Polymer Gels That Memorize Elements of Molecular Conformation

Alvarez‐Lorenzo, Carmen; Güney, Orhan; Oya, Taro; Sakai, Yasuzo; Kobayashi, Masatoshi; Enoki, Takashi; Takeoka, Yukikazu; Ishibashi, Tôru; Kuroda, Kenichi; Tanaka, Kazunori; Wang, Guoqiang; Grosberg, Alexander Y.; Masamune, Satoru; Tanaka, Toyoichi

doi:10.1021/ma000603v

Cited by 127 publications

(113 citation statements)

References 23 publications

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“…Consequently, in the swollen state, the affinity for the target increases slightly with the degree of cross-linking since the degree of swelling of the gel is reduced. In contrast, in the collapsed state an exponential decrease of the affinity with the cross-link density has been reported [77,78]. This unfavorability for the affinity has been understood to be a 'frustration' to the mobility of the adsorbing sites [57,77].…”

Section: Cross-linker Concentration Dependencementioning

confidence: 99%

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Multiple point adsorption in a heteropolymer gel and the Tanaka approach to imprinting: experiment and theory

Ito

Chuang

Alvarez‐Lorenzo

et al. 2003

Progress in Polymer Science

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Heteropolymer gels can be engineered to release specific molecules into or absorb molecules from a surrounding solution. This remarkable ability is the basis for developing gel applications in extensive areas such as drug delivery, waste cleanup, and catalysis. Furthermore, gels are a model system for proteins, many of whose properties they can be created to mimic. A key aspect of gels is their volume phase transition, which provides a macroscopic mechanism for effecting microscopic changes. The phase transition allows one to control the gel's affinity for target molecules through tiny changes in the solution temperature, salt concentration, pH, or the like. We summarize recent experiments that systematically characterize the gel affinity as a function of adsorbing monomer concentration, solution salt concentration, and cross-linker concentration, on both sides of the phase transition. We provide a physical theory that explains the results and discuss enhancements via imprinting.

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Section: Cross-linker Concentration Dependencementioning

confidence: 99%

“…To meet the third condition, that is, the minimization of the frustration, the 'imprinting technique' [63][64][65][66][67] was adopted. In this section, we discuss the early experimental successes [77][78][79][80][81][82][83][84] of the imprinting method and the application of the Tanaka equation to imprinted gels.…”

Section: Applications To Imprinted Gel Systemsmentioning

confidence: 99%

Multiple point adsorption in a heteropolymer gel and the Tanaka approach to imprinting: experiment and theory

Ito

Chuang

Alvarez‐Lorenzo

et al. 2003

Progress in Polymer Science

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“…self-healing materials, 7 drugdelivery, [8][9] chemical separation, 10 sensors, 11 shape-memory materials [12][13] and (self-driven) actuators. [14][15] The spatial stability of gels in the presence of a variety of solvents is based on their crosslinked network structure.…”

