Homogeneous protein analysis by magnetic core-shell nanorod probes

Stefan Schrittwieser, Beatriz Pelaz, Wolfgang J. Parak, Sergio Lentijo Mozo, Katerina Soulantica, Jan Dieckhoff, Frank Ludwig, Thomas Altantzis, Sara Bals, Joerg Schotter

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Studying protein interactions is of vital importance both to fundamental biology research and to medical applications. Here, we report on the experimental proof of a universally applicable label-free homogeneous platform for rapid protein analysis. It is based on optically detecting changes in the rotational dynamics of magnetically agitated core-shell nanorods upon their specific interaction with proteins. By adjusting the excitation frequency, we are able to optimize the measurement signal for each analyte protein size. In addition, due to the locking of the optical signal to the magnetic excitation frequency, background signals are suppressed, thus allowing exclusive studies of processes at the nanoprobe surface only. We study target proteins (soluble domain of the human epidermal growth factor receptor 2 - sHER2) specifically binding to antibodies (trastuzumab) immobilized on the surface of our nanoprobes and demonstrate direct deduction of their respective sizes. Additionally, we examine the dependence of our measurement signal on the concentration of the analyte protein, and deduce a minimally detectable sHER2 concentration of 440 pM. For our homogeneous measurement platform, good dispersion stability of the applied nanoprobes under physiological conditions is of vital importance. To that end, we support our measurement data by theoretical modeling of the total particle-particle interaction energies. The successful implementation of our platform offers scope for applications in biomarker-based diagnostics as well as for answering basic biology questions.
Original languageEnglish (US)
Pages (from-to)8893-8899
Number of pages7
JournalACS Applied Materials & Interfaces
Volume8
Issue number14
DOIs
StatePublished - Apr 4 2016

Fingerprint Dive into the research topics of 'Homogeneous protein analysis by magnetic core-shell nanorod probes'. Together they form a unique fingerprint.

Cite this