A molecularly imprinted poly 2-aminophenol-gold nanoparticle-reduced graphene oxide composite for electrochemical determination of flutamide in environmental and biological samples

Amplifying Flutamide Sensing through the Synergetic Combination of Actinidia-Derived Carbon Particles and WS2 Platelets

The development of electrochemical sensors for flutamide detection is a crucial step in biomedical research and environmental monitoring. In this study, a composite of Actinidia-derived carbon particles (CPs) and tungsten disulfide (WS2) was formed and used as an electrocatalyst for the electrochemical detection of flutamide. The CPs had an average diameter of 500 nm and contained surface hydroxyl and carbonyl groups. These groups may help anchor the CPs onto the WS2 platelets, resulting in the formation of a CPs-WS2 nanocomposite with a high surface area and a conducting network, enabling electron transfer. Using the CPs-WS2 composite supported at a glassy carbon electrode, a linear concentration range extending from 1 nM to 104 μM, a limit of detection of 0.74 nM, and a sensitivity of 26.9 ± 0.7 μA μM-1 cm-2 were obtained in the detection of flutamide in a phosphate buffer. The sensor showed good recovery, ranging from 88.47 to 95.02%, in river water samples, and exhibited very good selectivity in the presence of inorganic ions, including Al3+, Co2+, Cu2+, Fe3+, Zn2+, NO3 -, SO4 2-, CO3 2-, and Cl-.

Innovative molecularly imprinted electrochemical sensor for the nanomolar detection of Tenofovir as an anti-HIV drug

Tenofovir (TNF) is an antiviral medicine that is utilized to treat the human immunodeficiency virus (HIV). However, its level must be controlled in the human body and environment at the risk of causing kidney and liver problems. Therefore, determining TNF concentration in real samples with more advanced, inexpensive, and accurate sensing systems is essential. In this work, a novel electrochemical nanosensor for TNF determination based on molecularly imprinted polymer (MIP) on the screen-printed electrode modified with functionalized multi-walled carbon nanotubes, graphite carbon nitride, and platinum nanoparticles (MIP-Pt@g-C₃N₄/F-MWCNT/SPE) was constructed through the electro-polymerization approach. The molecularly imprinted polymers were prepared on the electrode surface with TNF as the template molecule and 2-aminophenol (2-AP) as the functional monomer. Moreover, factors that affect sensor response were optimized. Pt@g-C₃N₄/F-MWCNT nanocomposite had an excellent synergistic effect on MIP, allowing rapid and specific identification of the test substance. The results demonstrated that the electro-polymerization of 2-AP supplies large amounts of functional groups for the binding of the template molecules, which remarkably enhances the sensitivity and specific surface area of the MIP sensor. This surface enlargement increased the analyte accessibility to imprinted molecular cavities. Under optimum conditions, the oxidation peak current had a linear relationship with TNF concentration ranging from 0.005 to 0.69 μM with a low detection limit of 0.0030 μM (S/N = 3). The results demonstrated that the designed MIP sensor possesses acceptable sensitivity, repeatability, and reproducibility toward TNF determination. Moreover, the developed sensor was applied to biological and water samples to determine TNF, and satisfactory recovery results of 95.6-104.8% were obtained (RSD less than 10.0%). We confirm that combining as-synthesized nanocomposite Pt@g-C₃N₄/F-MWCNT with MIP improves the limitations of MIP-based nanosensors. The proposed electrode is also compatible with portable potentiostats, allowing on-site measurements and showing tremendous promise as a point-of-care (POC) diagnostic platform.

Copper-catalyzed [1,3]-nitrogen rearrangement of O-aryl ketoximes via oxidative addition of N–O bond in inverse electron flow†

The [1,3]-nitrogen rearrangement reactions of O-aryl ketoximes were promoted by N-heterocyclic carbene (NHC)-copper catalysts and BF₃·OEt₂ as an additive, affording ortho-aminophenol derivatives in good yields. The reaction of substrates with electron-withdrawing substituents on the phenol moiety are accelerated by adding silver salt and modifying the substituent at the nitrogen atom. Density functional theory calculations suggest that the rate-determining step of this reaction is the oxidative addition of the N–O bond of the substrate to the copper catalyst. The negative ρ values of the substituent at both the oxime carbon and phenoxy group indicate that the donation of electrons by the oxygen and nitrogen atoms accelerates the oxidative addition.

[1,3]-Nitrogen rearrangement reactions of O-aryl ketoximes was catalytically promoted by IPrCuBr and BF₃·OEt₂. The oxidative addition of the N–O bond to the Cu catalyst is accelerated by donation of electrons from both nitrogen and oxygen atoms.

In situ formation of Co3O4 nanoparticles embedded N-doped porous carbon nanocomposite: a robust material for electrocatalytic detection of anticancer drug flutamide and supercapacitor application

The one-step synthesis of heteroatom-doped porous carbons is reported with the in situ formation of cobalt oxide nanoparticles for dual electrochemical applications (i.e., electrochemical sensor and supercapacitor). A single molecular template of zeolitic imidazole framework-67 (ZIF-67) was utilized for the solid-state synthesis of cobalt oxide nanoparticle-decorated nitrogen-doped porous carbon (Co₃O₄@NPC) nanocomposite through a facile calcination treatment. For the first time, Co₃O₄@NPC nanocomposite derived from ZIF-67 has been applied as an electrode material for the efficient electrochemical detection of anticancer drug flutamide (FLU). The cyclic voltammetry studies were performed in the operating potential from 0.15 to - 0.65 V (vs. Ag/AgCl). Interestingly, the fabricated drug sensor exhibited a very low reduction potential (- 0.42 V) compared to other  reported sensors. The fabricated sensor exhibited good analytical performance in terms of low detection limit (12 nM), wide linear range (0.5 to 400 μM), and appreciable recovery results (~ 98%, RSD 1.7% (n = 3)) in a human urine sample. Hereafter, we also examined the supercapacitor performance of the Co₃O₄@NPC-modified Ni foam in a 1M KOH electrolyte, and noticeable a specific capacitance of 525 F g^-1 at 1.5 A g^-1 was attained, with long-term cycling stability. The Co₃O₄@NPC nanocomposite supercapacitor experiments outperform the associated MOF-derived carbons and the Co₃O₄-based nanostructure-modified electrodes.