Optimization of DNA-directed immobilization on mixed oligo(ethylene glycol) monolayers for immunodetection

Wen Pin Hu, Li Ya Huang, Tai Chih Kuo, Wei Wen Hu, Yung Chang, Chien Sheng Chen, Hong Cheng Chen, Wen Yih Chen

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


The development of protein chips has suffered from problems regarding long-term protein stability and activity. We present a protein sensor surface for immunodetection that is prepared by a DNA-directed protein immobilization method on a mixed self-assembled monolayer (SAM). By this approach, an immobilized single-stranded DNA (ssDNA) surface can be transferred/modified into a protein chip by flowing in ssDNA-conjugated protein when the protein chip measurement is needed. Therefore, the long-term stability of the protein chip will not be a problem for various applications. We tried various compositions for the SAM layer, the length of the ssDNA spacer, the end-point nucleotide composition, and the processes of ssDNA immobilization of the SAM for an optimized condition for shifting the DNA chip to a protein chip. The evaluations were made by using surface plasmon resonance. Our results indicated that a 50:1 ratio of oligo(ethylene glycol) (OEG)/COOH-terminated OEG and DNA sequences with 20 mer are the best conditions found here for making a protein chip via a DNA-directed immobilization (DDI) method. The designed end-point nucleotide composition contains a few guanines or cytosines, and ssDNA immobilization of the SAM by dehybridizing immobilized double-stranded DNA (dsDNA) can improve the hybridization efficiency.

Original languageEnglish
Pages (from-to)26-35
Number of pages10
JournalAnalytical Biochemistry
Issue number1
StatePublished - 1 Apr 2012


  • DNA-directed immobilization (DDI)
  • Oligo(ethylene glycol) (OEG)
  • Optimization
  • Self-assembled monolayer (SAM)
  • Surface plasmon resonance (SPR)


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