Inkjet 3D Research Articles

A novel data driven formulation for predicting jetting states and printing zone of high-viscosity nanosilver ink in inkjet-based 3D printing

Inkjet printing offers significant benefits for additive manufacturing (AM) and printed electronics, such as cost-effectiveness, scalability, non-contact printing, and the flexibility for ad-hoc customization. However, some challenges such as stable jetting states and defined printing zone still needs attention. Data driven modeling such as machine/deep learning (ML/DL) as a predictive methodology has proven to reduce the experimental cost and workload in AM for low-viscosity inks. However, there is an oversight in ML extension to high-viscosity inks due to some inherit challenges such as irregular shape formation, and adhesiveness. Therefore, this study is focused on the prediction of jetting states and defining the printing zone for three-dimensional (3D) inkjet printing of high-viscosity ink. The experimental data is comprised of equipment parameter settings, material properties, and camera-captured features. The jetting behavior is recorded with a high-speed camera and carefully categorized into five classes: no jetting, orifice adhesion, droplet jetting, orifice tail, and beads hanging. A robust and efficient high-viscosity 3D printing U-Net (HV3DP-UNet) model is proposed, that achieved the jetting state and printing zone prediction accuracy of 97.98% and 100% respectively. For the fair comparison, three traditional ML and two more DL models are tested and analyzed in detail. The robustness and efficacy of the proposed model is supplemented with four performance metrics, i.e., accuracy, precision, recall and f1-score. The models’ efficacy has been proved by achieving improved results on the public dataset, the proposed model has achieved overall prediction accuracy of 92.95%. The presented data-driven approach serves as a systematic framework for enhancing quality of inkjet-based 3D printing utilizing high-viscosity ink.

Solvent-free Acrylate/BCB drop-on-demand (DOD) inkjet dielectric ink for 3D printing

Currently, drop-on-demand (DOD) inkjet-printed dielectric inks used to produce next-generation high-frequency electronic devices fail to meet the requirements of circuit board substrates in terms of thermal, mechanical, and dielectric properties. To address this gap, we synthesized a low-viscosity acrylate monomer featuring an intrinsically low dielectric structure (hexafluorobisphenol A) and multiple cross-linking sites, and a benzocyclobutene monomer with low curing shrinkage and excellent thermomechanical properties. By mixing these monomers with other reactive diluents and verifying them through theoretical calculations and printing, we have developed a range of dielectric inks suitable for inkjet 3D printing. To enhance the overall performance of the cured inks, a sequential UV/thermal curing strategy was employed to form interpenetrating networks (IPNs). The optimal ink formulations met the requirements of circuit board substrates, demonstrating excellent heat resistance (Td5% = 334 °C, Tg = 181 °C), mechanical properties (tensile strength = 85 MPa, elongation at break = 13.5 %), and dielectric properties (Dk = 2.526 and Df = 0.113 at 15 GHz). These formulations meet the performance requirements for circuit board substrates and lead the industry in mechanical and dielectric properties. Furthermore, the feasibility of inkjet printing heterogeneous integrated electronic devices was verified, showing excellent print resolution and continuity of the conductive network. This work provides new insights into the future development of dielectric materials for inkjet 3D printing.

Predictive models for 3D inkjet material printer using automated image analysis and machine learning algorithms

Additive manufacturing (AM) is a smart manufacturing process to fabricate components with high precision, minimal post-processing, and increased component complexity in a variety of materials. This research focuses on developing automated image analysis and predictive models for a widely used 3D material inkjet printing (IJP) process. The interplay of four input process parameters, which include frequency, voltage, temperature, and meniscus vacuum, on the output metrics of the inkjet printer was evaluated using statistical measures (ANOVA). Droplet types were classified as no drop, satellite drop, and normal drop using four machine learning classifiers, including random forest, support vector classifier, k-nearest neighbor, and decision trees. Hyperparameter tuning was performed for each model for over 486 data points. Regression predictive models were developed for both ink droplet velocity and volume with three linear models (linear, lasso, and ridge regression) and four non-linear models (random forest, decision tree, support vector regression, and k-nearest neighbor). Mean squared error and the coefficient of determination, r-squared value, were used to evaluate the performance of the predictive models. For the drop type classification models, k-fold of 5 yielded the highest accuracy for the RF, KNN, and DT models of around 98%. Similarly, for the regression based predictive models RF, DT and KNN accuracy results ranged from 97 to 99%. All the machine learning models were validated with experimental data with high prediction accuracies accuracy. This research serves as a foundation for developing design guidelines for 3D material inkjet printing with applications in biosensors, flexible electronics, and regenerative tissue engineering.

