Tissue Printing Research Articles

Bioprinting of light-crosslinkable neutral-dissolved collagen to build implantable connective tissue with programmable cellular orientation

Fabricating connective tissue with printing fidelity, structural stability, biocompatibility, and cellular orientation remains a challenge for bioink. Collagen, as inherent fibers to provide strength in vivo, should be the ideal material for tissue printing. However, current collagen-bioink exhibits poor printability and mechanical properties. Here, the light-crosslinkable norbornene-collagen (NorCol) is developed to solve this dilemma. NorCol with complete collagen structure exhibits outstanding shear-thinning properties and light-crosslinking strength, realizing the construction of complicated constructs with excellent printing fidelity and structural stability. Neutral-dissolved NorCol with different concentrations is directly integrated to print pure collagen structure with composite modulus, providing top-class biocompatibility that mimics the heterogeneous microarchitecture of the extracellular matrix (ECM). This composite structure also permits extensive infiltration of host tissue and capillaries during subcutaneous transplants. By the designed tight interface of printed filaments, a geometric-guided and modulus-independent anisotropic mechanical environment is constructed, realizing cellular orientation. Furthermore, the cellular orientation is in the same direction as the printed high-concentration NorCol, which is the same case of cells and collagen fibers in vivo. This capability of NorCol breaks new ground for printing pure ECM protein-based, implantable and functional constructs, applicable in connective tissue engineering for human applications.

Inexpensive DIY Bioprinting in a Secondary School Setting.

Bioprinting is a technique that allows custom printing of cell-laden tissue using the principle of three-dimensional (3D) printing. The technique has various applications, ranging from tissue engineering to materials science. Bioprinting is an attractive topic for science, technology, engineering, and math education due to its novelty and interdisciplinary nature. Nonetheless, a basic commercial bioprinter could cost several thousand U.S. dollars. There have been attempts to construct low-cost do-it-yourself bioprinters for research purpose. However, those methods required expertise, uncommon reagents, and professional equipment, making it difficult for teachers and students in secondary schools to replicate. Here, we demonstrate how teachers and students in a secondary school can convert a 3D printer into a bioprinter for conducting a hands-on bioprinting activity using secondary school-available resources. Briefly, an open-source Creality Ender 3 V2 3D printer in a school was converted into a bioprinter using 3D-printed parts and other readily available materials. Cell-laden bioink and support medium were made using school-available reagents. The bioprinter can be easily constructed and operated by teachers and students who do not have prior knowledge in coding and engineering. We used the bioprinter to print a coronary artery model and an algae-laden artificial leaf. The photosynthetic activity of the artificial leaf could be observed and investigated using a hydrogen carbonate indicator. The work described in this paper could make bioprinting available, comprehensible, and enjoyable to secondary school students, opening a door for inexpensive innovative teaching and learning activities using bioprinting in secondary schools.

2023 TERMIS – AMERICAS Conference & Exhibition Boston Marriott Copley Place April 11–14, 2023

2023 TERMIS – AMERICAS Conference & Exhibition Boston Marriott Copley Place April 11–14, 2023

3D Bioprinting Using Synovium-Derived MSC-Laden Photo-Cross-Linked ECM Bioink for Cartilage Regeneration.

In this study, inspired by the components of cartilage matrix, a photo-cross-linked extracellular matrix (ECM) bioink composed of modified proteins and polysaccharides was presented, including gelatin methacrylate, hyaluronic acid methacrylate, and chondroitin sulfate methacrylate. The systematic experiments were performed, including morphology, swelling, degradation, mechanical and rheological tests, printability analysis, biocompatibility and chondrogenic differentiation characterization, and RNA sequencing (RNA-seq). The results indicated that the photo-cross-linked ECM hydrogels possessed suitable degradation rate and excellent mechanical properties, and the three-dimensional (3D) bioprinted ECM scaffolds obtained favorable shape fidelity and improved the basic properties, biological properties, and chondrogenesis of synovium-derived MSCs (SMSCs). The strong stimulation of transforming growth factor-beta 1 (TGF-β1) enhanced the aggregation, proliferation, and differentiation of SMSCs, thereby enhancing chondrogenic ECM deposition. In vivo animal experiments and gait analysis further confirmed that the ECM scaffold combined with TGF-β1 could effectively promote cartilage regeneration and functional recovery of injured joints. To sum up, the photo-cross-linked ECM bioink for 3D printing of functional cartilage tissue may become an attractive strategy for cartilage regeneration.

