文献类型：期刊文献

中文题名：Nanoscale Interfacial Activity of the Natural Lipopeptide, [Asp1, Glu5] Surfactin-C16, and DMPC in Mixed Monolayer

英文题名：Nanoscale Interfacial Activity of the Natural Lipopeptide, [Asp1, Glu5] Surfactin-C16, and DMPC in Mixed Monolayer

作者：Yang Ying[1,2];Zou Aihua[1,2];Song Changsheng[1,2,3];Mu Bozhong[1,2]

机构：[1]E China Univ Sci & Technol, Adv Mat Lab, Shanghai 200237, Peoples R China;[2]E China Univ Sci & Technol, Inst Appl Chem, Shanghai 200237, Peoples R China;[3]Taicang Entry Exit Inspect & Quarantine Bur, Taicang 215400, Jiangsu, Peoples R China

年份：2012

卷号：30

期号：12

起止页码：2869

中文期刊名：Chinese Journal of Chemistry

外文期刊名：CHINESE JOURNAL OF CHEMISTRY

收录：CSTPCD;;Scopus;WOS:【SCI-EXPANDED(收录号:WOS:000312942500024)】；CSCD:【CSCD2011_2012】；

基金：Dr. A. H. Zou gratefully acknowledges the support of this work by Research Fund for the New Teacher of the Doctoral Program of Higher Education of China (No. 200802511024). This work is supported by the National Natural Science Foundation of China (No. 50574040), the grant from Shanghai Science and Technology Commission (No. 071607014).

语种：英文

中文关键词：surfactin; DMPC; Langmuir film; atomic force microscopy

外文关键词：surfactin; DMPC; Langmuir film; atomic force microscopy

摘要：The dimyristoylphosphatidylcholine （DMPC） and a newly isolated surfactin analogue, [Asp1, Glus] surfactin-C16 in mixed monolayer was studied. Surface pressure-molecular area isotherms combined with atomic force microscopy （AFM） were used to probe the interfacial behavior of DMPC and surfactin-C16. The results show that the miscibility between DMPC and surfactin-C 16 is dependent on surfactin molar fraction （Xs） and surface pressure The two components are partially miscible on pure water （pH= 6） when Xs is 0.5, indicating that there exists mutual interactions between two components. AFM images showed similar pattern in surfactin-C16 monolayer and DMPC/surfactin-C 16 （Xs = 0.5） mixed monolayer. Based on the finding it is believed that DMPC would coalescent into surfactin-C 16 surface clusters in the mixed monolayer. Furthermore, the excess free energy of mixing （△ G^（ex）m ） was calculated to investigate the effect of subphase pH on the miscibility of two components in the mixed monolayer. It is found that the △ G^（ex）m was negative on alkaline subphase （pH= 10） when Xs equals to 0.75, indicating the molecular interactions between surfactin and DMPC are attractive at the condition. The results presented here suggest that hydrophobic interactions between surfactin-C 16 and DMPC play an important role in mutual interactions, and the interfacial activity was influenced by the ionization state of polar groups of surfactin-C 16.
The dimyristoylphosphatidylcholine (DMPC) and a newly isolated surfactin analogue, [Asp1, Glu5] surfactin-C16 in mixed monolayer was studied. Surface pressure-molecular area isotherms combined with atomic force microscopy (AFM) were used to probe the interfacial behavior of DMPC and surfactin-C16. The results show that the miscibility between DMPC and surfactin-C16 is dependent on surfactin molar fraction (XS) and surface pressure. The two components are partially miscible on pure water (pH=6) when XS is 0.5, indicating that there exists mutual interactions between two components. AFM images showed similar pattern in surfactin-C16 monolayer and DMPC/surfactin-C16 (XS=0.5) mixed monolayer. Based on the finding it is believed that DMPC would coalescent into surfactin-C16 surface clusters in the mixed monolayer. Furthermore, the excess free energy of mixing (?Gmex) was calculated to investigate the effect of subphase pH on the miscibility of two components in the mixed monolayer. It is found that the ?Gmex was negative on alkaline subphase (pH=10) when Xs equals to 0.75, indicating the molecular interactions between surfactin and DMPC are attractive at the condition. The results presented here suggest that hydrophobic interactions between surfactin-C16 and DMPC play an important role in mutual interactions, and the interfacial activity was influenced by the ionization state of polar groups of surfactin-C16.