3D bioprint me: a socioethical view of bioprinting human organs and tissues

Advances in tumor microenvironment: Applications and challenges of 3D bioprinting

The tumor microenvironment (TME) assumes a pivotal role in the treatment of oncological diseases, given its intricate interplay of diverse cellular components and extracellular matrices. This dynamic ecosystem poses a serious challenge to traditional research methods in many ways, such as high research costs, inefficient translation, poor reproducibility, and low modeling success rates. These challenges require the search for more suitable research methods to accurately model the TME, and the emergence of 3D bioprinting technology is transformative and an important complement to these traditional methods to precisely control the distribution of cells, biomolecules, and matrix scaffolds within the TME. Leveraging digital design, the technology enables personalized studies with high precision, providing essential experimental flexibility. Serving as a critical bridge between in vitro and in vivo studies, 3D bioprinting facilitates the realistic 3D culturing of cancer cells. This comprehensive article delves into cutting-edge developments in 3D bioprinting, encompassing diverse methodologies, biomaterial choices, and various 3D tumor models. Exploration of current challenges, including limited biomaterial options, printing accuracy constraints, low reproducibility, and ethical considerations, contributes to a nuanced understanding. Despite these challenges, the technology holds immense potential for simulating tumor tissues, propelling personalized medicine, and constructing high-resolution organ models, marking a transformative trajectory in oncological research.

Hydrogel-Based Vascularized Organ Tissue Engineering: A Systematized Review on Abdominal Organs

BACKGROUND

Biomedical engineering, especially tissue engineering, is trying to provide an alternative solution to generate functional organs/tissues for use in various applications. These include beyond the final goal of transplantation, disease modeling and drug discovery as well. The aim of this study is to comprehensively review the existing literature on hydrogel-based vascularized organ (i.e., liver, pancreas, kidneys, intestine, stomach and spleen) tissue engineering of the abdominal organs.

METHODS

A comprehensive literature search was conducted on the Scopus database (latest search 1 September 2024). The research studies including hydrogel-based vascularized organ tissue engineering in the organs examined here were eligible for the review.

RESULTS

Herein, 18 studies were included. Specifically, 10 studies included the liver or hepatic tissue, 5 studies included the pancreas or pancreatic islet tissue, 3 studies included the kidney or renal tissue, 1 study included the intestine or intestinal or bowel tissue, 1 study included the stomach or gastric tissue, and 0 studies included spleen tissue.

CONCLUSION

Hydrogels are biocompatible materials with ideal characteristics for use as scaffolds. Even though organ tissue engineering is a rapidly growing field, there are still many obstacles to overcome to create a fully functional and long-lasting organ.

Patient, parent and professional expert perspectives on personalized regenerative implants: a qualitative focus group study

Background: Perspectives of patients, parents and professional experts on personalized regenerative implants for regenerative medicine purposes are largely unknown.Method: To better understand these perspectives, we conducted four focus groups with professional experts of mixed European nationality (n = 8), Dutch patients with regular implants (n = 8), Dutch and Belgian (n = 5) and Spanish (n = 8) parents of children with cleft palate.Results: Two overarching themes were identified: 'patient-centered research and care' and 'ambivalent attitudes toward personalized regenerative implants'.Discussion: The results reveal that stakeholders should adopt a participatory rather than an impairment discourse and address the ambivalence among professional experts, patients and parents.Conclusion: Considering stakeholder perspectives facilitates ethical and responsible development and use of personalized regenerative implants.

3D bioprinting of liver models: A systematic scoping review of methods, bioinks, and reporting quality

Background

Effective communication is crucial for broad acceptance and applicability of alternative methods in 3R biomedical research and preclinical testing. 3D bioprinting is used to construct intricate biological structures towards functional liver models, specifically engineered for deployment as alternative models in drug screening, toxicological investigations, and tissue engineering. Despite a growing number of reviews in this emerging field, a comprehensive study, systematically assessing practices and reporting quality for bioprinted liver models is missing.

Methods

In this systematic scoping review we systematically searched MEDLINE (Ovid), EMBASE (Ovid) and BioRxiv for studies published prior to June 2nd, 2022. We extracted data on methodological conduct, applied bioinks, the composition of the printed model, performed experiments and model applications. Records were screened for eligibility and data were extracted from included articles by two independent reviewers from a panel of seven domain experts specializing in bioprinting and liver biology. We used RAYYAN for the screening process and SyRF for data extraction. We used R for data analysis, and R and Graphpad PRISM for visualization.

Results

Through our systematic database search we identified 1042 records, from which 63 met the eligibility criteria for inclusion in this systematic scoping review. Our findings revealed that extrusion-based printing, in conjunction with bioinks composed of natural components, emerged as the predominant printing technique in the bioprinting of liver models. Notably, the HepG2 hepatoma cell line was the most frequently employed liver cell type, despite acknowledged limitations. Furthermore, 51% of the printed models featured co-cultures with non-parenchymal cells to enhance their complexity. The included studies offered a variety of techniques for characterizing these liver models, with their primary application predominantly focused on toxicity testing. Among the frequently analyzed liver markers, albumin and urea stood out. Additionally, Cytochrome P450 (CYP) isoforms, primarily CYP3A and CYP1A, were assessed, and select studies employed nuclear receptor agonists to induce CYP activity.

Conclusion

Our systematic scoping review offers an evidence-based overview and evaluation of the current state of research on bioprinted liver models, representing a promising and innovative technology for creating alternative organ models. We conducted a thorough examination of both the methodological and technical facets of model development and scrutinized the reporting quality within the realm of bioprinted liver models. This systematic scoping review can serve as a valuable template for systematically evaluating the progress of organ model development in various other domains. The transparently derived evidence presented here can provide essential support to the research community, facilitating the adaptation of technological advancements, the establishment of standards, and the enhancement of model robustness. This is particularly crucial as we work toward the long-term objective of establishing new approach methods as reliable alternatives to animal testing, with extensive and versatile applications.