PM 7/31 (2) Citrus tristeza virus

<scp>PM</scp> 7/31 (2) Citrus tristeza virus

Background Causes for Criminal Liability for Bioprinting

Bioprinting is one of the newest scientific developments in the NBICS convergence (convergence of nano-, bio-, information and cognitive technologies), which is a global phenomenon on a global scale. Research in the field of 3D tissue and organ printing is of a complex interdisciplinary nature, and is projected onto the biomedical landscape of organ transplantation issues. The paper deals with the legal issues of bioprinting as a technology in the field of biomedicine amid innovative activities in the healthcare system. The stages of bioprinting (preprocessing, processing, postprocessing) successively pass into each other, forming a trace complex of unresolved legal issues. There is a new phenomenon of objective reality, expressed in actions aimed at creating a new biogenetic product, while no norm of the current positive legislation can describe the process of creating and applying a reprint organ (biomaterial). The need to develop and systematize Russian legislation on the use of the results of innovative technologies in healthcare is justified taking into account the high criminal risk of harm to the human embryo. The paper identifies two groups of criminogenic threats depending on the use of biosafety and bioinsecure technologies in the field of bioprinting. The current criminal legislation makes it possible to classify criminal acts in the field of 3D technologies using the general bodies of crimes in the Special part of the Criminal Code of the Russian Federation. However, the mechanisms of criminal legal protection need to be improved by developing special norms that block harm to biogenetic human rights. Since the common element in all crimes related to bioprinting technologies is the object of the crime, it is necessary to determine that the moment when criminal legal protection of human life begins is from the moment of fertilization of an egg by artificial or natural means. It is important to use the general term «human embryo», which includes all stages of embryonic and fetal development.

3D soft tissue printing—from vision to reality—review of current concepts

3D soft tissue printing—from vision to reality—review of current concepts

3D printed neural tissues with in situ optical dopamine sensors

Engineered neural tissues serve as models for studying neurological conditions and drug screening. Besides observing the cellular physiological properties, in situ monitoring of neurochemical concentrations with cellular spatial resolution in such neural tissues can provide additional valuable insights in models of disease and drug efficacy. In this work, we demonstrate the first three-dimensional (3D) tissue cultures with embedded optical dopamine (DA) sensors. We developed an alginate/Pluronic F127 based bio-ink for human dopaminergic brain tissue printing with tetrapodal-shaped-ZnO microparticles (t-ZnO) additive as the DA sensor. DA quenches the autofluorescence of t-ZnO in physiological environments, and the reduction of the fluorescence intensity serves as an indicator of the DA concentration. The neurons that were 3D printed with the t-ZnO showed good viability, and extensive 3D neural networks were formed within one week after printing. The t-ZnO could sense DA in the 3D printed neural network with a detection limit of 0.137 μM. The results are a first step toward integrating tissue engineering with intensiometric biosensing for advanced artificial tissue/organ monitoring.

