光交联自支撑丝素蛋白水凝胶的三维快速成型

将丝素蛋白(SF)光诱导自交联原理与挤出式三维(3D)打印相结合, 开发了光交联自支撑SF水凝胶的原位成型加工技术. 采用旋转流变仪、 光流变测试系统和改装的挤出式3D打印设备等对SF溶液的流变性能、 光交联性能和成型加工性能等进行研究. 结果表明, SF溶液主要表现为黏性特征, 结构强度和稳定性均较差. 利用SF的光诱导自交联特性, 以三联吡啶氯化钌[Ru(Ⅱ)]和过硫酸钾(KPS)为蓝光引发体系, 可实现SF水凝胶的快速光交联成型. SF光交联行为符合指数函数增长模型, 因“滤镜效应”, 当Ru(Ⅱ)的浓度为0.05 mmol/L时, SF具有最佳的光交联性能. 通过调节气压、 针头孔径、 移动速度及固化速率等参数, 采用3D打印设备可实现从单层几何结构到多层三维网络构型SF凝胶材料的高效、 精准构建, 为SF的生物3D打印提供了新思路.     

强韧支架用丝素蛋白基生物墨水及其3D打印支架模拟软件的开发

At present, the existing scaffold materials cannot well meet the high strength and toughness requirements for the repairing of typical stressed tissues. And the commercial software for 3D printing scaffold modeling and mechanical performance simulation is complex to operate and has poor interoperability with 3D printers. In order to solve these problems, a silk fibroin (SF) based bio-ink was prepared for tough scaffold, and a software was developed for compression performance simulation of 3D printing scaffold based on SF and finite element analysis strategy. The printability of the bio-ink and the mechanical properties of the corresponding hydrogels and 3D printing scaffolds were characterized. The cell compatibility of the related scaffolds was evaluated by using fibroblasts and living/dead staining kit. Based on the SF based bio-ink, scaffolds with different heights and porosities were designed and printed. By using the developed software and the universal testing machine, the compression performance of related scaffolds was simulated and tested separately, and further compared with each other. Results show that the SF based bio-ink has good printability. And the 3D printing scaffold prepared by this ink presents high strength and toughness (modulus of elasticity: (1.86 ± 0.28)MPa, modulus of compression: (1.95 ± 0.11)MPa, elongation at break: (114.03 ± 14.40)%, compression strain ≥ 70%). In addition, the scaffold has good cell compatibility (L929 cell viability≥92.4%), which is expected to be used for the repair and regeneration of stressed tissues. The software is easy to operate, and can be used not only for the modeling of 3D printing scaffolds, but also for accurately predicting their compressive mechanical properties. In addition, the model data can also be directly imported into the 3D printer to guide the efficient preparation of the corresponding 3D printing scaffolds. This research is expected to provide important guidance for the rapid design and fabrication of tissue specific 3D printing scaffolds with bionic structure and mechanical properties. © Eco-Vector, 2023. All rights reserved.     

丝素蛋白3D打印在生物医学领域中的应用

增材制造,也称为三维(3D)打印,正推动制造、工程、医学等领域的全面创新升级。3D打印技术由于能够个性化定制生物的复杂3D微结构,构建仿生的功能化活组织或人工器官,近十年来在生物医学领域中取得了长足的发展。丝素蛋白(SF)是一种来源丰富、生物可降解、力学性能优良、细胞相容性极佳的天然有机高分子,为3D打印墨水的设计提供了一种有前景的选择。然而,作为结构蛋白,单一组分的SF具有的生理功能有限,且其经过打印后的稳定性较差,限制了SF在3D打印以及生物医药领域中的进一步发展。为此,研究人员通过化学改性技术和先进3D打印技术相结合,使得改性后的SF能够更适用于3D打印,并发展成为一种具有应用价值的生物材料。本文综述了SF的结构特征、SF的化学修饰策略、打印墨水的制备策略以及3D打印SF材料在生物医学领域的最新应用进展,并展望了3D打印SF生物材料的未来发展趋势,为其在更广阔领域的应用提供一定的借鉴。     