Three-Dimensional Bioprinting in Vascular Tissue Engineering and Tissue Vascularization of Cardiovascular Diseases

In the 21st century, significant progress has been made in repairing damaged materials through material engineering. However, the creation of large-scale artificial materials still faces a major challenge in achieving proper vascularization. To address this issue, researchers have turned to biomaterials and three-dimensional (3D) bioprinting techniques, which allow for the combination of multiple biomaterials with improved mechanical and biological properties that mimic natural materials. Hydrogels, known for their ability to support living cells and biological components, have played a crucial role in this research. Among the recent developments, 3D bioprinting has emerged as a promising tool for constructing hybrid scaffolds. However, there are several challenges in the field of bioprinting, including the need for nanoscale biomimicry, the formulation of hydrogel blends, and the ongoing complexity of vascularizing biomaterials, which requires further research. On a positive note, 3D bioprinting offers a solution to the vascularization problem due to its precise spatial control, scalability, and reproducibility compared with traditional fabrication methods. This paper aims at examining the recent advancements in 3D bioprinting technology for creating blood vessels, vasculature, and vascularized materials. It provides a comprehensive overview of the progress made and discusses the limitations and challenges faced in current 3D bioprinting of vascularized tissues. In addition, the paper highlights the future research directions focusing on the development of 3D bioprinting techniques and bioinks for creating functional materials.

Constructing appropriate bioprinting regulations: the ethical importance of recognising a liminal technology

This article provides an analysis of bioprinting personalised medical device technology and its ethical challenges to regulation and research ethics. I argue the inclusion of bioprinting applications within existing regulatory frameworks does not adequately address the technologies disruption to the traditionally siloed activities of research and treatment. Using the conceptual framework of liminality, I offer a meaningful way to engage with this technology and address some identified concerns with how it will be categorised and the appropriate recognition of its evidentiary thresholds. I demonstrate these concerns through the exploration of limited conventional research methodologies tasked with the production of generalisable knowledge, specifically population-based evidence that is derived from Randomised Clinical Trials. I use Australian regulatory amendments introduced in 2021 as an example of current regulatory trajectories and highlight why I believe this approach to be insufficient. The significance of this argument will be to demonstrate the disruption of bioprinting applications to current approaches in medical policy, and how various jurisdictions are enacting regulation that is not fit for purpose.

Cellulose-alginate hydrogels and their nanocomposites for water remediation and biomedical applications

In the last decade, both cellulose and alginate polysaccharides have been extensively utilized for the synthesis of biocompatible hydrogels because of their alluring characteristics like low cost, biodegradability, hydrophilicity, biodegradability, ease of availability and non-toxicity. The presence of abundant hydrophilic functional groups (like carboxyl and hydroxyl) on the surface of cellulose and alginate or their derivatives makes these materials promising candidates for the preparation of hydrogels with appealing structures and characteristics, leading to growing research in water treatment and biomedical fields. These two polysaccharides are typically blended together to improve hydrogels' desired qualities (mechanical strength, adsorption properties, cellulose/alginate yield). So, keeping in view their extensive applicability, in the present review article, recent advances in the development of cellulose/nanocellulose-alginate-based hydrogels and their relevance in water treatment (adsorption of dyes, heavy metals, etc.) and biomedical field (wound healing, tissue engineering, drug delivery) has been reviewed. Further, impact of other inorganic/organic additives in cellulose/nanocellulose-alginate-based hydrogels properties like contaminants adsorption, drug delivery, tissue engineering, etc., has also been studied. Moreover, the current difficulties and future prospects of nanocellulose-alginate-based hydrogels regarding their water purification and biomedical applications are also discussed at the end.

Personalized 3D printed scaffolds: The ethical aspects

Personalized 3D printed scaffolds are a new generation of implants for tissue engineering and regenerative medicine purposes. Scaffolds support cell growth, providing an artificial extracellular matrix for tissue repair and regeneration and can biodegrade once cells have assumed their physiological and structural roles. The ethical challenges and opportunities of these implants should be mapped in parallel with the life cycle of the scaffold to assist their development and implementation in a responsible, safe, and ethically sound manner. This article provides an overview of these relevant ethical aspects. We identified nine themes which were linked to three stages of the life cycle of the scaffold: the development process, clinical testing, and the implementation process. The described ethical issues are related to good research and clinical practices, such as privacy issues concerning digitalization, first-in-human trials, responsibility and commercialization. At the same time, this article also creates awareness for underexplored ethical issues, such as irreversibility, embodiment and the ontological status of these scaffolds. Moreover, it exemplifies how to include gender in the ethical assessment of new technologies. These issues are important for responsible development and implementation of personalized 3D printed scaffolds and in need of more attention within the additive manufacturing and tissue engineering field. Moreover, the insights of this review reveal unresolved qualitative empirical and normative questions that could further deepen the understanding and co-creation of the ethical implications of this new generation of implants.

Three-Dimensional Bioprinting of Human Organs and Tissues: Bioethical and Medico-Legal Implications Examined through a Scoping Review

Three-dimensional bioprinting is a rapidly evolving technology that holds the promise of addressing the increasing demand for organs, tissues, and personalized medicine. By employing computer-aided design and manufacturing processes, 3D bioprinting allows for the precise deposition of living cells, biomaterials, and biochemicals to create functional human tissues and organs. The potential applications of this technology are vast, including drug testing and development, disease modeling, regenerative medicine, and ultimately, organ transplantation. However, as with any groundbreaking technology, 3D bioprinting presents several ethical, legal, and regulatory concerns that warrant careful consideration. As the technology progresses towards clinical applications, it is essential to address these challenges and establish appropriate frameworks to guide the responsible development of 3D bioprinting. This article, utilizing the Arksey and O'Malley scoping review model, is designed to scrutinize the bioethical implications, legal and regulatory challenges, and medico-legal issues that are intertwined with this rapidly evolving technology.

