Novel Spectroscopic and Electrochemical Sensors and Nanoprobes for the Characterization of Food and Biological Antioxidants

Abstract

Since an unbalanced excess of reactive oxygen/nitrogen species (ROS/RNS) causes various diseases, determination of antioxidants that can counter oxidative stress is important in food and biological analyses. Optical/electrochemical nanosensors have attracted attention in antioxidant activity (AOA) assessment because of their increased sensitivity and selectivity. Optical sensors offer advantages such as low cost, flexibility, remote control, speed, miniaturization and on-site/in situ analysis. Electrochemical sensors using noble metal nanoparticles on modified electrodes better catalyze bioelectrochemical reactions. We summarize the design principles of colorimetric sensors and nanoprobes for food antioxidants (including electron-transfer based and ROS/RNS scavenging assays) and important milestones contributed by our laboratory. We present novel sensors and nanoprobes together with their mechanisms and analytical performances. Our colorimetric sensors for AOA measurement made use of cupric-neocuproine and ferric-phenanthroline complexes immobilized on a Nafion membrane. We recently designed an optical oxidant/antioxidant sensor using N,N-dimethyl-p-phenylene diamine (DMPD) as probe, from which ROS produced colored DMPD-quinone cationic radicals electrostatically retained on a Nafion membrane. The attenuation of initial color by antioxidants enabled indirect AOA estimation. The surface plasmon resonance absorption of silver nanoparticles as a result of enlargement of citrate-reduced seed particles by antioxidant addition enabled a linear response of AOA. We determined biothiols with Ellman reagent−derivatized gold nanoparticles.

An Overview of Optical and Electrochemical Sensors and Biosensors for Analysis of Antioxidants in Food during the Last 5 Years

“…Optical sensors and assays investigate analytical data by utilizing optical transduction approaches such as, absorbance, reflectance, luminescence, etc. These techniques are proper for colored and turbid samples [ 12 ]. This review focuses on colorimetric and fluorescence assays which have been more widely used for antioxidant analysis than other optical techniques.…”

“…Nanomaterials are utilized as catalytic instruments, immobilization platforms or as optical or electroactive labels to enhance the sensing performance revealing higher sensitivity, stability, and selectivity [ 57 ]. Nanoparticle-based colorimetric sensors have particular advantages such as tiny size and great particular surface area, good reactivity, implanting process ability into narrow films, paper and other matrices that are able to combined to optical apparatus appropriate for automated assay development [ 12 ]. Moreover, they have several advantages compared to conventional antioxidant assays including portability, ease of use and uncomplicated operation, fast responses, low price, high sensitivity, robustness, reproducibility, long-term stability, no requirement for specialized equipment, and minimal need for sample pretreatment [ 25 ].…”

“…Oxidative stress is a devastating procedure caused by high levels of reactive oxygen/nitrogen species (ROS/RNS) or depletion of the antioxidant matrix. This process induces a disproportion between the oxidative and antioxidant systems that can stimulate rapid cellular death [ 5 , 12 ]. In this sense, it is vital to recognize antioxidants in food because of health beneficial functions and lower danger of diseases attached to oxidative stress [ 13 ].…”

“…In recent times, optical and electrochemical sensors/biosensors have been used for antioxidant activity estimation due to their high reactivity and selectivity [ 12 ]. Sensors/biosensors are a reliable substitute for classical techniques.…”

Noble Metal Nanoparticles Applications: Recent Trends in Food Control

“…Analysis of food continuously requires development of more robust, efficient, sensitive, and cost-effective analytical methodologies to determinate nutrients and bioactive compounds of food [53]. These determinations guarantee the safety, quality and traceability of food, in compliance with legislation and consumers’ demands.…”