Kumar, P. orcid.org/0000-0002-9965-8691, Zhang, Y., Ebbens, S.J. orcid.org/0000-0002-4727-4426 et al. (1 more author) (2022) 3D inkjet printed self-propelled motors for micro-stirring. Journal of Colloid and Interface Science, 623. pp. 96-108. ISSN 0021-9797
Abstract
Hypothesis
Microscopic self-propelled motors (SPMs) are an area of active research, but very little investigation has been conducted on millimetre-scale or macroscopic SPMs and exploring their potential in biomedical research. In this study, we tested if 3D reactive inkjet (RIJ) printing could be used for precise fabrication of millimetre-scale self-propelled motors (SPMs) with well-defined shapes from regenerated silk fibroin (RSF) by converting water soluble RSF (silk I) to insoluble silk fibroin (silk II). Secondly, we compared the different propulsion behaviour of the SPMs to put forward the best geometry and propulsion mechanism for potential applications in enhancing the sensitivity of diffusion-rate limited biomedical assays by inducing fluid flow.
Experiments
SPMs with four different geometric shapes and propelled by two different mechanisms (catalysis and surface tension gradient) were fabricated by 3D RIJ printing and compared. For bubble propulsion, the structures were selectively doped in specific regions with the enzyme catalase in order to produce motion via bubble generation and detachment in hydrogen peroxide solutions. For surface tension propulsion, PEG400-doped structures were propelled through surface tension gradients caused by leaching of PEG400 surfactant in deionized water.
Findings
The results demonstrated the ability of 3D inkjet printing to fabricate SPMs with desired propulsion mechanism and fine-tune the propulsion by precisely fabricating the different geometric shapes. The resulting 3D structures were capable of generating motion without external actuation, thereby enabling applications in biomedicine such as micro-stirring small fluid volumes to enhance biological assay sensitivity. The surface tension gradient caused by the leaching of surfactant led to faster propulsion velocities with smooth deceleration, whereas, in comparison, catalysis-induced bubble propulsion tended to be jerky and uneven in deceleration, and therefore less suitable for aforementioned applications. Computational fluid dynamic simulations were used to compare the various experimental SPMs ability to enhance mixing when deployed within 96-well plate microwells, to reveal the effect of both SPM shape and motion character on performance, and show viability for small scale mixing applications.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2022 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). |
Keywords: | Inkjet printing; Bioprinting; Biomaterials; Silk; Biomedical assay; Self-propulsion |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Chemical and Biological Engineering (Sheffield) |
Funding Information: | Funder Grant number ENGINEERING AND PHYSICAL SCIENCE RESEARCH COUNCIL EP/J002402/1 ENGINEERING AND PHYSICAL SCIENCE RESEARCH COUNCIL EP/N033736/1 Engineering and Physical Sciences Research Council EP/N023579/1 Engineering and Physical Sciences Research Council EP/N007174/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 08 Jul 2022 16:38 |
Last Modified: | 26 Jun 2023 10:30 |
Status: | Published |
Publisher: | Elsevier BV |
Refereed: | Yes |
Identification Number: | 10.1016/j.jcis.2022.05.011 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:188851 |