8
|
Dunér G, Anderson H, Myrskog A, Hedlund M, Aastrup T, Ramström O. Surface-confined photopolymerization of pH-responsive acrylamide/acrylate brushes on polymer thin films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:7559-7564. [PMID: 18563922 DOI: 10.1021/la800700h] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Dynamic acrylamide/acrylate polymeric brushes were synthesized at gold-plated quartz crystal surfaces. The crystals were initially coated with polystyrene-type thin films, derivatized with photolabile iniferter groups, and subsequently subjected to photoinitiated polymerization in acrylamide/acrylate monomer feeds. This surface-confined polymerization method enabled direct photocontrol over the polymerization, as followed by increased frequency responses of the crystal oscillations in a quartz crystal microbalance (QCM). The produced polymer layers were also found to be highly sensitive to external acid/base stimuli. Large oscillation frequency shifts were detected when the brushes were exposed to buffer solutions of different pH. The dynamic behavior of the resulting polymeric brushes was evaluated, and the extent of expansion and contraction of the films was monitored by the QCM setup in situ in real time. The resulting responses were rapid, and the effects were fully reversible. Low pH resulted in full contractions of the films, whereas higher pH yielded maximal expansion in order to minimize repulsion around the charged acrylate centers. The surfaces also proved to be very robust because the responsiveness was reproducible over many cycles of repeated expansion and contraction. Using ellipsometry, copolymer layers were estimated to be approximately 220 nm in a collapsed state and approximately 340 nm in the expanded state, effectively increasing the thickness of the film by 55%.
Collapse
Affiliation(s)
- Gunnar Dunér
- Royal Institute of Technology, Department of Chemistry, Teknikringen 30, S-10044 Stockholm, Sweden
| | | | | | | | | | | |
Collapse
|
9
|
Griffiths PC, Alexander C, Nilmini R, Pennadam SS, King SM, Heenan RK. Physicochemical Characterization of Thermoresponsive Poly(N-isopropylacrylamide)−poly(ethylene imine) Graft Copolymers. Biomacromolecules 2008; 9:1170-8. [DOI: 10.1021/bm701096p] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Peter C. Griffiths
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, Wales, United Kingdom, The School of Pharmacy, University of Nottingham, Boots Science Building, University Park, Nottingham NG7 2RD, United Kingdom, and ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - Cameron Alexander
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, Wales, United Kingdom, The School of Pharmacy, University of Nottingham, Boots Science Building, University Park, Nottingham NG7 2RD, United Kingdom, and ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - Renuka Nilmini
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, Wales, United Kingdom, The School of Pharmacy, University of Nottingham, Boots Science Building, University Park, Nottingham NG7 2RD, United Kingdom, and ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - Sivanand S. Pennadam
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, Wales, United Kingdom, The School of Pharmacy, University of Nottingham, Boots Science Building, University Park, Nottingham NG7 2RD, United Kingdom, and ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - Stephen M. King
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, Wales, United Kingdom, The School of Pharmacy, University of Nottingham, Boots Science Building, University Park, Nottingham NG7 2RD, United Kingdom, and ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - Richard K. Heenan
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, Wales, United Kingdom, The School of Pharmacy, University of Nottingham, Boots Science Building, University Park, Nottingham NG7 2RD, United Kingdom, and ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| |
Collapse
|
11
|
Plamper FA, Ruppel M, Schmalz A, Borisov O, Ballauff M, Müller AHE. Tuning the Thermoresponsive Properties of Weak Polyelectrolytes: Aqueous Solutions of Star-Shaped and Linear Poly(N,N-dimethylaminoethyl Methacrylate). Macromolecules 2007. [DOI: 10.1021/ma071203b] [Citation(s) in RCA: 318] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Felix A. Plamper
