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A Pseudopolyrotaxane for Glucose-Responsive Insulin Release: The Effect of Binding Ability and Spatial Arrangement of Phenylboronic Acid Group

Tomohiro Seki, Keigo Abe, Yuya Egawa, Ryotaro Miki, Kazuhiko Juni, Toshinobu Seki

Mol Pharm. 2016 Nov 7;13(11):3807-3815.

PMID: 27715064

Abstract:

A pseudopolyrotaxane (PPRX) comprising 3-carboxy-5-nitrophenylboronic acid modified γ-cyclodextrin (NPBA-γ-CyD) and naphthalene modified polyethylene glycol (Naph-PEG) as a sugar-responsive supramolecular structure is prepared. The binding of sugar by the NPBA group induced disintegration of the Naph-PEG/NPBA-γ-CyD PPRX, allowing the components to be dissolved. The Naph-PEG/NPBA-γ-CyD PPRX exhibited better sensitivity compared to that of a PPRX based on 4-carboxyphenylboronic acid modified γ-cyclodextrin (PBA-γ-CyD). We have previously reported the unique structure of Naph-PEG/PBA-γ-CyD PPRX, which formed an inclusion complex with a single-stranded PEG chain being threaded through the γ-CyD rings, with the remaining internal space being occupied by the sugar-sensing PBA moiety from a neighboring ring, thus shielding it from sugar molecules and reducing the sugar sensitivity of the PPRX. In contrast, structural analyses in this study revealed that the sugar-sensing NPBA moiety in the Naph-PEG/NPBA-γ-CyD PPRX is not included in the neighboring NPBA-γ-CyD. This spatial arrangement and the high affinity of NPBA for sugar contributed to the improved sugar responsivity. The enhanced NPBA-γ-CyD was then applied to a PPRX containing Naph-PEG-appended insulin (Naph-PEG-Ins) that showed an improved response for glucose-induced insulin release.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP101084815 3-Carboxy-5-nitrophenylboronic acid 3-Carboxy-5-nitrophenylboronic acid 101084-81-5 Price
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