Dissipative Particle Dynamics of Nano-Alumina Agglomeration in UV-Curable Inks.

Ultraviolet (UV) ink is a primary type of ink used in additive manufacturing with 3D inkjet printing. However, ink aggregation presents a challenge in nano-inkjet printing, affecting the stability and quality of the printing fluid and potentially leading to the clogging of nanometer-sized nozzles. This paper utilizes a Dissipative Particle Dynamics (DPD) simulation to investigate the aggregation behavior of alumina in a blend of 1,6-Hexanediol diacrylate (HDDA) and Trimethylolpropane triacrylate (TMPTA). By analyzing the effects of solid content, polymer component ratios, and dispersant concentration on alumina aggregation, the optimal ink formulation was identified. Compared to traditional experimental methods, DPD simulations not only reduce experimental costs and time but also reveal particle aggregation mechanisms that are difficult to explore through experimental methods, providing a crucial theoretical basis for optimizing ink formulations. This study demonstrates that alumina ceramic ink achieves optimal performance with a solid content of 20%, an HDDA-to-TMPTA ratio of 4:1, and 9% oleic acid as a dispersant.

3D inkjet printing of hybrid electroactive ink based on molecularly imprinted polymers for lipopolysaccharides detection

A hybrid electroactive ink based on molecularly imprinted polymer (MIP) hollow microparticles, zinc oxide nanoparticles (ZnO NPs) and conductive carbon paste (CP) is reported herein for the first time. The MIP/ZnO NPs/CP and corresponding non-imprinted NIP/ZnONPs/CP modified inks were screen-printed on plastic substrates via 3D inkjet technology to cover around 40 working screen-printed carbon electrodes (SPCE) pieces in a single batch. The custom-made electrochemical MIP/ZnONPs/CP@SPCE sensor was designed for the detection of bacterial endotoxins, i.e., lipopolysaccharides (LPS), derived from Pseudomonas aeruginosa. Hollow MIP silica microparticles with specific properties for 3D printing application, in terms of granulation and morphology, were synthesized via sol-gel method using tetraethyl orthosilicate and (3-aminopropyl) triethoxysilane as monomers. Following the structural and morphological characterization of microparticles, the evaluation of template rebinding indicated a clear specificity of MIPs for LPS compared to the NIPs. Hybrid MIP/ZnONPs/CP and NIP/ZnONPs/CP inks were characterized using morphological and structural methods, which confirmed a viscosity of 25.000 mPa.s, a granulation of <20 µm, and a solid powder content of <27 %, as well as a homogenous incorporation of MIP particles and ZnONPs in the conductive CP. Finally, the electrochemical evaluation of the modified MIP/ZnONPs/CP@SPCE sensor revealed a good sensitivity to LPS molecules in PBS at pH 7.4, in the linear working range 1 - 100 µM, where a 0.058 µM limit of detection (LOD) and a response time less than or equal to 1 min were determined. The selectivity of the MIP/ZnONPs/CP@SPCE sensor towards LPS from Salmonella enterica and Escherichia coli was also assessed, highlighting a clear difference between these structural resembling species.

High-precision inkjet 3D printing of curved multi-material structures: Morphology evolution and optimization

Multi-material printing is a significant developmental trend in the field of rapid prototyping. However, research on the simulation and prediction of multi-material formation is still at the droplet level and unable to calculate the changes in multi-material interface morphologies caused by flow and solidification. Additionally, it is not possible to predict the overall morphologies of the multi-material interfaces in a sample. Therefore, this paper proposes a multi-material morphology evolution prediction model based on convolution gradient calculations. Using semi-empirical model of multi-material droplet sliding and spreading, overlapping flow, and the multi-material droplet film solidification model, precise predictions of deposition, flow, and solidification between multiple materials were achieved and extended to curved surface deposition. Based on the prediction results, we designed an iterative optimization method for the droplet distribution and droplet grayscale to realize high-precision jet deposition, solidification, and sintering integrated forming technology for multi-material samples. This method has an interface inclination prediction error of less than 0.8° and height error of less than 10 μm, with the interface inclination approaching 0° after iterative optimization. This method can be used for the high-precision printing of devices such as antennas and metamaterials. Based on microstrip antenna printing results, the center frequency was 14.9 GHz, return loss at the center frequency was 34.22 dB, and return loss was 10 dB in the 13.6–15.4 GHz band, providing a foundation for the conformal manufacturing of high-performance multi-material electronic devices.