3D Printing of Silk Protein Structures by Aqueous Solvent‐Directed Molecular Assembly

Hierarchical molecular assembly is a fundamental strategy for manufacturing protein structures in nature. However, to translate this natural strategy into advanced digital manufacturing like three‐dimensional (3D) printing remains a technical challenge. This work presents a 3D printing technique with silk fibroin to address this challenge, by rationally designing an aqueous salt bath capable of directing the hierarchical assembly of the protein molecules. This technique, conducted under aqueous and ambient conditions, results in 3D proteinaceous architectures characterized by intrinsic biocompatibility/biodegradability and robust mechanical features. The versatility of this method is shown in a diversity of 3D shapes and a range of functional components integrated into the 3D prints. The manufacturing capability is exemplified by the single‐step construction of perfusable microfluidic chips which eliminates the use of supporting or sacrificial materials. The 3D shaping capability of the protein material can benefit a multitude of biomedical devices, from drug delivery to surgical implants to tissue scaffolds. This work also provides insights into the recapitulation of solvent‐directed hierarchical molecular assembly for artificial manufacturing.     

Recent Advances in 3D Printing of Photocurable Polymers: Types,Mechanism, and Tissue Engineering Application

The conversion of liquid resin into solid structures upon exposure to light of a specific wavelength is known as photopolymerization. In recent years, photopolymerization-based 3D printing has gained enormous attention for constructing complex tissue-specific constructs. Due to the economic and environmental benefits of the biopolymers employed, photo-curable 3D printing is considered an alternative method for replacing damaged tissues. However, the lack of suitable bio-based photopolymers, their characterization, effective crosslinking strategies, and optimal printing conditions are hindering the extensive application of 3D printed materials in the global market. This review highlights the present status of various photopolymers, their synthesis, and their optimization parameters for biomedical applications. Moreover, a glimpse of various photopolymerization techniques currently employed for 3D printing is also discussed. Furthermore, various naturally derived nanomaterials reinforced polymerization and their influence on printability and shape fidelity are also reviewed. Finally, the ultimate use of those photopolymerized hydrogel scaffolds in tissue engineering is also discussed. Taken together, it is believed that photopolymerized 3D printing has a great future, whereas conventional 3D printing requires considerable sophistication, and this review can provide readers with a comprehensive approach to developing light-mediated 3D printing for tissue-engineering applications.     

3D Printing of Poly(3-hydroxybutyrate) Porous Structures Using Selective Laser Sintering

Summary: Poly(3-hydroxybutyrate) (PHB) 3D porous cubes were successfully built with Selective Laser Sintering (SLS), one of the many existing 3D printing technologies. The resulting cubes presented shape and dimensions very close to the corresponding virtual model. Moreover, they were resistant to handling without presenting any visible damage. The PHB powder did not present variation in thermal properties and chemical composition after 32.15 hours of SLS process as observed by proton nuclear resonance (¹H NMR) and differential scanning calorimetry (DSC) analysis, indicating that it can be re-utilized to print additional structures without affecting the reproducibility of the process.     

聚合物前驱体3D打印制备高性能陶瓷

3D打印制备陶瓷可以实现结构-材料设计一体化,为复杂形状陶瓷材料快速成型提供了新途径。但是传统的3D打印制备陶瓷是以陶瓷粉末或陶瓷颗粒为打印材料,存在陶瓷构件尺寸精度差、表面光洁度低和力学性能不佳等问题。近年来,以聚合物前驱体为打印材料,通过3D打印成型、高温裂解等工艺制备高性能陶瓷技术的出现为改善这些不足提供了新方法,成为3D打印陶瓷领域的研究热点。本文概述了聚合物前驱体3D打印制备高性能陶瓷的研究进展,重点阐述了本体聚合物前驱体、聚合物前驱体/光敏化合物、聚合物前驱体/巯基化合物、光敏基团改性聚合物前驱体、增强体/聚合物前驱体五种典型材料体系的研究现状,并对其今后的发展方向进行了展望。     

