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Shmool TA, Martin LK, Jirkas A, Matthews RP, Constantinou AP, Vadukul DM, Georgiou TK, Aprile FA, Hallett JP. Unveiling the Rational Development of Stimuli-Responsive Silk Fibroin-Based Ionogel Formulations. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2023; 35:5798-5808. [PMID: 37576585 PMCID: PMC10413859 DOI: 10.1021/acs.chemmater.3c00303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 06/20/2023] [Indexed: 08/15/2023]
Abstract
We present an approach for the rational development of stimuli-responsive ionogels which can be formulated for precise control of multiple unique ionogel features and fill niche pharmaceutical applications. Ionogels are captivating materials, exhibiting self-healing characteristics, tunable mechanical and structural properties, high thermal stability, and electroconductivity. However, the majority of ionogels developed require complex chemistry, exhibit high viscosity, poor biocompatibility, and low biodegradability. In our work, we overcome these limitations. We employ a facile production process and strategically integrate silk fibroin, the biocompatible ionic liquids (ILs) choline acetate ([Cho][OAc]), choline dihydrogen phosphate ([Cho][DHP]), and choline chloride ([Cho][Cl]), traditional pharmaceutical excipients, and the model antiepileptic drug phenobarbital. In the absence of ILs, we failed to observe gel formation; yet in the presence of ILs, thermoresponsive ionogels formed. Systems were assessed via visual tests, transmission electron microscopy, confocal reflection microscopy, dynamic light scattering, zeta potential and rheology measurements. We formed diverse ionogels of strengths ranging between 18 and 642 Pa. Under 25 °C storage, formulations containing polyvinylpyrrolidone (PVP) showed an ionogel formation period ranging over 14 days, increasing in the order of [Cho][DHP], [Cho][OAc], and [Cho][Cl]. Formulations lacking PVP showed an ionogel formation period ranging over 32 days, increasing in the order of [Cho][OAc], [Cho][DHP] and [Cho][Cl]. By heating from 25 to 60 °C, immediately following preparation, thermoresponsive ionogels formed below 41 °C in the absence of PVP. Based on our experimental results and density functional theory calculations, we attribute ionogel formation to macromolecular crowding and confinement effects, further enhanced upon PVP inclusion. Holistically, applying our rational development strategy enables the production of ionogels of tunable physicochemical and rheological properties, enhanced drug solubility, and structural and energetic stability. We believe our rational development approach will advance the design of biomaterials and smart platforms for diverse drug delivery applications.
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Affiliation(s)
- Talia A. Shmool
- Department
of Chemical Engineering, Imperial College
London, South Kensington Campus, London SW7 2AZ, U.K.
| | - Laura K. Martin
- Department
of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, U.K.
| | - Andreas Jirkas
- Department
of Chemical Engineering, Imperial College
London, South Kensington Campus, London SW7 2AZ, U.K.
| | - Richard P. Matthews
- Department
of Chemical Engineering, Imperial College
London, South Kensington Campus, London SW7 2AZ, U.K.
- Department
of Bioscience, School of Health, Sports and Bioscience, University of East London, Stratford, London E15 4LZ, U.K.
| | - Anna P. Constantinou
- Department
of Materials, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K.
| | - Devkee M. Vadukul
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, London W12 0BZ, U.K.
| | - Theoni K. Georgiou
- Department
of Materials, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K.
| | - Francesco A. Aprile
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, London W12 0BZ, U.K.
- Institute
of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, London W12 0BZ, U.K.
| | - Jason P. Hallett
- Department
of Chemical Engineering, Imperial College
London, South Kensington Campus, London SW7 2AZ, U.K.
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Shmool TA, Constantinou A, Jirkas A, Zhao C, Georgiou TK, Hallett J. Next Generation Strategy for Tuning the Thermoresponsive Properties of Micellar and Hydrogel Drug Delivery Vehicles Using Ionic Liquids. Polym Chem 2022. [DOI: 10.1039/d2py00053a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Amongst the greatest challenges in developing injectable controlled thermoresponsive micellar and hydrogel drug delivery vehicles include tuning the cloud point (CP) and reducing the gelation temperature (Tgel), below 37 °C,...
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