Detection of Hg(II) at Part-Per-Quadrillion Levels by Fiber Optic Plasmonic Absorption Using DNA Hairpin and DNA-Gold Nanoparticle Conjugates

Shu Mei Fan, Chang Yue Chiang, Yen Ta Tseng, Tsung Yan Wu, Yen Ling Chen, Chun Jen Huang, Lai Kwan Chau

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Mercury ion (Hg2+) is extremely toxic even at very low concentrations and its detection mainly relies on bulky and high-cost analytical instruments. Here, we introduce a fast and ultrasensitive biosensing method developed by the integration of fiber optic particle plasmon resonance and a highly selective molecular beacon with a stem-loop DNA structure immobilized on the unclad surface of an optical fiber. In the presence of Hg2+ ions and a free assisting DNA probe, the stem-loop opens and forms thymine-Hg2+-thymine complexes. A DNA reporting probe conjugated to gold nanoparticles is used as a label to interrogate the recognition event by binding with the terminal DNA binding domain of the opened stem-loop. The method provides a wide linear range of at least 5 orders from 10-14 to 10-9 M and an extremely low detection limit of 4.37 fM (0.876 ppq). It takes less than 15 min to analyze the concentration of Hg2+ ions in aqueous samples. The method is desirable for point-of-use applications because of its low-cost instrumentation and sensor chips, easy operation, and portability.

Original languageEnglish
Pages (from-to)10128-10135
Number of pages8
JournalACS Applied Nano Materials
Volume4
Issue number10
DOIs
StatePublished - 22 Oct 2021

Keywords

  • biosensor
  • fiber optic nanogold-linked sorbent assay
  • mercury ion
  • molecular beacon
  • nanoplasmonic
  • oligodeoxyribonucleotide

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