3D Printing For Tissue Engineering Research Articles

Bacterial Cellulose: A Sustainable Source for Hydrogels and 3D-Printed Scaffolds for Tissue Engineering.

Bacterial cellulose is a biocompatible biomaterial with a unique macromolecular structure. Unlike plant-derived cellulose, bacterial cellulose is produced by certain bacteria, resulting in a sustainable material consisting of self-assembled nanostructured fibers with high crystallinity. Due to its purity, bacterial cellulose is appealing for biomedical applications and has raised increasing interest, particularly in the context of 3D printing for tissue engineering and regenerative medicine applications. Bacterial cellulose can serve as an excellent bioink in 3D printing, due to its biocompatibility, biodegradability, and ability to mimic the collagen fibrils from the extracellular matrix (ECM) of connective tissues. Its nanofibrillar structure provides a suitable scaffold for cell attachment, proliferation, and differentiation, crucial for tissue regeneration. Moreover, its mechanical strength and flexibility allow for the precise printing of complex tissue structures. Bacterial cellulose itself has no antimicrobial activity, but due to its ideal structure, it serves as matrix for other bioactive molecules, resulting in a hybrid product with antimicrobial properties, particularly advantageous in the management of chronic wounds healing process. Overall, this unique combination of properties makes bacterial cellulose a promising material for manufacturing hydrogels and 3D-printed scaffolds, advancing the field of tissue engineering and regenerative medicine.

The Use of Mesenchymal Stromal/Stem Cells (MSC) for Periodontal and Peri-implant Regeneration: Scoping Review.

The necessity for regenerating peri-implant and periodontal tissues is increasingly apparent. Periodontal diseases can result in a significant loss of clinical attachment level, and tissue regeneration stands as the ultimate goal of periodontal therapy. With the rise of osseointegration, the prosthetic rehabilitation of missing teeth using dental implants has surged, leading to a frequent need for alveolar bone regeneration around implants. This review assessed studies reporting various sources of mesenchymal stromal/stem cells (MSC) and their potential in regenerating periodontal and peri-implant bone tissue. A search was conducted across seven databases spanning the past decade. Three authors independently screened all identified titles and abstracts for eligibility, generating tables to summarize included studies in animals and humans separately. A total of 55 articles were chosen for final evaluation, showcasing five origins of MSC used in humans and animals for regenerating periodontal tissues and peri-implant bone, using different types of scaffolds. Overall, research from the past decades supports the effectiveness of MSC in promoting periodontal and peri-implant regeneration. However, the impact of MSC on regenerative therapies in humans is still in its initial stages. Future research should optimize MSC application protocols by combining techniques, such as the use of nanomedicine and 3D printing for tissue engineering. Clinical studies should also understand the long-term effects and compare MSC therapies with current treatment modalities. By addressing these areas, the scientific community can ensure that MSC therapies are both safe and effective, ultimately enhancing therapeutic strategies and treatment outcomes in Periodontology and Implantology.

Polycaprolactone, polylactic acid, and nanohydroxyapatite scaffolds obtained by electrospinning and 3D printing for tissue engineering

There is a deficit for bone tissue natural grafts that seek to be covered with synthetic substitutes. Scaffolds generated with 3D printing and electrospinning allow adequate mechanical properties maintaining a structure appropriate for cell growth. Here, a scaffold made up of three-dimensional (3D) printed PLA frameworks added with PCL/PLA/nHA nanofibers was manufactured. The framework showed mechanical properties similar to other reported bone substitutes, while the nanofibers showed diameters between 200 and 850 nm. Scaffolds were suitable for cell adhesion and proliferation when evaluated with fibroblasts, showing cell proliferation into the nanofiber network, a fundamental aspect in tissue engineering.

