title: Multicompartment polymer nanostructures with ratiometric dual-emission pH-sensitivity.
abstract: Pyrazine-labeled multicompartment nanostructures are shown to exhibit enhanced pH-responsive blue-shifted fluorescence emission intensities compared to their simpler core-shell spherical analogs. An amphiphilic linear triblock terpolymer of ethylene oxide, N-acryloxysuccinimide, and styrene, PEO(45)-b-PNAS(105)-b-PS(45), which lacks significant incompatibility for the hydrophobic block segments and undergoes gradual hydrolysis of the NAS units, underwent supramolecular assembly in mixtures of organic solvent and water to afford multicompartment micelles (MCMs) with a narrow size distribution. The assembly process was followed over time and found to evolve from individual polymer nanodroplets containing internally phase segregated domains, of increasing definition, and ultimately to dissociate into discrete micelles. Upon covalent cross-linking of the MCMs with pH-insensitive pyrazine-based diamino cross-linkers, pH-responsive, photonic multicompartment nanostructures (MCNs) were produced. These MCNs exhibited significant enhancement of overall structural stability, in comparison with the MCMs, and internal structural tunability through the cross-linking chemistry. Meanwhile, the complex compartmentalized morphology exerted unique pH-responsive fluorescence dual-emission properties, indicating promise in ratiometric pH-sensing applications.
authors.affiliation: Department of Chemistry, Texas A&M University, College Station, Texas 77842, USA.
authors.forename: Guorong
authors.initials: G
authors.lastname: Sun
authors.forename: Honggang
authors.initials: H
authors.lastname: Cui
authors.forename: Lily Yun
authors.initials: LY
authors.lastname: Lin
authors.forename: Nam S
authors.initials: NS
authors.lastname: Lee
authors.forename: Chao
authors.initials: C
authors.lastname: Yang
authors.forename: William L
authors.initials: WL
authors.lastname: Neumann
authors.forename: John N
authors.initials: JN
authors.lastname: Freskos
authors.forename: Jeng J
authors.initials: JJ
authors.lastname: Shieh
authors.forename: Richard B
authors.initials: RB
authors.lastname: Dorshow
authors.forename: Karen L
authors.initials: KL
authors.lastname: Wooley
mesh_terms: D003432:Cross-Linking Reagents / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008823:Micelles; D015394:Molecular Structure; D049329:Nanostructures / Q000737:chemistry*; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D011719:Pyrazines / Q000737:chemistry; D013050:Spectrometry, Fluorescence
chemical_list: D003432:Cross-Linking Reagents; D008823:Micelles; D011108:Polymers; D011719:Pyrazines