An antifouling peptide-based biosensor for determination of Streptococcus pneumonia markers in human serum

Po Han Chang, Chang Ching Weng, Bor Ran Li*, Yaw Kuen Li

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

We report a peptide-based sensor that involves a multivalent interaction with L-ascorbate 6-phosphate lactonase (UlaG), a protein marker of Streptococcus pneumonia. By integrating the antifouling feature of the sensor, we significantly improved the signal-to-noise ratio of UlaG detection. The antifouling surface was fabricated via electrodeposition using an equivalent mixture of 4-amino-N,N,N-trimethylanilinium and 4-aminobenzenesulfonate. This antifouling layer not only effectively reduces the non-specific adsorption on the biosensor but also decreases the charge transfer resistance (Rct) of the screen-printed carbon electrode. The aniline-modified S7 peptide, an UlaG-binding peptide, was pre-synthesized and further electrochemically modified to bind onto the antifouling layer. Bio-electrochemical analysis confirms that the antifouling S7-peptide sensor binds strongly to the UlaG with a dissociation constant (Kd) = 0.5 nM. This strong interaction can be attributed to a multivalent interaction between the biosensor and the heximeric form of UlaG. To demonstrate the potential for clinical application, further detection of Streptococcus pneumonia from 50 to 5×104 CFU/mL were successfully performed in 25% human serum.

Original languageEnglish
Article number111969
JournalBiosensors and Bioelectronics
Volume151
DOIs
StatePublished - 1 Mar 2020

Keywords

  • Antifouling
  • Electrodeposition
  • L-ascorbate-6-phosphate lactonase
  • Multivalent interaction
  • Peptide-based biosensor

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