scholarly journals Shape-programmed 3D printed swimming microtori for the transport of passive and active agents

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Remmi Danae Baker ◽  
Thomas Montenegro-Johnson ◽  
Anton D. Sediako ◽  
Murray J. Thomson ◽  
Ayusman Sen ◽  
...  

Abstract Through billions of years of evolution, microorganisms mastered unique swimming behaviors to thrive in complex fluid environments. Limitations in nanofabrication have thus far hindered the ability to design and program synthetic swimmers with the same abilities. Here we encode multi-behavioral responses in microscopic self-propelled tori using nanoscale 3D printing. We show experimentally and theoretically that the tori continuously transition between two primary swimming modes in response to a magnetic field. The tori also manipulated and transported other artificial swimmers, bimetallic nanorods, as well as passive colloidal particles. In the first behavioral mode, the tori accumulated and transported nanorods; in the second mode, nanorods aligned along the toriʼs self-generated streamlines. Our results indicate that such shape-programmed microswimmers have a potential to manipulate biological active matter, e.g. bacteria or cells.

2018 ◽  
Vol 939 ◽  
pp. 147-152 ◽  
Author(s):  
Anil K. Bastola ◽  
Milan Paudel ◽  
Lin Li

This article delineates the characterization of the 3D printed MR elastomer through a forced vibration technique in the squeeze mode of operation. An anisotropic hybrid magnetorheological (MR) elastomer is developed via 3D printing. The 3D printed MR elastomer consists of three different materials; magnetic particles, magnetic particles carrier fluid, and an elastomer. MR fluid filaments are encapsulated layer-by-layer within the elastomer matrix using a 3D printer. When a moderately strong magnetic field is applied, the 3D printed MR elastomer changes its elastic and damping properties. The hybrid 3D printed MR elastomer also shows an anisotropic behavior when the direction of the magnetic field is changed with respect to the orientation of the printed filaments. The relative MR effect is higher when the applied magnetic field is parallel to the orientation of the printed filaments. The maximum change in the stiffness is observed to be 65.2% when a magnetic field of 500 mT is applied to the MR elastomer system. This result shows that the new method, 3D printing could produce anisotropic hybrid MR elastomers or possibly other types.


2021 ◽  
Vol 144 (4) ◽  
Author(s):  
Dylan Joralmon ◽  
Evangeline Amonoo ◽  
Yizhen Zhu ◽  
Xiangjia Li

Abstract Lightweight and cost-effective polymer matrix composites (PMCs) with extraordinary mechanical performance will be a key to the next generation of diverse industrial applications, such as aerospace, electric automobile, and biomedical devices. Limpet teeth made of mineral-polymer composites have been proved as nature’s strongest material due to the unique hierarchical architectures of mineral fiber alignment. Here, we present an approach to build limpet teeth inspired structural materials with precise control of geometric morphologies of microstructures by magnetic field-assisted 3D printing (MF-3DP). α-Iron (III) oxide-hydroxide nanoparticles (α-FeOOHs) are aligned by the magnetic field during 3D printing and aligned α-FeOOHs (aFeOOHs) bundles are further grown to aligned goethite-based bundles (aGBs) by rapid thermal treatment after printing. The mechanical reinforcement of aGBs in PMCs can be modulated by adjusting the geometric morphology and alignment of α-FeOOHs encapsulated inside the 3D printed PMCs. In order to identify the mechanical enhancement mechanism, physics-based modeling, simulation, and tests were conducted, and the results further guided the design of bioinspired goethite-based PMCs. The correlation of the geometric morphology of self-assembled α-FeOOHs, curing characteristics of α-FeOOHs/polymer composite, and process parameters were identified to establish the optimal design of goethite-based PMCs. The 3D printed PMCs with aGBs show promising mechanical reinforcement compared with PMCs without aGBs. This study opens intriguing perspectives for designing high strength 3D printed PMCs on the basis of bioinspired architectures with customized configurations.


