3D printing of an extremely tough hydrogel

Wei, Junhua; Wang, Jilong; Su, Siheng; Wang, Shiren; Qiu, Jingjing; Zhang, Zhenhuan; Christopher, Gordon F.; Ning, Fuda; Cong, Weilong

doi:10.1039/c5ra16362e

Cited by 101 publications

(86 citation statements)

References 37 publications

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“…These properties are a function of the material itself, as well as bioprinting process parameters ( Figure 1B). Printed tensile specimens have been used to investigate the interaction of lines and layers [9][10][11][12][13][14][15][16][17], however, a systematic investigation of how process parameters influence these properties has not been conducted. Terminology to describe the tensile measurements include two crucial aspects.…”

Section: Introductionmentioning

confidence: 99%

Guidelines for standardization of bioprinting: a systematic study of process parameters and their effect on bioprinted structures

et al. 2016

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Biofabrication techniques including threedimensional bioprinting could be used one day to fabricate living, patient-specific tissues and organs for use in regenerative medicine. Compared to traditional casting and molding methods, bioprinted structures can be much more complex, containing for example multiple materials and cell types in controlled spatial arrangement, engineered porosity, reinforcement structures and gradients in mechanical properties. With this complexity and increased function, however, comes the necessity to develop guidelines to standardize the bioprinting process, so printed grafts can safely enter the clinics. The bioink material must firstly fulfil requirements for biocompatibility and flow. Secondly, it is important to understand how process parameters affect the final mechanical properties of the printed graft. Using a gellan-alginate physically crosslinked bioink as an example, we show shear thinning and shear recovery properties which allow good printing resolution. Printed tensile specimens were used to systematically assess effect of line spacing, printing direction and crosslinking conditions. This standardized testing allowed direct comparison between this bioink and three commercially-available products. Bioprinting is a promising, yet complex fabrication method whose outcome is sensitive to a range of process parameters. This study provides the foundation for highly needed best practice guidelines for reproducible and safe bioprinted grafts.

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Section: Introductionmentioning

confidence: 99%

Guidelines for standardization of bioprinting: a systematic study of process parameters and their effect on bioprinted structures

et al. 2016

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“…[21] More recently, agarose has been explored as a bioink for the 3D printing of umbilical artery endothelial cells; [22] however, tailoring mechanical properties of agarose gels requires changing the concentration of agarose and this profoundly impacts its rheological behavior, thus limiting its utilization as a mechanically tunable bioink. [23] Variations in the rheological properties imply two problems: First, the printing parameters have to be adjusted to the fluid's viscosity in order to yield droplets of consistent size, and second, changes in the viscosity and the printing parameters alter the fluid-induced shear stress experienced by cells. [24] In order to simplify the printing process and enhance cell viability, a thermogelling biomaterial with customizable mechanical properties in the gel state but constant viscosity in the solution state would be valuable.…”

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confidence: 99%

Mechanically Tunable Bioink for 3D Bioprinting of Human Cells

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Blaeser

Miessmer

et al. 2017

Adv Healthcare Materials

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COMMUNICATION (1 of 7)© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Mechanically Tunable Bioink for 3D Bioprinting of Human CellsAurelien Forget, Andreas Blaeser, Florian Miessmer, Marius Köpf, Daniela F. Duarte Campos, Nicolas H. Voelcker, Anton Blencowe, Horst Fischer,* and V. Prasad Shastri* DOI: 10.1002/adhm.201700255 medium-the bioink. [5] The former approach offers the advantage that the 3D scaffold does not have to be fabricated under cytocompatible conditions. Therefore, a broader range of materials can be employed, for example, thermoplasts, such as poly(caprolactone), [6] and additionally, other alternative scaffold fabrication techniques, such as electrospinning, or pressurized gyration can be combined with subsequent functionalization of the scaffold with proteins. [7] In contrast, the latter approach, that is, direct fabrication of cellloaded constructs by hydrogel molding or 3D printing, places high demands on the cytocompatibility of the material and the fabrication process and the resolution is limited by the size of the extrusion nozzle utilized in the fabrication process. [8] However, the advantage of direct fabrication techniques, especially of 3D bioprinting, is its ability to generate constructs with spatially defined cell and material composition. Moreover, biomaterials that are conventionally used in cell culture such as alginate, [9] Pluronic, [10] gelatin, [11] nanocellulose, [12] self-assembling peptides, [13] and agarose [14] are highly advantageous for direct cell printing as they are soluble in water and hence can be formulated as a cell carrier. There has been extensive effort to build on and improve the properties of watersoluble polymers as bioinks. [15,16] For example, to overcome the limitation of the solubilization of Pluronic and its limited diversity of mechanical properties, blending of Pluronic with alginate [17] and crosslinking using acrylate-modified Pluronic have been explored. [10] Notwithstanding these advances that utilize chemical crosslinking to control the mechanical properties of the bioinks, controlling the shear behavior and mechanical This study introduces a thermogelling bioink based on carboxylated agarose (CA) for bioprinting of mechanically defined microenvironments mimicking natural tissues. In CA system, by adjusting the degree of carboxylation, the elastic modulus of printed gels can be tuned over several orders of magnitudes (5-230 Pa) while ensuring almost no change to the shear viscosity (10-17 mPa) of the bioink solution; thus enabling the fabrication of 3D structures made of different mechanical domains under identical printing parameters and low nozzle shear stress. Human mesenchymal stem cells printed using CA as a bioink show significantly higher survival (95%) in comparison to when printed using native agarose (62%), a commonly used thermogelling hydrogel for 3D-bioprinting applications. This work paves the way toward the printing of complex tissue-like structures composed of a range of mechanically discrete microdomains that could potent...

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“…In semicrystalline polymer processing, shear or extensional flow is used to stretch polymer chains, which leads to the orientated crystals and enhanced performance. Similar to semicrystalline polymers, the physical hydrogel was demonstrated to has facile reprocessability recently 32,33 . That is to say physical hydrogels are promising to be processed with industrial method such as injection modeling or with microfabrication method such as 3D/4D printing, where the stretch of polymer chains is inevitably involved.…”

Section: Resultsmentioning

confidence: 99%

Stretching-induced ion complexation in physical polyampholyte hydrogels

et al. 2016

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Recently, we have developed a series of charge balanced polyampholytes (PA) physical hydrogels by random copolymerization in water, which show extraordinarily high toughness, self-healing ability and viscoelasticity. The excellent performance of PA hydrogels is ascribed to the dynamic ionic bonds formation through inter-and intra-chain interactions. The randomness makes ionic bonds of a wide strength distribution, the strong bonds, serve as permanent crosslinking, imparting the elasticity, while the weak bonds reversibly break and re-form, dissipating energy. In this work, we developed a simple physical method, named as pre-stretch method, to promote the performance of PA hydrogels.By imposing a pre-stretch on the sample at as-prepared state, the ion complexation during dialysis is prominently accelerated and the final performance is largely promoted. Further analysis suggests that the strong bonds formation induced by pre-stretch is responsible for the change in final performance. Pre-stretch decreases the entropy of system and increases the chain alignment, resulting in an increased possibility for strong bonds formation.

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3D printing of an extremely tough hydrogel

Abstract: A super tough hydrogel with tunable mechanical properties was 3D printed.

Cited by 101 publications

References 37 publications

Guidelines for standardization of bioprinting: a systematic study of process parameters and their effect on bioprinted structures

Guidelines for standardization of bioprinting: a systematic study of process parameters and their effect on bioprinted structures

Mechanically Tunable Bioink for 3D Bioprinting of Human Cells

Stretching-induced ion complexation in physical polyampholyte hydrogels

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