Article
Biophysics
Marco Laurati, Gavino Bassu, Emiliano Fratini
Summary: We investigated the effects of confinement imposed by poly(ethylene glycol) (PEG) hydrogel matrices on the dynamics of soft microgels through characterization of the internal structure. The microgel dynamics slowed down and changed from diffusive to sub-diffusive due to increasing confinement. The decrease in diffusivity can be attributed to hydrodynamic and steric effects in addition to the geometrical constriction of cylindrical pores. The dependence of the effective diffusion coefficient on the pore volume fraction suggests the presence of microgel-hydrogel interactions.
COLLOIDS AND SURFACES B-BIOINTERFACES
(2023)
Review
Engineering, Multidisciplinary
Xin Ning Zhang, Qiang Zheng, Zi Liang Wu
Summary: This paper reviews the recent progress in 3D printing of tough hydrogels and their applications. It provides an overview of the advantages and requirements of tough hydrogel systems for specific 3D printing technologies, and summarizes the network structures, mechanical performances, toughening mechanisms, and representative applications of the printed tough hydrogels. It also discusses the recent advances in 4D printing of tough hydrogels as a prospective direction for soft actuators and robots.
COMPOSITES PART B-ENGINEERING
(2022)
Article
Polymer Science
Sheila Maiz-Fernandez, Leyre Perez-alvarez, Unai Silvan, Jose Luis Vilas-Vilela, Senentxu Lanceros-Mendez
Summary: This study explores the limitations of hydrogel-based inks in 3D printing and successfully achieves direct 3D printing of chitosan structures using NaOH as a gelling media for biomedical and tissue engineering applications. The printed hydrogels exhibit good morphology, chemical interactions, swelling, and mechanical and rheological properties. The influence of printing parameters and cytocompatibility are also analyzed. In addition, the printed gels show electro-induced motion, highlighting their potential as soft actuators and active scaffolds.
Article
Chemistry, Multidisciplinary
Xiaoya Ding, Yunru Yu, Luoran Shang, Yuanjin Zhao
Summary: With the assistance of histidine, low-viscosity GO mixed polymer solutions can be prepared as printable inks through microfluidic 3D printing technique, forming hydrogel microfibers in histidine solutions. These hydrogel fibers support cell survival, exhibit excellent electrical conductivity, and can sense motion changes, offering a new option for the design and application of 3D printable aqueous GO inks in various fields.
Article
Chemistry, Multidisciplinary
Hamed Ramezani, Seyyed Mohammad Mirjamali, Yong He
Summary: This study used multiphysics simulation to predict the printability of chitosan hydrogel in extrusion-based 3D printing. The impact of different velocities and viscosities was investigated, and the model validation confirmed the high-quality printing outcomes. The results provide information for determining the optimum parameters for printing chitosan-based ink with high quality.
APPLIED SCIENCES-BASEL
(2022)
Article
Chemistry, Multidisciplinary
Matteo Hirsch, Alvaro Charlet, Esther Amstad
Summary: Many soft natural tissues possess unique mechanical properties achieved through complex interactions between structure and composition. To address the lack of control in soft synthetic materials, a novel 3D printing approach called double network granular hydrogels (DNGHs) has been introduced. These DNGHs are stiff enough to support high tensile loads and significantly tougher than pure polymeric networks. This ink allows for the printing of strong and tough objects with high shape fidelity, opening up new possibilities for soft robotic applications.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Ji Liu, James Garcia, Liam M. M. Leahy, Rijian Song, Daragh Mullarkey, Ban Fei, Adrian Dervan, Igor V. V. Shvets, Plamen Stamenov, Wenxin Wang, Fergal J. J. O'Brien, Jonathan N. N. Coleman, Valeria Nicolosi
Summary: Direct ink writing (DIW) is a viable 3D printing technology for custom production of functional conductive hydrogels. This study demonstrates a highly 3D printable PEDOT:PSS-based ink made from commercially accessible raw materials. The 3D-printed hydrogel exhibits high electrical conductivity, outstanding elasticity, stability in water, electromagnetic interference shielding, sensing capabilities, and biocompatibility, showing potential for implantable and tissue engineering applications. The fabrication strategy opens up new opportunities to create multifunctional hydrogels with custom features and expand the applications of hydrogel materials.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Review
Chemistry, Multidisciplinary
Gang Ge, Qian Wang, Yi-Zhou Zhang, Husam N. Alshareef, Xiaochen Dong
Summary: In the development of flexible electronics, particularly hydrogel-based stretchable ionotronic devices, researchers are exploring the potential of 3D printing for its excellent patterning capability and design complexity. Despite facing challenges in balancing printability, conductivity, and stretchability, this review offers guidelines on utilizing 3D printing to create high-performance devices, focusing on material considerations and printing quality. Various 3D printing methods for hydrogels and design principles are discussed, along with the potential applications in flexible sensors, soft robots, and other devices.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Multidisciplinary Sciences
Hongqiu Wei, Ming Lei, Ping Zhang, Jinsong Leng, Zijian Zheng, You Yu
Summary: The study demonstrates the successful preparation of tough conductive hydrogels using an orthogonal photochemistry-assisted printing technique, which features rapid, controllable chemical reactions and template-free fabrication of arbitrary structures.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Physical
S. Moser, C. Kenel, L. A. Wehner, R. Spolenak, D. C. Dunand
Summary: 3D printing and sintering were used to fabricate porous Si scaffolds for lithium-ion batteries, with a hierarchically-porous architecture created to accommodate volume changes during (dis)charging. The influence of sintering parameters on Si strut porosity and resulting properties was studied, showing that optimal performance is achieved at around -50% Si strut porosity.
