Patent ID: 7560070

Claim:
Sensor system ( 70 ) for detecting a target nucleotide strand in a reference liquid, comprising a measurement cantilever ( 71 ) being functionalized by application of a first coating to one of the measurement cantilever's surfaces, whereby this first coating comprises a first oligonucleotide that hybridizes to the target nucleotide strand, a reference cantilever ( 72 ) with a reference coating on one of the reference cantilever's surfaces, whereby this reference coating comprises a second oligonucleotide that does not hybridize to the target nucleotide strand, wherein the surfaces of the measurement cantilever ( 71 ) and the reference cantilever ( 72 ) exhibit the same physical properties and differ only in the base sequences of the first and second oligonucleotides, a cantilever holder ( 95 ) for exposing the measurement cantilever ( 71 ) and the reference cantilever ( 72 ) in a reference step to the reference liquid and in a detection step to the reference liquid with the target nucleotide strand, a detector unit ( 73 , 74 , 83 ) for determining the difference in static deflection of the measurement cantilever ( 71 ) and the reference cantilever ( 72 ) during the reference step and the detection step, wherein the difference in static deflection of the measurement cantilever ( 71 ) and the reference cantilever ( 72 ) is indicative of the target nucleotide strand in the reference liquid.