Ethical and social insights into synthetic biology: predicting research fronts in the post-COVID-19 era

As a revolutionary biological science and technology, synthetic biology has already spread its influence from natural sciences to humanities and social sciences by introducing biosafety, biosecurity, and ethical issues to society. The current study aims to elaborate the intellectual bases and research front of the synthetic biology field in the sphere of philosophy, ethics, and social sciences, with knowledge mapping and bibliometric methods. The literature records from the Social Sciences Citation Index and Arts & Humanities Citation Index in the Web of Science Core Collection from 1982 to 2021 were collected and analyzed to illustrate the intellectual structure of philosophical, ethical, and social research of synthetic biology. This study profiled the hotspots of research focus on its governance, philosophical and ethical concerns, and relevant technologies. This study offers clues and enlightenment for the stakeholders and researchers to follow the progress of this emerging discipline and technology and to understand the cutting-edge ideas and future form of this field, which takes on greater significance in the post-COVID-19 era.

The Ethical Implications of Tissue Engineering for Regenerative Purposes: A Systematic Review

Tissue Engineering (TE) is a branch of Regenerative Medicine (RM) that combines stem cells and biomaterial scaffolds to create living tissue constructs to restore patients' organs after injury or disease. Over the last decade, emerging technologies such as 3D bioprinting, biofabrication, supramolecular materials, induced pluripotent stem cells, and organoids have entered the field. While this rapidly evolving field is expected to have great therapeutic potential, its development from bench to bedside presents several ethical and societal challenges. To make sure TE will reach its ultimate goal of improving patient welfare, these challenges should be mapped out and evaluated. Therefore, we performed a systematic review of the ethical implications of the development and application of TE for regenerative purposes, as mentioned in the academic literature. A search query in PubMed, Embase, Scopus, and PhilPapers yielded 2451 unique articles. After systematic screening, 237 relevant ethical and biomedical articles published between 2008 and 2021 were included in our review. We identified a broad range of ethical implications that could be categorized under 10 themes. Seven themes trace the development from bench to bedside: (1) animal experimentation, (2) handling human tissue, (3) informed consent, (4) therapeutic potential, (5) risk and safety, (6) clinical translation, and (7) societal impact. Three themes represent ethical safeguards relevant to all developmental phases: (8) scientific integrity, (9) regulation, and (10) patient and public involvement. This review reveals that since 2008 a significant body of literature has emerged on how to design clinical trials for TE in a responsible manner. However, several topics remain in need of more attention. These include the acceptability of alternative translational pathways outside clinical trials, soft impacts on society and questions of ownership over engineered tissues. Overall, this overview of the ethical and societal implications of the field will help promote responsible development of new interventions in TE and RM. It can also serve as a valuable resource and educational tool for scientists, engineers, and clinicians in the field by providing an overview of the ethical considerations relevant to their work. Impact statement To our knowledge, this is the first time that the ethical implications of Tissue Engineering (TE) have been reviewed systematically. By gathering existing scholarly work and identifying knowledge gaps, this review facilitates further research into the ethical and societal implications of TE and Regenerative Medicine (RM) and other emerging biomedical technologies. Moreover, it will serve as a valuable resource and educational tool for scientists, engineers, and clinicians in the field by providing an overview of the ethical considerations relevant to their work. As such, our review may promote successful and responsible development of new strategies in TE and RM.

Ethical Issues of 4D Printed Medical Devices

Since the dawn of additive manufacturing technologies in the 1980s and 90s, now commonly named 3D printing, the possibility of processing raw materials into freeform designed objects with unprecedented shape complexity opened new avenues for the development of medical devices. Indeed, the geometries of nature and the human body are extremely multifaceted, with even fractal- like or multiscale levels of detail, counting with functional gradients of properties, including topology and topography optimizations, to cite some interesting features. In consequence, classical subtracting manufacturing technologies, shape forming tools, and mass production chains are suboptimal for personalizing medical devices and adequately emulating life.

Three-Dimensional (3D) Printing of Organs according to the Perspective of Islamic Law

The outburst of the fourth Industrial Revolution had a significant impact on many aspects of life. The discovery of new technologies in medicine has resulted in innovations: organ transplants. The introduction of three-dimensional (3D) organ printing technology promises improvements to the field. Organs such as the liver, kidneys, heart and others are printed to meet the needs of the actual organs. However, the production of prototype organs to replace the original organs is associated with the issue of changing the creation of Allah. Accordingly, this study will analyse the issue of changing the creation of God in three-dimensional (3D) organ printing technology according to the perspective of Islamic law. Several appropriate methodologies in Islamic law (usul fiqh) are used such as legal reasoning through maqasid shariah perspective and analogical reasoning. The result shows that three-dimensional (3D) organ printing technology falls under the permissible category of changing the creation of Allah because it can save human lives. The production of organs through 3D printing involving changes included in the category of necessity (daruri) and need (hajiy) is permissible, but the category of desirable (tahsini) requires further specifications.

Legal issues and underexplored data protection in medical 3D printing: A scoping review

Introduction: 3D printing has quickly found many applications in medicine. However, as with any new technology the regulatory landscape is struggling to stay abreast. Unclear legislation or lack of legislation has been suggested as being one hindrance for wide-scale adoption. Methods: A scoping review was performed in PubMed, Web of Science, SCOPUS and Westlaw International to identify articles dealing with legal issues in medical 3D printing. Results: Thirty-four articles fulfilling inclusion criteria were identified in medical/technical databases and fifteen in the legal database. The majority of articles dealt with the USA, while the EU was also prominently represented. Some common unresolved legal issues were identified, among them terminological confusion between custom-made and patient-matched devices, lack of specific legislation for patient-matched products, and the undefined legal role of CAD files both from a liability and from an intellectual property standpoint. Data protection was mentioned only in two papers and seems an underexplored topic. Conclusion: In this scoping review, several relevant articles and several common unresolved legal issues were identified including a need for terminological uniformity in medical 3D printing. The results of this work are planned to inform our own deeper legal analysis of these issues in the future.

