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Herein, we report the synthesis of mesoporous carbon materials from diblock star copolymers derived from polyacrylonitrile. The size of the pores was controlled by manipulating the length of the polymer blocks. Furthermore, the organization of polymers on the carbon nano-onion's surface resulted in materials of higher surface area and superficial electrochemical performance.

Fentanyl is a pain reliever stronger and deadlier than heroin. This lethal drug has killed many people in different countries recently. Due to the importance of the diagnosis of this drug, a fentanyl electrochemical sensor is developed based on a glassy carbon electrode (GCE) modified with the carbon nanoonions (CNOs) in this study. Accordingly, the electrochemical studies indicated the sensor is capable of the voltammetric determination of traces of fentanyl at a working potential of 0.85 (vs. Ag/AgCl). To obtain the great efficiency of the sensor some experimental factors such as time, the potential of accumulation and pH value of the electrolyte were optimized. The results illustrated a reduction and two oxidation peaks for fentanyl in phosphate buffer (PB) with pH = 7.0 under a probable mechanism of electrochemical-chemical-electrochemical (ECE). The differential pulse voltammetry (DPV) currents related to the fentanyl detection were linear with an increase of fentanyl concentrations in a linear range between 1 μM to 60 μM with a detection limit (LOD) of 300 nM. Furthermore, the values of the diffusion coefficient (D), transfer coefficient (α) and catalytic constant rate (k cat ) were calculated to be 2.76 × 10 -6  cm 2  s -1 , 0.54 and 1.76 × 10 4  M -1  s -1 , respectively. These satisfactory results may be attributed to utilizing the CNOs in the electrode modification process due to some of its admirable characterizations of this nanostructure including high surface area, excellent electrical conductivity and good electrocatalytic activity. Consequently, these finding points the achieving a simple sensing system to measure of the fentanyl as an important drug from the judicial perspective might be a dream coming true soon., (Copyright © 2020 Elsevier B.V. All rights reserved.)

This article presents a brief review of the knowledge concerning onion-like carbons (OLCs). These nanostructures are some of the most fascinating carbon forms due to their unusual structure and physico-chemical properties. Generally, OLCs consist of a hollowspherical fullerene core surrounded by concentric graphitic layers with increasing diameter. Nevertheless, they can have different size, shape and type of core, which determine their physicochemical properties. In this article, we review the most important literature reports in this area and briefly describe these nanostructures, their physical and chemical properties and their potential uses with a focus on biomedicine., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Small multilayer fullerenes, also known as carbon nano-onions (CNOs; 5-6 nm in diameter, 6-8 shells), show higher reactivity than other larger carbon nanostructures. Here we report the first example of an in situ polymerization of aniline on phenyleneamine-terminated CNO surfaces. The green, protonated, conducting emeraldine polyaniline (PANI) was directly synthesized on the surface of the CNO. The functionalized and soluble CNO/PANI composites were characterized by TEM, SEM, DSC, Raman, and infrared spectroscopy. The electrochemical properties of the conducting CNO/PANI films were also investigated. In comparison with pristine CNOs, functionalized carbon nanostructures show dramatically improved solubility in protic solvents, thus enabling their easy processing for coatings, nanocomposites, and biomedical applications., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)