3D printing of thermoreversible polyurethanes with targeted shape memory and precise in situ self-healing properties

2019 ◽  
Vol 7 (12) ◽  
pp. 6972-6984 ◽  
Author(s):  
Yue Zhang ◽  
Xiang-Yu Yin ◽  
Mingyue Zheng ◽  
Carolyn Moorlag ◽  
Jun Yang ◽  
...  
Keyword(s):  
3D Printing ◽  
Shape Memory ◽  
Critical Role ◽  
Smart Devices ◽  
Cross Linking ◽  
Self Healing ◽  
3D Structures ◽  
The Cross

3D printable thermoreversible polyurethanes (PDAPUs) are synthesized, which facilitate the manufacturing of smart devices with 3D structures. The cross-linking of aniline trimer in PDAPUs plays a critical role in realizing light controllable precise selfhealing and targeted shape memory.

scholarly journals Printable Alginate Hydrogels with Embedded Network of Halloysite Nanotubes: Effect of Polymer Cross-Linking on Rheological Properties and Microstructure

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4130
Author(s):  
Svetlana A. Glukhova ◽  
Vyacheslav S. Molchanov ◽  
Boris V. Lokshin ◽  
Andrei V. Rogachev ◽  
Alexey A. Tsarenko ◽  
...  
Keyword(s):  
3D Printing ◽  
Rheological Properties ◽  
Shear Thinning ◽  
Halloysite Nanotubes ◽  
Polymer Chains ◽  
Cross Linking ◽  
Saxs Data ◽  
Nanocomposite Hydrogels ◽  
Embedded Network ◽  
The Cross

Rapidly growing 3D printing of hydrogels requires network materials which combine enhanced mechanical properties and printability. One of the most promising approaches to strengthen the hydrogels consists of the incorporation of inorganic fillers. In this paper, the rheological properties important for 3D printability were studied for nanocomposite hydrogels based on a rigid network of percolating halloysite nanotubes embedded in a soft alginate network cross-linked by calcium ions. Particular attention was paid to the effect of polymer cross-linking on these properties. It was revealed that the system possessed a pronounced shear-thinning behavior accompanied by a viscosity drop of 4–5 orders of magnitude. The polymer cross-links enhanced the shear-thinning properties and accelerated the viscosity recovery at rest so that the system could regain 96% of viscosity in only 18 s. Increasing the cross-linking of the soft network also enhanced the storage modulus of the nanocomposite system by up to 2 kPa. Through SAXS data, it was shown that at cross-linking, the junction zones consisting of fragments of two laterally aligned polymer chains were formed, which should have provided additional strength to the hydrogel. At the same time, the cross-linking of the soft network only slightly affected the yield stress, which seemed to be mainly determined by the rigid percolation network of nanotubes and reached 327 Pa. These properties make the alginate/halloysite hydrogels very promising for 3D printing, in particular, for biomedical purposes taking into account the natural origin, low toxicity, and good biocompatibility of both components.

scholarly journals Smart polymers for cell therapy and precision medicine

2019 ◽  
Vol 26 (1) ◽  
Author(s):  
Hung-Jin Huang ◽  
Yu-Liang Tsai ◽  
Shih-Ho Lin ◽  
Shan-hui Hsu
Keyword(s):  
3D Printing ◽  
Cell Therapy ◽  
Shape Memory ◽  
Precision Medicine ◽  
Environmental Changes ◽  
Memory Performance ◽  
Soft Materials ◽  
Smart Polymers ◽  
Self Healing ◽  
Thermally Responsive

Abstract Soft materials have been developed very rapidly in the biomedical field over the past 10 years because of advances in medical devices, cell therapy, and 3D printing for precision medicine. Smart polymers are one category of soft materials that respond to environmental changes. One typical example is the thermally-responsive polymers, which are widely used as cell carriers and in 3D printing. Self-healing polymers are one type of smart polymers that have the capacity to recover the structure after repeated damages and are often injectable through needles. Shape memory polymers are another type with the ability to memorize their original shape. These smart polymers can be used as cell/drug/protein carriers. Their injectability and shape memory performance allow them to be applied in bioprinting, minimally invasive surgery, and precision medicine. This review will describe the general materials design, characterization, as well as the current progresses and challenges of these smart polymers.