- Makromolekulare Chemie II, Physikalische Chemie I, and Bayreuther Zentrum für Kolloide und Grenzflächen, Universität Bayreuth, D-95440 Bayreuth, Germany, and Institut Pluridisciplinaire de Recherche sur l'Environnement et les Matériaux, UMR 5254 CNRS/UPPA, 64053 Pau, France
| | - Markus Ruppel
- Makromolekulare Chemie II, Physikalische Chemie I, and Bayreuther Zentrum für Kolloide und Grenzflächen, Universität Bayreuth, D-95440 Bayreuth, Germany, and Institut Pluridisciplinaire de Recherche sur l'Environnement et les Matériaux, UMR 5254 CNRS/UPPA, 64053 Pau, France
| | - Alexander Schmalz
- Makromolekulare Chemie II, Physikalische Chemie I, and Bayreuther Zentrum für Kolloide und Grenzflächen, Universität Bayreuth, D-95440 Bayreuth, Germany, and Institut Pluridisciplinaire de Recherche sur l'Environnement et les Matériaux, UMR 5254 CNRS/UPPA, 64053 Pau, France
| | - Oleg Borisov
- Makromolekulare Chemie II, Physikalische Chemie I, and Bayreuther Zentrum für Kolloide und Grenzflächen, Universität Bayreuth, D-95440 Bayreuth, Germany, and Institut Pluridisciplinaire de Recherche sur l'Environnement et les Matériaux, UMR 5254 CNRS/UPPA, 64053 Pau, France
| | - Matthias Ballauff
- Makromolekulare Chemie II, Physikalische Chemie I, and Bayreuther Zentrum für Kolloide und Grenzflächen, Universität Bayreuth, D-95440 Bayreuth, Germany, and Institut Pluridisciplinaire de Recherche sur l'Environnement et les Matériaux, UMR 5254 CNRS/UPPA, 64053 Pau, France
| | - Axel H. E. Müller
- Makromolekulare Chemie II, Physikalische Chemie I, and Bayreuther Zentrum für Kolloide und Grenzflächen, Universität Bayreuth, D-95440 Bayreuth, Germany, and Institut Pluridisciplinaire de Recherche sur l'Environnement et les Matériaux, UMR 5254 CNRS/UPPA, 64053 Pau, France
| |
Collapse
|
12
|
Boyer C, Bulmus V, Liu J, Davis TP, Stenzel MH, Barner-Kowollik C. Well-Defined Protein−Polymer Conjugates via in Situ RAFT Polymerization. J Am Chem Soc 2007; 129:7145-54. [PMID: 17500523 DOI: 10.1021/ja070956a] [Citation(s) in RCA: 368] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Biotechnology, biomedicine, and nanotechnology applications would benefit from methods generating well-defined, monodisperse protein-polymer conjugates, avoiding time-consuming and difficult purification steps. Herein, we report the in situ synthesis of protein-polymer conjugates via reversible addition-fragmentation chain transfer polymerization (RAFT) as an efficient method to generate well-defined, homogeneous protein-polymer conjugates in one step, eliminating major postpolymerization purification steps. A water soluble RAFT agent was conjugated to a model protein, bovine serum albumin (BSA), via its free thiol group at Cys-34 residue. The conjugation of the RAFT agent to BSA was confirmed by UV-visible spectroscopy, matrix-assisted laser desorption ionization--time of flight (MALDI-TOF), and 1H NMR. BSA-macroRAFT agent was then used to control the polymerization of two different water soluble monomers, N-isopropylacrylamide (NIPAAm) and hydroxyethyl acrylate (HEA), in aqueous medium at 25 degrees C. The growth of the polymer chains from BSA-macroRAFT agent was characterized by size exclusion chromatography (SEC), 1H NMR, MALDI-TOF, and polyacrylamide gel electrophoresis (PAGE) analyses. The controlled character of the RAFT polymerizations was confirmed by the linear evolution of molecular weight with monomer conversion. The SEC analyses showed no detectable free, nonconjugated polymer formation during the in situ polymerization. The efficiency of BSA-macroRAFT agent to generate BSA-polymer conjugates was found to be ca. 1 by deconvolution of the SEC traces of the polymerization mixtures. The structural integrity and the conformation-related esterase activity of BSA were found to be unaffected by the polymerization conditions and the conjugation of the polymer chain. BSA-poly(NIPAAm) conjugates showed hybrid temperature-dependent phase separation and aggregation behavior. The lower critical solution temperature values of the conjugates were found to increase with the decrease in molecular weight of poly(NIPAAm) block conjugated to BSA.
Collapse
Affiliation(s)
- Cyrille Boyer
- Centre for Advanced Macromolecular Design (CAMD), School of Chemical Sciences and Engineering, The University of New South Wales, Sydney NSW 2052 Australia
| | | | | | | | | | | |
Collapse
|