title: Liquid crystal based sensors monitoring lipase activity: a new rapid and sensitive method for cytotoxicity assays.
abstract: In this work we present liquid crystal (LC) based sensor devices to monitor cell viability. The sensing layer is composed by the LC and a planar monolayer of phospholipids. In the presence of minute traces of phospholipases, which hydrolyze enzymatically phospholipids, the LC-lipid interface is disintegrated. This event causes a change in orientation of the LC, which was followed in a polarized microscope. The lipase activity can be used to measure the cell viability, since members of this enzyme family are released by cells, as they undergo necrosis. The described sensor was used to monitor the presence of the lipases released from three different cell lines, which were either exposed to highly cytotoxic model compounds (sodium azide and paracetamol) or subjected to freeze-thaw cycles to induce cell death by a non-chemical based inducer for apoptosis, such as temperature. Finally, the comparison of lipase activity detected by a state-of-the-art fluorescence assay to the LC based system resulted in the superiority of the LC system concerning incubation time and sensitivity.
authors: SONY Deutschland GmbH, Materials Science Laboratory, Hedelfingerstrasse 61, 70327 Stuttgart, Germany.
authors: Zakir
authors: Z
authors: Hussain
authors: Laboratory for Synthetic Bio-architectures, Department of Nanobiotechnology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 11, A-1190 Vienna, Austria.
authors: Christian
authors: C
authors: Zafiu
authors: Laboratory for Synthetic Bio-architectures, Department of Nanobiotechnology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 11, A-1190 Vienna, Austria.
authors: Seta
authors: S
authors: Küpcü
authors: SONY Deutschland GmbH, Materials Science Laboratory, Hedelfingerstrasse 61, 70327 Stuttgart, Germany.
authors: Lucineia
authors: L
authors: Pivetta
authors: SONY Deutschland GmbH, Materials Science Laboratory, Hedelfingerstrasse 61, 70327 Stuttgart, Germany.
authors: Nadine
authors: N
authors: Hollfelder
authors: SONY Deutschland GmbH, Materials Science Laboratory, Hedelfingerstrasse 61, 70327 Stuttgart, Germany.
authors: Akira
authors: A
authors: Masutani
authors: SONY Deutschland GmbH, Materials Science Laboratory, Hedelfingerstrasse 61, 70327 Stuttgart, Germany. Electronic address: kilickiran@cast-tyrol.com.
authors: Pinar
authors: P
authors: Kilickiran
authors: Laboratory for Synthetic Bio-architectures, Department of Nanobiotechnology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 11, A-1190 Vienna, Austria. Electronic address: eva.sinner@boku.ac.at.
authors: Eva-Kathrin
authors: EK
authors: Sinner
mesh_terms: D001419:Bacteria / Q000201:enzymology; D015374:Biosensing Techniques / Q000379:methods*; D002470:Cell Survival; D057075:Enzyme Assays / Q000379:methods*; D005453:Fluorescence; D056945:Hep G2 Cells; D006801:Humans; D050866:Liquid Crystals / Q000737:chemistry*; D010740:Phospholipases / Q000378:metabolism*; D010743:Phospholipids / Q000737:chemistry / Q000378:metabolism*; D013499:Surface Properties
chemical_list: D010743:Phospholipids; D010740:Phospholipases
keywords: Biosensor; Cytotoxicity; Lipase; Liquid crystal; Phospholipid