Development of a five-axis printer for the fabrication of hybrid 3D scaffolds: From soft to hard phases and planar to curved surfaces

Three-dimensional (3D) printing of hybrid scaffolds with material gradients, combining soft and hard phases, is an appealing frontier in additive manufacturing. However, most 3D printers are limited to either three-axis or mono-material capabilities, rendering them unsuitable for fabricating hybrid scaffolds. Additionally, printing on curved surfaces requires advanced printing capabilities. Our work aims to advance additive manufacturing by developing a hybrid piezoelectric inkjet-extrusion printer equipped with five-axis functionalities. The printer could be used to fabricate customized hybrid scaffolds, surpassing conventional mono-material or linear three-axis printing strategies. The soft phase comprises a low-viscosity photocurable resin and a high-viscosity peptide hydrogel, while the hard phase comprises 3D-printed polylactic acid and hydroxyapatite parts. To validate the system, we fabricated three hybrid scaffolding use cases, characterized by multi-material porous structures fabricated on planar, single-curved, and free-form surfaces. The scaffolds were subsequently analyzed using digital microscopy to assess their accuracy, particularly the feature sizes of pores and struts (i.e., 0.8&amp;ndash;3.6 mm). In the first part of the study, we demonstrated the versatility of inkjet and extrusion printing by hybrid printing an interconnected network in the soft phase on top of a planar ceramic hard phase. A pore width and height deviation of 6% was achieved compared to the intended design. In the second part of the study, we evaluated the 3D inkjet printing of a multi-material porous scaffold on a single-curved surface for osteochondral defects. The circumferential pore width and radial pore height deviated by 0.8% and 2%, respectively. Finally, we inkjet-printed a mesh structure on a free-form surface, which acted as a membrane for palatal implants. In this case, the pore width deviations were -16% in the printing direction and 2% perpendicular to the printing direction.

Solid Oxide Fuel Cells with 3D Inkjet Printing Modified LSM-YSZ Interface

In this study, pillar shaped yttria-stabilized zirconia (YSZ) 3D microstructures with ∼60 to 90 μm diameter and 12 to 20 μm height are fabricated by 3D inkjet printing to improve the topology of the electrolyte/cathode interface. The microstructures increase the surface area of the cell by ∼2.4% to 4.0% and enhance the connection between the dense YSZ electrolyte and mixed YSZ-lanthanum strontium manganite (LSM) cathode. The morphology and microstructure of the YSZ interface are characterized with scanning electron microscopy. Polarization curves confirm that the power density improves by 47% to 107% at 0.55 V, depending on the dimensions of the microstructures, in comparison to a flat interface. The non-linear improvement in power density with the size of microstructures is confirmed by calculating the uncertainty with repeated tests. Based on electrochemical impedance spectroscopy and distribution of relaxation times analysis, the performance improvement is attributed to changes in the oxygen surface exchange kinetics and O2− diffusivity in the cathode.

Enabling high-fidelity personalised pharmaceutical tablets through multimaterial inkjet 3D printing with a water-soluble excipient

Additive manufacturing offers manufacture of personalised pharmaceutical tablets through design freedoms and material deposition control at an individual voxel level. This control goes beyond geometry and materials choices: inkjet based 3D printing enables the precise deposition (10–80 μm) of multiple materials, which permits integration of precise doses with tailored release rates; in the meanwhile, this technique has demonstrated its capability of high-volume personalised production. In this paper we demonstrate how two dissimilar materials, one water soluble and one insoluble, can be co-printed within a design envelope to dial up a range of release rates including slow (0.98 ± 0.04 mg/min), fast (4.07 ± 0.25 mg/min) and multi-stepped (2.17 ± 0.04 mg/min then 0.70 ± 0.13 mg/min) dissolution curves. To achieve this, we adopted poly-4-acryloylmorpholine (poly-ACMO) as a new photocurable water-soluble carrier and demonstrated its contemporaneous deposition with an insoluble monomer. The water soluble ACMO formulation with aspirin incorporated was successfully printed and cured under UV light and a wide variety of shapes with material distributions that control drug elution was successfully fabricated by inkjet based 3D printing technique, suggesting its viability as a future personalised solid dosage form fabrication routine.