Polymerization-induced self-assembly for the fabrication of polymeric nano-objects with enhanced structural stability by cross-linking

2020 ◽  
Vol 11 (22) ◽  
pp. 3654-3672 ◽  
Author(s):  
Wen-Jian Zhang ◽  
Jamshid Kadirkhanov ◽  
Chang-Hui Wang ◽  
Sheng-Gang Ding ◽  
Chun-Yan Hong ◽  
...  
Keyword(s):  
Structural Stability ◽  
Self Assembly ◽  
Cross Linking ◽  
The Cross

This review discusses the strategies of core-cross-linking in most of the PISA literatures (including post-polymerization cross-linking, photo-cross-linking and in situ cross-linking) and the applications of the cross-linked nano-objects.

scholarly journals Vitrimer-Like Shape Memory Polymers: Characterization and Applications in Reshaping and Manufacturing

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2330
Author(s):  
Tao Xi Wang ◽  
Hong Mei Chen ◽  
Abhijit Vijay Salvekar ◽  
Junyi Lim ◽  
Yahui Chen ◽  
...  
Keyword(s):  
Solid State ◽  
3D Printing ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Memory Performance ◽  
Shape Memory Polymers ◽  
Cross Linking ◽  
Potential Applications ◽  
Actual Shape

The shape memory effect (SME) refers to the ability of a material to recover its original shape, but only in the presence of a right stimulus. Most polymers, either thermo-plastic or thermoset, can have the SME, although the actual shape memory performance varies according to the exact material and how the material is processed. Vitrimer, which is between thermoset and thermo-plastic, is featured by the reversible cross-linking. Vitrimer-like shape memory polymers (SMPs) combine the vitrimer-like behavior (associated with dissociative covalent adaptable networks) and SME, and can be utilized to achieve many novel functions that are difficult to be realized by conventional polymers. In the first part of this paper, a commercial polymer is used to demonstrate how to characterize the vitrimer-like behavior based on the heating-responsive SME. In the second part, a series of cases are presented to reveal the potential applications of vitrimer-like SMPs and their composites. It is concluded that the vitrimer-like feature not only enables many new ways in reshaping polymers, but also can bring forward new approaches in manufacturing, such as, rapid 3D printing in solid state on space/air/sea missions.

scholarly journals Extrusion-Printing of Multi-Channeled Two-Component Hydrogel Constructs from Gelatinous Peptides and Anhydride-Containing Oligomers

Biomedicines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 370
Author(s):  
Jan Krieghoff ◽  
Johannes Rost ◽  
Caroline Kohn-Polster ◽  
Benno Müller ◽  
Andreas Koenig ◽  
...  
Keyword(s):  
3D Printing ◽  
Peripheral Nerve ◽  
Nerve Regeneration ◽  
Peripheral Nerve Regeneration ◽  
Organic N ◽  
Cross Linking ◽  
Two Component ◽  
The Cross ◽  
Small Channels

The performance of artificial nerve guidance conduits (NGC) in peripheral nerve regeneration can be improved by providing structures with multiple small channels instead of a single wide lumen. 3D-printing is a strategy to access such multi-channeled structures in a defined and reproducible way. This study explores extrusion-based 3D-printing of two-component hydrogels from a single cartridge printhead into multi-channeled structures under aseptic conditions. The gels are based on a platform of synthetic, anhydride-containing oligomers for cross-linking of gelatinous peptides. Stable constructs with continuous small channels and a variety of footprints and sizes were successfully generated from formulations containing either an organic or inorganic gelation base. The adjustability of the system was investigated by varying the cross-linking oligomer and substituting the gelation bases controlling the cross-linking kinetics. Formulations with organic N‑methyl-piperidin-3-ol and inorganic K2HPO4 yielded hydrogels with comparable properties after manual processing and extrusion-based 3D-printing. The slower reaction kinetics of formulations with K2HPO4 can be beneficial for extending the time frame for printing. The two-component hydrogels displayed both slow hydrolytic and activity-dependent enzymatic degradability. Together with satisfying in vitro cell proliferation data, these results indicate the suitability of our cross-linked hydrogels as multi-channeled NGC for enhanced peripheral nerve regeneration.