Smart and sustainable: Exploring the future of PHAs biopolymers for 3D printing in tissue engineering

Polyhydroxyalkanoates (PHAs) are biodegradable biopolymers (polyesters), produced by a wide range of bacterial strains. They are gaining increasing interest in different research fields, due to their sustainability and environmental-friendly properties. Additionally, PHAs are also biocompatible, which makes them interesting for tissue engineering and regenerative medicine. At the same time, they are characterized by properties ideal for 3D printing processing, such as high tensile strength, easy processability and thermoplasticity. To date, the techniques employed in PHAs printing mostly include fused deposition modeling (FDM), selective laser sintering (SLS), electrospinning (ES), and melt electrospinning (MES). In this review, we provide a comprehensive summary of the versatile and sustainably sourced bacterial PHAs, also modified by blending with natural and synthetic polymers (e.g., PLA, PGA) or combining them with inorganic fillers (e.g., nanoparticles, glass), used for 3D printing in biomedical applications. We specify focus on the printing conditions and the properties of the obtained scaffolds with a focus on the print resolution and scaffolds mechanical and biological properties. New perspectives in the emerging field of PHAs biofabrication process, characterized by sustainability and efficiency of the scaffold production, are demonstrated. The use of alternative printing techniques, i.e. melt electrowriting (MEW), and producing smart and functional materials degrading on demand under in vitro and in vivo conditions is proposed.

Additive manufacturing of biomaterials: A review

The growing field of 3D printing has undergone impressive expansion because of its flexible manufacturing technique for layer-by-layer part fabrication utilizing CAD models without the requirement for specialist machinery. 3D printing, which was first used to create pre-surgical models, has become a crucial process for creating specific patient instruments, implants, and scaffolds for applications in tissue engineering. The availability of inexpensive printers has stoked renewed interest in the use of stem cells and tailored scaffolds to promote personalized medicine. As a result, the development of printed biomaterials has significantly increased over time. A thorough analysis of current and previous developments in the creation of biomaterials and bioinks is provided in this paper. Intricate tissues, such as those present in the craniomaxillofacial complex's bone, bones, cartilage, muscles, arteries, and nerves, are frequently restored using 3D printers. Furthermore, these printers have been successfully employed in fabricating complex organs featuring intricate 3D microarchitectures, including the liver and lymphoid organs. By shedding light on the latest developments and potential avenues for further exploration, this article aims to highlight the immense potential of 3D printing in tissue engineering and personalized medicine. The ever-growing capabilities of 3D printing technology have the potential to revolutionize the medical field, opening new possibilities for tailored and highly effective treatments.

Synthesis and Exfoliation of Calcium Organophosphonates for Tailoring Rheological Properties of Sodium Alginate Solutions: A Path toward Polysaccharide-Based Bioink.

Layered nanoparticles with surface charge are explored as rheological modifiers for extrudable materials, utilizing their ability to induce electrostatic repulsion and create a house-of-cards structure. These nanoparticles provide mechanical support to the polymer matrix, resulting in increased viscosity and storage modulus. Moreover, their advantageous aspect ratio allows for shear-induced orientation and decreased viscosity during flow. In this work, we present a synthesis and liquid-based exfoliation procedure of phenylphosphonate-phosphate particles with enhanced ability to be intercalated by hydrophilic polymers. These layered nanoparticles are then tested as rheological modifiers of sodium alginate. The effective rheological modification is proved as the viscosity increases from 101 up to 103 Pa·s in steady state. Also, shear-thinning behavior is observed. The resulting nanocomposite hydrogels show potential as an extrudable bioink for 3D printing in tissue engineering and other biomedical applications, with good shape fidelity, nontoxicity, and satisfactory cell viability confirmed through encapsulation and printing of mouse fibroblasts.

Performance Comparison of PVA/SA Composite Hydrogels for 3D Printing of Cartilage Scaffolds with Different Compositions

Physical blend is the method always used to modify the properties of composite hydrogels for 3D printing in tissue engineering. In this paper, polyvinyl alcohol (PVA) blending with sodium alginate (SA) was applied to enhance the mechanical properties of SA. The PVA/SA blending hydrogels with different components (5:5, 4:6, 3:7, 2:8, 1:9, and 0:10) were prepared through cross-linking method, and their properties were studied from microstructure, mechanical property, hydrophilicity, and printability, so the optimal composition ratio of the composite hydrogel can be selected for 3D printing cartilage scaffold. Results show that with PVA increasing in composite hydrogel, the pore size of the composite hydrogel becomes smaller and more even. The tensile strength and toughness of PVA/SA hydrogels increased firstly and then decreased with the increase of PVA content, and the composite hydrogel of 2PVA/8AS has the best tensile strength. Moreover, the water content and printability of hydrogels decrease with the increase of PVA, which is in good agreement with the pore structures of hydrogels. Based on the above results, we believe that 8AS/2PVA blend hydrogel is the most suitable for 3D printing cartilage scaffolds.

