Frutiger, Andreas

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PhD student, 2015 to 2020

Guest lino Biotech AG, 2020 to 2023

Research Objective

Label-free biosensors enable to monitor biomolecular interactions in real-time. In particular, optical biosensors – and more precisely – refractometric biosensor concepts are well-established and extremely sensitive (pg/mm²). However, these approaches such as SPR (Surface Plasmon Resonance) ^[1] exhibit inherent drawbacks. Since they measure any change in refractive index on the surface they are susceptible to fluctuations in temperature, buffer composition and most importantly, any nonspecific binding to the sensor surface will generate a signal. These inherent problems bring experimental limitations, especially the inability to measure biochemical interactions in their biological environment (serum, plasma). Diffractometric sensor technologies do not suffer these limitations, since their architecture is inherently self-referencing. Nevertheless, to date, these technologies were an order of magnitude less sensitive than refractometric approaches. ^[2] Recently, a diffractometric technology - Focal Molography - was introduced that is expected to be comparably sensitive like SPR and is real-time, label free and not restricted by non-specific binding ^[3].

At ETH we investigate Focal Molography in all its details. We develop optical instruments, perform optical simulation of the expected scattered intensity distribution of molecular lenses, assemble molecular holograms, design and simulate phase mask, perform nanopattering of non-fouling polymer layers on waveguide substrates on a normal labbench and develop state of the art immunoassay. The close collaboration with Roche makes our work matter. If you want to be part of this amazing adventure please contact me via email.

test-2 — a) General working principle of diffractometric sensor. The molecules form a diffraction grating and the intensity in the higher order beams is quadratically proportional to the bound mass. b) SEM image of a phase mask used to create the molecular diffraction grating. c) RCWA simulation of the field distribution behind the phase mask for a certain grating period. d) Schematic of the molographic structure. This structure focuses the diffracted light beam into a diffraction-limited focal spot. e) Representative sensitivity curves of a waveguide as a function of thickness for the two fundamental modes. f) An instrumentation example build during a bachelor thesis. A miniaturized reader for focal molography.

Open Student Projects

For reason of intellectual property, I do not want to post the project description on this website. Please contact me directly if you are interested in a project and we will define something that suits your interest. I offer scientific (Investigation of new optical sensing concepts and structures) as well as more engineering type of projects (Building optical instrumentation as well as programming setups).

In case you are interested, send me your CV, your current average mark, your present mystudies overview and a copy of your last project (this can even be your matura work).

Open projects:

Investigation of a DFL (Distributed Feedback Laser) for integrated biosensing (master thesis)

Research Interests

Optical Biosensors in all their beauty
Real-time biosensors for complex biological samples - i.e. - blood
Instrumentation
Lasers and Waveguides
Nanofabrication
Phase mask lithography

References

[1] J. Homola, Chem. Rev. 2008, 108, 462.

[2] J. B. Goh, P. L. Tam, R. W. Loo, M. Cynthia Goh, Anal. Biochem. 2003, 313, 262.

[3] C. Fattinger, Phys. Rev. X 2014, 4, 031024.