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    Fabrication of PAMP/Au and GO/PAMP/Au nanosensors for electrochemical detection of paracetamol in pharmaceutical preparations
    (Springer, 2021) Bilici, Ali; Denizhan, Nuray; Emre, Deniz; Soylukan, Caner; Algı, Fatih; Yılmaz, Selehattin
    This paper reports on the modification of Pencil Graphite Electrode (PGE) surface with the poly(2-amino-4-methylphenol)/gold (PAMP/Au) and graphene oxide/poly(2-amino-4-methylphenol)/gold (GO/PAMP/Au) nanocomposites, in two steps. The first step is based on the one-pot preparation of composites by template-free chemical oxidation process. In the second step, composites are deposited at PGE surface by electro-oxidation process. Both nanocomposites and modified PGE surfaces are characterized by X-Ray Diffraction method (XRD), Scanning Electron Microscopy (SEM), EDAX, and CV analyses. The electrochemical performances of modified electrodes (abbreviated as PAMP/Au-PGE and GO/PAMP/Au-PGE) were investigated. The limit of detection values for PGE, PAMP/Au-PGE, and GO/PAMP/Au-PGE were found to be 2.74 × 10–6, 5.29 × 10–7, and 2.91 × 10–8 mol/dm3, respectively. The limit of quantification values were determined as 9.14 × 10–6, 1.76 × 10–6, and 9.69 × 10–8 mol/dm3 for PGE, PAMP/Au-PGE, and GO/PAMP/Au-PGE, respectively.
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    Graphene quantum dots-polyfluorene hybrid nanobiosensor for mitomycin C-DNA interaction sensing
    (Elsevier, 2024) Emre, Deniz; Denizhan, Nuray; Özkan Arıksoysal, Dilşat; Bilici, Ali; Sonkaya, Ömer; Algı, Fatih; Algı, Fatih; Yılmaz, Selehattin
    A novel graphene quantum dots (GQD) / polyfluorene (PF) nanocomposite was deposited on the disposable pencil tip graphite electrode (PGE) and proven to be an efficient nanosensor for analysis of the electrochemical interaction between the antitumor compound mitomycin C (MC) with double stranded DNA (ds-DNA). This modified electrode (GQD@PF-PGE) was prepared in four steps: hydrothermal, chemical oxidation, ultra-sonication and electro-oxidation processes. GQD, PF, GQD@PF and GQD@PF-PGE have been characterized by different analytical techniques such as SEM, TEM, XRD, FTIR, UV-Vis, EIS. Compared to bare PGE, GQD@PF modified PGE performed approximately 56 times more sensitive analysis when evaluating the guanine oxidation signals measured by DPV. CV and EIS measurements also showed that GQD@PF-PGE possesses a fast electron transfer as compared to bare electrode and exhibit a remarkable electrocatalytic activity towards both guanine and MC electrooxidation. Comprehensive optimization studies have also been carried out for the developed new nanobiosensor.