Faried Miftah, Suga Keishi, Okamoto Yukihiro, Shameli Kamyar, Miyake Mikio, Umakoshi Hiroshi
Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan.
Department of Environment and Green Technology, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, Kuala Lumpur 54100, Malaysia.
ACS Omega. 2019 Aug 19;4(9):13687-13695. doi: 10.1021/acsomega.9b01073. eCollection 2019 Aug 27.
A gold nanoparticle (AuNP) has a localized surface plasmon resonance peak depending on its size, which is often utilized for surface-enhanced Raman scattering (SERS). To obtain information on the cholesterol (Chol)-incorporated lipid membranes by SERS, AuNPs (5, 100 nm) were first functionalized by 1-octanethiol and then modified by lipids (AuNP@lipid). In membrane surface-enhanced Raman spectroscopy (MSERS), both signals from 1,2-dioleoyl--glycero-3-phosphocholine (DOPC) and Chol molecules were enhanced, depending on preparation conditions (size of AuNPs and lipid/AuNP ratio). The enhancement factors (EFs) were calculated to estimate the efficiency of AuNPs on Raman enhancement. The size of AuNP@lipid was 152.0 ± 12.8 nm, which showed an surface enhancement Raman spectrum with an EF value of 111 ± 9. The size of AuNP@lipid prepared with a lipid/AuNP ratio of 1.38 × 10 (lipid molecule/particle) was 275.3 ± 20.2 nm, which showed the highest enhancement with an EF value of 131 ± 21. On the basis of fluorescent probe analyses, the membrane fluidity and polarity of AuNP@lipid were almost similar to DOPC/Chol liposome, indicating an intact membrane of DOPC/Chol after modification with AuNPs. Finally, the membrane properties of AuNP@lipid systems were also discussed on the basis of the obtained MSERS signals.
金纳米颗粒（AuNP）具有取决于其尺寸的局域表面等离子体共振峰，该峰常被用于表面增强拉曼散射（SERS）。为了通过SERS获取有关掺入胆固醇（Chol）的脂质膜的信息，首先用1-辛硫醇对AuNP（5、100纳米）进行功能化，然后用脂质进行修饰（AuNP@脂质）。在膜表面增强拉曼光谱（MSERS）中，1,2-二油酰基-sn-甘油-3-磷酸胆碱（DOPC）和Chol分子的信号均会增强，这取决于制备条件（AuNP的尺寸和脂质/AuNP比例）。计算增强因子（EFs）以估计AuNP对拉曼增强的效率。AuNP@脂质的尺寸为152.0±12.8纳米，其表面增强拉曼光谱的EF值为111±9。以1.38×10（脂质分子/颗粒）的脂质/AuNP比例制备的AuNP@脂质的尺寸为275.3±20.2纳米，其显示出最高的增强效果，EF值为131±21。基于荧光探针分析，AuNP@脂质的膜流动性和极性与DOPC/Chol脂质体几乎相似，表明用AuNP修饰后DOPC/Chol的膜是完整的。最后，还根据获得的MSERS信号讨论了AuNP@脂质系统的膜性质。
