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https://www.readbyqxmd.com/read/28439560/direct-4d-printing-via-active-composite-materials
#1
Zhen Ding, Chao Yuan, Xirui Peng, Tiejun Wang, H Jerry Qi, Martin L Dunn
We describe an approach to print composite polymers in high-resolution three-dimensional (3D) architectures that can be rapidly transformed to a new permanent configuration directly by heating. The permanent shape of a component results from the programmed time evolution of the printed shape upon heating via the design of the architecture and process parameters of a composite consisting of a glassy shape memory polymer and an elastomer that is programmed with a built-in compressive strain during photopolymerization...
April 2017: Science Advances
https://www.readbyqxmd.com/read/28429796/spatial-control-of-functional-response-in-4d-printed-active-metallic-structures
#2
Ji Ma, Brian Franco, Gustavo Tapia, Kubra Karayagiz, Luke Johnson, Jun Liu, Raymundo Arroyave, Ibrahim Karaman, Alaa Elwany
We demonstrate a method to achieve local control of 3-dimensional thermal history in a metallic alloy, which resulted in designed spatial variations in its functional response. A nickel-titanium shape memory alloy part was created with multiple shape-recovery stages activated at different temperatures using the selective laser melting technique. The multi-stage transformation originates from differences in thermal history, and thus the precipitate structure, at various locations created from controlled variations in the hatch distance within the same part...
April 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28242061/patient-specific-in-vitro-models-for-hemodynamic-analysis-of-congenital-heart-disease-additive-manufacturing-approach
#3
Rafael Medero, Sylvana García-Rodríguez, Christopher J François, Alejandro Roldán-Alzate
Non-invasive hemodynamic assessment of total cavopulmonary connection (TCPC) is challenging due to the complex anatomy. Additive manufacturing (AM) is a suitable alternative for creating patient-specific in vitro models for flow measurements using four-dimensional (4D) Flow MRI. These in vitro systems have the potential to serve as validation for computational fluid dynamics (CFD), simulating different physiological conditions. This study investigated three different AM technologies, stereolithography (SLA), selective laser sintering (SLS) and fused deposition modeling (FDM), to determine differences in hemodynamics when measuring flow using 4D Flow MRI...
February 7, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28195832/four-dimensional-printing-hierarchy-scaffolds-with-highly-biocompatible-smart-polymers-for-tissue-engineering-applications
#4
Shida Miao, Wei Zhu, Nathan J Castro, Jinsong Leng, Lijie Grace Zhang
The objective of this study was to four-dimensional (4D) print novel biomimetic gradient tissue scaffolds with highly biocompatible naturally derived smart polymers. The term "4D printing" refers to the inherent smart shape transformation of fabricated constructs when implanted minimally invasively for seamless and dynamic integration. For this purpose, a series of novel shape memory polymers with excellent biocompatibility and tunable shape changing effects were synthesized and cured in the presence of three-dimensional printed sacrificial molds, which were subsequently dissolved to create controllable and graded porosity within the scaffold...
