Lipid monolayer formation and lipid exchange monitored by a graphene field-effect transistor
Blaschke, Benno M. (Technische Universität München. Walter Schottky Institute)
Böhm, Philip (Ludwig-Maximilians-Universität München. Center for NanoScience)
Drieschner, Simon (Technische Universität München. Walter Schottky Institute)
Nickel, Bert (Ludwig-Maximilians-Universität München. Center for NanoScience)
Garrido, Jose (Institut Català de Nanociència i Nanotecnologia)

Data:	2018
Resum:	Anionic and cationic lipids are key molecules involved in many cellular processes; their distribution in biomembranes is highly asymmetric, and their concentration is well-controlled. Graphene solution-gated field-effect transistors (SGFETs) exhibit high sensitivity toward the presence of surface charges. Here, we establish conditions that allow the observation of the formation of charged lipid layers on solution-gated field-effect transistors in real time. We quantify the electrostatic screening of electrolyte ions and derive a model that explains the influence of charged lipids on the ion sensitivity of graphene SGFETs. The electrostatic model is validated using structural information from X-ray reflectometry measurements, which show that the lipid monolayer forms on graphene. We demonstrate that SGFETs can be used to detect cationic lipids by self-exchange of lipids. Furthermore, SGFETs allow measuring the kinetics of layer formation induced by vesicle fusion or spreading from a reservoir. Because of the high transconductance and low noise of the electrical readout, we can observe characteristic conductance spikes that we attribute to bouncing-off events of lipid aggregates from the SGFET surface, suggesting a great potential of graphene SGFETs to measure the on-off kinetics of small aggregates interacting with supported layers.
Ajuts:	European Commission 696656 Ministerio de Economía y Competitividad SEV-2013-0295
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Llengua:	Anglès
Document:	Article ; recerca ; Versió sotmesa a revisió
Matèria:	Cellular process ; Electrostatic modeling ; Electrostatic screening ; Graphene field-effect transistors ; High sensitivity ; Ion sensitivities ; Structural information ; X-ray reflectometry ; Anions ; Electricity ; Graphite ; Ions ; Lipids
Publicat a:	Langmuir, Vol. 34, issue 14 (April 2018) , p. 4224-4233, ISSN 1520-5827

DOI: 10.1021/acs.langmuir.8b00162

Preprint 34 p, 774.3 KB

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