A Need of Shariah Compliant Model of 3D Bioprinting

One of the credible inventions is 3D Bioprinting or organ printing which uses layer by layer fabrication manner and is an emerging and developing technology offered by the research industry and can help the humanity in certain areas of life e.g., health, food, etc. The technology has been found beneficial in wide spectrum within the medical industry in fighting the shortage of organ and tissues donations. It is also helpful for the pharmaceuticals for determining effectiveness of new drugs and the food industry players to develop new type of edible meat for humans’ consumption. However, behind all these benefits, there are unresolved issues that need be discussed critically and addressed properly within the ethics, law and orders of Islamic worldview. This study aims to indentify the Sharī‘ah related issues raised consequent upon the invention of 3D bioprinting. The study uses data collection from scholars’ writings, academic journals, and Islamic fatwa related to bioethics. The data are analysed thematically. The results show that there is a loophole in bioethics research on Sharī‘ah compliant guidelines for the Muslims users with regards to bioprinting usage. It is suggested for the experts to do thorough research on Sharī‘ah compliant guidelines of bioprinting to be the benchmark guideline for authorities such as JAKIM in Malaysia and other authorities such as the Ministry of Health in treating the Muslim patients. Keywords:3D Bioprinting, Ethical and Legal Issues, Organ Printing, Sharī ‘ah Compliance.

A Review on Techniques and Biomaterials Used in 3D Bioprinting

Three-dimensional (3D) bioprinting is a cutting-edge technology that has come to light recently and shows a promising potential whose progress will change the face of medicine. This article reviews the most commonly used techniques and biomaterials for 3D bioprinting. We will also look at the advantages and limitations of various techniques and biomaterials and get a comparative idea about them. In addition, we will also look at the recent applications of these techniques in different industries. This article aims to get a basic idea of the techniques and biomaterials used in 3D bioprinting, their advantages and limitations, and their recent applications in various fields.

Structured Data Storage for Data-Driven Process Optimisation in Bioprinting

Bioprinting is a method to fabricate 3D models that mimic tissue. Future fields of application might be in pharmaceutical or medical context. As the number of applicants might vary between only one patient to manufacturing tissue for high-throughput drug screening, designing a process will necessitate a high degree of flexibility, robustness, as well as comprehensive monitoring. To enable quality by design process optimisation for future application, establishing systematic data storage routines suitable for automated analytical tools is highly desirable as a first step. This manuscript introduces a workflow for process design, documentation within an electronic lab notebook and monitoring to supervise the product quality over time or at different locations. Lab notes, analytical data and corresponding metadata are stored in a systematic hierarchy within the research data infrastructure Kadi4Mat, which allows for continuous, flexible data structuring and access management. To support the experimental and analytical workflow, additional features were implemented to enhance and build upon the functionality provided by Kadi4Mat, including browser-based file previews and a Python tool for the combined filtering and extraction of data. The structured research data management with Kadi4Mat enables retrospective data grouping and usage by process analytical technology tools connecting individual analysis software to machine-readable data exchange formats.

Smart Bioinks for the Printing of Human Tissue Models

3D bioprinting has tremendous potential to revolutionize the field of regenerative medicine by automating the process of tissue engineering. A significant number of new and advanced bioprinting technologies have been developed in recent years, enabling the generation of increasingly accurate models of human tissues both in the healthy and diseased state. Accordingly, this technology has generated a demand for smart bioinks that can enable the rapid and efficient generation of human bioprinted tissues that accurately recapitulate the properties of the same tissue found in vivo. Here, we define smart bioinks as those that provide controlled release of factors in response to stimuli or combine multiple materials to yield novel properties for the bioprinting of human tissues. This perspective piece reviews the existing literature and examines the potential for the incorporation of micro and nanotechnologies into bioinks to enhance their properties. It also discusses avenues for future work in this cutting-edge field.

Applications of 3D Bioprinting in Tissue Engineering and Regenerative Medicine

Regenerative medicine is an emerging field that centers on the restoration and regeneration of functional components of damaged tissue. Tissue engineering is an application of regenerative medicine and seeks to create functional tissue components and whole organs. Using 3D printing technologies, native tissue mimics can be created utilizing biomaterials and living cells. Recently, regenerative medicine has begun to employ 3D bioprinting methods to create highly specialized tissue models to improve upon conventional tissue engineering methods. Here, we review the use of 3D bioprinting in the advancement of tissue engineering by describing the process of 3D bioprinting and its advantages over other tissue engineering methods. Materials and techniques in bioprinting are also reviewed, in addition to future clinical applications, challenges, and future directions of the field.

3D Printing-A Cutting Edge Technology for Treating Post-Infarction Patients

The increasing complexity of cardiovascular interventions requires advanced peri-procedural imaging and tailored treatment. Three-dimensional printing technology represents one of the most significant advances in the field of cardiac imaging, interventional cardiology or cardiovascular surgery. Patient-specific models may provide substantial information on intervention planning in complex cardiovascular diseases, and volumetric medical imaging from CT or MRI can be translated into patient-specific 3D models using advanced post-processing applications. 3D printing and additive manufacturing have a great variety of clinical applications targeting anatomy, implants and devices, assisting optimal interventional treatment and post-interventional evaluation. Although the 3D printing technology still lacks scientific evidence, its benefits have been shown in structural heart diseases as well as for treatment of complex arrhythmias and corrective surgery interventions. Recent development has enabled transformation of conventional 3D printing into complex 3D functional living tissues contributing to regenerative medicine through engineered bionic materials such hydrogels, cell suspensions or matrix components. This review aims to present the most recent clinical applications of 3D printing in cardiovascular medicine, highlighting also the potential for future development of this revolutionary technology in the medical field.