Author(s):  
Dylan Joralmon ◽  
Evangeline Amonoo ◽  
Yizhen Zhu ◽  
Xiangjia Li

Abstract Lightweight and cost-effective polymer matrix composites (PMCs) with extraordinary mechanical performance will be a key to the next generation of diverse industrial applications such as aerospace, electric automobile, and biomedical devices. Limpet teeth made of mineral-polymer composites have been proved as nature’s strongest material due to the unique hierarchical architectures of mineral fiber alignment. Here, we present an approach to build limpet teeth inspired structural materials with precise control of geometric morphologies of microstructures by magnetic field-assisted 3D printing (MF-3DP). α-Iron (III) oxide-hydroxide nanoparticles (α-FeOOHs) are aligned by the magnetic field during 3D printing and aligned α-FeOOHs bundles are further grown to aligned goethite-based bundles (aGBs) by rapid thermal treatment after printing. The mechanical reinforcement of goethite-based fillers in PMCs can be modulated by adjusting the geometric morphology and alignment of mineral particles encapsulated inside the 3D printed PMCs. In order to identify the mechanical enhancement mechanism, physics-based modeling, simulation, and tests were conducted and the results further guided the design of bioinspired goethite-based PMCs. The correlation of the geometric morphology of self-assembled α-FeOOHs, curing characteristics of α-FeOOHs/polymer composite, and process parameters were identified to establish the optimal design of goethite-based PMCs. The 3D-printed PMCs with aGBs show promising mechanical reinforcement. This study opens intriguing perspectives for designing high strength 3D printed PMCs on the basis of bioinspired architectures with customized configurations.


2019 ◽  
Vol 31 (3) ◽  
pp. 377-388 ◽  
Author(s):  
AK Bastola ◽  
M Paudel ◽  
L Li

This article presents the development of line-patterned magnetorheological elastomers via 3D printing and their magnetorheological characterization. Herein, we consider five different patterns of magnetorheological fluid filaments that are printed and encapsulated within the elastomer matrix. The 3D-printed magnetorheological elastomers could represent the conventional isotropic and anisotropic magnetorheological elastomers. First, the effect of patterning the magnetorheological fluid filaments and the effect of change in the direction of the magnetic field is studied for all five patterns. Thereafter, the dynamic properties of 3D-printed magnetorheological elastomers under uniaxial deformation are presented. Magnetorheological effect shown by 3D-printed magnetorheological elastomers was found to be depended on the printed patterns as well as the direction of the applied magnetic field. This result showed that the 3D printing method has the potential to produce anisotropic magnetorheological elastomers or unique configuration of magnetic particles within the elastomer matrix. The dynamic testing showed that the storage modulus of 3D-printed magnetorheological elastomers is increased with increasing frequency and decreased with increasing strain amplitude, which signifies that the 3D-printed hybrid magnetorheological elastomers are also viscoelastic materials and the properties are magnetic field dependent as that of current magnetorheological elastomers.


Author(s):  
Michael A. Luzuriaga ◽  
Danielle R. Berry ◽  
John C. Reagan ◽  
Ronald A. Smaldone ◽  
Jeremiah J. Gassensmith

Biodegradable polymer microneedle (MN) arrays are an emerging class of transdermal drug delivery devices that promise a painless and sanitary alternative to syringes; however, prototyping bespoke needle architectures is expensive and requires production of new master templates. Here, we present a new microfabrication technique for MNs using fused deposition modeling (FDM) 3D printing using polylactic acid, an FDA approved, renewable, biodegradable, thermoplastic material. We show how this natural degradability can be exploited to overcome a key challenge of FDM 3D printing, in particular the low resolution of these printers. We improved the feature size of the printed parts significantly by developing a post fabrication chemical etching protocol, which allowed us to access tip sizes as small as 1 μm. With 3D modeling software, various MN shapes were designed and printed rapidly with custom needle density, length, and shape. Scanning electron microscopy confirmed that our method resulted in needle tip sizes in the range of 1 – 55 µm, which could successfully penetrate and break off into porcine skin. We have also shown that these MNs have comparable mechanical strengths to currently fabricated MNs and we further demonstrated how the swellability of PLA can be exploited to load small molecule drugs and how its degradability in skin can release those small molecules over time.


