Browsing by Subject "Biosensor applications"

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    ItemOpen Access
    Peptide-mediated constructs of quantum dot nanocomposites for enzymatic control of nonradiative energy transfer
    (American Chemical Society, 2011) Seker U.O.S.; Ozel, T.; Demir, Hilmi Volkan
    A bottom-up approach for constructing colloidal semiconductor quantum dot (QDot) nanocomposites that facilitate nonradiative Förster-type resonance energy transfer (FRET) using polyelectrolyte peptides was proposed and realized. The electrostatic interaction of these polypeptides with altering chain lengths was probed for thermodynamic, structural, and morphological aspects. The resulting nanocomposite film was successfully cut with the protease by digesting the biomimetic peptide layer upon which the QDot assembly was constructed. The ability to control photoluminescence decay lifetime was demonstrated by proteolytic enzyme activity, opening up new possibilities for biosensor applications.
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    ItemOpen Access
    Using nanogap in label-free impedance based electrical biosensors to overcome electrical double layer effect
    (Springer Verlag, 2017) Okyay, Ali Kemal; Hanoglu, O.; Yuksel, M.; Acar, H.; Sülek, S.; Tekcan, B.; Agan, S.; Bıyıklı, Necmi; Güler, Mustafa O.
    Point-of-care biosensor applications require low-cost and low-power solutions. They offer being easily accessible at home site. They are usable without any complex sample handling or any kind of special expertise. Impedance spectroscopy has been utilized for point-of-care biosensor applications; however, electrical double layer formed due to ions in the solution of interest has been a challenge, due to shielding of the electric field used for sensing the target molecules. Here in this study, we demonstrate a nanogap based biosensor structure with a relatively low frequency (1–100 kHz) measurement technique, which not only eliminates the undesired shielding effect of electrical double layer but also helps in minimizing the measurement volume and enabling low concentration (µ molar level) detection of target molecules (streptavidin). Repeatability and sensitivity tests proved stable and reliable operation of the sensors. These biosensors might offer attributes such as low-cost label-free detection, fast measurement and monolithic chip integrability.