PLATON PolyIMPD - Polymer injection molded photonic devices

Partners:
Hubertus Goller GmbH
Phadia Austria GmbH (Thermo Fisher Scientific)

At present, most medical diagnostic tools often involve laborious labelling techniques and expensive equipment operated by specially trained staff. This prevents their routinely application for early or preventive screening . With early or preventive screening an early diagnosis of diseases before their clinical manifestation is often possible, and, thus, makes it attractive for all players in the health care system because it allows for more effective treatment and reduces the costs per patient. However, only the availability of low cost diagnostic tools will allow implementing early or preventive screening as a routinely applied measure in health care. Key parameters to open up the market of diagnostic screening tools are a) multi-parameter measurements comprehensive in covering all relevant inclusion and exclusion markers for a certain disease, b) a low-priced and easy-to-use sensor platform, and c) cost-effective production of single-use sensor chips. Integrated label-free optical waveguide biosensors based on the evanescent wave principle inherently fulfill the first two requirements. In addition, these biosensors feature real-time measurement capability, which gives access to the binding kinetics and, thus, could provide an added diagnostic value as compared to current state of the art end point measurements. With respect to the fabrication of sensor chips polymer technologies offer the ultimately cost effective solution

The goal of the PolyIMPD project was the realization of all-polymer interferometric evanescent wave sensors for the label-free detection of bio-molecules utilizing the combination of injection molding and spin-coating as high volume fabrication platform. Suitable polymers for the substrate, waveguide layer and cladding have been chosen and fully tested, an injection molding process using silicon wafers as exchangeable mold insert for the nanopatterning of polymer substrates has been developed, and grating coupling and waveguiding has been successfully demonstrated. Moreover, an optimized functionalization protocol for biotin-streptavidin binding fully compatible with the requirements given by the optical sensor concept has been established and applied to a polymer waveguide sensor.

However, the realization of injection molded single-mode waveguides required in Mach Zehnder interferometers still represented a challenging task. In order to put the achieved results to best advantage the final efforts focussed on the replication process of single mode waveguide structures. The injection molding process was optimized by employing silicon stamps with slanted profiles, which improved the demolding characteristics and reduced defects along the waveguides. Moreover, a thin inorganic high refractive index coating was deposited on the injection molded substrates in order to improve the overall index contrast of the waveguide layer system. After spin-coating of the polymer waveguide and cladding layer, the suitability of the fabrication process for single mode waveguiding could be basically demonstrated. Nevertheless, the propagation losses were still too high to perform biosensing experiments.

A clear highlight of the PolyIMPD project was the successful demonstration of the detection of antibodies in serum, which is highly relevant for the diagnosis of autoimmune diseases such as rheumatoid arthritis, on polyimide waveguides spin-coated on patterned inorganic substrates.

This work was supported by the Austrian NANO Initiative of the Austrian Research Promotion Agency (FFG) under the PLATON PolyIMPD grants (project no. 836084 & 819659).

References:

E. Melnik, R. Bruck, P. Muellner, T. Schlederer, R. Hainberger, M. Lämmerhofer, „Human IgG detection in serum on polymer based Mach-Zehnder interferometric biosensors”, J. Biophoton., 9 pp: 218–223 (doi:10.1002/jbio.201500280) (2016) 

R. Bruck, E. Melnik, P. Muellner, R. Hainberger, M. Lämmerhofer, "Integrated polymer-based Mach-Zehnder interferometer label-free streptavidin biosensor compatible with injection molding", Biosensors and Bioelectronics 26 (9), pp. 3832–3837 (2011) (doi:10.1016/j.bios.2011.02.042) 

E. Melnik, R. Bruck, R. Hainberger, M . Lämmerhofer, "Multi-step surface functionalization of polyimide based evanescent wave photonic biosensors and application for DNA hybridization by Mach-Zehnder interferometer", Analytica Chimica Acta 699 (2), pp. 206–215 (2011) (doi:10.1016/j.aca.2011.05.017)