Real-Time wash-free detection of unlabeled PNA-DNA hybridization using discrete FET sensor

Matti Kaisti, Anssi Kerko, Eero Aarikka, Petri Saviranta, Zhanna Boeva, Tero Soukka, Ari Lehmusvuori

    Research output: Contribution to journalArticleScientificpeer-review

    22 Citations (Scopus)


    We demonstrate an electrochemical sensor for detection of unlabeled single-stranded DNA using peptide nucleic acid (PNA) probes coupled to the field-effect transistor (FET) gate. The label-free detection relies on the intrinsic charge of the DNA backbone. Similar detection schemes have mainly concentrated on sensitivity improvement with an emphasis on new sensor structures. Our approach focuses on using an extended-gate that separates the FET and the sensing electrode yielding a simple and mass fabricable device. We used PNA probes for efficient hybridization in low salt conditions that is required to avoid the counter ion screening. As a result, significant part of the target DNA lies within the screening length of the sensor. With this, we achieved a wash-free detection where typical gate potential shifts are more than 70 mV with 1 μM target DNA. We routinely obtained a real-Time, label-and wash-free specific detection of target DNA in nanomolar concentration with low-cost electronics and the responses were achieved within minutes after introducing targets to the solution. Furthermore, the results suggest that the sensor performance is limited by specificity rather than by sensitivity and using low-cost electronics does not limit the sensor performance in the presented sensor configuration.

    Original languageEnglish
    Article number15734
    Pages (from-to)15734
    JournalScientific Reports
    Issue number1
    Publication statusPublished - 16 Nov 2017
    MoE publication typeA1 Journal article-refereed


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