3D bioprinting as a future of regenerative medicine and hope for transplantology

Introduction: 3D bioprinting is a continuously refined technology that enables tissue structures to be faithfully reproduced, using specially developed bioinks and 3D printers. Thanks to its versatility, it is possible to use it in regenerative medicine and transplantation, which could have a positive impact on the survival and comfort of patients with injuries and those awaiting transplantation.&#x0D; Aim of the study: Summarise the current state of knowledge on the use of 3D bioprinting technology in the field of regenerative medicine and transplantation, to present the extent of the method's capabilities and examples of its applications, and to outline what role it will play in the future of medicine.&#x0D; Methods and materials: A review of the literature available in the PubMed database and Google Scholar from the last 5 years was conducted, using the following keywords: 3d bioprinting, regenerative medicine, tissue biofabrication.&#x0D; Results: Significant progress has been made in the field of bioprinting and various types of tissue are now being printed and tested. Current research into the printing of skin tissue leads us to believe that in the coming years, 3D bioprinting using stem cells will make it possible to significantly improve the treatment of skin injuries. Researchers are also working on using this technology in the field of neurology and bone damage. &#x0D; Conclusion: The dynamic development of 3D bioprinting technology offers the hope of eliminating the main transplantation problem related to donor availability. However, the road to wider clinical application of this technology is still a long one, due to the numerous technological difficulties associated with the development of bioprinters, advanced printers and a thorough understanding of human tissue architecture. With the current intensified research in this field, it is expected that these problems will be eliminated in time and the technology will gain more interest from clinicians.&#x0D;

Progress in research and development of soft tissue three-dimensional bioprinting and its supporting equipment

As a cutting-edge technology of tissue engineering, three-dimensional bioprinting can accurately fabricate biomimetic tissue, which has made great progress in the field of hard tissue printing such as bones and teeth. Meanwhile, the research on soft tissue bioprinting is also developing rapidly. This article mainly discussed the development progress in various bioprinting technologies and supporting equipment including printing software, printing hardware, supporting consumables, and bioreactors for soft tissue three-dimensional bioprinting, and made a prospect for the future research and development direction of soft tissue three-dimensional bioprinting.

PixelPrint: Three-dimensional printing of patient-specific soft tissue and bone phantoms for CT.

Patient-based CT phantoms, with realistic image texture and densities, are essential tools for assessing and verifying CT performance in clinical practice. This study extends our previously presented 3D printing solution (PixelPrint) to patient-based phantoms with soft tissue and bone structures. To expand the Hounsfield Unit (HUs) range, we utilize a stone-based filament. Applying PixelPrint, we converted patient DICOM images directly into FDM printer instructions (G-code). Density was modeled as the ratio of filament to voxel volume to emulate attenuation profiles for each voxel, with the filament ratio controlled through continuous modification of the printing speed. Two different phantoms were designed to demonstrate the high reproducibility of our approach with micro-CT acquisitions, and to determine the mapping between filament line widths and HU values on a clinical CT system. Moreover, a third phantom based on a clinical cervical spine scan was manufactured and scanned with a clinical spectral CT scanner. CT image of the patient-based phantom closely resembles the original CT image both in texture and contrast levels. Measured differences between patient and phantom are around 10 HU for bone marrow voxels and around 150 HU for cortical bone. In addition, stone-based filament can accurately represent boney tissue structures across the different x-ray energies, as measured by spectral CT. This study demonstrates the feasibility of our 3D-printed patient-based phantoms to be extended to soft-tissue and bone structure while maintaining accurate organ geometry, image texture, and attenuation profiles for spectral CT.

Marketing Strategies for Cultured Meat: A Review

Environmentally intense and negative consequences relateing to conventional meat production systems have induced some actors to suggest alternative meat sources. Diseases carried by animals, human perception of cruelty to animals, and public health concerns about cardiovascular diseases have provided the basis for the development of cultured meat. The current market is influenced by many factors, including regulators, affordability, religion, and media perception. The existing cultured meat market is also regulated by legislatures, affordability, consumer religion, and the media. Consumer perception is distributed across various aspects, including ethical priorities, nutritional profile of the meat consumed, age-based acceptance, gender differentiation, political orientation, land-based attitude, education status, socioeconomic factors, and familiarity factor with the existing product in the market. Inhibiting barriers reported among consumers—including low naturalness, safety, nutritional concerns, trust, neophobia, economic, and ethical approaches—should be employed as marketing tactics directly to address their respective concerns. Tissue culture, starter cells, printing, and 3D printing are some of the methods currently being used for the production of cultured meat. Similarly, many hybrid technologies are also being used to produce meat-like products to increase consumer familiarity along and market presence. Existing research frameworks have improved the previous mindset of consumers with media coverage, educational frameworks, and the textural attributes of cultured meat. Additional benefits of CUME may include being environmentally friendly with less production of greenhouse gases. However, consumer trust, affordability, improving nutritional status, and widescale adoption are just a few of the parameters that need to be addressed to enhance consumer acceptability of these products. The aim of this article was to analyze the current state of cultured meat and the marketing content challenges and strategies used to advance public acceptance of cultured meat.