光固化3D打印及其在齿科行业中的应用

光固化3D打印是最早出现的3D打印技术,经过30多年的发展,先后发展出液态树脂固化或光固化（stereolithography,SLA）、数字光处理（digital light processing,DLP）、液晶显示（liquid crystal display,LCD）、连续无分层液体界面提取技术（layerless continuous liquid interface production,CLIP）、双光子3D打印（two-photon polymerization,TPP）、全息3D打印技术等多种打印技术。光固化3D打印技术具有精度高、成型速度快等特点,因此在许多领域都有良好的应用,且前景广阔。在众多领域中,齿科领域个性化特征明显,对打印材料精度要求高,是目前光固化3D打印最有应用潜力和高附加值的领域。本文综述了光固化3D打印技术的种类、原理和技术的优缺点,并简述了光固化3D打印在齿科领域的应用。     

3D打印生物医用材料研究进展

3D打印(亦称增材制造)技术因其独特的材料成型优势,在组织工程、航空航天、汽车制造、以及电子工业等众多领域显示出巨大的应用潜力。然而,在实际生物医学应用中,3D打印生物器件和组织器官除了要求具有复杂的结构和优异的生物学性能外,其打印结构的表面性质也需满足某些特定的要求,如3D打印组织骨架和器官必须具有生物相容性、抗菌性及细胞粘附性等。因此,将3D打印与传统表面修饰技术相结合,在不改变材料三维结构的基础上调控其表面生物化学性质,从而赋予3D打印生物骨架器官多功能化,可实现更为广泛的应用。本文以3D打印生物骨架及器官的表面修饰为主要内容对就近年来3D打印生物医用材料的最新研究进展进行了综述。     

3D打印光敏树脂的研究进展

以光敏树脂为原料的立体快速成形3D打印技术,具有成本低、精度高、成型快等优点,在各个领域得到广泛的应用。但是,与之相适应的光敏树脂价格较高,并被国外的一些大公司所垄断,而国内相关研发起步较晚,能够生产和研发性能优良的3D打印光敏树脂的企业较少。简要阐述了3D打印光敏树脂的成形方式、固化原理和组成,重点讨论了配方设计的基本方法和评价指标,并对该领域进行了展望。     

Physical Models from Physical Templates Using Biocompatible Liquid Crystal Elastomers as Morphologically Programmable Inks For 3D Printing

Advanced manufacturing has received considerable attention as a tool for the fabrication of cell scaffolds however, finding ideal biocompatible and biodegradable materials that fit the correct parameters for 3D printing and guide cells to align remain a challenge. Herein, a photocrosslinkable smectic-A (Sm-A) liquid crystal elastomer (LCE) designed for 3D printing is presented, that promotes cell proliferation but most importantly induces cell anisotropy. The LCE-based bio-ink allows the 3D duplication of a highly complex brain structure generated from an animal model. Vascular tissue models are generated from fluorescently stained mouse tissue spatially imaged using confocal microscopy and subsequently processed to create a digital 3D model suitable for printing. The 3D structure is reproduced using a Digital Light Processing (DLP) stereolithography (SLA) desktop 3D printer. Synchrotron Small-Angle X-ray Diffraction (SAXD) data reveal a strong alignment of the LCE layering within the struts of the printed 3D scaffold. The resultant anisotropy of the LCE struts is then shown to direct cell growth. This study offers a simple approach to produce model tissues built within hours that promote cellular alignment.     

Creating Complex Polyacrylamide Hydrogel Structures Using 3D Printing with Applications to Mechanobiology

Due to its favorable physical and chemical properties, including chemical inertness, low fouling by biological molecules, high porosity and permeability, optical transparency, and adjustable elasticity, polyacrylamide has found a wide range of biomedical and non‐biomedical applications. To further increase its versatility, this communication describes a simple method, using readily available reagents and equipment, for 3D printing polyacrylamide hydrogels at a resolution of 100–150 μm to create complex structures. As a demonstration of the application, the method is used for creating a lab‐on‐a‐chip cell culture surface with micropatterned stiffness, which then leads to the discovery of stiffness‐guided collective cell segregation distinct from durotaxis. The present technology is expected to unleash new applications such as the construction of biocompatible elastic medical devices and artificial organs.     

