title: Physiologically relevant, pH-responsive PEG-based block and statistical copolymers withN,N-diisopropylamine units.
abstract: In order to impart pH-responsiveness within a physiologically-relevant context to PEG-based biomaterials, a new tertiary amine containing repeat unit,N,N-diisopropyl ethanolamine glycidyl ether (DEGE), was developed and incorporated into statistical and block copolymers with ethylene oxide (EO), and allyl glycidyl ether (AGE)viaanionic ring-opening polymerization. The reactivity of this novel monomeric building block in copolymerizations with EO was investigated by spectroscopy with observed reactivity ratios ofrDEGE= 1.28 ± 0.14 andrEO= 0.82 ± 0.10. It was further demonstrated that DEGE containing copolymers could serve as building blocks for the formation of new pH-responsive materials with a pKaofca. 9, which allowed macroscopic hydrogels to be prepared from symmetric triblock copolymers PDEGE5.3k-b-PEO20k-b-PDEGE5.3k. The triblock copolymers exhibited clear sol-to-gel transitions in a physiologically-relevant critical gelation range of pH 5.8-6.6 and pH-dependent viscoelastic properties. On the nanometer scale, the preparation of pH-responsive micro- or nanogels was demonstrated by crosslinking P(DEGE-co-AGE) copolymers in miniemulsion droplets stabilized by PEO-b-P(DEGE-co-AGE) diblock terpolymers. These nanoparticles exhibited a reversible pH-dependent swelling profile with a volume phase transition at physiological pH 6.5-7.5.
authors.affiliation: Materials Research Laboratory, Department of Chemistry and Biochemistry, and the Materials Department, University of California, Santa Barbara, California 93106, USA.
authors.forename: Annabelle
authors.initials: A
authors.lastname: Lee
authors.affiliation: Materials Research Laboratory, Department of Chemistry and Biochemistry, and the Materials Department, University of California, Santa Barbara, California 93106, USA.
authors.forename: Pontus
authors.initials: P
authors.lastname: Lundberg
authors.affiliation: Materials Research Laboratory, Department of Chemistry and Biochemistry, and the Materials Department, University of California, Santa Barbara, California 93106, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Klinger
authors.affiliation: Materials Research Laboratory, Department of Chemistry and Biochemistry, and the Materials Department, University of California, Santa Barbara, California 93106, USA.
authors.forename: Bongjae F
authors.initials: BF
authors.lastname: Lee
authors.affiliation: Materials Research Laboratory, Department of Chemistry and Biochemistry, and the Materials Department, University of California, Santa Barbara, California 93106, USA.
authors.forename: Craig J
authors.initials: CJ
authors.lastname: Hawker
authors.affiliation: Materials Research Laboratory, Department of Chemistry and Biochemistry, and the Materials Department, University of California, Santa Barbara, California 93106, USA.
authors.forename: Nathaniel A
authors.initials: NA
authors.lastname: Lynd