Contact
    Start Publications Surface Chemistry Studies on the Formation of Mixed Stearic ...
    ←  Publication Finder
    KSV NIMA

    Surface Chemistry Studies on the Formation of Mixed Stearic Acid/Phenylalanine Dehydrogenase Langmuir and Langmuir-Blodgett Films

    Year: 2021

    Journal: Langmuir, Volume 37, JUN 29, page 7771–7779

    Authors: Cruz Gomes da Silva, Rafael Leonardo; Sharma, Shiv K.; Paudyal, Suraj; Mintz, Keenan J.; Leblanc, Roger M.; Caseli, Luciano

    Organizations: Sao Paulo Research Foundation (FAPESP) [2018/00291-9, 2019/01797-6, 2019/03239-0, 2018/22214-6]; University of Miami (Miami, Florida); Federal University of Sao Paulo (Diadema, Sao Paulo)

    This work investigates the physicochemical properties of mixed stearic acid (HSt)/phenylalanine dehydrogenase enzyme (PheDH) Langmuir films and their immobilization onto solid supports as Langmuir-Blodgett (LB) films. PheDH from the aqueous subphase enters the surfactant matrix up to an exclusion surface pressure of 25.3 mN/m, leading to the formation of stable and highly condensed mixed Langmuir monolayers. Hydrophobic interactions between the enzyme and HSt nonpolar groups tuned the secondary structure of PheDH, evidenced by the presence of beta-sheet structures as demonstrated by infrared and circular dichroism spectra. The floating monolayers were successfully transferred to solid quartz supports, yielding Y-type LB films, and then characterized employing fluorescence, circular dichroism, and microscopic techniques, which indicated that PheDH was co-immobilized with HSt proportionally to the number of transferred layers. The enzyme fluidized the HSt monolayers, reducing their maximum dipoles when condensed to their maximum, and disorganized the alkyl chains of the fatty acid, as detected with infrared spectroscopy. The stability of the mixed floating monolayers enabled their transfer to solid supports as LB films, which is important for producing optical and electrochemical sensors for phenylalanine whose molecular architecture can be controlled with precision.
    View publication