Graphene- and aptamer-based electrochemical biosensor.
This study investigated the effectiveness of a graphene- and aptamer-based field-effect-transistor-like (FET-like) sensor in detecting lead and potassium ions. The sensor consists of a graphene-covered Si/SiO2 wafer with thrombin binding aptamer (TBA) attached to the graphene layer and terminated by a methylene blue (MB) molecule. K(+) and Pb(2+) both bind to TBA and cause a conformational change, which results in MB moving closer to the graphene surface and donating an electron. Thus, the abundance of K(+) and Pb(2+) can be determined by monitoring the current across the source and drain channel. Device transfer curves were obtained with ambipolar field effect observed. Current readings were taken for K(+) concentrations of 100 μM to 50 mM and Pb(2+) concentrations of 10 μM to 10 mM. As expected, I d decreased as ion concentration increased. In addition, there was a negative shift in V Dirac in response to increased ion concentration.
Department of Electrical and Computer Engineering, University of Illinois, Chicago, IL 60607, USA.
Ke
K
Xu
Xenia
X
Meshik
Barbara M
BM
Nichols
Eugene
E
Zakar
Mitra
M
Dutta
Michael A
MA
Stroscio
D052157:Aptamers, Nucleotide; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002412:Cations; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods*; D006108:Graphite; D007854:Lead / Q000032:analysis* / Q000737:chemistry; D008751:Methylene Blue; D011188:Potassium / Q000032:analysis* / Q000737:chemistry; D012822:Silicon Dioxide
D052157:Aptamers, Nucleotide; D002412:Cations; C081676:thrombin aptamer; D007854:Lead; D012822:Silicon Dioxide; D006108:Graphite; D011188:Potassium; D008751:Methylene Blue