM, and post-treatments. Thus, this article firstly reviews the state-of-the-art of scaffold design, including computer-aided design, reverse modeling, topology optimization, and mathematical modeling. In addition, the current characteristics of several typical AM techniques, including selective laser sintering, fused deposition modeling (FDM), and electron beam melting (EBM), especially their advantages and limitations are presented. In particular, selective laser sintering is able to obtain scaffolds with nanoscale grains, due to its high heating rate and a short holding time. However, this character usually results in insufficient densification. FDM can fabricate scaffolds with a relative high accuracy of pore structure but with a relative low mechanical strength. EBM with a high beam-material coupling efficiency can process high melting point metals, but it exhibits a low-resolution and poor surface quality. Furthermore, the common post-treatments, with main focus on heat and surface treatments, which are applied to improve the comprehensive performance are also discussed. Finally, this review also discusses the future directions for AM scaffolds for bone tissue engineering.