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- Amaia Beatriz, Ortega-Santos, 1995-, et al.
(författare)
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Enzymatic biofuel cells embedded polymer-based soft actuators
- 2022
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Enzymatic biofuel cells are presented as an untethered alternative energy source that could power small implantable or wearable medical devices. However, most of these catalytic processes do not provide with enough energy to power common small electronic-mechanical devices. On the other hand, conducting polymer-based actuators are of great interest for their biocompatibility, flexibility, processability, possibility to be miniaturized and low power consumption. So far, these artificial muscles have been driven by external power sources that prevent them for being completely autonomous. There is a need for a novel power source to elaborate actuators that could use physiological processes as a driving force. These soft actuators’ low power consumption matches the electrical power generated by the biocatalysis of some enzymes, such as glucose oxidase and laccase in presence of glucose and oxygen in aqueous media. Here, we present the latest results in the development of polypyrrole-based soft actuators powered by enzymatic biofuel cells. The actuator consists of a tri-layer conductive substrate on which the polypyrrole is electrodeposited in both sides. The polypyrrole layers act as the active part, expanding and contracting upon a redox reaction, resulting in a bending movement. Tetrathiofulvlene-7,7,8,8-tetracyanoquinodimethane (TTF-TCNQ) and 2,2′-azino-di-(3-ethylbenzthiazoline sulfonic acid) (ABTS) electron transfer mediators are cast on the surface of the polypyrrole to help the electron transmission. The glucose oxidase and laccase enzymes are immobilized in the modified-conducting polymer surface, integrating the electrode to the actuator. The bio-catalysis of enzymes in presence of glucose and oxygen in aqueous solution provides the actuator with the electrons needed for the redox reaction, converting the chemical energy into mechanical energy, i.e., movement. The glucose-self-powered soft actuator may contribute to the development of more complex implantable, ingestible, or wearable biomedical devices such as cardio-stimulators, insulin pumps, or muscle implants.
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| 3. |
- Aziz, Shazed, 1985-, et al.
(författare)
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PEDOT:PSS coated twisted and coiled yarn actuators
- 2021
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Ingår i: EuroEAP 2021.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Commercial yarns can be functionalized with conducting polymers (CPs) todevelop yarn and textile actuators. Here we show a method of functionalizationof commercial polyamide yarns by poly-3,4-ethylenedioxythiophene:polystyrenesulfonate (PEDOT:PSS) coating. Aftercoating, while PEDOT:PSS is drying, it is possible to twist and coil the yarns,resulting in a major improvement of their linear strain and speed of movement.By using a potential window between +0.6 V and -1.2 V vs Ag/AgCl it waspossible to obtain a fully reversible actuation of a coiled yarn providing up to1.62% strain. A strain higher than 1% was achieved in less than 1 second.Compared to the untwisted, regular yarns, the twisted and coiled yarns produce>9× and >20× higher strain, respectively. These results are a step forward towardsthe development of soft, silent and compliant smart textile exoskeletons.
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| 4. |
- Backe, Carin, et al.
(författare)
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Multi-Assembly of Soft Electroactive Polymeric Yarn Actuators by Using Textile Processes
- 2021
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Textile assembly methods offer great possibilities to create complex, large-scale, multi-functional 2D materials (fabrics) by a continuous process of structuring yarns together, in an architected manner. By designing a specific pattern and using functionalized yarns the properties of such a fabric can enable a variety of roles for example actuation and mechanical stimuli. Moreover, actuation can be achieved in several directions as the textile assembly enables the construction of a network where yarns can be independently addressed in X and/or Y direction. These are advantages that can be utilized in the field of soft robotics in many ways. The requirements for human-robotic interactions call for soft and compliant materials that are safe for such collaborative interactions and involve several types of functionalities. Textiles are easily conformed to the body, whether that is a robotic or a human one. Here we report on the integration of novel functional actuating yarns in the purpose of creating pliable textile actuators that also exhibit versatile morphing capabilities. The yarns consist of three layers; two of which are made of thin poly (3, 4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT: PSS) coatings that cover opposite sides of the third layer, an ionogel. This stretchable gel supplies the system with ions for the actuation mechanism and therefore enables in-air actuation. The yarns are transformed into fabrics by using woven assembly techniques. This is an additive method that structures one set of yarns in a parallel sequence that is perpendicular to another second set of yarns. By structuring a number of yarns together in parallel the performance in terms of force output including blocking force is shown to increase. The textile assembly process allows for two approaches, collective and individual addressing for the actuating yarns. For the former, arranging the yarns into different pre-determined segments enable collective actuation of each segment to change the overall shape of the textile structure. In regards to the latter, by individual addressing we show that a specific and targeted actuation can be achieved. Furthermore, the arrangement in which the yarns are interlaced in the fabric enables switching the modality of the actuation. This means that we can alter a motion specific to the yarns into another by their arrangement in the textile structure. With our developed textile assembly method, we are approaching low-cost, large-scale production of actuating systems for human-robotic applications
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| 7. |
- Cao, Danfeng, 1991-, et al.