2020 ◽  
Vol 16 ◽  
Author(s):  
Wei Liu ◽  
Shifeng Liu ◽  
Yunzhe Li ◽  
Peng Zhou ◽  
Qian ma

Abstract:: Surgery to repair damaged tissue, which is caused by disease or trauma, is being carried out all the time, and a desirable treatment is compelling need to regenerate damaged tissues to further improve the quality of human health. Therefore, more and more research focus on exploring the most suitable bionic design to enrich available treatment methods. 3D-printing, as an advanced materials processing approach, holds promising potential to create prototypes with complex constructs that could reproduce primitive tissues and organs as much as possible or provide appropriate cell-material interfaces. In a sense, 3D printing promises to bridge between tissue engineering and bionic design, which can provide an unprecedented personalized recapitulation with biomimetic function under the precise control of the composition and spatial distribution of cells and biomaterials. This article describes recent progress in 3D bionic design and the potential application prospect of 3D printing regenerative medicine including 3D printing biomimetic scaffolds and 3D cell printing in tissue engineering.


Author(s):  
Juan Sebastian Cuellar ◽  
Dick Plettenburg ◽  
Amir A Zadpoor ◽  
Paul Breedveld ◽  
Gerwin Smit

Various upper-limb prostheses have been designed for 3D printing but only a few of them are based on bio-inspired design principles and many anatomical details are not typically incorporated even though 3D printing offers advantages that facilitate the application of such design principles. We therefore aimed to apply a bio-inspired approach to the design and fabrication of articulated fingers for a new type of 3D printed hand prosthesis that is body-powered and complies with basic user requirements. We first studied the biological structure of human fingers and their movement control mechanisms in order to devise the transmission and actuation system. A number of working principles were established and various simplifications were made to fabricate the hand prosthesis using a fused deposition modelling (FDM) 3D printer with dual material extrusion. We then evaluated the mechanical performance of the prosthetic device by measuring its ability to exert pinch forces and the energy dissipated during each operational cycle. We fabricated our prototypes using three polymeric materials including PLA, TPU, and Nylon. The total weight of the prosthesis was 92 g with a total material cost of 12 US dollars. The energy dissipated during each cycle was 0.380 Nm with a pinch force of ≈16 N corresponding to an input force of 100 N. The hand is actuated by a conventional pulling cable used in BP prostheses. It is connected to a shoulder strap at one end and to the coupling of the whiffle tree mechanism at the other end. The whiffle tree mechanism distributes the force to the four tendons, which bend all fingers simultaneously when pulled. The design described in this manuscript demonstrates several bio-inspired design features and is capable of performing different grasping patterns due to the adaptive grasping provided by the articulated fingers. The pinch force obtained is superior to other fully 3D printed body-powered hand prostheses, but still below that of conventional body powered hand prostheses. We present a 3D printed bio-inspired prosthetic hand that is body-powered and includes all of the following characteristics: adaptive grasping, articulated fingers, and minimized post-printing assembly. Additionally, the low cost and low weight make this prosthetic hand a worthy option mainly in locations where state-of-the-art prosthetic workshops are absent.


2019 ◽  
Vol 24 (2) ◽  
pp. 254-270 ◽  
Author(s):  
Luke Heemsbergen ◽  
Angela Daly ◽  
Jiajie Lu ◽  
Thomas Birtchnell

This article outlines preliminary findings from a futures forecasting exercise where participants in Shenzhen and Singapore considered the socio-technological construction of 3D printing in terms of work and social change. We offered participants ideal political-economic futures across local–global knowledge and capital–commons dimensions, and then had them backcast the contextual waypoints across markets, culture, policy, law and technology dimensions that help guide towards each future. Their discussion identified various contextually sensitive points, but also tended to dismiss the farthest reaches of each proposed ideal, often reverting to familiar contextual signifiers. Here, we offer discussion on how participants saw culture and industry shaping futures for pertinent political economic concerns in the twenty-first century.


Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 125
Author(s):  
Martino Colonna ◽  
Benno Zingerle ◽  
Maria Federica Parisi ◽  
Claudio Gioia ◽  
Alessandro Speranzoni ◽  
...  

The optimization of sport equipment parts requires considerable time and high costs due to the high complexity of the development process. For this reason, we have developed a novel approach to decrease the cost and time for the optimization of the design, which consists of producing a first prototype by 3D printing, applying the forces that normally acts during the sport activity using a test bench, and then measuring the local deformations using 3D digital image correlation (DIC). The design parameters are then modified by topological optimization and then DIC is performed again on the new 3D-printed modified part. The DIC analysis of 3D-printed parts has shown a good agreement with that of the injection-molded ones. The deformation measured with DIC are also well correlated with those provided by finite element method (FEM) analysis, and therefore DIC analysis proves to be a powerful tool to validate FEM models.


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