Electrochemical Sensing of Casein Based on the Interaction between Its Phosphate Groups and a Ruthenium(III) Complex

Abstract

A reaction to casein, along with β-lactoglobulin, is a main cause of milk allergies, and also is a useful indicator of protein in allergic analyses. In the present study, a simple casein sensor was developed based on the interaction between a phosphate group of casein and electroactive [Ru(NH3)6](3+). We evaluated the voltammetric behavior of a casein-[Ru(NH3)6](3+) complex using a glassy carbon electrode. When the ruthenium(III) complex was combined with the phosphate groups of casein, the structure of the casein was changed. Since the hydrophobicity of casein was increased due to the binding, the casein was adsorbed onto the electrode. Furthermore, we modified an electrode with a ruthenium(III) ions/collagen film. When the sensor was applied to the detection of the casein contained in milk, the values coincided with those indicated by the manufacturer. Accordingly, this electrode could be a powerful sensor for the determination of casein in several foods.

Construction of tethered bilayer lipid membrane with oriented membrane proteins on surface modified mica substrate

“…The formation of tBLM including membrane proteins with a size of about several nm on mica substrate should bring the possibility for the clear and neutral structural or reactive detection for membrane proteins as in the biological membrane. With reference to the previous studies, [25][26][27][28] we conducted the below process for the formation of uniform SAM on mica. First, a phosphonic acid derivative, 11-Aminoundecylphosphonic acid (11-AUPA; Dojindo, Japan) having an amino group and a phosphonic acid group at each terminal was reacted with a mica substrate, and then a SAM having a Ni chelate derivative at the end was formed by reaction with isothiocyanobenzyl nitrilotriacetic acid (ITC-Bz-NTA; Dojindo, Japan).…”

New applications of advanced instrumental techniques for the characterization of food allergenic proteins

“…They can be categorized as potentiometric, amperometric, voltammetric, conductometric or impedimetric, sensors according to the electrochemical principle involved. The use of specific antibodies has allowed the development of immunosensors for the selective detection of food allergenic proteins from peanut (Singh et al 2010;Alves et al 2015; V. R. V. , milk (Montiel et al 2015;Inaba, Kuramitz, and Sugawara 2016;), egg ( Cadkov a et al 2015Bened e et al 2018), shrimp (Angulo-Ibañez et al 2019), tomato (Pereira-Barros et al 2019 or hazelnut (Montiel et al 2017). However, limitations due to the use of antibodies such as nonspecific binding or the liability to degrade should be considered in immunosensor development.…”

Electrochemical Sensor Based on Casein and Carbon Black for Bisphenol A Detection

“…The CAS-CB/GCE presented good results due to the synergic effect between the conductivity and electrocatalytic effect of CB [21] and the adsorption capability of the CAS [38,57] resulting in a higher catalytic activity for the modified electrode.…”