Browsing by Author "Altuner, Elif Esra"

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Citation - WoS: 29
Citation - Scopus: 36
Development of Electrochemical Aptasensors Detecting Phosphate Ions on Tmb Substrate With Epoxy-Based Mesoporous Silica Nanoparticles
(Pergamon-elsevier Science Ltd, 2022) Altuner, Elif Esra; Ozalp, Veli Cengiz; Yilmaz, M. Deniz; Sudagidan, Mert; Aygun, Aysenur; Acar, Elif Esma; Sen, Fatih
This study, it is aimed to develop an electrochemical aptasensor that can detect phosphate ions using 3.3 & PRIME;5.5 & PRIME; tetramethylbenzidine (TMB). It is based on the principle of converting the binding affinity of the target molecule phosphate ion (PO43-) into an electrochemical signal with specific aptamer sequences for the aptasensor to be developed. The aptamer structure served as a gate for the TMB to be released and was used to trap the TMB molecule in mesoporous silica nanoparticles (MSNPs). The samples for this study were characterized by transmission electron spectroscopy (TEM), Brunner-Emmet-Teller, dynamic light scattering & electrophoretic light scattering, and induction coupled plasma atomic emission spectroscopy. According to TEM analysis, MSNPs have a morphologically hexagonal structure and an average size of 208 nm. In this study, palladium-carbon nano particles (Pd/C NPs) with catalytic reaction were used as an alternative to the biologically used horseradish peroxidase (HRP) enzyme for the release of TMB in the presence of phosphate ions. The limit of detection (LOD) was calculated as 0.983 mu M, the limit of determination (LOQ) was calculated as 3.276 mu M, and the dynamic linear phosphate range was found to be 50-1000 mu M. The most important advantage of this bio-based aptasensor assembly is that it does not contain molecules such as a protein that cannot be stored for a long time at room temperature, so its shelf life is very long compared to similar systems developed with antibodies. The proposed sensor shows good recovery in phosphate ion detection and is considered to have great potential among electrochemical sensors.
Citation - WoS: 23
Citation - Scopus: 28
High-Efficiency Application of Cts-Co Nps Mimicking Peroxidase Enzyme on Tmb(ox)
(Pergamon-elsevier Science Ltd, 2022) Altuner, Elif Esra; Ozalp, Veli Cengiz; Yilmaz, M. Deniz; Bekmezci, Muhammed; Sen, Fatih
In this study, analytical studies of Chitosan-Cobalt(II) (CTS-Co(II)) nanoparticles (CTS - Co NPs) by mimicking horseradish peroxidase (HRP) were evaluated. In the applications, it was observed that CTS-Co NPs 3,3 ' 5,5 ' tetramethylbenzidine (TMB) oxidized in the presence of hydrogen peroxide (H2O2). The required CTS-Co NPs were synthesized at 50 degrees C in 30 min and characterized using Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), inductively coupled plasma-optical emission spectroscopy (ICP-OES), and Xray photon spectroscopy (XPS) was done. CTS-Co NPs were studied to develop a selective TMB biosensor on TMB (ox) substrate. The synthesized CTS-Co NPs formed a catalytic reaction with 30% 0.2 mM H2O2 on 0.2 M TMB substrate. After the catalytic reaction, sensitive signals were obtained from the desired biosensor. Electrochemical measurements were taken as low limit of 10 mg and a high limit of 20 mg for the determination of CTSCo NPs to TMB(ox). In the microplate study; The sensors were applied on 1.5 mu g and 3 mu g CTS-Co NPs TMB(ox) substrate, respectively. CTS- Co NPs; for TMB(ox) determination, optical density (OD) measurement was taken as a low limit of 1.5 mu g and a high limit of 3 mu g. Electrochemical applications of particles and microplate reader results were compared with horseradish peroxidase (HRP) enzyme for sensor properties. According to the data obtained, it was observed that it behaved similarly to the CTS-Co NPs peroxidase enzyme. This work presents innovations for nanoparticle extraction and sensor study from chitosan and other naturally sourced polymers.