TY - JOUR
T1 - Preparation of thermosensitive polymer nanoparticles by protein-mimetic cross-linking
AU - Kaihara, Sachiko
AU - Narikawa, Masatoshi
AU - Fujimoto, Keiji
N1 - Funding Information:
This work was supported by High-Tech Research Center Project for Private Universities: matching fund subsidy from MEXT.
PY - 2012/8
Y1 - 2012/8
N2 - Thermosensitive nanoparticles were prepared by mimicking protein folding where polymer aggregates were formed by precipitation of thermosensitive polymer chains followed by disulfide formation of their thiol groups. N-Isopropylacrylamide (NIPAM) and methacryloxy succini-mide (SuMA) were co-polymerized and then cysteamine was allowed to react with succinimide moieties of the polymer to render thiol moieties. A polymer aqueous solution precipitated to form nano-sized aggregates by increasing temperature above its lower critical solution temperature (LCST), and their sizes were monodispersed and tunable by the polymer concentration. The aggregates were cross-linked to produce nanoparticles by oxidation of thiol groups in a manner similar to formation of a disulfide bond of protein. As a result, the cross-linked nanoparticles exhibited swelling by decreasing temperature below the LCST of the copolymer. Fluorescein and bovine serum albumin (BSA) were chosen as a small and a large substance, respectively, and were encapsulated into the swollen nanoparticles at 25 °C. Fluorescein was rapidly released from both swollen and shrunken nanoparticles. Although BSA exhibited little release at any temperatures, it was released from nanopar-ticles by adding the reducing agent to dissociate the disul-fide cross-linking and incubating below the LCST.
AB - Thermosensitive nanoparticles were prepared by mimicking protein folding where polymer aggregates were formed by precipitation of thermosensitive polymer chains followed by disulfide formation of their thiol groups. N-Isopropylacrylamide (NIPAM) and methacryloxy succini-mide (SuMA) were co-polymerized and then cysteamine was allowed to react with succinimide moieties of the polymer to render thiol moieties. A polymer aqueous solution precipitated to form nano-sized aggregates by increasing temperature above its lower critical solution temperature (LCST), and their sizes were monodispersed and tunable by the polymer concentration. The aggregates were cross-linked to produce nanoparticles by oxidation of thiol groups in a manner similar to formation of a disulfide bond of protein. As a result, the cross-linked nanoparticles exhibited swelling by decreasing temperature below the LCST of the copolymer. Fluorescein and bovine serum albumin (BSA) were chosen as a small and a large substance, respectively, and were encapsulated into the swollen nanoparticles at 25 °C. Fluorescein was rapidly released from both swollen and shrunken nanoparticles. Although BSA exhibited little release at any temperatures, it was released from nanopar-ticles by adding the reducing agent to dissociate the disul-fide cross-linking and incubating below the LCST.
KW - Disulfide cross-linking
KW - Nanoparticles
KW - PNIPAM
KW - Protein encapsulation
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U2 - 10.1007/s00396-012-2654-6
DO - 10.1007/s00396-012-2654-6
M3 - Article
AN - SCOPUS:84865123127
VL - 290
SP - 1317
EP - 1325
JO - Colloid and Polymer Science
JF - Colloid and Polymer Science
SN - 0303-402X
IS - 13
ER -