Time-resolved PCA of 'droplet impedance' identifies DNA hybridization at nM concentration

Seyedehaida Ebrahimi, Muhammad A. Alam

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

We have developed a droplet-based non-Faradaic impedance sensing (NFIS) scheme for label-free, selective detection of short strands of DNA molecules suspended in solution. The frequency-resolved impedance of microliter-sized droplets evaporating on the superhydrophobic surface of the biosensor is monitored through several incubation/heating cycles, providing a time-resolved fingerprint of the analyte under consideration. To selectively differentiate target solutions with different levels of base-pair mismatch, the corresponding time-resolved signals are analyzed using a statistical technique called Principal Component Analysis (PCA). The approach allows us to selectively detect hybridization of 22-mer target DNA molecules at concentrations down to ∼2 nM in solution. The changes in the density of 'trapped' counterions as a result of hybridization are reflected in the corresponding impedance signals. The impedance readout permits label-free, indicator-less, and parallel detection of small volumes of target oligonucleotides in solution without inquiring any optical/magnetic tagging, reference electrode, analyte amplification, or probe immobilization.

Original languageEnglish (US)
Pages (from-to)215-224
Number of pages10
JournalSensors and Actuators, B: Chemical
Volume215
DOIs
StatePublished - Aug 1 2015

Fingerprint

principal components analysis
Principal component analysis
DNA
deoxyribonucleic acid
impedance
Labels
Molecules
time signals
oligonucleotides
Oligonucleotides
immobilization
bioinstrumentation
Biosensors
strands
marking
Amplification
readout
molecules
Heating
cycles

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry

Cite this

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Time-resolved PCA of 'droplet impedance' identifies DNA hybridization at nM concentration. / Ebrahimi, Seyedehaida; Alam, Muhammad A.

In: Sensors and Actuators, B: Chemical, Vol. 215, 01.08.2015, p. 215-224.

Research output: Contribution to journalArticle

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