October 2016: Tissue Engineering. Part C, Methods
https://www.readbyqxmd.com/read/28048927/mo-fg-bra-05-dosimetric-and-radiobiological-validation-of-respiratory-gating-in-conventional-and-hypofractionated-radiotherapy-of-the-lung-effect-of-dose-dose-rate-gating-window-and-breathing-pattern
#5
L Cervino, D Soultan, N Pettersson, A Yock, M Cornell, J Aguilera, J Murphy, B Gill, S Advani, V Moiseenko
PURPOSE: to evaluate the dosimetric and radiobiological consequences from having different gating windows, dose rates, and breathing patterns in gated VMAT lung radiotherapy. METHODS: A novel 3D-printed moving phantom with central high and peripheral low tracer uptake regions was 4D FDG-PET/CT-scanned using ideal, patient-specific regular, and irregular breathing patterns. A scan of the stationary phantom was obtained as a reference. Target volumes corresponding to different uptake regions were delineated...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047932/tu-h-campus-iep3-02-neurovascular-4d-parametric-imaging-using-co-registration-of-biplane-dsa-sequences-with-3d-vascular-geometry-obtained-from-cone-beam-ct
#6
A Balasubramoniam, D Bednarek, S Rudin, C Ionita
PURPOSE: To create 4D parametric images using biplane Digital Subtraction Angiography (DSA) sequences co-registered with the 3D vascular geometry obtained from Cone Beam-CT (CBCT). METHODS: We investigated a method to derive multiple 4D Parametric Imaging (PI) maps using only one CBCT acquisition. During this procedure a 3D-DSA geometry is stored and used subsequently for all 4D images. Each time a biplane DSA is acquired, we calculate 2D parametric maps of Bolus Arrival Time (BAT), Mean Transit Time (MTT) and Time to Peak (TTP)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28009155/three-dimensional-printing-of-shape-memory-composites-with-epoxy-acrylate-hybrid-photopolymer
#7
Ran Yu, Xin Yang, Ying Zhang, Xiaojuan Zhao, Xiao Wu, Tingting Zhao, Yulei Zhao, Wei Huang
Four-dimensional printing, a new process to fabricate active materials through three-dimensional (3D) printing developed by MIT's Self-Assembly Lab in 2014, has attracted more and more research and development interests recently. In this paper, a type of epoxy-acrylate hybrid photopolymer was synthesized and applied to fabricate shape memory polymers through a stereolithography 3D printing technique. The glass-to-rubbery modulus ratio of the printed sample determined by dynamic mechanical analysis is as high as 600, indicating that it may possess good shape memory properties...
January 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/27997104/direct-write-fabrication-of-4d-active-shape-changing-structures-based-on-a-shape-memory-polymer-and-its-nanocomposite
#8
Hongqiu Wei, Qiwei Zhang, Yongtao Yao, Liwu Liu, Yanju Liu, Jinsong Leng
Four-dimensional (4D) active shape-changing structures based on shape memory polymers (SMPs) and shape memory nanocomposites (SMNCs) are able to be controlled in both space and time and have attracted increasing attention worldwide. However, conventional processing approaches have restricted the design space of such smart structures. Herein, 4D active shape-changing architectures in custom-defined geometries exhibiting thermally and remotely actuated behaviors are achieved by direct-write printing of ultraviolet (UV) cross-linking poly(lactic acid)-based inks...
December 20, 2016: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/27936286/ultrafast-digital-printing-toward-4d-shape-changing-materials
#9
Limei Huang, Ruiqi Jiang, Jingjun Wu, Jizhou Song, Hao Bai, Bogeng Li, Qian Zhao, Tao Xie
Ultrafast 4D printing (<30 s) of responsive polymers is reported. Visible light triggered polymerization of commercial monomers defines digitally stress distribution in a 2D polymer film. Releasing the stress after the printing converts the structure into 3D. An additional dimension can be incorporated by choosing the printing precursors. The process overcomes the speed limiting steps of typical 3D (4D) printing.
December 9, 2016: Advanced Materials
https://www.readbyqxmd.com/read/27918636/4d-printing-of-shape-memory-based-personalized-endoluminal-medical-devices
#10
Matt Zarek, Nicola Mansour, Shir Shapira, Daniel Cohn
The convergence of additive manufacturing and shape-morphing materials is promising for the advancement of personalized medical devices. The capability to transform 3D objects from one shape to another, right off the print bed, is known as 4D printing. Shape memory thermosets can be tailored to have a range of thermomechanical properties favorable to medical devices, but processing them is a challenge because they are insoluble and do not flow at any temperature. This study presents here a strategy to capitalize on a series of medical imaging modalities to construct a printable shape memory endoluminal device, exemplified by a tracheal stent...
