Characterisation of hydrogenated silicon–carbon alloy filters with different carbon composition for on-chip fluorescence detection of biomolecules

Lipovšek, Benjamin; Jóskowiak, Agnieszka; Krč, Janez; Topič, Marko; Prazeres, D.M.F.; Chu, V.; Conde, J.P.

doi:10.1016/j.sna.2010.07.016

Cited by 20 publications

(9 citation statements)

References 17 publications

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“…Such approaches allow rapid analysis of disease diagnostics, drug discovery, or food and environmental analysis. In microarray applications, each pixel in the array is functionalised with well-defined probe molecules and a molecular recognition reaction occurs between the probe and the target molecules to be detected [40]. Hsu et al [41] has recently developed a-SiC as a protective coating for MEMS-based Si penetrating microelectrodes.…”

Section: Microelectrode Arraysmentioning

confidence: 99%

“…Fluorescence detection, however, requires the development of efficient light management to prevent the excitation light from reaching the detector and at the same time allow the emission light to be transmitted to the detector. Lipovesk et al [40] proposed a layer of hydrogenated amorphous silicon carbide (a-SiC:H) as a suitable optical filter which can be easily integrated with a-Si:H photosensors for on-chip detection of biomolecules labelled with Alexa Fluor 430 or PyMPO. Simple fabrication of absorbing a-SiC:H filters (single-layer, low cost, with low dependence on the incidence angle) presents an important advantage compared to other filtering solutions, such as interference filters [44] where a large number of layers need to be tuned accurately during deposition.…”

Section: Biofiltrationmentioning

confidence: 99%

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Silicon Carbide: A Biocompatible Semiconductor Used in Advanced Biosensors and BioMEMS/NEMS

Mahmoodi¹,

Ghazanfari²

2012

Physics and Technology of Silicon Carbide Devices

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Section: Microelectrode Arraysmentioning

confidence: 99%

Section: Biofiltrationmentioning

confidence: 99%

Silicon Carbide: A Biocompatible Semiconductor Used in Advanced Biosensors and BioMEMS/NEMS

Mahmoodi¹,

Ghazanfari²

2012

Physics and Technology of Silicon Carbide Devices

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“…3͑b͒, showing that the a-SiC:H filter efficiently cuts the light below 480 nm. 43,58 The sensitivity of measurements made with a voltage bias of 0 V is limited by the light rejection characteristics of the a-SiC:H filter used and not by the dark current of the a-Si:H photodiode.…”

Section: A Integrated Photodiode Characteristicsmentioning

confidence: 99%

Heterogeneous immunoassays in microfluidic format using fluorescence detection with integrated amorphous silicon photodiodes

et al. 2011

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Miniaturization of immunoassays through microfluidic technology has the potential to decrease the time and the quantity of reactants required for analysis, together with the potential of achieving multiplexing and portability. A lab-on-chip system incorporating a thin-film amorphous silicon (a-Si:H) photodiode microfabricated on a glass substrate with a thin-film amorphous silicon-carbon alloy directly deposited above the photodiode and acting as a fluorescence filter is integrated with a polydimethylsiloxane-based microfluidic network for the direct detection of antibody-antigen molecular recognition reactions using fluorescence. The model immunoassay used consists of primary antibody adsorption to the microchannel walls followed by its recognition by a secondary antibody labeled with a fluorescent quantum-dot tag. The conditions for the flow-through analysis in the microfluidic format were defined and the total assay time was 30 min. Specific molecular recognition was quantitatively detected. The measurements made with the a-Si:H photodiode are consistent with that obtained with a fluorescence microscope and both show a linear dependence on the antibody concentration in the nanomolar-micromolar range.

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“…The content of carbon in the films, which is controlled by the flow rates of SiH 4 and C 2 H 4 during deposition, defines the optical bandgap (E opt ) of the material , which in turn determines the edge of the optical absorption of the short-wavelength light. The E opt is set so that it efficiently absorbs the wavelengths of the excitation light while transmitting the emission wavelengths to reach the detector [14]. Despite several advantages of this filtering solution (single layer, low cost, simple integration into a-Si:H photodetectors) they are inefficient when excitation and emission wavelengths are in close proximity as in the case of small Stokes' shift fluorophores (Δλ < 50 nm).…”

Section: Introductionmentioning

confidence: 99%

Modelling of diffraction grating based optical filters for fluorescence detection of biomolecules

Kovačič

Krč

Lipovšek

et al. 2014

Biomed. Opt. Express

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Abstract:The detection of biomolecules based on fluorescence measurements is a powerful diagnostic tool for the acquisition of genetic, proteomic and cellular information. One key performance limiting factor remains the integrated optical filter, which is designed to reject strong excitation light while transmitting weak emission (fluorescent) light to the photodetector. Conventional filters have several disadvantages. For instance absorbing filters, like those made from amorphous silicon carbide, exhibit low rejection ratios, especially in the case of small Stokes' shift fluorophores (e.g. green fluorescent protein GFP with λ exc = 480 nm and λ em = 510 nm), whereas interference filters comprising many layers require complex fabrication. This paper describes an alternative solution based on dielectric diffraction gratings. These filters are not only highly efficient but require a smaller number of manufacturing steps. Using FEM-based optical modelling as a design optimization tool, three filtering concepts are explored: (i) a diffraction grating fabricated on the surface of an absorbing filter, (ii) a diffraction grating embedded in a host material with a low refractive index, and (iii) a combination of an embedded grating and an absorbing filter. Both concepts involving an embedded grating show high rejection ratios (over 100,000) for the case of GFP, but also high sensitivity to manufacturing errors and variations in the incident angle of the excitation light. Despite this, simulations show that a 60 times improvement in the rejection ratio relative to a conventional flat absorbing filter can be obtained using an optimized embedded diffraction grating fabricated on top of an absorbing filter.

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Characterisation of hydrogenated silicon–carbon alloy filters with different carbon composition for on-chip fluorescence detection of biomolecules

Cited by 20 publications

References 17 publications

Silicon Carbide: A Biocompatible Semiconductor Used in Advanced Biosensors and BioMEMS/NEMS

Silicon Carbide: A Biocompatible Semiconductor Used in Advanced Biosensors and BioMEMS/NEMS

Heterogeneous immunoassays in microfluidic format using fluorescence detection with integrated amorphous silicon photodiodes

Modelling of diffraction grating based optical filters for fluorescence detection of biomolecules

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