Virus-on-a-chip: Integration of plant virus particles with electronic chips for label-free biosensing (ViroChip)

• Applicants: Professor Dr. Michael J. Schöning; Professorin Dr. Christina Wege
• Subject Area: Microsystems ; Biomedical Systems Technology ; Synthesis and Properties of Functional Materials
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 446507449

Plant virus-based soft matter particles such as nanotubular tobacco mosaic virus-like particles (TMV-LPs) emerge as beneficial, richly available bionanoscaffolds with a high surface-to-volume ratio and an extremely high density of surface docking sites for functional molecules, e.g., enzymatic bioreceptors. They allow an efficient immobilization of up to about 2000 biomolecules per 300 nm and can stabilize them over many repeated uses and months. Main objective of this proposal is the integration of TMV-LP/enzyme bionanohybrids with capacitive EIS (electrolyte-insulator-semiconductor) chips modified with pH-responsive weak polyelectrolytes (PE) as universal platform for a new class of highly sensitive field-effect biosensors. Two TMV-LP types will be tailored to display enzymes: TMV nanotubes flat-lying parallel, and 2D TMV nanoring arrays oriented perpendicular to the EIS sensor surface. An amplified output signal and thus excellent analyte sensitivity are expected due to the positively charged PE intended to mediate efficient electrostatic adsorption and surface coverage of the oppositely charged TMV-LP adapters, to install unprecedented amounts of long-term stabilized enzymes per sensor area. The new approach will be scrutinized by realizing penicillin, urea and sucrose biosensors. The selected model enzyme/substrate systems generate or consume H+ ions (penicillinase/penicillin and urease/urea, respectively), and also include bi-enzyme cascade reactions (invertase/sucrose & glucose oxidase/glucose), in order to establish broadly applicable sensor design rules. Different methods and techniques will be examined and optimized to prepare TMV-LP variants, PE/TMV-LP bilayers, and to immobilize enzymes onto the TMV-LP surface. Physical and electrochemical characterization will provide fundamental information on each surface modification step. Basic working characteristics (sensitivity, detection limit and range, response time, long-term stability, etc.) of the PE/TMV-LP/enzyme-modified field-effect EIS biosensors will be studied and a theoretical model of biosensor functioning will be developed.Field-effect sensors have not been equipped with weak PE/TMV-LPs (nanotubes or nanorings) so far. The proposed project will therefore address this subject as a universal concept for constructing a new class of advantageous field-effect enzyme biosensors for a wide variety of analytes. The intended collaboration enables target-oriented work on this multidisciplinary project and combines complementary scientific expertise in a perfect match, as proven through recent initial joint publications.

• DFG Programme: Research Grants