The effect of surface roughness on the performance of 3D printed surface plasmon resonance sensors for refractive index measurements

In this study, a polymer-based surface plasmon resonance (SPR) sensor for refractive index measurements was designed and manufactured via inkjet 3D printing; then, it was optically characterized. Next, it was investigated how the surface finish of the 3D printed optical waveguide affects the sensor performance, i.e., its sensitivity. More in detail, it was studied how the surface roughness changes with the placement of the 3D printed items on the building platform. To achieve this purpose, a Phase I distribution-free quality monitoring analysis of the selected manufacturing process was implemented for a small pilot production run. The aim was to check the stability of surface roughness versus the placement of the 3D printed parts on the building platform. The 3D printed sensor’s surface roughness was assessed through a profilometry study. In particular, the surface roughness was determined for the core of the optical waveguide used to excite the SPR phenomena. Furthermore, the SPR sensors were optically characterized to find the existing relationship between their sensitivity and the considered quality of surface finish. In particular, by varying the surface roughness of the used waveguide, the light scattering in the waveguide changes, and the SPR sensitivity changes too, similarly to the light-diffusing fibers covered by gold nanofilms where the guided light is scattered through a plurality of voids distributed in the core. The procedure followed to investigate the sensor roughness, and establishing their performance enabled the optimal operative range for their application in practice to be identified. Finally, a better knowledge of the 3D printing manufacturing process has been achieved to improve quality of surface finish.

3D-Printed Fluorescent Hydrogel Consisting of Conjugated Polymer and Biomacromolecule for Fast and Sensitive Detection of Cr(VI) in Vegetables.

Portable fluorescent film sensors offer a solution to the contamination issue in homogeneous sensor detection systems. However, their special structure leads to low sensitivity and a long response time, resulting in a significant scientific challenge limiting their development and application. In this work, we propose a dual design strategy to prepare highly sensitive film sensors for rapidly detecting Cr2O72-. Specifically, P(Fmoc-Osu)-SA hydrogel films were developed by integrating the biological macromolecule sodium alginate (SA) with the conjugated polymer poly(N-(9-Fluorenylmethoxycarbonyloxy)succinimide) (P(Fmoc-Osu)), using both mold and inkjet 3D printing methods. The "molecular wire effect" of the sensing unit P(Fmoc-Osu) and the water channel within the film substrate are responsible for the improved sensitivity and the reduced response time of this thin film sensor. P(Fmoc-Osu)-SA hydrogel films prepared by these two methods can rapidly detect Cr2O72- with limits of detection of 1.18 and 0.078 nM, respectively. Considering that 3D-printed hydrogel films can be tailored to different shapes according to detection needs, the P(Fmoc-Osu)-SA hydrogel films produced from this method were effectively applied in vegetable samples. This study provides an innovative and effective strategy for the development of biocompatible hydrogel sensors that offer the potential for determining trace amounts of Cr2O72- in agriculture.

Preparation of thiolated poly (lactic acid) microspheres by amine ester reaction to simulate three-dimensional inkjet printing (3DP) biocompatible scaffolds

3D inkjet printing (3DP) technology offers the advantages of fast processing speed and high precision, but achieving a strong combination of “powder” and “ink“ in polymer materials remains a great challenge. In this work, thiolated poly(lactic acid) (PLA) microspheres are fabricated through the amine-ester reaction between cysteine and PLA in a “green” water environment. 3DP is then simulated using thiolated PLA microspheres as the “powder”, and acryloylmorpholine containing double bonds as the “ink”. By virtue of the fast “thiol-ene click” reaction, the PLA scaffolds with a covalent bonding interface are fabricated within 20 s. Both the thiolated microspheres and scaffolds exhibit good biocompatibility, and the tensile strength of the scaffolds can reach 13.2 MPa, with the Young's modulus of 722 MPa, meeting the performance requirements of bone tissue scaffolds. Therefore, a new strategy to solve the interfacial bonding problem in 3DP technology are provided, facilitating the 3DP molding of PLA powder and promoting its application in the field of life and health.

A Dielectric Ink Combining Acrylate and Cyanate Moieties for Inkjet 3D Printing with Good Thermal Stability

A Dielectric Ink Combining Acrylate and Cyanate Moieties for Inkjet 3D Printing with Good Thermal Stability

Structural Effects of 3D Inkjet-Printed Ni(O)-YSZ Pillared Electrodes on Performances of Solid Oxide Electrochemical Reactors.