Applications of 3D Bio-Printing in Tissue Engineering and Biomedicine

In recent years, 3D bio-printing technology has developed rapidly and become an advanced bio-manufacturing technology. At present, 3D bio-printing technology has been explored in the fields of tissue engineering, drug testing and screening, regenerative medicine and clinical disease research and has achieved many research results. Among them, the application of 3D bio-printing technology in tissue engineering has been widely concerned by researchers, and it contributing many breakthroughs in the preparation of tissue engineering scaffolds. In the future, it is possible to print fully functional tissues or organs by using 3D bio-printing technology which exhibiting great potential development prospects in th applications of organ transplantation and human body implants. It is expected to solve thebiomedical problems of organ shortage and repair of damaged tissues and organs. Besides,3Dbio-printing technology will benefit human beings in more fields. Therefore, this paper reviews the current applications, research progresses and limitations of 3D bio-printing technology in biomedical and life sciences, and discusses the main printing strategies of 3D bio-printing technology. And, the research emphases, possible development trends and suggestions of the application of 3D bio-printing are summarized to provide references for the application research of 3D bio-printing.

Three-Dimensional Engineered Peripheral Nerve: Toward a New Era of Patient-Specific Nerve Repair Solutions

Reconstruction of peripheral nerve injuries (PNIs) with substance loss remains challenging because of limited treatment solutions and unsatisfactory patient outcomes. Currently, nerve autografting is the first-line management choice for bridging critical-sized nerve defects. The procedure, however, is often complicated by donor site morbidity and paucity of nerve tissue, raising a quest for better alternatives. The application of other treatment surrogates, such as nerve guides, remains questionable, and it is inefficient in irreducible nerve gaps. More importantly, these strategies lack customization for personalized patient therapy, which is a significant drawback of these nerve repair options. This negatively impacts the fascicle-to-fascicle regeneration process, critical to restoring the physiological axonal pathway of the disrupted nerve. Recently, the use of additive manufacturing (AM) technologies has offered major advancements to the bioengineering solutions for PNI therapy. These techniques aim at reinstating the native nerve fascicle pathway using biomimetic approaches, thereby augmenting end-organ innervation. AM-based approaches, such as three-dimensional (3D) bioprinting, are capable of biofabricating 3D-engineered nerve graft scaffolds in a patient-specific manner with high precision. Moreover, realistic in vitro models of peripheral nerve tissues that represent the physiologically and functionally relevant environment of human organs could also be developed. However, the technology is still nascent and faces major translational hurdles. In this review, we spotlighted the clinical burden of PNIs and most up-to-date treatment to address nerve gaps. Next, a summarized illustration of the nerve ultrastructure that guides research solutions is discussed. This is followed by a contrast of the existing bioengineering strategies used to repair peripheral nerve discontinuities. In addition, we elaborated on the most recent advances in 3D printing and biofabrication applications in peripheral nerve modeling and engineering. Finally, the major challenges that limit the evolution of the field along with their possible solutions are also critically analyzed.

Applications of 3D printed bone tissue engineering scaffolds in the stem cell field

Due to traffic accidents, injuries, burns, congenital malformations and other reasons, a large number of patients with tissue or organ defects need urgent treatment every year. The shortage of donors, graft rejection and other problems cause a deficient supply for organ and tissue replacement, repair and regeneration of patients, so regenerative medicine came into being. Stem cell therapy plays an important role in the field of regenerative medicine, but it is difficult to fill large tissue defects by injection alone. The scientists combine three-dimensional (3D) printed bone tissue engineering scaffolds with stem cells to achieve the desired effect. These scaffolds can mimic the extracellular matrix (ECM), bone and cartilage, and eventually form functional tissues or organs by providing structural support and promoting attachment, proliferation and differentiation. This paper mainly discussed the applications of 3D printed bone tissue engineering scaffolds in stem cell regenerative medicine. The application examples of different 3D printing technologies and different raw materials are introduced and compared. Then we discuss the superiority of 3D printing technology over traditional methods, put forward some problems and limitations, and look forward to the future.

Extrusion-Based Bioprinting of Multilayered Nanocellulose Constructs for Cell Cultivation Using In Situ Freezing and Preprint CaCl2 Cross-Linking

Extrusion-based bioprinting with a preprint cross-linking agent and an in situ cooling stage provides a versatile method for the fabrication of 3D structures for cell culture. We added varying amounts of calcium chloride as a precross-linker into native nanofibrillated cellulose (NFC) hydrogel prior to 3D bioprinting to fabricate structurally stable multilayered constructs without the need for a separate cross-linking bath. To further enhance their stability, we bioprinted the multilayered structures onto an in situ temperature-controlled printing stage at 25, 0, and -10 °C. The extruded and subsequently freeze-dried volumetric constructs maintained their structures after being immersed into a cell culture medium. The ability to maintain the shape after immersion in cell media is an essential feature for the fabrication of stem cell-based artificial organs. We studied the viability and distribution of mouse embryonic fibroblast cells into the hydrogels using luminescence technique and confocal microscopy. Adding CaCl2 increased the stability of the multilayered nanocellulose structures, making them suitable for culturing cells inside the 3D hydrogel environment. Lower stage temperature considerably improved the structural stability of the 3D printed structures, however, had no effect on cell viability.

