Switching of Fluorescence Wavelength Caused by Phase Separation of Pyrene in Poly(<i>N</i>-isopropylacrylamide) Gel

Hamasaki, Atom; Sato, Noriko; Kubo, K; Katsuki, Akio; Ozeki, Sumio

doi:10.1246/cl.190391

Cited by 7 publications

(6 citation statements)

References 20 publications

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“…We attributed this observation to the sudden dissolution of the preassociated pyrene into the (comparably more) hydrophobic polymer backbone, once a threshold d s was surpassed. This phenomenon was discovered recently and in parallel to our own work by Hamasaki and co-workers on pyrene solution-blended into poly( N- isopropylacrylamide) hydrogels . However, in our materials, this effect was considerably more pronounced as the covalent attachment of the pyrene units to the polymer backbone allowed higher pyrene loading preventing its precipitation from aqueous solution at high d s .…”

Section: Hydrogels From Pyrene Macro-cross-linkerssupporting

confidence: 72%

“…This phenomenon was discovered recently and in parallel to our own work by Hamasaki and co-workers on pyrene solution-blended into poly( N- isopropylacrylamide) hydrogels. 38 However, in our materials, this effect was considerably more pronounced as the covalent attachment of the pyrene units to the polymer backbone allowed higher pyrene loading preventing its precipitation from aqueous solution at high d s . Aggregation-caused quenching (ACQ) as origin for these observations 39 was ruled out due to the increase of the monomer emission accompanying the decrease of the excimer emission ( Figure S27 ).…”

Section: Hydrogels From Pyrene Macro-cross-linkersmentioning

confidence: 71%

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Gated Photoreactivity of Pyrene Copolymers in Multiresponsive Cross-Linked starPEG-Hydrogels

Rasch

Göstl

2021

ACS Polym. Au

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The synthesis and manufacturing of multiresponsive polymer hydrogels using simple components is a notable challenge. Pyrene is an excimer-forming fluorophore mostly used as microenvironmental probe and for the localization of molecules in close proximity in artificial and biomaterials. Here we make use of the solvophobic preaggregation and photolysis properties of pyrene to construct multiresponsive hydrogels. We synthesize poly(ethylene glycol) (PEG) hydrogels from well-defined pyrene-substituted macro-cross-linkers and elucidate their intricate intra- and intermolecular excimer formation pathways. We find that controlling the water content of the hydrogels through the degree of swelling acts as a gating stimulus governing the photoinduced solvolysis of pyrenylmethyl esters from their poly(methacrylate) backbone. This allows the implementation of a simple transient photolithography process. We thus demonstrate that multiresponsive soft materials with complex optical and mechanical responses can be obtained with comparatively little synthetic effort.

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Section: Hydrogels From Pyrene Macro-cross-linkerssupporting

confidence: 72%

Section: Hydrogels From Pyrene Macro-cross-linkersmentioning

confidence: 71%

Gated Photoreactivity of Pyrene Copolymers in Multiresponsive Cross-Linked starPEG-Hydrogels

Rasch

Göstl

2021

ACS Polym. Au

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“…Li and co‐workers developed a method of visualizing and detecting protein coacervates with an aggregation‐induced emission fluorogen [27] . Pyrene (py) is a hydrophobic and fluorescent molecule due to the four conjugated benzene rings [28] . Wong and co‐workers introduced a light‐switching dipyrene probe to detect phase‐separated biomolecules taking advantage of the difference in fluorescent intensities of the monomers in hydrophobic environments of the coacervates and excimers in aqueous solutions [25] .…”

Section: Introductionmentioning

confidence: 99%

Photo‐Responsive Phase‐Separating Fluorescent Molecules for Intracellular Protein Delivery

Bao,

Chen,

et al. 2023

Angew Chem Int Ed

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Cellular membranes, including the plasma and endosome membranes, are barriers to outside proteins. Various vehicles have been devised to deliver proteins across the plasma membrane, but in many cases, the payload gets trapped in the endosome. Here we designed a photo‐responsive phase‐separating fluorescent molecule (PPFM) with a molecular weight of 666.8 daltons. The PPFM compound condensates as fluorescent droplets in the aqueous solution by liquid‐liquid phase separation (LLPS), which disintegrate upon photoirradiation with a 405 nm LED lamp within 20 min or a 405 nm laser within 3 min. The PPFM coacervates recruit a wide range of peptides and proteins and deliver them into mammalian cells. Photolysis disperses the payload from condensates into the cytosolic space. Altogether, a type of small molecules that are photo‐responsive and phase separating are discovered; their coacervates can serve as transmembrane vehicles for intracellular delivery of proteins, whereas photo illumination triggers the cytosolic distribution of the payload.

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“…35−38 We recently reported that if water was introduced to a PNIPA gel with trapped pyrene, pyrene excimers formed even if the concentration of trapped pyrene was low. 39 Because hydrophobic pyrene molecules have low solubility in water, the pyrene and water were thought to separate in the gel. We found that the pyrene actually formed an excimer in the swollen gel.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Because of the carboxyl groups and amino groups, poly- N -isopropylacrylamide (PNIPA) can become hydrated at low temperatures and swell as it absorbs water. However, PNIPA gel has a lower critical solution temperature (LCST) of approximately 306.5 K, which means that it hydrates and dehydrates rapidly. − We recently reported that if water was introduced to a PNIPA gel with trapped pyrene, pyrene excimers formed even if the concentration of trapped pyrene was low . Because hydrophobic pyrene molecules have low solubility in water, the pyrene and water were thought to separate in the gel.…”

Section: Introductionmentioning

confidence: 99%

Reversible Change between Excimer and Monomer Forms of Perylene Induced by Water Absorption and Dehydration of Poly-N-isopropylacrylamide Gel

et al. 2021

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Several fluorescence patterns derived from the excimer states of perylene have been reported, but most of these have been obtained from rigid forms such as crystals or for perylene embedded in hard polymers. We observed perylene excimer emission on absorption of water by a poly-N-isopropylacrylamide gel containing perylene molecules, which were not fixed to the gel framework by chemical bonding. We propose that this emission arises because the hydrophobic perylene molecules cannot dissolve in water and form aggregates. The perylene aggregation was quickly lost on dehydration of the gel, and the luminescence reverted to that of the monomer. In a dehydrated environment, perylene was rapidly dispersed in the gel network. In other words, solid–liquid phase separation of perylene was induced by uptake of water into the gel, and perylene dissolved in the gel on dehydration. Because the outside of the gel is always in an aqueous environment, perylene will remain semipermanently in the gel. Therefore, monomer emission and excimer emission can be switched reversibly and repeatedly.

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Switching of Fluorescence Wavelength Caused by Phase Separation of Pyrene in Poly(N-isopropylacrylamide) Gel

Cited by 7 publications

References 20 publications

Gated Photoreactivity of Pyrene Copolymers in Multiresponsive Cross-Linked starPEG-Hydrogels

Gated Photoreactivity of Pyrene Copolymers in Multiresponsive Cross-Linked starPEG-Hydrogels

Photo‐Responsive Phase‐Separating Fluorescent Molecules for Intracellular Protein Delivery

Reversible Change between Excimer and Monomer Forms of Perylene Induced by Water Absorption and Dehydration of Poly-N-isopropylacrylamide Gel

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