Increasing densities of reaction sites for gaseous reactants in solid oxide electrochemical reactors (SOERs), is a key strategy for achieving enhanced performance in either fuel cell or electrolysis modes. Fabrication of 3D structured components in SOERs can enhance those densities of reaction sites, which is achieved by 3D inkjet printing with high reproducibility, having developed inks with appropriate properties. First, the effects of pillar geometries on SOER performances are predicted through numerical simulations, enabling subsequent 3D printing to focus on the more effective geometries. Herein, the study reports the results of experimental validation of those predictions by evaluating the electrochemical performances of cells with various heights of 3D inkjet-printed Ni(O)- yttria stabilized zirconia (YSZ) pillars and YSZ pillars. Those measurements prove that increasing pillar heights generally increases SOER peak power densities in fuel cell mode and increased current densities at the thermoneutral potential (1.285V) in steam electrolysis mode, as predicted by simulations. With increasing pillar heights, more limitations in performance enhancement are found with YSZ electrolyte pillars than with Ni-YSZ pillars, again as predicted by simulations. The subsequent microstructural analysis of Ni-YSZ pillars proves the suitability of the Ni(O)-YSZ composite particle ink formulation and the reliability of 3D printing.

3D Inkjet Printing of Biomaterials with Solvent‐Free, Thiol‐Yne‐Based Photocurable Inks

Abstract3D inkjet printing is a fast, reliable, and non‐contact bottom–up approach to printing small and large models and is one of the fastest additive manufacturing technologies available. These attributes position inkjet printing as a promising tool for the additive manufacturing of biomaterials, for example, tissue engineering scaffolds. However, due to the stringent technical rheological requirements of current inkjet technologies, there is a lack of photopolymer resins suitable for the inkjet printing of biomaterials. Hence, a novel ink engineered for 3D piezoelectric inkjet printing of biomaterials is designed and developed. The novel resin leverages a biodegradable amino acid phosphorodiamidate matrix copolymerized with a dialkyne ether to modulate the viscosity. Copolymerization with commercially available thiols facilitates the photochemical thiol‐yne curing reaction. The ink exhibits optimal viscosity, eliminating the need for solvents, as well as reliable jetting and sufficiently swift curing kinetics. Furthermore, the formulation is successfully demonstrated in an industrial inkjet printhead. Notably, the resulting materials have low cytotoxicity and, hence, have significant promise in advancing the applications of 3D inkjet printing of biological scaffolds.

Additive and Lithographic Manufacturing of Biomedical Scaffold Structures Using a Versatile Thiol-Ene Photocurable Resin.

Additive and lithographic manufacturing technologies using photopolymerisation provide a powerful tool for fabricating multiscale structures, which is especially interesting for biomimetic scaffolds and biointerfaces. However, most resins are tailored to one particular fabrication technology, showing drawbacks for versatile use. Hence, we used a resin based on thiol-ene chemistry, leveraging its numerous advantages such as low oxygen inhibition, minimal shrinkage and high monomer conversion. The resin is tailored to applications in additive and lithographic technologies for future biofabrication where fast curing kinetics in the presence of oxygen are required, namely 3D inkjet printing, digital light processing and nanoimprint lithography. These technologies enable us to fabricate scaffolds over a span of six orders of magnitude with a maximum of 10 mm and a minimum of 150 nm in height, including bioinspired porous structures with controlled architecture, hole-patterned plates and micro/submicro patterned surfaces. Such versatile properties, combined with noncytotoxicity, degradability and the commercial availability of all the components render the resin as a prototyping material for tissue engineers.

Inkjet-Printed Dielectric Layer for the Enhancement of Electrowetting Display Devices.

Electrowetting with a dielectric layer is commonly preferred in practical applications. However, its potential is often limited by factors like the properties of the dielectric layer and its breakdown, along with the complexity of the deposition method. Fortunately, advancements in 3D inkjet printing offer a more adaptable solution for making patterned functional layers. In this study, we used a negative photoresist (HN-1901) to create a new dielectric layer for an electrowetting display on a 3-inch ITO glass using a Dimatix DMP-2580 inkjet printer. The resulting devices performed better due to their enhanced resistance to dielectric breakdown. We meticulously investigated the physical properties of the photoresist material and printer settings to achieve optimal printing. We also controlled the uniformity of the dielectric layer by adjusting ink drop spacing. Compared to traditional electrowetting display devices, those with inkjet-printed dielectric layers showed significantly fewer defects like bubbles and electrode corrosion. They maintained an outstanding response time and breakdown resistance, operating at an open voltage of 20 V. Remarkably, these devices achieved faster response times of ton 22.3 ms and toff 14.2 ms, surpassing the performance of the standard device.