Current standards and ethical landscape of engineered tissues-3D bioprinting perspective

Tissue engineering is an evolving multi-disciplinary field with cutting-edge technologies and innovative scientific perceptions that promise functional regeneration of damaged tissues/organs. Tissue engineered medical products (TEMPs) are biomaterial-cell products or a cell-drug combination which is injected, implanted or topically applied in the course of a therapeutic or diagnostic procedure. Current tissue engineering strategies aim at 3D printing/bioprinting that uses cells and polymers to construct living tissues/organs in a layer-by-layer fashion with high 3D precision. However, unlike conventional drugs or therapeutics, TEMPs and 3D bioprinted tissues are novel therapeutics and need different regulatory protocols for clinical trials and commercialization processes. Therefore, it is essential to understand the complexity of raw materials, cellular components, and manufacturing procedures to establish standards that can help to translate these products from bench to bedside. These complexities are reflected in the regulations and standards that are globally in practice to prevent any compromise or undue risks to patients. This review comprehensively describes the current legislations, standards for TEMPs with a special emphasis on 3D bioprinted tissues. Based on these overviews, challenges in the clinical translation of TEMPs & 3D bioprinted tissues/organs along with their ethical concerns and future perspectives are discussed.

Uncertain But Not Unregulated: Medical Product Regulation in the Light of Three-Dimensional Printed Medical Products

As applications of three-dimensional (3D) printed medical products are being translated into clinical practice, stakeholders are increasingly concerned about whether current regulatory frameworks are able to regulate such products. With more additive manufacturing (AM) and 3D printed medical products being brought into clinical use and the assumption that usage will be more widespread in the future, a (perceived) lack of or inadequacy of regulation by some stakeholders is often depicted as a hindrance to the comprehensive translation of AM and 3D printed medical products into clinical use. This article addresses this uncertainty by analyzing existing medical product regulations and their applicability to AM and 3D printed medical products to assess the degree of regulatory oversight they administer. It concludes that there are specific legal questions that need to be clarified, but the products are not expected to "disrupt" existing legal frameworks.

Aplicaciones de la impresión 3D en cirugía plástica reconstructiva

La impresión 3D es una tecnología interesante en constante evolución. También conocida como manufactura aditiva, consiste en la conversión de diseños digitales a modelos físicos mediante la adición de capas sucesivas de material. En años recientes, y tras el vencimiento de múltiples patentes, diversos campos de las ciencias de la salud se han interesado en sus posibles usos, siendo la cirugía plástica una de las especialidades médicas que más ha aprovechado sus ventajas y aplicaciones, en especial la capacidad de crear dispositivos altamente personalizados a costos accesibles. Teniendo en cuenta lo anterior, el objetivo del presente artículo es describir los usos de la impresión 3D en cirugía plástica reconstructiva a partir de una revisión de la literatura.Las principales aplicaciones de la impresión 3D descritas en la literatura incluyen su capacidad para crear modelos anatómicos basados en estudios de imagen de pacientes, que a su vez permiten planificar procedimientos quirúrgicos, fabricar implantes y prótesis personalizadas, crear instrumental quirúrgico para usos específicos y usar biotintas en ingeniería tisular.La impresión 3D es una tecnología prometedora con el potencial de implementar cambios positivos en la práctica de la cirugía plástica reconstructiva en el corto y mediano plazo.

3D Bioprinting: The Emergence of Programmable Biodesign

Until recently, bioprinting was largely limited to highly interdisciplinary research teams, as the process requires significant input from specialists in the fields of materials science, engineering, and cell biology. With the advent of commercially available high-performance bioprinters, the field has become accessible to a wider range of research groups, who can now buy the hardware off the shelf instead of having to build it from scratch. As a result, bioprinting has rapidly expanded to address a wide array of research foci, which include organotypic in vitro models, complex engineered tissues, and even bioprinted microbial systems. Moreover, in the early days, the range of suitable bioinks was limited. Now, there is a plethora of viable options to suit many cell phenotypes. This rapidly evolving dynamic environment creates endless opportunities for scientists to design and construct highly complex biological systems. However, this scientific diversity presents its own set of challenges, such as defining standardized protocols for characterizing bioprinted structures, which is essential for eventual organ replacement. In this progress report, the current state-of-the-art in the field of bioprinting is discussed, with a special emphasis on recent hardware developments, bioprinting for regenerative medicine, and late-breaking nontraditional topics.

Sex and Gender Bias in Kidney Transplantation: 3D Bioprinting as a Challenge to Personalized Medicine

In this article, we explore to what extent sex and gender differences may be reproduced in the 3D bioprinting of kidneys. Sex and gender differences have been observed in kidney function, anatomy, and physiology, and play a role in kidney donation and transplantation through differences in kidney size (sex aspect) and altruism (gender aspect). As a form of personalized medicine, 3D bioprinting might be expected to eliminate sex and gender bias. On the basis of an analysis of recent literature, we conclude that personalized techniques such as 3D bioprinting of kidneys alone do not mean that sex and gender bias does not happen. Therefore, sex and gender considerations should be included into every step of developing and using 3D-bioprinted kidneys: in the choice of design, cells, biomaterials, and X-chromosome-activated cells.

Novel Strategies in Artificial Organ Development: What Is the Future of Medicine?

The technology of tissue engineering is a rapidly evolving interdisciplinary field of science that elevates cell-based research from 2D cultures through organoids to whole bionic organs. 3D bioprinting and organ-on-a-chip approaches through generation of three-dimensional cultures at different scales, applied separately or combined, are widely used in basic studies, drug screening and regenerative medicine. They enable analyses of tissue-like conditions that yield much more reliable results than monolayer cell cultures. Annually, millions of animals worldwide are used for preclinical research. Therefore, the rapid assessment of drug efficacy and toxicity in the early stages of preclinical testing can significantly reduce the number of animals, bringing great ethical and financial benefits. In this review, we describe 3D bioprinting techniques and first examples of printed bionic organs. We also present the possibilities of microfluidic systems, based on the latest reports. We demonstrate the pros and cons of both technologies and indicate their use in the future of medicine.