Section: Polymeric Gels: From Macro To Micromentioning

confidence: 99%

Light-Sensitive Polymeric Nanoparticles Based on Photo-Cleavable Chromophores

Klinger

2013

Springer Theses

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This thesis focuses on the design, synthesis and characterization of novel photo-sensitive microgels and nanoparticles as potential materials for the loading and light-triggered release/accessibility of functional compounds. In order to realize this concept, different approaches to irradiation-dependent response mechanisms have been investigated.Novel light-cleavable divinyl functionalized monomeric crosslinkers based on o-nitrobenzyl derivatives were synthesized and used for the preparation of either PMMA or hydroxyl functionalized PHEMA microgels swellable and degradable in organic solvents. By the introduction of anionic MAA moieties into the PHEMA microgels, this concept was successfully transferred to double stimuli-responsive p(HEMA-co-MAA) hydrogel nanoparticles exhibiting a pH-dependent swelling and light-induced degradation behavior in aqueous media. This sensitivity to two orthogonal triggers is proposed to combine a pHinduced post-formation loading mechanism with a pH-and light-triggered release. In addition, a new class of enzyme-and light-sensitive PAAm microgels based on (meth-)acrylate functionalized dextrans as photo-and enzymatically degradable macromolecular crosslinkers was developed by introducing a photo-labile linker between the enzymatically degradable dextran chain and the polymerizable vinyl moieties. Here, the water solubility of the crosslinkers is assumed to enable an in situ loading approach of hydrophilic compounds.A different approach to the loading of microgels is based on photo-labile covalent microgel-drug conjugates. The first step to the realization of this concept was achieved by the development of a novel functional monomer consisting of a doxorubicin molecule covalently attached to a radically polymerizable methacrylate group via a photo-cleavable linker.Moreover, in order to enable the release of hydrophobic substances in aqueous media, hydrophobic nanoparticles consisting of a photo-resist polymer were designed to be degradable upon irradiation in water. Light-triggered conversion of the initial hydrophobic polymer into hydrophilic PMAA induced in situ particle dissolution and release of nile red.Since the introduction of a stimuli-responsive shell around a microgel is assumed to prevent leakage of embedded compounds, studies on non-stimuli-responsive shell formation around preformed microgel seed particles and the formation of microgel cores in polymeric shells were conducted to investigate potential synthetic pathways to this approach.In a last attempt, the surface of PHEMA and p(HEMA-co-MAA) microgels was functionalized with cinnamoyl groups in order to trigger the (reversible) particles interaction with each other by light-induced [2+2] cycloaddition reactions.

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“…A very interesting fact is that, some of the heteropolymer gels systems can memorize molecular conformation (Alvarez-Lorenzo et al 2000. It is known that the junctional basal laminae of the vertebrate muscle fiber retains information and guides reinnervation of the fiber by the axon, demonstrating an informational role for the matrix.…”

Section: Electrical Field Effects On the Optical Properties Of Transpmentioning

confidence: 99%

Wave onset in central gray matter - its intrinsic optical signal and phase transitions in extracellular polymers

Fernandes-De-Lima

Kogler

Bennaton

et al. 2001

An. Acad. Bras. Ciênc.

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The brain is an excitable media in which excitation waves propagate at several scales of time and space. ''Onedimensional'' action potentials (millisecond scale) along the axon membrane, and spreading depression waves (seconds to minutes) at the three dimensions of the gray matter neuropil (complex of interacting membranes) are examples of excitation waves. In the retina, excitation waves have a prominent intrinsic optical signal (IOS). This optical signal is created by light scatter and has different components at the red and blue end of the spectrum. We could observe the wave onset in the retina, and measure the optical changes at the critical transition from quiescence to propagating wave. The results demonstrated the presence of fluctuations preceding propagation and suggested a phase transition. We have interpreted these results based on an extrapolation from Tasaki's experiments with action potentials and volume phase transitions of polymers. Thus, the scatter of red light appeared to be a volume phase transition in the extracellular matrix that was caused by the interactions between the cellular membrane cell coat and the extracellular sugar and protein complexes. If this hypothesis were correct, then forcing extracellular current flow should create a similar signal in another tissue, provided that this tissue was also transparent to light and with a similarly narrow extracellular space. This control tissue exists and it is the crystalline lens. We performed the experiments and confirmed the optical changes. Phase transitions in the extracellular polymers could be an important part of the long-range correlations found during wave propagation in central nervous tissue.

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Polymer Gels That Memorize Elements of Molecular Conformation

Cited by 127 publications

References 23 publications

Multiple point adsorption in a heteropolymer gel and the Tanaka approach to imprinting: experiment and theory

Multiple point adsorption in a heteropolymer gel and the Tanaka approach to imprinting: experiment and theory

Light-Sensitive Polymeric Nanoparticles Based on Photo-Cleavable Chromophores

Wave onset in central gray matter - its intrinsic optical signal and phase transitions in extracellular polymers

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