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ACS Sens. 2017 Sep 22;2(9):1278-1286. doi: 10.1021/acssensors.7b00187. Epub 2017 Aug 30.

Direct, Label-Free, and Rapid Transistor-Based Immunodetection in Whole Serum.

Author information

BioMed X Innovation Center , 69120 Heidelberg, Germany.
Institute for Physical Chemistry, Universität Heidelberg , 69120 Heidelberg, Germany.
Institute for Materials Science, Technische Universität Dresden , 01062 Dresden, Germany.


Transistor-based biosensors fulfill many requirements posed upon transducers for future point-of-care diagnostic devices such as scalable fabrication and label-free and real-time quantification of chemical and biological species with high sensitivity. However, the short Debye screening length in physiological samples (<1 nm) has been a major drawback so far, preventing direct measurements in serum. In this work, we demonstrate how tailoring the sensing surface with short specific biological receptors and a polymer polyethylene glycol (PEG) can strongly enhance the sensor response. In addition, the sensor performance can be dramatically improved if the measurements are performed at elevated temperatures (37 °C instead of 21 °C). With this novel approach, highly sensitive and selective detection of a representative immunosensing parameter-human thyroid-stimulating hormone-is shown over a wide measuring range with subpicomolar detection limits in whole serum. To the best of our knowledge, this is the first demonstration of direct immunodetection in whole serum using transistor-based biosensors, without the need for sample pretreatment, labeling, or washing steps. The presented sensor is low-cost, can be easily integrated into portable diagnostics devices, and offers a competitive performance compared to state-of-the-art central laboratory analyzers.


Debye length; biosensor; field-effect transistor (FET); label-free; serum; thyroid-stimulating hormone (TSH)


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