January 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/27910820/4d-bioprinting-the-next-generation-technology-for-biofabrication-enabled-by-stimuli-responsive-materials
#11
Yi-Chen Li, Yu Shrike Zhang, Ali Akpek, Su Ryon Shin, Ali Khademhosseini
Four-dimensional (4D) bioprinting, encompassing a wide range of disciplines including bioengineering, materials science, chemistry, and computer sciences, is emerging as the next-generation biofabrication technology. By utilizing stimuli-responsive materials and advanced three-dimensional (3D) bioprinting strategies, 4D bioprinting aims to create dynamic 3D patterned biological structures that can transform their shapes or behavior under various stimuli. In this review, we highlight the potential use of various stimuli-responsive materials for 4D printing and their extension into biofabrication...
December 2, 2016: Biofabrication
https://www.readbyqxmd.com/read/27768844/adsorption-behavior-of-i3-and-i-ions-at-a-nanoporous-nio-acetonitrile-interface-studied-by-x-ray-photoelectron-spectroscopy
#12
Matteo Bonomo, Danilo Dini, Andrea G Marrani
The adsorption of I(-) and I3(-) anions, i.e., the two species constituting the most common redox couple of dye-sensitized solar cells (DSCs), onto the surface of screen-printed nanoporous NiO was studied by means of X-ray photoelectron spectroscopy (XPS). Nanoporous NiO films were deposited on transparent metallic fluorine-doped tin oxide (FTO) and polarized as working electrodes in a three-electrode cell with differently concentrated I(-)/I3(-) electrolytes to simulate the different conditions experienced by the NiO cathodes during the lifecycle of a p-type DSC (p-DSC) at those atomic sites not passivated by the dye...
November 8, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/27643891/toward-4d-nanoprinting-with-tip-induced-organic-surface-reactions
#13
Carlos Carbonell, Adam B Braunschweig
Future nanomanufacturing tools will prepare organic materials with complex four-dimensional (4D) structure, where the position (x, y, z) and chemical composition within a volume is controlled with sub-1 μm spatial resolution. Such tools could produce substrates that mimic biological interfaces, like the cell surface or the extracellular matrix, whose topology and chemical complexity combine to direct some of the most sophisticated biological events. The control of organic materials at the nanoscale-level of spatial resolution could revolutionize the assembly of next generation optical and electronic devices or substrates for tissue engineering or enable fundamental biological or material science investigations...
September 19, 2016: Accounts of Chemical Research
https://www.readbyqxmd.com/read/27567735/retrospective-4d-mr-image-construction-from-free-breathing-slice-acquisitions-a-novel-graph-based-approach
#14
Yubing Tong, Jayaram K Udupa, Krzysztof C Ciesielski, Caiyun Wu, Joseph M McDonough, David A Mong, Robert M Campbell
PURPOSE: Dynamic or 4D imaging of the thorax has many applications. Both prospective and retrospective respiratory gating and tracking techniques have been developed for 4D imaging via CT and MRI. For pediatric imaging, due to radiation concerns, MRI becomes the de facto modality of choice. In thoracic insufficiency syndrome (TIS), patients often suffer from extreme malformations of the chest wall, diaphragm, and/or spine with inability of the thorax to support normal respiration or lung growth (Campbell et al...
January 2017: Medical Image Analysis
https://www.readbyqxmd.com/read/27499417/multimaterial-4d-printing-with-tailorable-shape-memory-polymers
#15
Qi Ge, Amir Hosein Sakhaei, Howon Lee, Conner K Dunn, Nicholas X Fang, Martin L Dunn
We present a new 4D printing approach that can create high resolution (up to a few microns), multimaterial shape memory polymer (SMP) architectures. The approach is based on high resolution projection microstereolithography (PμSL) and uses a family of photo-curable methacrylate based copolymer networks. We designed the constituents and compositions to exhibit desired thermomechanical behavior (including rubbery modulus, glass transition temperature and failure strain which is more than 300% and larger than any existing printable materials) to enable controlled shape memory behavior...
