Detection of uncharged or feebly charged small molecules by field-effect transistor biosensors.
This paper describes a new technique for the detection of uncharged or feebly charged small molecules (<400Da) using Si field-effect transistor (FET) biosensors that are signal-enhanced by gold nanoparticle (NP) charges under dry measurement conditions. NP charges are quickly induced by a chemical deposition (that is, Au deposition) and the indirect competitive immunogold assay, and strongly enhance the electrical signals of the FET biosensors. For the validation of signal enhancement of FET biosensors based on NP charges and detection of uncharged or feebly charged small molecules, mycotoxins (MTXs) of aflatoxin-B1 (AFB1), zearalenone (ZEN), and ochratoxin-A (OTA) were used as target molecules. According to our experimental results, the signal is 100 times more enhanced than the use of the existing solution FET biosensing techniques. Furthermore, this method enables the FET biosensor to quantitatively detect target molecules, regardless of the ionic strengths, isoelectric points (pI), or pHs of the measured sample solutions.
Biosensor Research Team, Electronics and Telecommunications Research Institute, 218 Gajeong-ro, Yuseong-gu, Daejeon 305-700, Republic of Korea. acs@etri.re.kr
Chil Seong
CS
Ah
Chan Woo
CW
Park
Jong-Heon
JH
Yang
Joon Sung
JS
Lee
Wan-Joong
WJ
Kim
Kwang Hyo
KH
Chung
Yo Han
YH
Choi
In Bok
IB
Baek
Jungho
J
Kim
Gun Yong
GY
Sung
D016604:Aflatoxin B1 / Q000032:analysis*; D015374:Biosensing Techniques / Q000295:instrumentation*; D006046:Gold / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D009793:Ochratoxins / Q000032:analysis*; D014173:Transistors, Electronic; D015025:Zearalenone / Q000032:analysis*
D009793:Ochratoxins; C025589:ochratoxin A; D015025:Zearalenone; D006046:Gold; D016604:Aflatoxin B1