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Investigation of the Orientation of Purple Membrane Sheets in Langmuir‐Blodgett Films by a Quartz Crystal Microbalance
Author(s) -
Lu Tao,
Rothe Ulrich,
Liebau Maik,
Schaffer Heike,
Hufnagel Peter,
Bakowsky Udo
Publication year - 1999
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/713803549
Subject(s) - quartz crystal microbalance , quartz , desorption , adsorption , membrane , crystal (programming language) , materials science , analytical chemistry (journal) , monolayer , crystallography , chemistry , chemical engineering , nanotechnology , chromatography , organic chemistry , composite material , biochemistry , engineering , computer science , programming language
Abstract By means of the quartz crystal microbalance (QCM), a convenient method was developed to determine the degree of orientation of purple membrane (PM) sheets on the air/water interface. Langmuir‐Blodgett films from both wild‐type and SH‐mutant PM (bR D36C) were vertically deposited on the surface of goldsputtered AT‐cut quartz crystals. The shift of resonance frequency of the QCM during a special washing protocol allowed us to differentiate between physically adsorbed PM fragments and any PM attached to the gold surface via chemical bonds. By washing with organic solvents, complete desorption of the wild‐type PM was achieved, whereas for the SH‐mutant, 60% of the PM fragments could not be detached from the surface. These PM sheets should be oriented with the cytoplasmic side facing the water subphase so that their SH‐groups can chemically bind to the gold surface of the quartz plate.