Nanoscale porous silicon waveguide for label-free DNA sensing

ArticleinBiosensors & Bioelectronics 23(10):1572-6 · June 2008with17 Reads
DOI: 10.1016/j.bios.2008.01.017 · Source: PubMed
Abstract
Porous silicon (PSi) is an excellent material for biosensing due to its large surface area and its capability for molecular size selectivity. In this work, we report the experimental demonstration of a label-free nanoscale PSi resonant waveguide biosensor. The PSi waveguide consists of pores with an average diameter of 20nm. DNA is attached inside the pores using standard amino-silane and glutaraldehyde chemistry. Molecular binding in the PSi is detected optically based on a shift of the waveguide resonance angle. The magnitude of the resonance shift is directly related to the quantity of biomolecules attached to the pore walls. The PSi waveguide sensor can selectively discriminate between complementary and non-complementary DNA. The advantages of the PSi waveguide biosensor include strong field confinement and a sharp resonance feature, which allow for high sensitivity measurements with a low detection limit. Simulations indicate that the sensor has a detection limit of 50nM DNA concentration or equivalently, 5pg/mm2.
    • "The reaction between the oxidized surface and the organosilane is based on the condensa‐ tion between the Si–O–Si of the silane and the OH present on the device; generally, besides the hydroxyl groups already present on the native silicon oxide layer, a thermal oxidation is a common procedure to form a new efficient oxide film [40][41][42]in order to assure a plenty of silanol groups for an efficient coverage of the organic layer. Furthermore, after silanization, APTES layer was cured at high temperature [43]. "
    Full-text · Chapter · Mar 2016
    • "e adsorbed DNA helix. The stabilization and hybridization of DNA inside the PSi layer is confirmed using ATR-FTIR. The hybridization was verified by the large and reproducible impedance changes at the interface layer. It was concluded that the PSi DNA sensor paves the way for the label-free detection of oligonucleotide sequences in DNA microarrays. Rong et al. (2008) consider too that the PSi is an excellent material for biosensing due to its large surface area and its capability for molecular size selectivity. They have developed the labelfree nanoscale PSi resonant waveguide biosensor with the average diameter of pores in 20 nm. DNA was attached inside the pores through successive application of s"
    [Show abstract] [Hide abstract] ABSTRACT: Previously it was mentioned that silicon is very widespread. Now it is used intensively in electronics and according to a number of given demonstrations, PSi is a perspective transducer in different types of biosensors. It turns out that the construction of PSi-based biosensors is very simple; the created devices may be applied in field condition and may provide analysis in an online regime. As a rule, the sensitivity of such types of biosensors respond to practice demands for the screening observation.
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    • "These predominantly consist of pSi in the form of thin films [81, 82], microcavities [117, 128], rugate filters [33, 129], Bragg mirrors [38] and waveguides [112, 130]. By utilizing changes in photoluminescence or optical reflectivity of pSi, the detection of proteins [42, 81, 131], enzymatic activity [91, 132, 133], DNA [82, 112, 134], viruses [116] and bacteria [41, 117] have all been shown. The desired selectivity is achieved by chemically tuning the large surface area with biomolecular probes that effectively bind the target molecule from a complex mixture [128]. "
    [Show abstract] [Hide abstract] ABSTRACT: The versatility of porous silicon (pSi), due to the myriad of possible structures, ease of chemical modification and inherent biocompatibility, has resulted in it being readily tailored for numerous biomedical applications. Commonly prepared via the anodisation of crystalline silicon wafers in HF electrolyte, pSi can be produced as films, microparticles, nanoparticles and free-standing membranes. The combination of both its unique physical properties and the incorporation of stable surface functionalities have been fundamental to its performance. Through an immense number of modification techniques, numerous species from antibodies to polymers can be integrated into pSi structures. This adaptability has produced materials with an increased half-life both in vitro and in vivo and enabled the development of both targeted detection platforms and local delivery of therapeutic payloads. As a result, modified pSi has been readily applied to a range of biomedical applications including molecular detection, drug delivery, cancer therapy, imaging and tissue engineering.
    Full-text · Chapter · Jan 2015
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