Mohammad Nabil Abo-Zeid

Bio: Mohammad Nabil Abo-Zeid is an academic researcher from Assiut University. The author has contributed to research in topics: Lipophilicity & Hydrazide. The author has an hindex of 6, co-authored 7 publications receiving 97 citations.

Modification of N,S co-doped graphene quantum dots with p-aminothiophenol-functionalized gold nanoparticles for molecular imprint-based voltammetric determination of the antiviral drug sofosbuvir

Abstract: A molecularly imprinted polymer (MIP) was developed for the electrochemical determination of the antiviral drug sofosbuvir (SOF). The MIP was obtained by polymerization of p-aminothiophenol (p-ATP) on N,S co-doped graphene quantum dots (N,S@GQDs) in the presence of gold nanoparticles to form gold-sulfur covalent network. The presence of quantum dots improves the electron transfer rate, enhances surface activity and amplifies the signal. The nanocomposites were characterized by FTIR, TEM, EDX, and SEM. The electrochemical performance of the electrode was investigated by differential pulse voltammetry and cyclic voltammetry. The sensor uses hexacyanoferrate as the redox probe and is best operated at a potential of around 0.36 V vs. Ag/AgCl. It has a linear response over the concentration range of 1–400 nM SOF, with a detection limit of 0.36 nM. Other features include high selectivity, good reproducibility and temporal stability. The sensor was applied to the determination of SOF in spiked human plasma.

Molecularly imprinted polymer/reduced graphene oxide‒based carbon‒paste sensor for highly sensitive determination of the anti‒HCV drug daclatasvir dihydrochloride

Abstract: The recent discovery of the novel viral RNA‒dependent RNA polymerases for treatment of HCV opened the doors for the development of a large number of anti−HCV drugs which require a concurrent development of sensitive analytical methods for their quality‒control and analysis. In this work, we report the first molecularly imprinted polymer‒based electrochemical sensor for the determination of the anti−HCV drug, daclatasvir dihydrochloride (DCT). Since liver patients require continuous medical follow up during the period of their treatment, it is very necessary to develop a simple and fast method for monitoring the DCT concentration in the patient’s biological fluids. In addition, quality control laboratories are in an urgent need for various rapid analytical methods for such a novel drug. The sensor is based on the modification of the traditional carbon‒paste sensor with molecularly imprinted methacrylic acid, cross linked with ethylene glycol dimethacrylate, as a selective adsorbent for DCT, and reduced graphene oxide (RGO) as a sensitizer. The Hartree‒Fock method of calculation was used to optimize the template/functional monomer ratios so as to avoid trial‒and‒error experimental synthesis procedures and to give information about the binding of the template to the functional monomer. The sensor was fully characterized with the aid of cyclic voltammetry, FTIR analysis and scanning electron microscopy (SEM). After optimization of the analytical parameters, the sensor was found to work efficiently at pH 2.5 (Britton Robinson buffer) and a scan rate of 500 mV/s. The sensor showed a good linearity over the concentration range of 40.6 pg/mL to 812 μg/mL with a correlation coefficient of 0.9881. The detection and quantification limits were found to be 12.2 and 40.2 pg/mL, respectively. The proposed sensor was applied for the determination of DCT in bulk solution, pharmaceutical formulation and human urine and plasma samples and excellent recovery values ranging from 99.48 to 103.70% were obtained indicating the accuracy of the proposed sensor.