Label-free detection of Cu(II) in a human serum sample by using a prion protein-immobilized FET sensor

We have developed a field effect transistor (FET) sensor to sensitively detect copper ions (Cu²⁺) in a human serum (HS) sample for promising health-care diagnosis. By utilizing a Cu²⁺-binding prion protein that was immobilized on the FET gate surface, such an FET sensor can provide a simple, label free and highly selective performance, even in HS samples. We demonstrated the sensitivity of the sensor at the nanomolar level, 0-100 nM, which is very useful for the detection range of Cu²⁺ deficiency in practical applications.