Photochemical patterning of hydrogels

Contacts:

Stephan Keller, DTU Nanotech, 4525-5846 (stephan.keller@nanotech.dtu.dk)

Gabriela Blagoi, DTU Nanotech, 4525-5850 (gabriela.blagoi@nanotech.dtu.dk)

Schematic of photo-patterning method: (a) Absorption of Antraquinone molecules; (b) patterning with UV-light; (c) attachment of hydrogel.

The functionalization of the surface with receptor molecules is an important step in the fabrication of biosensors. We have introduced a new functionalization method based on photochemical modification of polymer-based sensor surfaces as illustrated on the figure (step (a) and (b)). A molecule called Antraquinone (AQ) is deposited on the polymer SU-8. The AQ photolinker is exposed to UV-light and is attached to the polymer surface. The use of a photomask allows the definition of patterns of functionalized area. The advantage of this method is that it can be done in the same cleanroom environment that is used for the fabrication of the sensors.

In this project, the developed method for surface functionalization will be used for the definition of hydrogel patterns on a polymer surface (step (c)). The vision is to attach the hydrogel to a free-standing polymer cantilever acting as a valve. This valve will be actuated due to the swelling or contraction of the hydrogel upon changes of the pH in the surrounding liquid. The project is experimental and includes cleanroom fabrication of the polymer samples, wet chemistry and characterization of the samples with different methods such as fluorescence microscopy, ellipsometry and atomic force microscopy.