Morphing Hydrogel Patterns by Thermo-Reversible Fluorescence Switching

• Published in: Macromolecular rapid communications. Vol. 35; no. 14; pp. 1260 - 1265
• Main Authors: Bat, Erhan, Lin, En-Wei, Saxer, Sina, Maynard, Heather D.
• Format: Journal Article
• Language: English
• Published: Weinheim Blackwell Publishing Ltd 01.07.2014; Wiley
• Subjects: Applied sciences; Chemical compounds; Electron beam lithography; Exact sciences and technology; Fluorescence; Fluorescent Dyes - chemistry; Gels; Hydrogel, Polyethylene Glycol Dimethacrylate - chemistry; Hydrogels; Methacrylates - chemistry; Microscopy, Atomic Force; Microscopy, Fluorescence; Morphing; oligo­(ethylene glycol); Organic polymers; Physicochemistry of polymers; Polymerization; Polymers; Polymers - chemistry; Properties and characterization; Solution and gel properties; stimuli-responsive surfaces; Surface Properties; Switching; Temperature; thermo-responsive polymers; Fluorescent tracer; Swelling; Electron beam lithography; Atom transfer polymerization; oligo-(ethylene glycol); Temperature effect; Fluorescence; Surface topography; Experimental study; stimuli-responsive surfaces; Radiochemical crosslinking; thermo-responsive polymers; Colloidal gel; Cloud point; Labelled copolymer; Fluorescent labelling; Preparation; Luminescence quenching; Self quenching; Methacrylate copolymer; Aqueous solution; Fluorescence microscopy; oligo­(ethylene glycol); electron beam lithography; fluorescence
• ISSN: 1022-1336; 1521-3927; 1521-3927
• DOI: 10.1002/marc.201400160

Stimuli responsive surfaces that show reversible fluorescence switching behavior in response to temperature changes were fabricated. Oligo(ethylene glycol) methacrylate thermoresponsive polymers with amine end‐groups were prepared by atom transfer radical polymerization (ATRP). The polymers were patterned on silicon surfaces by electron beam (e‐beam) lithography, followed by conjugation of self‐quenching fluorophores. Fluorophore conjugated hydrogel thin films were bright when the gels were swollen; upon temperature‐induced collapse of the gels, self‐quenching of the fluorophores led to significant attenuation of fluorescence. Importantly, the fluorescence was regained when the temperature was cooled. The fluorescence switching behavior of the hydrogels for up to ten cycles was investigated and the swelling‐collapse was verified by atomic force microscopy. Morphing surfaces that change shape several times upon increase in temperature were obtained by patterning multiple stimuli responsive polymers. Stimuli‐responsive surfaces that show reversible fluorescence switching behavior in response to temperature changes are presented. Fluorophore‐conjugated hydrogel thin films are bright when the gels are swollen; upon collapsing of the gels, self‐quenching of fluorophores leads to significant attenuation of fluorescence. Morphing surfaces are obtained by patterning multiple stimuli‐responsive polymers using electron beam lithography.