In Situ Cross-linking Polymerization-Induced Self-Assembly: Not Only Generates Cross-linked Structures But Also Promotes Morphology Transition by the Cross-linker

2021 ◽  
Author(s):  
Jamshid Kadirkhanov ◽  
Cheng-Lin Yang ◽  
Zi-Xuan Chang ◽  
Ren-Man Zhu ◽  
Cai-Yuan Pan ◽  
...  
Keyword(s):  
Self Assembly ◽  
Cross Linking ◽  
Morphology Transition ◽  
Convenient Approach ◽  
Cross Linker ◽  
The Cross

Compared with the post-polymerization cross-linking strategy, in situ cross-linking by divinyl comonomers in polymerization-induced self-assembly (PISA) is a more straightforward and convenient approach to produce structurally stabilized nano-objects. However, cross-linking...

scholarly journals Targeted in situ cross-linking mass spectrometry and integrative modeling reveal the architectures of Nsp1, Nsp2, and Nucleocapsid proteins from SARS-CoV-2

2021 ◽  
Author(s):  
Moriya Slavin ◽  
Joanna Zamel ◽  
Keren Zohar ◽  
Siona Eliyahu ◽  
Merav Braitbard ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Full Length ◽  
Integrative Model ◽  
Cross Linking ◽  
Cross Link ◽  
Integrative Modeling ◽  
Cellular Context ◽  
Cross Links ◽  
The Cross

AbstractAtomic structures of several proteins from the coronavirus family are still partial or unavailable. A possible reason for this gap is the instability of these proteins outside of the cellular context, thereby prompting the use of in-cell approaches. In situ cross-linking and mass spectrometry (in situ CLMS) can provide information on the structures of such proteins as they occur in the intact cell. Here, we applied targeted in situ CLMS to structurally probe Nsp1, Nsp2, and Nucleocapsid (N) proteins from SARS-CoV-2, and obtained cross-link sets with an average density of one cross-link per twenty residues. We then employed integrative modeling that computationally combined the cross-linking data with domain structures to determine full-length atomic models. For the Nsp2, the cross-links report on a complex topology with long-range interactions. Integrative modeling with structural prediction of individual domains by the AlphaFold2 system allowed us to generate a single consistent all-atom model of the full-length Nsp2. The model reveals three putative metal binding sites, and suggests a role for Nsp2 in zinc regulation within the replication-transcription complex. For the N protein, we identified multiple intra- and inter-domain cross-links. Our integrative model of the N dimer demonstrates that it can accommodate three single RNA strands simultaneously, both stereochemically and electrostatically. For the Nsp1, cross-links with the 40S ribosome were highly consistent with recent cryo-EM structures. These results highlight the importance of cellular context for the structural probing of recalcitrant proteins and demonstrate the effectiveness of targeted in situ CLMS and integrative modeling.

scholarly journals The Influence of the Size and Oxidation Degree of Graphene Flakes on the Process of Creating 3D Structures during Its Cross-Linking

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 681 ◽  
Author(s):  
Łukasz Kaczmarek ◽  
Tomasz Warga ◽  
Magdalena Makowicz ◽  
Karol Kyzioł ◽  
Bartosz Bucholc ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
3D Structure ◽  
Cross Linking ◽  
Oxidation Degree ◽  
3D Structures ◽  
Chemical Structures ◽  
Infrared And Raman Spectroscopy ◽  
Graphene Flakes ◽  
The Cross ◽  
Specific Oxidation

This article presents the results of the cross-linking of oxidized flake graphene (GO) using hydrazine at room temperature. Conducting the process at temperatures up to 30 °C allowed to eliminate the phenomenon of thermal GO reduction to its non-oxidized form. In addition, based on the Infrared and Raman spectroscopy as well as X-ray photoelectron spectroscopy (XPS) analysis, the cross-linking ability of GO was observed depending on its size and degree of oxidation. These parameters were associated with selected physicochemical and electrical properties of obtained 3D structures. Three GO flakes sizes were tested in three different oxidation degrees. It was shown that, regardless of the size of GO, it is crucial to achieve a specific oxidation degree threshold which for the conducted tests was a >20% share of oxygen atoms in the whole structure. This value determines the ability to cross-link with hydrazine thanks to which it is possible to synthesize the spatial structure in which the π–π interactions among individual flakes are significantly reduced. This directly translates into the fact that the 3D structure shows an electrical resistance value in the range of 4–103 Ω, depending on the size and oxidation degree of the used material. The explanation of this phenomenon related to the electrical conductivity of 3D structures was confirmed based on the molecular modeling of the chemical structures.

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