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Herein, the usage of polyacrylic acid (AA) based and N,N′‐bis(acryloyl)cystamine (BAC) cross‐linked microgel (AA‐BAC) as a doxorubicin (DOX) carrier and stimuli‐responsive material for the controllable drug release is described. The carboxylic groups of AA provide a pH‐responsive and DOX‐holding ability of the polymer matrix, while sulfur groups of BAC provide a covalent immobilization of the AA‐BAC microgel onto the gold electrode surface. The microgel is responsive to electrochemically generated pH decrease due to ascorbate oxidation. As a result of the local pH drop on the electrode interface electrostatic attraction between the carrier and the positively charged DOX diminishes, which together with the shrinkage of the matrix results in the controlled release of DOX from the microgel. The electrodes modified by microgel based on N,N′‐methylene‐bis‐acrylamide (BIS) as a crosslinker are used as a control. However, AA‐BIS microgel does not contain sulfur groups and it can only be not explicitly adsorbed on the gold electrode while the efficacy of this modification is significantly worse compared to covalent immobilization of AA‐BAC via sulfur groups of BAC. Thus, electrode surface area covered by adsorbed (AA‐BIS)‐DOX microgel is approximately estimated as 34% compared to 90% for covalently immobilized (AA‐BAC)‐DOX microgel.
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Transparency Change Mechanochromism Based on a Robust PDMS‐Hydrogel Bilayer Structure
Abstract Hydrogels and polydimethylsiloxane (PDMS) are complementary to each other, since the hydrophobic PDMS provides a more stable and rigid substrate, while the water‐rich hydrogel possesses remarkable hydrophilicity, biocompatibility, and similarity to biological tissues. Herein a transparent and stretchable covalently bonded PDMS‐hydrogel bilayer (PHB) structure is prepared via in situ free radical copolymerization of acrylamide and allylamine‐exfoliated‐ZrP (AA‐e‐ZrP) on a functionalized PDMS surface. The AA‐e‐ZrP serves as cross‐linking nano‐patches in the polymer gel network. The covalently bonded structure is constructed through the addition reaction of vinyl groups of PDMS surface and monomers, obtaining a strong interfacial adhesion between the PDMS and the hydrogel. A mechanical‐responsive wrinkle surface, which exhibs transparency change mechanochromism, is created via introducing a cross‐linked polyvinyl alcohol film atop the PHB structure. A finite element model is implemented to simulate the wrinkle formation process. The implication of the present finding for the interfacial design of the PHB and PDMS‐hydrogel‐PVA trilayer (PHPT) structures is discussed.
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- Award ID(s):
- 1762661
- PAR ID:
- 10240190
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Macromolecular Rapid Communications
- Volume:
- 42
- Issue:
- 1
- ISSN:
- 1022-1336
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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