Self-Healing Injectable Hydrogels for Tissue Regeneration.

Biomaterials with the ability to self-heal and recover their structural integrity offer many advantages for applications in biomedicine. The past decade has witnessed the rapid emergence of a new class of self-healing biomaterials commonly termed injectable, or printable in the context of 3D printing. These self-healing injectable biomaterials, mostly hydrogels and other soft condensed matter based on reversible chemistry, are able to temporarily fluidize under shear stress and subsequently recover their original mechanical properties. Self-healing injectable hydrogels offer distinct advantages compared to traditional biomaterials. Most notably, they can be administered in a locally targeted and minimally invasive manner through a narrow syringe without the need for invasive surgery. Their moldability allows for a patient-specific intervention and shows great prospects for personalized medicine. Injected hydrogels can facilitate tissue regeneration in multiple ways owing to their viscoelastic and diffusive nature, ranging from simple mechanical support, spatiotemporally controlled delivery of cells or therapeutics, to local recruitment and modulation of host cells to promote tissue regeneration. Consequently, self-healing injectable hydrogels have been at the forefront of many cutting-edge tissue regeneration strategies. This study provides a critical review of the current state of self-healing injectable hydrogels for tissue regeneration. As key challenges toward further maturation of this exciting research field, we identify (i) the trade-off between the self-healing and injectability of hydrogels vs their physical stability, (ii) the lack of consensus on rheological characterization and quantitative benchmarks for self-healing injectable hydrogels, particularly regarding the capillary flow in syringes, and (iii) practical limitations regarding translation toward therapeutically effective formulations for regeneration of specific tissues. Hence, here we (i) review chemical and physical design strategies for self-healing injectable hydrogels, (ii) provide a practical guide for their rheological analysis, and (iii) showcase their applicability for regeneration of various tissues and 3D printing of complex tissues and organoids.

Defining Soft Tissue: Bitmap Printing of Soft Tissue for Surgical Planning.

Nearly all applications of 3D printing for surgical planning have been limited to bony structures and simple morphological descriptions of complex organs due to the fundamental limitations in accuracy, quality, and efficiency of the current modeling paradigms and technologies. Current approaches have largely ignored the constitution of soft tissue critical to most surgical specialties where multiple high-resolution variations transition gradually across the interior of the volume. Differences in the scales of organization related to unique organs require special attention to capture fine features critical to surgical procedures. We present a six-material bitmap printing technique for creating 3D models directly from medical images, which are superior in spatial and contrast resolution to current 3D modeling methods, and contain previously unachievable spatial fidelity for soft tissue differentiation. A retrospective exempt IRB was obtained for all data through the Colorado Multiple Institution Review Board #21-3128.

Three-Dimensional Skin Tissue Printing with Human Skin Cell Lines and Mouse Skin-Derived Epidermal and Dermal Cells.

Since the skin covers most surfaces of the body, it is susceptible to damage, which can be fatal depending on the degree of injury to the skin because it defends against external attack and protects internal structures. Various types of artificial skin are being studied for transplantation to repair damaged skin, and recently, the production of replaceable skin using three-dimensional (3D) bioprinting technology has also been investigated. In this study, skin tissue was produced using a 3D bioprinter with human skin cell lines and cells extracted from mouse skin, and the printing conditions were optimized. Gelatin was used as a bioink, and fibrinogen and alginate were used for tissue hardening after printing. Printed skin tissue maintained a survival rate of 90% or more when cultured for 14 days. Culture conditions were established using 8 mM calcium chloride treatment and the skin tissue was exposed to air to optimize epidermal cell differentiation. The skin tissue was cultured for 14 days after differentiation induction by this optimized culture method, and immunofluorescent staining was performed using epidermal cell differentiation markers to investigate whether the epidermal cells had differentiated. After differentiation, loricrin, which is normally found in terminally differentiated epidermal cells, was observed in the cells at the tip of the epidermal layer, and cytokeratin 14 was expressed in the lower cells of the epidermis layer. Collectively, this study may provide optimized conditions for bioprinting and keratinization for three-dimensional skin production.

