Construction of 5‐amino‐1,10‐phenanthroline‐Fe(II) Nanostructures on Glassy Carbon Electrode: Simultaneous and Selective Determination of Purine and Pyrimidine DNA Bases

Abstract

5‐amino‐1,10‐phenanthroline‐Fe(II) complex is immobilized onto GC electrode and used for determination of DNA bases. Modifications are traced by electrochemical methods. All DNA bases are electroactive on the modified electrode. The Ips increased linearly with increase of DNA bases concentration. A wide response range was observed for each base (∼4 orders for guanine (GA) and adenine (A); and ∼2.5 orders for thymine (T) and cytosine (C)) with DLs of 0.15, 4.44, 133.0 and 230.0 nM, respectively. The electrode was applied for determination of calf‐thymus DNA bases. The value obtained for [(GA+C)/(A+T)], 0.78, is in good agreement with standard value, 0.77.

Nanobioconjugated System Formed of Folic Acid–Deferrioxamine–Ga(III) on Gold Surface: Preparation, Characterization, and Activities for Capturing of Mouse Breast Cancer Cells 4T1

“…Formation of the MPA layer on Au surface has shown a blocking behavior against redox reaction of [Fe(CN) 6 ] 3−/4− (Figure 2, curves a and b), leading to a decrease in the peak current (I p ), a potential shift to unfavorable direction, and an increase in the charge-transfer resistance (R ct ), which is, of course, a known effect. 49 Likewise, we may expect the immobilized folic acid (Au-MPA-FOA) to impose a blocking effect against redox probe; however, an opposite effect is observed; the I p is increased, and peak separation (ΔE peak ) and R ct are decreased (Figure 2, curve c). This effect is due to large electrostatic attraction (dominating effect) between highly protonated (positively charged) immobilized FOA at working pH 3.0 (pK a,surface of Au-MPA-FOA electrode is ∼7.0, Figure S6), with negatively charged [Fe(CN) 6 ] 3−/4− .…”

An Electrochemical Sensor Based on Gold Nanoparticles Incorporated in Mesoporous MFI Zeolite for Determination of Purine Bases in DNA

“…Direct electrooxidation of guanine and adenine on the electrode surfaces have been reported in the past decades by using various modified materials such as β‐cyclodextrins , polymers film , graphene‐based composites , , carbon nanotubes‐based composites , mesoporous carbon , , metal or metal oxide nanoparticles and other nanocomposites . Although these sensors exhibit improved sensitivity, some problems are obvious such as slow electron transfer kinetics, higher oxidation potential and easy surface fouling.…”