Schlichter, Lisa, Piras, Carmen Cristina orcid.org/0000-0002-7128-2979 and Smith, David Kelham orcid.org/0000-0002-9881-2714 (2021) Spatial and Temporal Diffusion-Control of Dynamic Multi-Domain Self-Assembled Gels. Chemical Science. pp. 4162-4172. ISSN 2041-6539
Abstract
The dynamic assembly of a pH-responsive low-molecular-weight gelator (LMWG) within the pre-formed matrix of a second LMWG has been achieved via diffusion of an acid from a reservoir cut into the gel. Self-assembly of the acid-triggered LMWG as it converts from micellar aggregates at basic pH into gel nanofibers at lower pH values can be both spatially and temporally controlled. The pH-responsive LMWG has an impact on the stiffness of the pre-formed gel in the domains in which it assembles. When low acid concentrations are used, LMWG assembly is transient – after the initial proton diffusion phase, the pH rises and disassembly occurs as the system equilibrates. Re-application of additional acid as ‘fuel’ can then re-assemble the LMWG network. Using glucono-delta-lactone (which slowly hydrolyses to gluconic acid) instead of HCl gives slower, more spatially-restricted assembly, and creates longer-lasting pH gradients within the gel. The presence of an agarose polymer gel network improves the mechanical strength of the gels and appears to slightly enhance the rate of proton diffusion. More sophisticated reservoir shapes can be cut into these more mechanically robust gels, enabling the creation of diffusion waves with different geometries, and hence different patterns of LMWG activation. Multiple reservoirs can be used to create overlapping proton diffusion waves, hence achieving differentiated pH patterns in the gel. Using acid diffusion in this way within gels is an intriguing and powerful way of dynamic patterning. The ability to temporally-evolve spatially-resolved patterns using biocompatible weak acids, and the change in rheological performance of the triggered domains, suggest potential future applications of this strategy in tissue engineering.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2021 The Author(s). |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Chemistry (York) |
Funding Information: | Funder Grant number EPSRC EP/P03361X/1 |
Depositing User: | Pure (York) |
Date Deposited: | 09 Feb 2021 17:10 |
Last Modified: | 23 Jan 2025 00:24 |
Published Version: | https://doi.org/10.1039/D0SC06862D |
Status: | Published online |
Refereed: | Yes |
Identification Number: | 10.1039/D0SC06862D |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:170944 |