Bioethical and Legal Issues in 3D Bioprinting

Bioethical and legal issues of three-dimensional (3D) bioprinting as the emerging field of biotechnology have not yet been widely discussed among bioethicists around the world, including Russia. The scope of 3D bioprinting includes not only the issues of the advanced technologies of human tissues and organs printing but also raises a whole layer of interdisciplinary problems of modern science, technology, bioethics, and philosophy. This article addresses the ethical and legal issues of bioprinting of artificial human organs.

[Current concepts and new developments of 3D printing in trauma surgery]

The use of 3D printing (synonyms "rapid prototyping" and "additive manufacturing") has played an increasing role in the industry for many years and finds more and more interest and application in musculoskeletal surgery, especially orthopedic trauma surgery.In this article the current literature is systematically reviewed, presented and evaluated in a condensed and comprehensive way according to anatomical (upper and lower extremities) and functional aspects. As many of the publications analyzed were feasibility studies, the degree of evidence is low and methodological weaknesses are obvious and numerous; however, this pioneering work is extremely stimulating and important for further development because the technical, medical and economic potential of this technology is huge and interesting for all those involved in the treatment of musculoskeletal problems.

Self-Healing Hydrogels: The Next Paradigm Shift in Tissue Engineering?

Given their durability and long-term stability, self-healable hydrogels have, in the past few years, emerged as promising replacements for the many brittle hydrogels currently being used in preclinical or clinical trials. To this end, the incompatibility between hydrogel toughness and rapid self-healing remains unaddressed, and therefore most of the self-healable hydrogels still face serious challenges within the dynamic and mechanically demanding environment of human organs/tissues. Furthermore, depending on the target tissue, the self-healing hydrogels must comply with a wide range of properties including electrical, biological, and mechanical. Notably, the incorporation of nanomaterials into double-network hydrogels is showing great promise as a feasible way to generate self-healable hydrogels with the above-mentioned attributes. Here, the recent progress in the development of multifunctional and self-healable hydrogels for various tissue engineering applications is discussed in detail. Their potential applications within the rapidly expanding areas of bioelectronic hydrogels, cyborganics, and soft robotics are further highlighted.

Bioprinting a Synthetic Smectic Clay for Orthopedic Applications

Bioprinting technology has emerged as an important approach to bone and cartilage tissue engineering applications, because it allows the printing of scaffolds loaded with various components, such as cells, growth factors, or drugs. In this context, the bone has a very complex architecture containing highly vascularized and calcified tissues, while cartilage is avascular and has low cellularity and few nutrients. Owing to this complexity, the repair and regeneration of these tissues are highly challenging. Identification of the appropriate biomaterial and fabrication technologies can provide sustainable solutions to this challenge. Here, nanosized Laponite^® (Laponite is a trademark of the company BYK Additives Ltd.) has shown to be a promising material due to its unique properties such as excellent biocompatibility, facile gel formation, shear-thinning property (reversible physical crosslinking), high specific surface area, degrade into nontoxic products, and with osteoinductive properties. Even though Laponite and Laponite-based composite for 3D bioprinting application are considered as soft gels, they may therefore not be thought exhibiting sufficient mechanical strength for orthopedic applications. However, through the merging with suitable composite and, also by incorporation of crosslinking step, desired mechanical strength for orthopedic application can be obtained. In this review, recent advances and future perspective of bioprinting Laponite and Laponite composites for orthopedic applications are highlighted.

Three-dimensional Printing in Anatomy Education: Assessing Potential Ethical Dimensions

New technological developments have frequently had major consequences for anatomy education, and have raised ethical queries for anatomy educators. The advent of three-dimensional (3D) printing of human material is showing considerable promise as an educational tool that fits alongside cadaveric dissection, plastination, computer simulation, and anatomical models and images. At first glance its ethical implications appear minimal, and yet the more extensive ethical implications around clinical bioprinting suggest that a cautious approach to 3D printing in the dissecting room is in order. Following an overview of early groundbreaking studies into 3D printing of prosections, organs, and archived fetal material, it has become clear that their origin, using donated bodies or 3D files available on the Internet, has ethical overtones. The dynamic presented by digital technology raises questions about the nature of the consent provided by the body donor, reasons for 3D printing, the extent to which it will be commercialized, and its comparative advantages over other available teaching resources. In exploring questions like these, the place of 3D printing within a hierarchical sequence of value is outlined. Discussion centers on the significance of local usage of prints, the challenges created by regarding 3D prints as disposable property, the importance of retaining the human side to anatomy, and the unacceptability of obtaining 3D-printed material from unclaimed bodies. It is concluded that the scientific tenor of 3D processes represents a move away from the human person, so that efforts are required to prevent them accentuating depersonalization and commodification.

Three-dimensional bioprinting of stem-cell derived tissues for human regenerative medicine

Stem cell technology in regenerative medicine has the potential to provide an unlimited supply of cells for drug testing, medical transplantation and academic research. In order to engineer a realistic tissue model using stem cells as an alternative to human tissue, it is essential to create artificial stem cell microenvironment or niches. Three-dimensional (3D) bioprinting is a promising tissue engineering field that offers new opportunities to precisely place stem cells within their niches layer-by-layer. This review covers bioprinting technologies, the current development of 'bio-inks' and how bioprinting has already been applied to stem-cell culture, as well as their applications for human regenerative medicine. The key considerations for bioink properties such as stiffness, stability and biodegradation, biocompatibility and printability are highlighted. Bioprinting of both adult and pluriopotent stem cells for various types of artificial tissues from liver to brain has been reviewed. 3D bioprinting of stem-cell derived tissues for human regenerative medicine is an exciting emerging area that represents opportunities for new research, industries and products as well as future challenges in clinical translation.This article is part of the theme issue 'Designer human tissue: coming to a lab near you'.