Direct Ink 3D Printing of Porous Carbon Monoliths for Gas Separations

Additive manufacturing or 3D printing is the advanced method of manufacturing monolithic adsorbent materials. Unlike beads or pellets, 3D monolithic adsorbents possess the advantages of widespread structural varieties, low heat and mass transfer resistance, and low channeling of fluids. Despite a large volume of research on 3D printing of adsorbents having been reported, such studies on porous carbons are highly limited. In this work, we have reported direct ink 3D printing of porous carbon; the ink consisted of commercial activated carbon, a gel of poly(4-vinylphenol) and Pluronic F127 as plasticizer, and bentonite as the binder. The 3D printing was performed in a commercial 3D printer that has been extensively modified in the lab. Upon 3D printing and carbonization, the resultant 3D printed porous carbon demonstrated a stable structure with a BET area of 400 m²/g and a total pore volume of 0.27 cm³/g. The isotherms of six pure-component gases, CO₂, CH₄, C₂H₆, N₂, CO, and H₂, were measured on this carbon monolith at 298 K and pressure up to 1 bar. The selectivity of four gas pairs, C₂H₆/CH₄, CH₄/N₂, CO/H₂, and CO₂/N₂, was calculated by Ideally Adsorbed Solution Theory (IAST) and reported. Ten continuous cycles of adsorption and desorption of CO₂ on this carbon confirmed no loss of working capacity of the adsorbent.     

Chitosan and Whey Protein Bio-Inks for 3D and 4D Printing Applications with Particular Focus on Food Industry

The application of chitosan (CS) and whey protein (WP) alone or in combination in 3D/4D printing has been well considered in previous studies. Although several excellent reviews on additive manufacturing discussed the properties and biomedical applications of CS and WP, there is a lack of a systemic review about CS and WP bio-inks for 3D/4D printing applications. Easily modified bio-ink with optimal printability is a key for additive manufacturing. CS, WP, and WP–CS complex hydrogel possess great potential in making bio-ink that can be broadly used for future 3D/4D printing, because CS is a functional polysaccharide with good biodegradability, biocompatibility, non-immunogenicity, and non-carcinogenicity, while CS–WP complex hydrogel has better printability and drug-delivery effectivity than WP hydrogel. The review summarizes the current advances of bio-ink preparation employing CS and/or WP to satisfy the requirements of 3D/4D printing and post-treatment of materials. The applications of CS/WP bio-ink mainly focus on 3D food printing with a few applications in cosmetics. The review also highlights the trends of CS/WP bio-inks as potential candidates in 4D printing. Some promising strategies for developing novel bio-inks based on CS and/or WP are introduced, aiming to provide new insights into the value-added development and commercial CS and WP utilization.     

Advanced Polymer Designs for Direct-Ink-Write 3D Printing

The rapid development of additive manufacturing techniques, also known as three-dimensional (3D) printing, is driving innovations in polymer chemistry, materials science, and engineering. Among current 3D printing techniques, direct ink writing (DIW) employs viscoelastic materials as inks, which are capable of constructing sophisticated 3D architectures at ambient conditions. In this perspective, polymer designs that meet the rheological requirements for direct ink writing are outlined and successful examples are summarized, which include the development of polymer micelles, co-assembled hydrogels, supramolecularly cross-linked systems, polymer liquids with microcrystalline domains, and hydrogels with dynamic covalent cross-links. Furthermore, advanced polymer designs that reinforce the mechanical properties of these 3D printing materials, as well as the integration of functional moieties to these materials are discussed to inspire new polymer designs for direct ink writing and broadly 3D printing.     