Research Progress of 3D Printing Technology for Pharmaceutical Preparation

Abstract: Pharmaceutical preparation is a kind of finished pharmaceutical product made by combining raw materials with various auxiliary materials in a certain form. At present, the field of pharmaceutical preparations can meet most drug needs, but there are some limitations. It is difficult to realize the production of personalized preparations. Because 3D printing technology has the ability of precise dose control and flexible shape customization, it can realize precise control of drug dosage, release behavior and local targeting in pharmaceutical preparations. Therefore, in medicine, 3D printing technology is increasingly used in the field of pharmaceutical preparations. 3D printing technology provides an important means for new drug printing and personalized drug customization of pharmaceutical preparations in the medical field. The 3D printing technology of drugs will inject fresh vitality into individualized drug delivery. Therefore, the development trend of 3D printing technology for pharmaceutical preparations has attracted more and more attention. In order to optimize the wide application of 3D printing technology in pharmaceutical preparation, 3D printing technology such as inkjet 3D printing technology, extrusion 3D printing technology and laser 3D printing technology were studied. In this paper, the selection, classification and introduction of 3D printing technology such as inkjet 3D printing technology, extrusion 3D printing technology and laser 3D printing technology in pharmaceutical preparations are reviewed. Through the investigation of various patents of 3D printing technology applied to pharmaceutical preparation in medicine, this paper summarizes and analyzes the main problems of 3D printing technology applied to pharmaceutical preparations, such as printing stability, production quality, etc. In addition, the development trend of 3D printing technology is also discussed. Optimization of various 3D printing technologies applied to pharmaceutical preparation in medicine is beneficial to improve printing stability and production quality in medicine. More related patents will be invented in the future.

A novel approach to tailoring the microstructure and electrophysical properties of Ni/GDC-based anodes by combining 3D-inkjet printing and layer-by-layer laser treatment

This work proposes an original method for tailoring the microstructure and electrical properties of Ni/GDC anodes by using 3D inkjet printing of high-viscosity functional compositions with intermediate laser treatment of each layer after each printing pass. Based on a mixture of highly dispersed oxides NiO and CeO2 doped with gadolinium (GDC), paste formulations for 3D inkjet printing have been developed. The effects of 3D printing and laser treatment conditions on the porosity and shrinkage ratio of the NiO/GDC anodes during sintering were investigated. The reduction of the anode support workpieces to produce Ni/GDC cermet was carried out and the effect of laser exposure on the morphology and electrical characteristics of the resulting samples was studied. It was found that an increase in the laser exposure values during layer-by-layer laser treatment of printing compositions leads to a two-fold increase in the porosity of the solid oxide fuel cell components, an increase in the average pore size from 0.2 to 0.3 to 2–5 μm, and to a five-fold decrease in the sintering shrinkage ratio. It was also found that the electrical conductivity of the Ni/GDC cermet, produced by the reduction of the laser treated NiO/GDC, increased by 5–10 times as the laser exposure values increased. The influence mechanism of the layer-by-layer laser treatment of the original NiO/GDC samples on the electrical conductivity of their reduced counterparts, Ni/GDC cermet anodes, has been proposed. An increase in the electrical conductivity was shown to be due to in situ reduction of NiO, partial sintering of Ni nanoparticles and the formation of a percolation network. This new method of hybrid 3D printing opens up great prospects for tailoring the morphological and electrical characteristics of SOFC anode supports.

Techniques and applications of 3D bioprinting

3D bioprinting is an emerging technology that uses computer printing technology and unique bio-ink components to create artificial organs and biomedical objects. It is an interdisciplinary development technology integrating biology, chemistry, materials science, life science and other disciplines, and the technology behind biological 3D printing has improved in its development over the past few decades. Precisely printed biomaterials could benefit both tissue engineering and regenerative medicine. 3D bioprinting technology makes it possible to print tissues and organs, providing favorable conditions for organ transplantation and medical experiments. This paper mainly reviews the development of bioprinting technology and related concepts. According to the morphological change and chemical composition, the commonly used bioprinting materials (bio-inks) and their characteristics are described. The main methods of bioprinting are summarized, including traditional inkjet 3D bioprinting, extrusion 3D bioprinting, laser-assisted 3D bioprinting, photocuring 3D bioprinting and emerging 4D bioprinting and in situ bioprinting technologies. Finally, the paper introduces the development trend of bioprinting in the transplantation of skin, blood vessels and complex organs, as well as the precision research of tumors. In addition, current research challenges and prospects for future bioprinted 3D printing materials are discussed.