Patent DE-102013106380-A1 (DE)
Title: Liquid-based sensor device, useful for detecting the presence of analyte e.g. bacteria cell, comprises substrates, liquid crystal layer, and phospholipid layer, reaction layer, electrodes, and insulating layer and/or alignment layer
Inventor: KILICKIRAN PINAR
IPC: C12Q1/02
Filed: 2013-06-19
Abstract: The liquid-based sensor device comprises a first substrate, a liquid crystal layer disposed on the first substrate, and a phospholipid layer disposed on the liquid crystal layer. The device does not include a detection member or a recognition molecule that is bound directly to a surface of the first substrate. The phospholipid comprises recognition moiety or a recognition molecule such as a receptor, an enzyme, or an antibody, and 10-15 wt.% of cholesterol. The device further comprises reaction layer disposed on the liquid crystal layer, and a first electrode . The liquid-based sensor device comprises a first substrate, a liquid crystal layer disposed on the first substrate, and a phospholipid layer disposed on the liquid crystal layer. The device does not include a detection member or a recognition molecule that is bound directly to a surface of the first substrate. The phospholipid comprises recognition moiety or a recognition molecule such as a receptor, an enzyme, or an antibody, and 10-15 wt.% of cholesterol. The device further comprises a reaction layer disposed on the liquid crystal layer, a first electrode positioned between the first substrate and the liquid crystal layer, an insulating layer and/or an alignment layer or insulation and alignment layers coated the electrode, a second substrate disposed opposite to the first substrate and the liquid crystal layer, an intermediate layer disposed between the first and second substrate, crossed polarizers positioned below and above the liquid crystal layer and in planes of the first and second substrate respectively, a unit to measure an electrical quantity, a microfluidic device in fluid communication with a reaction chamber, and a filter unit for filtering any material from the sample. The reaction layer includes a lipid layer, lipopolysaccharide (LPS) layer and/or a fatty acid layer. A gap is present between the second substrate and the phospholipid layer or between the second substrate and the reaction layer, and acts as the reaction chamber for receiving a sample to be analyzed. The second substrate comprises a second electrode disposed on the second substrate, and an insulating layer on the second electrode. The insulating layer faces the first substrate phospholipid/liquid crystal layer and reaction layer/liquid crystal layer. The first and/or second substrate comprises glass or plastic. The liquid crystal layer has a homeotropic alignment, a homogeneous alignment, or any predefined orientation, and comprises a liquid crystal including thermotropic liquid crystals having positive/negative or no dielectric anisotropy, dual-frequency liquid crystals, discotic and/or lyotropic liquid crystals, a single liquid crystal compound, a mixture of different liquid crystalline compounds and/or a liquid crystal mixture mixed with dopants such as nanoparticles or small organic molecules. The liquid crystal layer is doped with dichroic dye, fluorescence dye or with a quantum dot. The phospholipid and the reaction layers include a single phospholipid compound or a mixture of different phospholipid compounds. The reaction layer comprises a single fatty acid compound or a mixture of different fatty acid compounds. The insulating layer is constructed on the first and/or second electrode. The first electrode and the second electrode include a non-interdigitated electrode, a plane electrode, or an interdigitated electrode. The alignment layer includes a heat/photo-curable polyimide layer providing for a defined pre-tilt angle of the liquid crystal in the liquid crystal layer, a self assembled monolayer, or an obliquely evaporated oxide layer, such as silica providing for a pre-tilt of the liquid crystal in the liquid crystal layer depending on the evaporation angle of the oxide. The first and/or second electrode is a transparent or non-transparent electrode. The crossed polarizers allow to measure changes in the liquid crystal alignment by measuring changes of transmission/reflection of polarized light, and the substrate underneath the liquid crystal layer is a reflective substrate. The measuring unit allows to measure changes in the liquid crystal alignment by measuring changes in such electrical quantity such as capacitance, resistance or current. The reaction chamber has a depth of 900 nm to 30 mu m, includes a circular chamber having a width or diameter of 25-500 mu m, and/or is made of glass, plastic or metal walls such as gold walls.