Quantitative single molecule measurements on the interaction forces of poly(L-glutamic acid) with calcite crystals.
The interaction between poly(L-glutamic acid) (PLE) and calcite crystals was studied with AFM-based single molecule force spectroscopy. Block copolymers of poly(ethylene oxide) (PEO) and PLE were synthesized and covalently attached to the tip of an AFM cantilever. In desorption measurements the molecules were allowed to adsorb on the calcite crystal faces and afterward successively desorbed. The corresponding desorption forces were detected with high precision, showing for example a force transition between the two blocks. Because of its importance in the crystallization process in biominerals, the PLE-calcite interaction was investigated as a function of the pH as well as the calcium concentration of the aqueous solution. The sensitivity of the technique was underlined by resolving different interaction forces for calcite (104) and calcite (100).
Sonnenberg
Lars
L
Lehrstuhl für Angewandte Physik and Center for NanoScience, Ludwig-Maximilians-Universität München, Amalienstrasse 54, 80799 München, Germany. sonnenberg@physik.uni-muenchen.de
Luo
Yufei
Y
Schlaad
Helmut
H
Seitz
Markus
M
Cölfen
Helmut
H
Gaub
Hermann E
HE
D000327:Adsorption; D002119:Calcium Carbonate / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D011099:Polyglutamic Acid / Q000737:chemistry*
D011099:Polyglutamic Acid; D002119:Calcium Carbonate