JOURNAL OF POWER SOURCES
(2021)
Article
Materials Science, Multidisciplinary
Rong Yang, Chuanchuan Fan, Yiming Dou, Xiaoping Zhang, Ziyang Xu, Qian Zhang, Yage Sun, Qiang Yang, Wenguang Liu
Summary: This study introduces gelatin as a sacrificial rheological modifier material to enable the direct printability of high-strength and stiff hydrogel. The printed hydrogel, made from N-acryloylsemicarbazide monomer and gelatin, demonstrates robust mechanical properties, potential as a meniscus substitute, and built-in antibacterial activity for minimizing infection-induced implantation failure.
APPLIED MATERIALS TODAY
(2021)
Article
Chemistry, Multidisciplinary
Adam C. Farsheed, Adam J. Thomas, Brett H. Pogostin, Jeffrey D. Hartgerink
Summary: 3D printing is extensively utilized in biomedical research, particularly for creating structures that mimic the mechanical properties of biological tissues. However, there is a challenge in 3D printing hydrogels due to the difficulty in patterning soft materials in three dimensions. To address this, novel hydrogels with desirable biological properties are needed as 3D printable inks.
ADVANCED MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Bo Xu, Hezhen Wang, Zixiong Luo, Jiping Yang, Zhijian Wang
Summary: Mechanochromic double network hydrogels in arbitrary shapes were created using a multi-material microgel direct ink writing (DIW) printing method. Micro-particles were prepared by grinding freeze-dried polyelectrolyte hydrogel, and then immobilized in the precursor solution to produce the printing ink. The multi-material DIW 3D printing technique was utilized to fabricate various 3D hydrogel structures that can change into a colorful pattern when force is applied.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Biochemistry & Molecular Biology
Mengfan Zhang, Tingting Wan, Penghui Fan, Kai Shi, Xiao Chen, Hongjun Yang, Xin Liu, Yingshan Zhou
Summary: Chitosan hydrogel has great potential in biomedical applications due to its biocompatibility and similarity to native extracellular matrix. However, 3D printing of chitosan hydrogel often faces challenges with formability and mechanical properties. This study introduces a novel chitosan hydrogel prepared from maleic chitosan and thiol-terminated poly (ethylene glycol) which showed improved gelling rate and compressive strength compared to pure chitosan hydrogel. The 3D printing of this hydrogel demonstrates printing accuracy and scaffold stability, making it a promising material for biomedical applications like tissue engineering and drug delivery.
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
(2021)
Article
Chemistry, Multidisciplinary
Nicholas A. Sather, Hiroaki Sai, Ivan R. Sasselli, Kohei Sato, Wei Ji, Christopher Synatschke, Ryan T. Zambrotta, John F. Edelbrock, Ryan R. Kohlmeyer, James O. Hardin, John Daniel Berrigan, Michael F. Durstock, Peter Mirau, Samuel Stupp
Summary: Liquid crystalline hydrogels can be 3D printed from aqueous supramolecular polymer inks, with pH and salt concentration influencing intermolecular interactions and ink viscosity. Enhanced hierarchical interactions in high viscosity inks lead to greater nanoscale alignment, enabling the creation of materials with anisotropic properties and scaffolds that promote cell alignment.
Review
Chemistry, Multidisciplinary
Huachuan Du, Esther Amstad
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2020)
Article
Chemistry, Analytical
Efe Armagan, Shankar Thiyagarajan, Kongchang Wei, Akin Gursoy, Giuseppino Fortunato, Esther Amstad, Rene Michel Rossi, Claudio Toncelli
Article
Chemistry, Physical
Huachuan Du, Clemence Courregelongue, Jacinta Xto, Alan Bohlen, Mathias Steinacher, Camelia N. Borca, Thomas Huthwelker, Esther Amstad
CHEMISTRY OF MATERIALS
(2020)
Article
Chemistry, Multidisciplinary
Alvaro Charlet, Matteo Hirsch, Sanjay Schreiber, Esther Amstad
Summary: Sustainable materials, such as recyclable polymers, are becoming more important due to their environmentally friendly nature. Fast prototyping methods are needed for customized products, and there is a need for soft materials that can meet contradictory requirements.
