A comparative study of capacitive immunosensors based on self-assembled monolayers formed from thiourea, thioctic acid, and 3-mercaptopropionic acid

Warakorn Limbut, Proespichaya Kanatharana, Bo Mattiasson, Punnee Asawatreratanakul, Panote Thavarungkul

Research output: Contribution to journalArticlepeer-review

109 Citations (SciVal)

Abstract

A procedure was developed for the covalent coupling of anti-alpha-fetoprotein antibody (anti-AFP) to a gold surface modified with a self-assembled monolayer (SAM) of thiourea (TU). The performance of the SAM-antibody layer was compared to those of similar layers based on thioctic acid (TA) and 3-mercaptopropionic acid (MPA) by using flow injection capacitive immunosensor system. Covalent coupling of anti-AFP on self-assembled thiourea monolayer (SATUM) modified gold electrode can be used to detect alpha-fetoprotein with high efficiency, similar sensitivity, the same linear range (0.01-10 mu g l(-1)) and detection limit (10ng l(-1)) as those obtained from sensors based on self-assembled thioctic acid monolayer (SATAM) and self-assembled 3-mercaptopropionic acid monolayer (SAMPAM). The system is specific for alpha-fetoprotein and can be regenerated and reused up to 48 times. Therefore, self-assembled monolayer using thiourea which is cheaper than thioctic acid and 3-mercaptopropionic acid is a good alternative for biosensor applications when SAMs are used. (c) 2006 Elsevier B.V. All rights reserved.
Original languageEnglish
Pages (from-to)233-240
JournalBiosensors & Bioelectronics
Volume22
Issue number2
DOIs
Publication statusPublished - 2006

Subject classification (UKÄ)

  • Industrial Biotechnology

Keywords

  • acid
  • 3-mercaptopropionic
  • thioctic acid
  • thiourea
  • capacitive immunosensor
  • self-assembled monolayer
  • alpha-fetoprotein

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