Combating Malaysia's Involvement in Worldwide Organ Trafficking by Tapping into the Potential of Bioprinting

Objective - Organ shortages have caused many Malaysian people to travel to India or China to purchase organs illegally and to have those organs transplanted into their body, thus contributing to the worldwide problem of organ trafficking. Bioprinting presents the potential to develop human organs in the future. The objective of this study is to explore, through empirical research, the potential of bioprinting as a means of addressing Malaysia’s organ shortages, thereby discouraging Malaysians from obtaining illicitly acquired organs abroad. Methodology/Technique – This is a qualitative study involving primary data including binding international agreements, soft law (non-binding documents issued by international organizations) and Malaysian legislation dealing with organ trafficking. These legal documents are interpreted through a textual analysis. A content analysis was also conducted on the secondary resources consisting of journals, book chapters, conference and working papers, newspaper reports, and other internet materials. Findings - The results of the study show that between 2014 and 2018, Malaysia experienced significant organ shortages, particularly shortages of kidneys. They also suffered from a lack of transplant specialists and medical teams as well as overburdened government hospitals. The Organ and Tissue Transplantation Bill, a new law replacing the Human Tissues Act of 1974, aims to ban organ trading and regulate organ donations. Malaysian research universities have embraced bioprinting through the production of blood vessels and skin, and the Malaysian government has introduced grants and technology transfers that are hoped to accelerate bioprinting. This has the potential to curb Malaysian involvement in worldwide organ trafficking. Novelty – This study is novel as it proposes bioprinting as a technological solution to illicit organ trading and transplantation within the Malaysian context, which has not been previously suggested. Type of Paper: Review. JEL Classification: K10, K14, K49. Keywords: 2000 Protocol to Prevent, Suppress and Punish Trafficking in Persons, Especially Women and Children; Bioprinting; Guiding Principles on Human Cell; Transplantation Bill; Organ Trafficking.

Biomedicine, self and society: An agenda for collaboration and engagement

The commitment of massive resources - financial, social, organisational, and human - drives developments in biomedicine. Fundamental transformations in the generation and application of knowledge are challenging our understandings and experiences of health, illness, and disease as well as the organisation of research and care. Coupled with the accelerated pace of change, it is pressing that we build authentic collaborations across and between the biomedical sciences, humanities and social sciences, and wider society. It is only in this way that we can ask and answer the penetrating questions that will shape improvements in human health now and in the decades ahead. We delineate the need for such commitments across five key areas of human and societal experience that impact on and are impacted by developments in biomedicine: disease; bodies; global movements and institutions; law; and, science-society engagements. Interactions between ideas, researchers, and communities across and within these domains can provide a way into creating the new knowledges, methods, and partnerships we believe are essential if the promises of biomedicine are to be realised.

3D bioactive composite scaffolds for bone tissue engineering

Bone is the second most commonly transplanted tissue worldwide, with over four million operations using bone grafts or bone substitute materials annually to treat bone defects. However, significant limitations affect current treatment options and clinical demand for bone grafts continues to rise due to conditions such as trauma, cancer, infection and arthritis. Developing bioactive three-dimensional (3D) scaffolds to support bone regeneration has therefore become a key area of focus within bone tissue engineering (BTE). A variety of materials and manufacturing methods including 3D printing have been used to create novel alternatives to traditional bone grafts. However, individual groups of materials including polymers, ceramics and hydrogels have been unable to fully replicate the properties of bone when used alone. Favourable material properties can be combined and bioactivity improved when groups of materials are used together in composite 3D scaffolds. This review will therefore consider the ideal properties of bioactive composite 3D scaffolds and examine recent use of polymers, hydrogels, metals, ceramics and bio-glasses in BTE. Scaffold fabrication methodology, mechanical performance, biocompatibility, bioactivity, and potential clinical translations will be discussed.

3D Bioprinting Technology: Scientific Aspects and Ethical Issues

The scientific development of 3D bioprinting is rapidly advancing. This innovative technology involves many ethical and regulatory issues, including theoretical, source, transplantation and enhancement, animal welfare, economic, safety and information arguments. 3D bioprinting technology requires an adequate bioethical debate in order to develop regulations in the interest both of public health and the development of research. This paper aims to initiate and promote ethical debate. The authors examine scientific aspects of 3D bioprinting technology and explore related ethical issues, with special regard to the protection of individual rights and transparency of research. In common with all new biotechnologies, 3D bioprinting technology involves both opportunities and risks. Consequently, several scientific and ethical issues need to be addressed. A bioethical debate should be carefully increased through a multidisciplinary approach among experts and also among the public.

Microscale Electro-Hydrodynamic Cell Printing with High Viability

Cell printing has gained extensive attentions for the controlled fabrication of living cellular constructs in vitro. Various cell printing techniques are now being explored and developed for improved cell viability and printing resolution. Here an electro-hydrodynamic cell printing strategy is developed with microscale resolution (<100 µm) and high cellular viability (>95%). Unlike the existing electro-hydrodynamic cell jetting or printing explorations, insulating substrate is used to replace conventional semiconductive substrate as the collecting surface which significantly reduces the electrical current in the electro-hydrodynamic printing process from milliamperes (>0.5 mA) to microamperes (<10 µA). Additionally, the nozzle-to-collector distance is fixed as small as 100 µm for better control over filament deposition. These features ensure high cellular viability and normal postproliferative capability of the electro-hydrodynamically printed cells. The smallest width of the electro-hydrodynamically printed hydrogel filament is 82.4 ± 14.3 µm by optimizing process parameters. Multiple hydrogels or multilayer cell-laden constructs can be flexibly printed under cell-friendly conditions. The printed cells in multilayer hydrogels kept alive and gradually spread during 7-days culture in vitro. This exploration offers a novel and promising cell printing strategy which might benefit future biomedical innovations such as microscale tissue engineering, organ-on-a-chip systems, and nanomedicine.