When consumed in excessive amounts, histamine (HIS), a naturally occurring component in seafood, is known to produce an unpleasant inflammatory reaction. Hence, proper histamine measurement and detection in seafood are of utmost importance. Herein, a histamine electrochemical biosensor based on a molecularly imprinted polymer (MIP) was fabricated using a gold (Au) inverse opal (IO) electrode. Prior to the MIP synthesis, the scaffold of Au IO was modified by electropolymerizing 3,4-ethylenedioxythiophene (EDOT), providing a substrate with improved electrical characteristics. The fabrication of the MIP film was achieved by electropolymerizing aniline in circumstances that preserved the chemical structure of HIS. The electron transport properties of a standard redox probe [Fe(CN) 6 ] 3−/4− were evaluated by making use of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). We describe a synergistic strategy for constructing a hierarchical recognition material using an electrochemical approach that successfully integrates three independent approaches, including semicovalent, molecular imprinting, and inverse opal structure, to enhance selectivity and sensitivity. The fabricated HIS electrochemical biosensor exhibited a linear response from 50 nM to 500 μM, a detection limit of 1.07 nM, and was selective against different analytes as well. Moreover, the fabricated HIS electrochemical biosensor outperforms its contemporary counterparts as it also exhibited low error, high accuracy, specificity, stability, and good relative standard deviation % (RSD %).

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Fresh water scarcity and pollution turn out to be a most serious issue throughout the world due to the rapid population growth. The application of nanomaterials (NMs) for the removal of pollutants from water has attracted significant attention. The nanofiltration membrane was fabricated through the evaporative casting (EC) method using multiwalled carbon nanotubes (MWCNT) and chitosan (CHIT) as the surfactant to enable water purification. The developed EC membrane properties were characterized in mechanical, surface charging (zeta potential), surface morphology, and hydrophobicity properties. Results demonstrated that incorporation of MWCNT and the biopolymers (chitosan) resulted in suitable developments in mechanical properties of the membrane. For example, the membrane has shown values for tensile strength (28 ± 1 MPa), elongation (10.2 ± 1.2%), Young’s modulus (1.2 ± 0.1 GPa), and toughness of (1.9 ± 0.2 J/g). When more significant changes were investigated on the surface morphology of the EC membrane, it was observed that the pores on the surface morphology of the EC membrane decreased as the evaporative casting method was used. Moreover, the permeability of the membrane towards water, inorganic salts, and pH effect on salt rejections was studied using the NF/RO system. These established nanocomposite membranes signify the promising candidates for fresh water desalination and elimination of organic impurities.

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