2016: Scientific Reports
https://www.readbyqxmd.com/read/27488822/self-healing-hydrogels
#16
Danielle Lynne Taylor, Marc In Het Panhuis
Over the past few years, there has been a great deal of interest in the development of hydrogel materials with tunable structural, mechanical, and rheological properties, which exhibit rapid and autonomous self-healing and self-recovery for utilization in a broad range of applications, from soft robotics to tissue engineering. However, self-healing hydrogels generally either possess mechanically robust or rapid self-healing properties but not both. Hence, the development of a mechanically robust hydrogel material with autonomous self-healing on the time scale of seconds is yet to be fully realized...
August 4, 2016: Advanced Materials
https://www.readbyqxmd.com/read/27460011/towards-scanning-probe-lithography-based-4d-nanoprinting-by-advancing-surface-chemistry-nanopatterning-strategies-and-characterization-protocols
#17
Xiaoming Liu, Carlos Carbonell, Adam B Braunschweig
Biointerfaces direct some of the most complex biological events, including cell differentiation, hierarchical organization, and disease progression, or are responsible for the remarkable optical, electronic, and biological behavior of natural materials. Chemical information encoded within the 4D nanostructure of biointerfaces - comprised of the three Cartesian coordinates (x, y, z), and chemical composition of each molecule within a given volume - dominates their interfacial properties. As such, there is a strong interest in creating printing platforms that can emulate the 4D nanostructure - including both the chemical composition and architectural complexity - of biointerfaces...
July 27, 2016: Chemical Society Reviews
https://www.readbyqxmd.com/read/27251982/4d-printing-smart-biomedical-scaffolds-with-novel-soybean-oil-epoxidized-acrylate
#18
Shida Miao, Wei Zhu, Nathan J Castro, Margaret Nowicki, Xuan Zhou, Haitao Cui, John P Fisher, Lijie Grace Zhang
Photocurable, biocompatible liquid resins are highly desired for 3D stereolithography based bioprinting. Here we solidified a novel renewable soybean oil epoxidized acrylate, using a 3D laser printing technique, into smart and highly biocompatible scaffolds capable of supporting growth of multipotent human bone marrow mesenchymal stem cells (hMSCs). Porous scaffolds were readily fabricated by simply adjusting the printer infill density; superficial structures of the polymerized soybean oil epoxidized acrylate were significantly affected by laser frequency and printing speed...
2016: Scientific Reports
https://www.readbyqxmd.com/read/27092661/non-spherical-particle-generation-from-4d-optofluidic-fabrication
#19
Kevin S Paulsen, Aram J Chung
Particles with non-spherical shapes can exhibit properties which are not available from spherical shaped particles. Complex shaped particles can provide unique benefits for areas such as drug delivery, tissue engineering, structural materials, and self-assembly building blocks. Current methods of creating complex shaped particles such as 3D printing, photolithography, and imprint lithography are limited by either slow speeds, shape limitations, or expensive processes. Previously, we presented a novel microfluidic flow lithography fabrication scheme combined with fluid inertia called optofluidic fabrication for the creation of complex shaped three-dimensional (3D) particles...
August 2, 2016: Lab on a Chip
https://www.readbyqxmd.com/read/27071543/multi-shape-active-composites-by-3d-printing-of-digital-shape-memory-polymers
#20
Jiangtao Wu, Chao Yuan, Zhen Ding, Michael Isakov, Yiqi Mao, Tiejun Wang, Martin L Dunn, H Jerry Qi
Recent research using 3D printing to create active structures has added an exciting new dimension to 3D printing technology. After being printed, these active, often composite, materials can change their shape over time; this has been termed as 4D printing. In this paper, we demonstrate the design and manufacture of active composites that can take multiple shapes, depending on the environmental temperature. This is achieved by 3D printing layered composite structures with multiple families of shape memory polymer (SMP) fibers - digital SMPs - with different glass transition temperatures (Tg) to control the transformation of the structure...
April 13, 2016: Scientific Reports
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