Interfacial charge regulation of protein blocking layers in transistor biosensor for direct measurement in serum

Sungwook Park, Minsoo Kim, Dongkap Kim, Seok Ho Kang, Kwan Hyi Lee, Youngdo Jeong

    Research output: Contribution to journalArticlepeer-review

    19 Citations (Scopus)


    Ion-sensitive field-effect transistor (ISFET) as a biosensor facilitates a process of data-acquisition through label-free and real-time monitoring. Direct quantification of a biomarker in serum is challenging in ISFET biosensor since charged proteins in serum interfere transduction to electrical signals. Here, we report the fabrication of protein blocking layers (PBLs) with intended interfacial charges to minimize non-specific protein bindings on ISFET. Use of charged protein precursors enables to regulate the interfacial charge of PBLs, preserving their intrinsic electric features (neutral: hemoglobin, positively charged: lysozyme, negatively charged: BSA). The effect of this interfacial charge on the signal was demonstrated through PSMA (prostate cancer biomarker) sensing using a dual-gate ISFET biosensor. The neutral PBL showed the minimum noise compared to the negatively and positively charged PBLs, enabling the ISFET to exhibit the same detection range in untreated serum as with pre- or post-treatment (1 fg/ml to 100 ng/ml). The introduction of neutral PBLs to ISFET biosensors would allow the application of the ISFET biosensor as a point-of-care device.

    Original languageEnglish
    Article number111737
    JournalBiosensors and Bioelectronics
    Publication statusPublished - 2020 Jan 1


    • Biosensor
    • Field-effect transistor
    • Non-specific binding
    • Protein blocking layer
    • Serum

    ASJC Scopus subject areas

    • Biotechnology
    • Biophysics
    • Biomedical Engineering
    • Electrochemistry


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