Water‐soluble complex formation of fullerene and thermo‐responsive diblock copolymer. Issue 15 (29th May 2017)

• Record Type: Journal Article
• Authors: Yano, Junki; Ishihara, Kazuhiko; Yusa, Shin‐ichi
• Is Part Of: Journal of polymer science. Volume 55:Issue 15(2017)
• Page Start: 2432
• Page End: 2439
• Publication Date: 2017-05-29
• Subjects: biocompatible -- fullerene -- RAFT -- thermos‐responsive; 547
• DOI: 10.1002/pola.28557
• Languages: English
• ISSNs: 0887-624X

Abstract

ABSTRACT: A diblock copolymer (P98 N100 ) composed of a biocompatible water‐soluble block (PMPC) and a lower critical solution temperature (LCST) type thermo‐responsive block (PNIPAM) was prepared via controlled radical polymerization. To dissolve fullerene (C60 ) in water, the C60 /P98 N100 complex was prepared by mixing C60 and P98 N100 powders. The maximum solubilized C60 concentration in water was 1.39 g/L, as estimated from UV–vis adsorption, when the polymer concentration was 5.0 g/L. The percent transmittance of the aqueous solution of the C60 /P98 N100 complex decreased above 36 °C due to inter‐complex association above the LCST for the PNIPAM block. While the hydrodynamic radius of C60 /P98 N100 complex was 135 nm at 20 °C, it increased to 161 nm at 50 °C. Despite the observation of 1 H NMR signals from PMPC and PNIPAM blocks for the C60 /P98 N100 complex in D2 O at room temperature, the signals from PNIPAM disappeared above 35 °C due to restricted motion of PNIPAM. Generation of singlet oxygen ( 1 O2 ) from the C60 /P98 N100 complex by photo‐irradiation was confirmed using 9, 10‐anthracene dipropionic acid (ADPA). The absorbance of ADPA decreased with increasing irradiation time due to oxidation of ADPA by 1 O2 . It is expected that the C60 /P98 N100 complex can be applied as a thermo‐responsive carrier for photodynamic therapy. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem.2017, 55, 2432–2439 Abstract : A diblock copolymer (P98 N100 ) composed of a biocompatible water‐soluble block and a lower critical solution temperature (LCST) type thermo‐responsive block can dissolve fullerene (C60 ) in water to form a water‐soluble C60 /P98 N100 complex, which can generate singlet oxygen ( 1 O2 ) by photo‐irradiation. Above 35 °C, inter‐complex association between C60 /P98 N100 complexes occurs. It is expected that the C60 /P98 N100 complex can be applied as a thermo‐responsive carrier for photodynamic therapy (PDT).