• MARYAM NAZARI

Articles written in Bulletin of Materials Science

• A focus on the features of polyaniline nanofibres prepared via developing the single crystals of their block copolymers with poly(ethylene glycol)

Poly(ethylene glycol) (PEG)–polyaniline (PANI) diblock and triblock copolymers were synthesized viacopolymerization of aniline with amine-terminated PEG by interfacial polymerization using sulphuric acid as dopant andammonium peroxydisulfate (APS) as well as potassium hydrogen diiodate (PHD) as oxidants. The PHD-based synthesizedPANI nanorods possessed longer lengths, narrower diameter distribution and higher conductivity. The electroactivity ofsynthesized copolymers was characterized using ultraviolet–visible (UV–Vis) spectrometry, cyclic voltammetry (CV) andresistivity measurement. Even in the presence of dielectric PEG blocks, the synthesized block copolymers had a conductivityaround 3 S cm$^{−1}$. In a further step, the solution-grown single crystals were prepared to investigate the general features ofgrafted PANI nanorods using small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and atomicforce microscopy (AFM). Based on AFM and SAXS analyses, the bimodal gel permeation chromatography (GPC) tracesobtained from the block copolymers were originated from the diameter distribution of nanofibres, not from the dispersity oftheir lengths and molecular weights.

• Laccase immobilized onto graphene oxide nanosheets and electrodeposited gold–cetyltrimethylammonium bromide complex to fabricate a novel catechol biosensor

In this study, a new biosensor is developed with reliable and easy-to-use biodevice properties for catechol determination in real samples. A method is proposed for the fabrication of biosensors to sense catechol based on theadsorption method of laccase immobilization. Hence, a glassy carbon electrode was modified via graphene oxide nanosheets and then it was modified with a gold–cetyltrimethylammonium bromide nanocomposite to adsorb and immobilize laccase on the electrode surface. The results showed laccase immobilization onto the reformed glassy carbon electrode, and a direct electron transfer reaction between laccase and the electrode. The mechanism of electron transferring was EC$^{\prime}$. Also, $k_s$ and $\alpha$ were calculated as 0.41 s$^{−1}$ and 0.33, respectively. For this biosensor two linear ranges, $0.1 \times 10^{−6}$ to $5 \times 10^{−6}$ M and $16.7\times 10^{−6}$ to $166 \times 10^{−6}$ M, and a detection limit of $1.5 \times 10^{−6}$ M were obtained.

• Novel fabrication of a laccase biosensor to detect phenolic compounds using a carboxylated multiwalled carbon nanotube on the electropolymerized support

Biosensors research is one of the fastest growing fields in which tens of thousands of papers have been published over the years; even more, numerous biosensors have been developed for the detection of phenolic compounds, such as catechol which reacts with an appropriate enzymatic bioreceptor like laccase. A biosensing electrode for catechol detection was investigated by covalent immobilization of laccase on a glassy carbon electrode modified by conducting polymers built of poly(3,4-ethylenedioxythiophene), gold nanoparticles and carboxylated multiwalled carbon nanotubes. The fabrication process of the sensing surface was investigated by Fourier transform infrared spectroscopy, scanning electron microscopy and electrochemical procedures. The electrochemical results demonstrate that the enzyme was immobilized covalently onto the modified glassy carbon electrode by the interaction between carboxyl groups of the carboxylated multiwalled carbon nanotubes and laccase. The biosensor demonstrates a direct electron transfer between the electrode and immobilized laccase. Under optimum conditions, it presented two linear responses in the range of 0.1–0.5 and 11.99–94.11 $\mu$M. The limits ofdetection were found to be 0.11 and 12.26 $\mu$M.

• Bulletin of Materials Science

Volume 44, 2021
All articles
Continuous Article Publishing mode

• Dr Shanti Swarup Bhatnagar for Science and Technology

Posted on October 12, 2020

Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020