Natural Materials for 3D Printing and Their Applications.

In recent years, 3D printing has gradually become a well-known new topic and a research hotspot. At the same time, the advent of 3D printing is inseparable from the preparation of bio-ink. Natural materials have the advantages of low toxicity or even non-toxicity, there being abundant raw materials, easy processing and modification, excellent mechanical properties, good biocompatibility, and high cell activity, making them very suitable for the preparation of bio-ink. With the help of 3D printing technology, the prepared materials and scaffolds can be widely used in tissue engineering and other fields. Firstly, we introduce the natural materials and their properties for 3D printing and summarize the physical and chemical properties of these natural materials and their applications in tissue engineering after modification. Secondly, we discuss the modification methods used for 3D printing materials, including physical, chemical, and protein self-assembly methods. We also discuss the method of 3D printing. Then, we summarize the application of natural materials for 3D printing in tissue engineering, skin tissue, cartilage tissue, bone tissue, and vascular tissue. Finally, we also express some views on the research and application of these natural materials.

Application of medical imaging methods and artificial intelligence in tissue engineering and organ-on-a-chip.

Organ-on-a-chip (OOC) is a new type of biochip technology. Various types of OOC systems have been developed rapidly in the past decade and found important applications in drug screening and precision medicine. However, due to the complexity in the structure of both the chip-body itself and the engineered-tissue inside, the imaging and analysis of OOC have still been a big challenge for biomedical researchers. Considering that medical imaging is moving towards higher spatial and temporal resolution and has more applications in tissue engineering, this paper aims to review medical imaging methods, including CT, micro-CT, MRI, small animal MRI, and OCT, and introduces the application of 3D printing in tissue engineering and OOC in which medical imaging plays an important role. The achievements of medical imaging assisted tissue engineering are reviewed, and the potential applications of medical imaging in organoids and OOC are discussed. Moreover, artificial intelligence - especially deep learning - has demonstrated its excellence in the analysis of medical imaging; we will also present the application of artificial intelligence in the image analysis of 3D tissues, especially for organoids developed in novel OOC systems.

Tissue Engineering Strategies for Peripheral Nerve Regeneration.

A peripheral nerve injury (PNI) has severe and profound effects on the life of a patient. The therapeutic approach remains one of the most challenging clinical problems. In recent years, many constructive nerve regeneration schemes are proposed at home and abroad. Nerve tissue engineering plays an important role. It develops an ideal nerve substitute called artificial nerve. Given the complexity of nerve regeneration, this review summarizes the pathophysiology and tissue-engineered repairing strategies of the PNI. Moreover, we discussed the scaffolds and seed cells for neural tissue engineering. Furthermore, we have emphasized the role of 3D printing in tissue engineering.

3D Bioprinting Constructs to Facilitate Skin Regeneration

AbstractIn the last decade, the advent of 3D printing for tissue engineering and regenerative medicine has engendered great interest for those involved in skin repair and regeneration. 3D bioprinting allows spatial distribution of skin cells into predefined custom‐made structures to produce living skin mimics on the bench for grafting or drug testing. The key aspect of 3D bioprinting lies in the formulation of printable bioinks serving as matrix mimics to house skin cells, alongside an appropriate combination of cells. In this review, bioink formulations, cell combinations, as well as manufacturing methods exploited to develop 3D bioprinted constructs for skin regeneration are summarized. Issues to do with the selection of suitable materials and cells to ensure the functionality of the resulting skin constructs and fabrication of skin appendages are also addressed.

Advances in 3D Printing for Tissue Engineering.

Tissue engineering (TE) scaffolds have enormous significance for the possibility of regeneration of complex tissue structures or even whole organs. Three-dimensional (3D) printing techniques allow fabricating TE scaffolds, having an extremely complex structure, in a repeatable and precise manner. Moreover, they enable the easy application of computer-assisted methods to TE scaffold design. The latest additive manufacturing techniques open up opportunities not otherwise available. This study aimed to summarize the state-of-art field of 3D printing techniques in applications for tissue engineering with a focus on the latest advancements. The following topics are discussed: systematics of the available 3D printing techniques applied for TE scaffold fabrication; overview of 3D printable biomaterials and advancements in 3D-printing-assisted tissue engineering.

