Monitoring of DNA molecules in a lab on a chip with
femtosecond laser written waveguides
M. Pollnau,1 C. Dongre,1 R. Dekker,1 H.J.W.M. Hoekstra,1 R. Martinez-Vazquez,2 R. Osellame,2 R. Ramponi,2 G. Cerullo,2 R. van Weeghel,3 G.A.J. Besselink,4 and H.H. van den Vlekkert4
1
Integrated Optical MicroSystems (IOMS), MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
2
Istituto di Fotonica e Nanotecnologie del CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
3
Zebra Bioscience BV, W. Beversstraat 185, 7543 BK Enschede, The Netherlands
4
LioniX BV, PO Box 456, 7500 AH Enschede, The Netherlands
Using femtosecond laser writing, optical waveguides were monolithically integrated into a commercial microfluidic lab-on-a-chip device, with the waveguides intersecting a microfluidic channel [1,2]. Continuous-wave laser excitation through these optical waveguides confines the excitation window to a width of 12 μm, enabling high-resolution monitoring of the passage of different types of fluorescent analytes, when migrating and being separated in the microfluidic channel by microchip capillary electrophoresis. We demonstrate on-chip-integrated waveguide excitation and detection of a biologically relevant species, fluorescently labeled Deoxyribonucleic acid (DNA) molecules (Fig. 1a), as well as separation of different dyes, Rhodamine-6G and Rhodamine-B (Fig. 1b) during microchip capillary electrophoresis [3]. Well-controlled plug formation as required for on-chip integrated capillary electrophoresis separation of DNA molecules, and the combination of waveguide excitation and a low detection limit will enable monitoring of extremely small quantities with high spatial resolution.
Fig. 1. Passage in a microfluidic channel, and across an excitation waveguide, of (a) fluorescently labeled DNA plugs and (b) fluorescent dyes Rhodamine-6G and Rhodamine-B
References
[1] R. Martinez Vazquez, R. Osellame, D. Nolli, C. Dongre, H.H. van den Vlekkert, R. Ramponi, M. Pollnau, G. Cerullo, Lab Chip, accepted for publication (2008).
[2] R. Martinez Vazquez, R. Osellame, M. Cretich, M. Chiari, C. Dongre, H.J.W.M. Hoekstra, M. Pollnau, H. van den Vlekkert, R. Ramponi, G. Cerullo, Analyt. Bioanalyt. Chem., accepted for publication (2008).
[3] C. Dongre, R. Dekker, H.J.W.M. Hoekstra, M. Pollnau, R. Martinez-Vazquez, R. Osellame, G. Cerullo, R. Ramponi, R. van Weeghel, G.A.J. Besselink, H.H. van den Vlekkert, Opt. Lett., accepted for publication (2008).
