Quantitative analyses of PEGylated phospholipids adsorbed on single walled carbon nanohorns by high resolution magic angle spinning ¹H NMR

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• 作者：Masaru Aoyagi^a ; ^{masaru-aoyagi@aist.go.jp" class="auth_mail" title="E-mail the corresponding author} ; Masako Yudasaka^b ; ^e ; Hiroyuki Minamikawa^a ; Masumi Asakawa^c ; Mitsutoshi Masuda^a ; Toshimi Shimizu^d ; Sumio Iijima^e
• 刊名：Carbon
• 出版年：2016
• 出版时间：May 2016
• 年：2016
• 卷：101
• 期：Complete
• 页码：213-217
• 全文大小：707 K

文摘

Adsorption of polyethylene glycol conjugated phospholipids with various PEG chain length (DSPE-PEG5000, 2000, 750) onto single-walled carbon nanohorns (SWCNH), a type of graphene nano-tubule, in aqueous solution was investigated by means of high-resolution magic angle spinning (HRMAS) ¹H NMR. Peak integral ratio of PEG chains and alkyl chains of DSPE-PEGs in the NMR spectra linearly decreased to zero with the increase of SWCNH quantity, indicating that the adsorption of DSPE-PEGs on SWCNH was virtually irreversible. The area of SWCNH surface allocated to the individual DSPE-PEG5000, 2000, 750 molecule were estimated to be 7.06, 5.18, and 4.45 nm², respectively. Coverages of the alkyl chains on the surface area of SWCNH were about 28%, 39% for DSPE-PEG5000, 2000 and 46% for DSPE-PEG750, suggesting single layer adsorption. We presumed that the electrostatic repulsion may prevent DSPE-PEGs from multiple layer and keep away neighbouring DSPE-PEGs on the surface. According to the molecular areas of the DSPE-PEGs, PEG5000 and 2000 chains were considered to be in brush-regimes, while PEG750 was considered to be in mushroom regime on the SWCNH surface.