3D Printed porous tissue engineering scaffolds with the self-folding ability and controlled release of growth factor

Abstract

3D printing in tissue engineering: a state of the art review of technologies and biomaterials

PurposeIn the past decade, three-dimensional (3D) printing has gained attention in areas such as medicine, engineering, manufacturing art and most recently in education. In biomedical, the development of a wide range of biomaterials has catalysed the considerable role of 3D printing (3DP), where it functions as synthetic frameworks in the form of scaffolds, constructs or matrices. The purpose of this paper is to present the state-of-the-art literature coverage of 3DP applications in tissue engineering (such as customized scaffoldings and organs, and regenerative medicine).Design/methodology/approachThis review focusses on various 3DP techniques and biomaterials for tissue engineering (TE) applications. The literature reviewed in the manuscript has been collected from various journal search engines including Google Scholar, Research Gate, Academia, PubMed, Scopus, EMBASE, Cochrane Library and Web of Science. The keywords that have been selected for the searches were 3 D printing, tissue engineering, scaffoldings, organs, regenerative medicine, biomaterials, standards, applications and future directions. Further, the sub-classifications of the keyword, wherever possible, have been used as sectioned/sub-sectioned in the manuscript.Findings3DP techniques have many applications in biomedical and TE (B-TE), as covered in the literature. Customized structures for B-TE applications are easy and cost-effective to manufacture through 3DP, whereas on many occasions, conventional technologies generally become incompatible. For this, this new class of manufacturing must be explored to further capabilities for many potential applications.Originality/valueThis review paper presents a comprehensive study of the various types of 3DP technologies in the light of their possible B-TE application as well as provides a future roadmap.

Addressing present pitfalls in 3D printing for tissue engineering to enhance future potential.

Additive manufacturing in tissue engineering has significantly advanced in acceptance and use to address complex problems. However, there are still limitations to the technologies used and potential challenges that need to be addressed by the community. In this manuscript, we describe how the field can be advanced not only through the development of new materials and techniques but also through the standardization of characterization, which in turn may impact the translation potential of the field as it matures. Furthermore, we discuss how education and outreach could be modified to ensure end-users have a better grasp on the benefits and limitations of 3D printing to aid in their career development.

Solvent-based Extrusion 3D Printing for the Fabrication of Tissue Engineering Scaffolds.

Three-dimensional (3D) printing has been emerging as a new technology for scaffold fabrication to overcome the problems associated with the undesirable microstructure associated with the use of traditional methods. Solvent-based extrusion (SBE) 3D printing is a popular 3D printing method, which enables incorporation of cells during the scaffold printing process. The scaffold can be customized by optimizing the scaffold structure, biomaterial, and cells to mimic the properties of natural tissue. However, several technical challenges prevent SBE 3D printing from translation to clinical use, such as the properties of current biomaterials, the difficulties associated with simultaneous control of multiple biomaterials and cells, and the scaffold-to-scaffold variability of current 3D printed scaffolds. In this review paper, a summary of SBE 3D printing for tissue engineering (TE) is provided. The influences of parameters such as ink biomaterials, ink rheological behavior, cross-linking mechanisms, and printing parameters on scaffold fabrication are considered. The printed scaffold structure, mechanical properties, degradation, and biocompatibility of the scaffolds are summarized. It is believed that a better understanding of the scaffold fabrication process and assessment methods can improve the functionality of SBE-manufactured 3D printed scaffolds.