Assessing the 3D Printability of an Elastomeric Poly(caprolactone-co-lactide) Copolymer as a Potential Material for 3D Printing Tracheal Scaffolds.

The advent of 3D printing technology has made remarkable progress in the field of tissue engineering. Yet, it has been challenging to reproduce the desired mechanical properties of certain tissues by 3D printing. This was majorly due to the lack of 3D printable materials possessing mechanical properties similar to the native tissue. In this study, we have synthesized four different ratios of poly(caprolactone-co-lactide (PLCL) and tested their 3D printing capabilities. The physicochemical properties of the material were characterized using Fourier-transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). Furthermore, the mechanical properties were assessed using the universal testing machine (UTM). The ratio with the higher lactide content was found to have better printability. Out of the different ratios assessed, a suitable ratio having the desired mechanical properties and printability was identified and 3D printed into a tracheal scaffold. Thus, PLCL can be a potential material for 3D printing of tissues like the trachea.

Biomimetic 3D tissue printing to create an in vitro bone model for Gaucher disease

Biomimetic 3D tissue printing to create an in vitro bone model for Gaucher disease

The mechanical reliability of vat photopolymerization 3D printing of isosorbide-derived polyester porous tissue engineering scaffolds.

Photo-crosslinkable polymers are being studied as a potential 3D printable solution to the well-established need for biocompatible, highly elastic, and resorbable materials. Among the emerging materials that meet this need is a sugar-based polymer, an isosorbide-derived polyester, which represents a candidate for use in tissue engineered medical devices. Isosorbide polyesters are known to exhibit time-certain resorption profiles, offering not just biocompatibility and biodegradability, but can also be 3D printed by photocrosslinking. The 3D printing of medical devices requires accuracy, minimally, in the 10’s of microns range. Preliminary data showing isosorbide-derived polyester 3D printing of scaffolds with an internal porosity is reported here. The pore geometry we used is Schoen’s gyroid. Using an EnvisionTEC 3D printer (Dearborn, MI) we designed cylinders with 81% porosity using the gyroid pore geometry with a pore size of 800 µm and a strut size of 1000 µm.

A review on 3D printing functional brain model.

Modern neuroscience increasingly relies on 3D models to study neural circuitry, nerve regeneration, and neural disease. Several different biofabrication approaches have been explored to create 3D neural tissue model structures. Among them, 3D bioprinting has shown to have great potential to emerge as a high-throughput/high precision biofabrication strategy that can address the growing need for 3D neural models. Here, we have reviewed the design principles for neural tissue engineering. The main challenge to adapt printing technologies for biofabrication of neural tissue models is the development of neural bioink, i.e., a biomaterial with printability and gelation properties and also suitable for neural tissue culture. This review shines light on a vast range of biomaterials as well as the fundamentals of 3D neural tissue printing. Also, advances in 3D bioprinting technologies are reviewed especially for bioprinted neural models. Finally, the techniques used to evaluate the fabricated 2D and 3D neural models are discussed and compared in terms of feasibility and functionality.

Tissue Print Hybridization for Detection and Characterization of Viroids.

Simplifying sample preparation by transferring plant sap (from plant sections) directly onto a membrane is advantageous for any routine viroid detection technique, such as tissue printing. After fixing the samples on the membrane, hybridization steps similar to Northern or dot blot can be successfully implemented as long as factors like stringency and low viroid titer are properly adjusted to enable enhancement of the detection limit. The protocol described allows for indexing hundreds of field samples as a phytosanitary control measure.