Baets, Roel

Bienstman, Peter

Claes, Tom

De Vos, Katrien

Debackere, Peter

Yurtsever, Günay

English

Ghent University Academic Bibliography

 ` Photonic Biosensors in Silicon-on-Insulator  Gunay Yurtsever, Katrien De Vos, Tom Claes, Peter Debackere, Peter Bienstman and Roel Baets  Ghent University – IMEC, Photonics Research Group, Department of Information Technology (INTEC) , Sint-Pietersnieuwstraat 41, 9000 Gent, Belgium gunay@intec.ugent.be  We report on recent research activities of our group on several photonic biosensors. The silicon-on-insulator (SOI) material platform and deep UV lithography is used to fabricate photonic structures for label-free detection of bio-molecular interactions and for tissue imaging [1]. For label free sensors, several approaches are being investigated: ring resonators, slotted waveguides and surface plasmon interferometry. Additionally, we investigate basic SOI photonic structures for optical coherence tomography (OCT) components for tissue imaging. We demonstrated simultaneous detection of multiple antibodies in a highly specific way based on microring resonator arrays. We will discuss important considerations for high throughput sensing with silicon-on-insulator photonics, including detection limit, microfluidics packaging, receptor binding through a thin poly ethylene glycol  layer, and camera based parallel readout. We introduce simultaneous measurement of refractive index and thickness of thin molecular layers, used to study conformational biomolecular changes [2].   We numerically optimized SOI slot waveguides for label-free biosensing of proteins and will present a slot-waveguide-based ring resonator in SOI with a footprint of only 13 µm x 10 µm.  Experiments showed that it has 298  nm/RIU  sensitivity  and  a  detection  limit  of 4.2x 10-5 RIU for refractive index changes of the complete top cladding. We prove that surface chemistry for selective label-free sensing of proteins can be applied inside a 100 nm- wide slot region and demonstrated that the application of a slot waveguide instead of a normal waveguide increases the sensitivity of an SOI ring resonator with a factor 3.5 for the detection of proteins [3].  Evanescent field sensors provide another means for the label-free detection of target molecules and for  real-time  monitoring  of  solutions  and  binding events that occur near the sensor surface. Experimental evidence supporting the use of a surface-plasmon interferometer as a biosensor is presented. The device is shown to be capable of bulk refractive index sensing (bulk refractometry) and has a spectral interrogation sensitivity of 315.145 nm/ RIU. Qualitative agreement between measurement results and theoretical data has been obtained. Furthermore, we have shown this device is capable of detecting bulk refractive index changes, a first and indispensable  step  toward  label-free  biosensing.  The measured  blueshift,  although  not  yet  as  large  as theoretically  predicted,  shows  the  potential  of  this device to be used as a sensitive and label-free bio-sensor [4]. Optical Coherence Tomography (OCT) is an non-invasive, 3D imaging modality that  is analogous to ultrasound but instead of using sound waves it uses broadband light and measures the echo time delay of backscattered photons. Typically, OCT can image tissue cross sections with 10 micron resolution at depths exceeding 2 cm in transparent tissues (human eye, animal embryos) and 2-3 mm in highly scattering (non-transparent) tissues, such as the skin. Miniaturization of OCT has the potential to expand its applications and serve other areas in health care and industry. We present a basic Micheson interferometer in SOI for OCT. Integrated components designed for OCT in SOI can significantly reduce the size of the system [5].   References:  [1] ePIXfab - the silicon photonics platform (www.epixfab.eu) [2] K. De Vos et al., Multiplexed antibody detection with an array of silicon-on-insulator microring resonators,IEEE Photonics Journal, 1(4), p.225-235 (2009) [3] T. Claes et al, Label-Free Biosensing With a Slot-Waveguide-Based Ring Resonator  in Silicon on Insulator, IEEE Photonics Journal, 1(3), p.197-204 (2009) [4] P.P.P. Debackere, R. Baets, P. Bienstman, Bulk sensing experiments using a surface-plasmon interferometer, Optics Letters, 34(18), p.2858-2860 (2009) [5] (to appear) G. Yurtsever, P. Dumon, W. Bogaerts, R. Baets, Integrated Photonic Circuit in Silicon on Insulator for Fourier Domain Optical Coherence Tomography, Proceedings of Proc. of SPIE Photonics West 2010-BIOS: Coherence Domain Optical Methods and Optical Coherence Tomography in Biomedicine XIV, San Francisco, CA, United States, (2010)  

Photonic biosensors in silicon-on-insulator

https://biblio.ugent.be/publication/1144632/file/1144639.pdf

Photonic biosensors in silicon-on-insulator

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Ghent University Academic Bibliography