Article
Polymer Science
Michael Kessler, Quentin Nassisi, Esther Amstad
Summary: This study investigates the effect of microgel size and concentration on the processing and toughness of microgel-reinforced hydrogels (MRHs). It is found that processing and toughness depend on the inter-microgel connectivity, while the stress at break is solely dependent on the microgel size.
MACROMOLECULAR RAPID COMMUNICATIONS
(2022)
Article
Nanoscience & Nanotechnology
Gaia De Angelis, Viviane Lutz-Bueno, Esther Amstad
Summary: Ionically crosslinked hydrogels with metal coordination motifs have attracted researchers' interest due to their self-healing and adhesive properties. However, little is known about thin viscoelastic membranes with similar chelator-ion pair motifs. This study compares the mechanical properties of ionically crosslinked hydrogels and viscoelastic membranes, and finds that the viscoelastic membranes follow a similar trend as the hydrogels, becoming stronger with increased ion-chelator affinity. These findings enable the targeted design of self-healing, adhesive membranes with tunable mechanical properties.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Ran Zhao, Nina Kolln Wittig, Gaia De Angelis, Tianyu Yuan, Matteo Hirsch, Henrik Birkedal, Esther Amstad
Summary: Nature creates hard functional materials from soft organic scaffolds that are mineralized, often making parts of these minerals porous to achieve energy-efficient locomotion. However, methods to produce synthetic minerals with a similar level of control over their porous structure remain elusive. This study presents a room temperature process that combines localized mineralization with emulsion-based 3D printing to create cm-sized biominerals with pores ranging from the 100 nm to mm length scale. These biominerals have high compressive strength and can form different types of bioactive minerals. The ability to 3D print these materials under benign conditions makes this energy-efficient process suitable for constructing lightweight yet load-bearing structures for various applications.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Polymer Science
Michael Kessler, Tianyu Yuan, John M. Kolinski, Esther Amstad
Summary: The stiffness and toughness of conventional hydrogels decrease with increasing swelling, making them less suitable for load-bearing applications. However, reinforcing hydrogels with microgels can enhance their toughness. The volume fraction of microgels in the reinforced hydrogels determines their connectivity, which affects their stiffness and fracture toughness in fully swollen state.
MACROMOLECULAR RAPID COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Gaia De Angelis, Natascha Gray, Viviane Lutz-Bueno, Esther Amstad
Summary: Micrometer sized capsules with very thin shells of order 10 nm, formed by ionically crosslinking surfactants functionalized with catechol-derivatives, are impermeable to molecules as small as 340 Da even if loaded with cell culture media, indicating their potential for biomedical applications.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Engineering, Environmental
Matteo Hirsch, Livia D'Onofrio, Qinghua Guan, Josie Hughes, Esther Amstad
Summary: Recent development in soft actuation requires resilient and responsive materials that can exhibit significant actuation forces. Hydrogels are responsive to stimuli but suffer from a stiffness-toughness compromise. 3D printing of hydrogels allows for controlled variations in local composition. Introducing metal-reinforced double network hydrogels (mrDNGHs) enables the combination of stiffness, toughness, and processability.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Materials Science, Multidisciplinary
Matteo Hirsch, Lorenzo Lucherini, Ran Zhao, Alexandra Clara Saracho, Esther Amstad
Summary: Nature can control the structure and composition of materials, resulting in organic/inorganic composites with superior mechanical properties. Inspired by this, researchers have developed a process that utilizes compartmentalization to fabricate high-strength porous CaCO3-based composites using nature-derived materials. This system has potential applications in art restoration, coral regeneration, and repair of natural mineral-based materials.
Article
Materials Science, Biomaterials
Matteo Hirsch, Mathias Steinacher, Ran Zhao, Esther Amstad
Summary: The study introduces a competitive ligand-mediated approach to selectively and interchangeably reinforce metal-coordinated hydrogels, achieving controllable changes in mechanical properties and design innovation.
BIOMATERIALS SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Alvaro Charlet, Viviane Lutz-Bueno, Raffaele Mezzenga, Esther Amstad
Summary: Metal-coordinated hydrogels are physically crosslinked by complexes between ligands and metal ions, and their mechanical properties are dependent on the interactions' density. The properties of these hydrogels can be tuned by selecting different types of ions, impacting the relaxation times and resulting in different mechanical behaviors.
Article
Chemistry, Multidisciplinary
Matteo Hirsch, Alvaro Charlet, Esther Amstad
Summary: Many soft natural tissues possess unique mechanical properties achieved through complex interactions between structure and composition. To address the lack of control in soft synthetic materials, a novel 3D printing approach called double network granular hydrogels (DNGHs) has been introduced. These DNGHs are stiff enough to support high tensile loads and significantly tougher than pure polymeric networks. This ink allows for the printing of strong and tough objects with high shape fidelity, opening up new possibilities for soft robotic applications.
ADVANCED FUNCTIONAL MATERIALS
(2021)