A New Class of Biochemically Degradable, Stimulus‐Responsive Triblock Copolymer Gelators

Li, Chengming; Madsen, Jeppe; Armes, Steven P.; Lewis, Andrew L.

doi:10.1002/anie.200600324

Cited by 236 publications

(199 citation statements)

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“…Recently, stimulus-responsive polymer gels have become an important area of research, with thermo-, [1][2][3][4] pH-, 4,5 redox- 6 and light-responsive 7 examples being reported in the literature. There are two main classes of polymer gels.…”

Section: Introductionmentioning

confidence: 99%

Tuning the critical gelation temperature of thermo-responsive diblock copolymer worm gels

et al. 2014

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Abstract. Amphiphilic diblock copolymer nano-objects can be readily prepared using reversible addition-fragmentation chain transfer (RAFT) polymerization. For example, poly(glycerol monomethacrylate) (PGMA) chain transfer agents (CTA) can be chain-extended using 2-hydroxypropyl methacrylate (HPMA) via RAFT aqueous dispersion polymerization to form welldefined spheres, worms or vesicles at up to 25% solids. The worm morphology is of particular interest, since multiple inter-worm contacts lead to the formation of soft free-standing gels, which undergo reversible degelation on cooling to sub-ambient temperatures. However, the critical gelation temperature (CGT) for such thermo-responsive gels is < 20C, which is relatively low for certain biomedical applications. In this work, a series of new amphiphilic diblock copolymers are prepared in which the core-forming block comprises a statistical mixture of HPMA and di(ethylene glycol) methyl ether methacrylate (DEGMA), which is a more hydrophilic monomer than HPMA.Statistical copolymerizations proceeded to high conversion and low polydispersities were achieved in all cases (Mw/Mn < 1.20). The resulting PGMA-P(HPMA-stat-DEGMA) diblock copolymers undergo polymerization-induced self-assembly at 10% w/w solids to form free-standing worm gels. SAXS studies indicate that reversible (de)gelation occurs below the CGT as a result of a worm-to-sphere transition, with further cooling to 5 °C affording weakly interacting copolymer chains with a mean aggregation number of approximately four. This corresponds to almost molecular dissolution of the copolymer spheres. The CGT can be readily tuned by varying the mean degree of polymerization and the DEGMA content of the core-forming statistical block. For example, a CGT of 31°C was obtained for PGMA59-P(HPMA91-stat-DEGMA39). This is sufficiently close to physiological temperature (37°C) to suggest that these new copolymer gels may offer biomedical applications as readily-sterilizable scaffolds for mammalian cells, since facile cell harvesting can be achieved after a single thermal cycle.

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Section: Introductionmentioning

confidence: 99%

Tuning the critical gelation temperature of thermo-responsive diblock copolymer worm gels

et al. 2014

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“…Irreversible biochemical degradation of novel PNIPAM-PMPC-S-S-PMPC-PNIPAM "flower micelles" to free-flowing sulfhydryl-terminating micelles by the cleavage of intermicellar bridges is mediated by the tripeptide, glutathione. The reductive degradation of the interacting micelles to free-flowing micelles results in approximate halving of the original copolymer molecular weight (Modified from Reference [243]). Strategy for the fabrication of a reversibly antigen responsive gel.…”

Section: Resultsmentioning

confidence: 99%

“…A novel class of biochemically degradable ABA triblock copolymer where A is 2-(methacryloyloxy)ethyl phosphorylcholine (MPC) and B is N-isopropylacrylamide (NIPAM) was fabricated to form "flower micelles" under physiologically relevant conditions at a copolymer concentration above approximately 8% w/v [243]. Glutathione mediated degradation of these flower micelles resulted in alterations of the rheological properties of the gel due to the breakdown of the "flower structure".…”

Section: 32mentioning

confidence: 99%

Smart polymeric gels: Redefining the limits of biomedical devices

Chaterji

Kwon

Park

2007

Progress in Polymer Science

559

364

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This review describes recent progresses in the development and applications of smart polymeric gels, especially in the context of biomedical devices. The review has been organized into three separate sections: defining the basis of smart properties in polymeric gels; describing representative stimuli to which these gels respond; and illustrating a sample application area, namely, microfluidics. One of the major limitations in the use of hydrogels in stimuli-responsive applications is the diffusion rate limited transduction of signals. This can be obviated by engineering interconnected pores in the polymer structure to form capillary networks in the matrix and by downscaling the size of hydrogels to significantly decrease diffusion paths. Reducing the lag time in the induction of smart responses can be highly useful in biomedical devices, such as sensors and actuators. This review also describes molecular imprinting techniques to fabricate hydrogels for specific molecular recognition of target analytes. Additionally, it describes the significant advances in bottom-up nanofabrication strategies, involving supramolecular chemistry. Learning to assemble supramolecular structures from nature has led to the rapid prototyping of functional supramolecular devices. In essence, the barriers in the current performance potential of biomedical devices can be lowered or removed by the rapid convergence of interdisciplinary technologies.

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“…[62][63][64][65][66][67][68][69][70][71] However, the structural changes of protein-responsive hydrogels in the literature were based on the degradation of polymer networks caused by an enzymatic reaction. Studies on protein-responsive hydrogels that undergo reversible swelling/shrinking in response to a target protein have not been undertaken in spite of their potential applications as smart biomaterials.…”

Section: Antigen-responsive Hydrogelsmentioning

confidence: 99%

Preparation of smart soft materials using molecular complexes

Miyata

2010

Polym J

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This article provides a short overview of our research regarding the preparation of smart soft materials using molecular complexes that reversibly associate and dissociate in response to environmental changes. Stimuli-responsive hydrogels that show swelling/shrinking in response to pH and temperature were prepared by copolymerization of a monomer bearing a phosphate group and other various monomers. Hydrogels with phosphate groups were useful tools for the construction of self-regulated drug delivery systems. Furthermore, we proposed a strategy for the preparation of biomolecule-responsive hydrogels that use reversible crosslinks in the networks of biomolecular complexes. Based on this strategy, we have prepared two types of biomolecule-responsive hydrogel that undergo changes in volume in response to target biomolecules. This was accomplished using biomolecular complexes such as antigen-antibody complexes and saccharide-lectin complexes and both a biomolecule-crosslinked hydrogel and a biomolecule-imprinted hydrogel have been synthesized with this approach. Biomolecule-crosslinked hydrogels, such as glucose-and antigen-responsive hydrogels, swelled in the presence of a target biomolecule due to the dissociation of biomolecular complexes that act as reversible crosslinks. On the other hand, biomolecule-imprinted hydrogels, such as tumor marker glycoprotein-responsive hydrogels, shrank in response to a target biomolecule due to the formation of a complex between ligands (lectin and antibody) and the target biomolecule. Thus, biomolecule-responsive hydrogels have many potential applications as smart biomaterials in biomedical fields. Although most smart soft materials prepared using molecular complexes still require further research, they are likely to become important materials in the future.

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A New Class of Biochemically Degradable, Stimulus‐Responsive Triblock Copolymer Gelators

Cited by 236 publications

References 40 publications

Tuning the critical gelation temperature of thermo-responsive diblock copolymer worm gels

Tuning the critical gelation temperature of thermo-responsive diblock copolymer worm gels

Smart polymeric gels: Redefining the limits of biomedical devices

Preparation of smart soft materials using molecular complexes

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