(författare)
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Biohybrid Variable-Stiffness Soft Actuators that Self-Create Bone
- 2022
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Ingår i: Advanced Materials. - Weinheim, Germany : Wiley-VCH Verlag GmbH & Co. KGaA. - 0935-9648 .- 1521-4095. ; 34:8
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Tidskriftsartikel (refereegranskat)abstract
- Inspired by the dynamic process of initial bone development, in which a soft tissue turns into a solid load-bearing structure, the fabrication, optimization, and characterization of bioinduced variable-stiffness actuators that can morph in various shapes and change their properties from soft to rigid are hereby presented. Bilayer devices are prepared by combining the electromechanically active properties of polypyrrole with the compliant behavior of alginate gels that are uniquely functionalized with cell-derived plasma membrane nanofragments (PMNFs), previously shown to mineralize within 2 days, which promotes the mineralization in the gel layer to achieve the soft to stiff change by growing their own bone. The mineralized actuator shows an evident frozen state compared to the movement before mineralization. Next, patterned devices show programmed directional and fixated morphing. These variable-stiffness devices can wrap around and, after the PMNF-induced mineralization in and on the gel layer, adhere and integrate onto bone tissue. The developed biohybrid variable-stiffness actuators can be used in soft (micro-)robotics and as potential tools for bone repair or bone tissue engineering.
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| 8. |
- Cao, Danfeng, 1991-, et al.
(författare)
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Biohybrid Variable-Stiffness Soft Actuators that Self-Create Bone
- 2022
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Ingår i: International conference on Electromechanically Active Polymer(EAP) transducers & artificial muscles, Tuscany, June 7-9, 2022. - : EuroEAP 2022.
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Konferensbidrag (populärvet., debatt m.m.)abstract
- We herein describe the fabrication, optimisation and characterisation of a biohybrid variable stiffness actuator that creates its own bone. By combining the electroresponsive properties of polypyrrole (PPy) with the compliant response of alginate gels functionalised with cell-derived plasma membrane nanofragments (PMNFs) it was possible to obtain bio-induced variable stiffness actuators. When the PMNFs were incubated into MEM, i.e. exposure to Ca, this caused the formation of calcium-phosphate minerals (i.e. amorphous calcium phosphate and hydroxyapatite) in the alginate gel, resulting in a more rigid layer and thus reducing and finally impeding the movement of the actuator, locking it in a fixed position within only 2 days. These actuators could morph in various, pre-programmed shapes and change their properties from soft to rigid. Adding different patterns to the actuator allowed locking the device in a predetermined shape without energy consumption, facilitating its application as soft-to-hard robotics as a biohybrid variant of so-called 4D manufacturing. The devices could wrap around and integrate into bone by the induced mineralisation in and on the gel layer. This illustrates its use as a potential tool to repair bone or in bone tissue engineering.
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| 9. |
- Cao, Danfeng, 1991-, et al.
(författare)
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Soft actuators that self-create bone for biohybrid (micro)robotics
- 2022
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Ingår i: Proceedings of The 5th International Conference on Manipulation, Automation, And Robotics at Small Scales (MARSS 2022). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781665459730 - 9781665459747 ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- Here we present a new class of variable stiffness actuators for soft robotics based on biohybrid materials that change their state from soft-to-hard by creating their own bones. The biohybrid variable stiffness soft actuators were fabricated by combining the electromechanically active polymer polypyrrole (PPy) with a soft substrate of polydimethylsiloxane or alginate gel. These actuators were functionalized with cell-derived plasma membrane nanofragments (PMNFs), which promote rapid mineralization within 2 days. These actuators were used in robotic devices, and PMNF mineralization resulted in the robotic devices to achieve a soft to stiff state change and thereby a decreased or stopped actuation. Moreover, perpendicularly and diagonally patterned actuators were prepared. The patterned actuators showed programmed directional actuation motion and could be fixated in this programmed state. Finally, patterned actuators that combined soft and rigid parts in one actuator showed more complex actuation motion. Together, these variable stiffness actuators could expand the range of applications of morphing robotics with more complex structures and functions.
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| 10. |
- Cao, Danfeng, et al.
(författare)
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Variable Stiffness Actuators with Covalently Attached Nanofragments that Induce Mineralization
- 2023
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Ingår i: Advanced Materials Technologies. - : WILEY. - 2365-709X. ; 8:8
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Tidskriftsartikel (refereegranskat)abstract
- Soft robotics has attracted great attention owing to their immense potential especially in human-robot interfaces. However, the compliant property of soft robotics alone, without stiff elements, restricts their applications under load-bearing conditions. Here, biohybrid soft actuators, that create their own bone-like rigid layer and thus alter their stiffness from soft to hard, are designed. Fabrication of the actuators is based on polydimethylsiloxane (PDMS) with an Au film to make a soft substrate onto which polypyrrole (PPy) doped with poly(4-styrenesulfonic-co-maleic acid) sodium salt (PSA) is electropolymerized. The PDMS/Au/PPy(PSA) actuator is then functionalized, chemically and physically, with plasma membrane nanofragments (PMNFs) that induce bone formation within 3 days, without using cells. The resulting stiffness change decreased the actuator displacement; yet a thin stiff layer couldnot completely stop the actuators movement, while a relatively thick segment could, but resulted in partial delamination the actuator. To overcome the delamination, an additional rough Au layer was electroplated to improve the adhesion of the PPy onto the substrate. Finally, an alginate gel functionalized with PMNFs was used to create a thicker mineral layer mimicking the collagen-apatite bone structure, which completely suppressed the actuator movement without causing any structural damage.
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