Optical properties of daylight curable resin doped with nanodiamond powder

In this paper creating optical elements with the use of 3D printing technology was elaborated on. A special focus was put on the properties of nanodiamond and possibilities of applying it in 3D printing process in a mixture with the standard 3D printing resin. Several printouts have been completed, starting from the calibration printouts and ending with optical flats and both cylindrical and spherical lenses. The printouts have been tested for their abilities to transmit and absorb light in a wide spectrum of wavelengths. Full Text: PDF ReferencesL. Ding, R. Wei, and H. Che, Development of a BIM-based automated construction system, Procedia Engineering 85, 123-131 (2014). CrossRef L. Fang, T. Chen, R. Li, S. Liu, Application of embedded fiber Bragg grating (FBG) sensors in monitoring health to 3D printing structures, IEEE Sensors Journal, 16(17), 6604-6610 (2016). CrossRef G. B. Kim, S. Lee, H. Kim, D. H. Yang, Y. H. Kim, Y. S. Kyung, et al., Three-dimensional printing: basic principles and applications in medicine and radiology, Korean Journal of Radiology, 17(2), 182-197 (2016). CrossRef J. W. Stansbury, M. J. Idacavage, 3D printing with polymers: Challenges among expanding options and opportunities, Dental Materials, 32(1), 54-64 (2016). CrossRef G. H. Wu, S. H. Hsu, Polymeric-based 3D printing for tissue engineering, Journal of Medical and Biological Engineering, 35(3), 285-292 (2015). CrossRef https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=6973&tabname=N-BK7 DirectLink https://www.thorlabs.com/images/TabImages/UVFS_Transmission_780.gif DirectLink U. Kalsoom, A. Peristyy, P. N. Nesterenko, B. Paull, A 3D printable diamond polymer composite: a novel material for fabrication of low cost thermally conducting devices, RSC Advances, 6(44), 38140-38147 (2016). CrossRef K. M. El-Say, Nanodiamond as a drug delivery system: Applications and prospective, Journal of Applied Pharmaceutical Science, 01(06), 29-39 (2011). DirectLink K. Królewski, MA thesis, 3D printing of optical elements from diamond powders, (2018).

Fabrication and characterization of porous polycaprolactone scaffold via extrusion-based cryogenic 3D printing for tissue engineering

Earlier reports of fabricating 3D porous PCL scaffolds for tissue engineering applications were overshadowed by several limitations such as additional molds cost, relatively low efficiency, and lacking process control. In present study, combined extrusion-based cryogenic 3D printing (ECP) (−20 °C) and subsequent freeze-drying approaches were employed to facilely fabricate polycaprolactone (PCL) scaffolds, with high porosity and fidelity. Freeze-drying caused shrinkage of the scaffolds along X, Y, and Z-axes to some extent. The porosities of CP600, CP800, and CP1000 were found to be 64.0 ± 1.2%, 70.1 ± 1.3%, and 74.3 ± 0.6%, respectively. The fabricated scaffolds were characterized for various structural features and compared with the ones fabricated through traditional extrusion-based melt 3D printing (EMP). The crystallinity of PCL in ECP scaffolds was lower (57.1 ± 2.2%) than EMP scaffolds (69.8 ± 1.3%). The ECP scaffolds showed high alkaline degradation, but low compression properties. The ECP scaffolds promoted the adhesion and proliferation of MCT3T-E1 cells with well-spread morphology on the porous filaments. Together, these features justify the suitability of printed PCL scaffolds for potential TE applications.

Biofabrication of glass scaffolds by 3D printing for tissue engineering

This paper reports a study on the development of bioactive glass powders for biofabrication of scaffolds by an additive manufacturing technique, three-dimensional printing (3DP). Several formulations of the glass were developed from the CaO·P2O5·TiO2 system and prepared on the basis of the results for the commercial powder characterization (average particle size, particle size distribution, microstructural and crystallographic analysis). For printing the glass models in the prototyping machine, a virtual model defined as the “standard model” was produced in commercial powder, and a systematic study of the relevant processing parameters (binder composition, formulation of powder, saturation level in the shell and core, bleed compensation, and printed layer thickness) was carried out in order to determine the most suitable conditions for the fabrication of porous structures for tissue engineering applications. The printed glass models were sintered through specific thermal programs and then characterized in terms of dimensions, structure, morphological features, and mechanical properties. Finally, the sintered models were submitted to mineralization tests in simulated physiological media. In this work, it was demonstrated that it is possible to use a printing machine to manufacture 3DP glassy porous structures with suitable features for tissue engineering applications as temporary scaffolds. The mechanical properties of the produced structures and its mineralization capability in physiological fluids suggest that they have potential to be used in bone tissue regeneration under low load-bearing situations.

Efficacy of Silk Fibroin Based Bio-Ink in 3D Printing for Tissue Engineering

Efficacy of Silk Fibroin Based Bio-Ink in 3D Printing for Tissue Engineering