Lipophilic probe behavior in microemulsions evaluated by fluorescence correlation spectroscopy

Autor: Johtaro Yamamoto, Yoshio Suzuki, Yoshikatsu Ogawa, Tomoyuki Kamata, Hinako Hashimoto, Masashi Kunitake, Dai kato
Rok vydání: 2021
Předmět:
Zdroj: Analytical sciences : the international journal of the Japan Society for Analytical Chemistry. 38(2)
ISSN: 1348-2246
Popis: We evaluated the dispersion and diffusion of fluorescent-labeled lipophilic vitamin E (VE) in microemulsions (MEs) including water-in-oil (W/O) type ME, oil-in-water (O/W) type ME, and bicontinuous ME (BME), using fluorescence correlation spectroscopy (FCS). We prepared a fluorescent ATTO 488 or BODIPY group labeled VE (VE-ATTO or VE-BODIPY). VE-ATTO possesses lipophilic and hydrophilic parts, while VE-BODIPY consists solely of the lipophilic part. The VE-ATTO dissolved in heptane solution as an oil phase appeared hot pink in color due to the solvatochromism effect under room light and almost no fluorescent signal, which was unlike the VE-ATTO dissolved in ME solutions and all the VE-BODIPY solutions (typical fluorescent green color). The FCS measurement proved that VE-BODIPY diffuses faster than VE-ATTO. This is presumably because the "surfactant-like" VE-ATTO is localized and trapped at the micro-water/micro-oil interface of the MEs, while the VE-BODIPY exists in the ME phase and macro-oil phase with good dispersion. These results demonstrate that FCS is a powerful tool for the rapid evaluation of the lipophilic probe behavior in heterogeneous ME solutions.
Databáze: OpenAIRE