A possibility of detection of the non-charge based analytes using ultra-thin body field-effect transistors

Jeng-Tzong Sheu*, C. C. Chen, K. S. Chang, Yaw-Kuen Li

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Ultra-thin body of p-type field-effect transistors were developed as transducer for biosensors. Changes of conductance resulted from the changes of the surface potentials of ultra-thin body field-effect transistors (UTB-FETs) due to surface chemical modifications were demonstrated. The channel surface of UTB-FETs were modified with N-[3-(trimethoxysilyl)propyl]ethylenediamine (AEAPTMS) and then gold nanoparticles (AuNPs) to immobilize the bio-component, the genetically engineered Δ5-3-ketosteroid isomerase (Art_KSI) or the Art_KSI conjugated with charged reporter (Art_KSI_mA51). The binding of charge-based molecules or nanoparticles has been demonstrated to strongly affect the conductivity of UTB-FETs; the increase or decrease of the conductance depends on the polarity of the immobilized molecules or nanoparticles. A new protocol involving the detection of a non-charged analyte relied on the competitive binding of analyte (19-norandrostendione) and a charged reporter (mA51) with KSI. When exposed to a 19-norandrostendione solution (10 μM), the conductance of Art_KSI_mA51-modified UTB-FET increased by 265 nS (∼12%). On the other hand, conductance of Art_KSI-modified UTB-FET showed no distinct change under the same detection conditions.

Original languageAmerican English
Pages (from-to)1883-1886
Number of pages4
JournalBiosensors and Bioelectronics
Issue number12
StatePublished - 15 Jul 2008


  • Δ-3-Ketosteroid isomerase
  • 19-Norandrostendione
  • Biosensors
  • Gold nanoparticles
  • N-[3-(Trimethoxysilyl)propyl]ethylenediamine
  • Ultra-thin body field-effect transistor


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