Cell‐Laden Hydrogels for Multikingdom 3D Printing

Living materials are created through the embedding of live, whole cells into a matrix that can house and sustain the viability of the encapsulated cells. Through the immobilization of these cells, their bioactivity can be harnessed for applications such as bioreactors for the production of high‐value chemicals. While the interest in living materials is growing, many existing materials lack robust structure and are difficult to pattern. Furthermore, many living materials employ only one type of microorganism, or microbial consortia with little control over the arrangement of the various cell types. In this work, a Pluronic F127‐based hydrogel system is characterized for the encapsulation of algae, yeast, and bacteria to create living materials. This hydrogel system is also demonstrated to be an excellent material for additive manufacturing in the form of direct write 3D‐printing to spatially arrange the cells within a single printed construct. These living materials allow for the development of incredibly complex, immobilized consortia, and the results detailed herein further enhance the understanding of how cells behave within living material matrices. The utilization of these materials allows for interesting applications of multikingdom microbial cultures in immobilized bioreactor or biosensing technologies.     

3D printing to innovate biopolymer materials for demanding applications: A review

Biopolymers are widely available, low-/nontoxic, biodegradable, biocompatible, chemically versatile, and inherently functional, making them highly potential for a broad range of applications such as biomedicine, food, textile, and cosmetics. 3D printing (3DP) is capable of fabricating some customized, complex material structures composed of single or multiple material constituents that cannot be achieved by conventional methodologies (e.g. internal structures design); thus, 3DP can greatly expand the application of biopolymer materials. This review presents a comprehensive survey of the latest literature in 3DP technology for materials from biopolymers such as polysaccharides and proteins. The most commonly used 3DP techniques (i.e. inkjet printing, extrusion-based printing, stereolithography, selective laser sintering, and binder jetting) in biomedical and food fields are discussed. Critical factors affecting the quality and accuracy of 3D-printed constructs, including rheological characteristics, printing parameters (e.g. printing rate, and nozzle diameter, movement rate, and height), and post-printing processes (e.g. baking, drying, and crosslinking) are analyzed. The properties and the emerging applications of 3D-printed biopolymer materials in biomedical, food, and even wider applications (e.g. wastewater treatment and sensing) are summarized and evaluated. Finally, challenges and future perspectives are discussed. This review can provide insights into the development of new biopolymer-based inks and new biopolymer-based 3D-printed materials with enhanced properties and functionality.     

Emulsion Inks for 3D Printing of High Porosity Materials

Photocurable emulsion inks for use with solid freeform fabrication (SFF) to generate constructs with hierarchical porosity are presented. A high internal phase emulsion (HIPE) templating technique was utilized to prepare water‐in‐oil emulsions from a hydrophobic photopolymer, surfactant, and water. These HIPEs displayed strong shear thinning behavior that permitted layer‐by‐layer deposition into complex shapes and adequately high viscosity at low shear for shape retention after extrusion. Each layer was actively polymerized with an ultraviolet cure‐on‐dispense (CoD) technique and compositions with sufficient viscosity were able to produce tall, complex scaffolds with an internal lattice structure and microscale porosity. Evaluation of the rheological and cure properties indicated that the viscosity and cure rate both played an important role in print fidelity. These 3D printed polyHIPE constructs benefit from the tunable pore structure of emulsion templated material and the designed architecture of 3D printing. As such, these emulsion inks can be used to create ultra high porosity constructs with complex geometries and internal lattice structures not possible with traditional manufacturing techniques.

     

植物纤维及其提取物增强聚合物的3D打印成型研究

3D打印技术作为新型成型技术,近年来受到了巨大的关注,但常见的PLA、ABS等单体打印耗材由于其自身的不同缺点,限制了其进一步的应用。本文综述了植物纤维及其提取物增强聚合物复合材料在3D打印领域的应用研究进展,重点阐述了木纤维、竹纤维,秸秆纤维等常见植物纤维用于3D打印的研究现状,还介绍了纤维素、木质素、半纤维素等植物纤维提取物增强聚合物用于3D打印的研究情况。同时对植物纤维/聚合物材料存在的一些问题及改性方法进行了分析与展望。