Label-Free Aptasensor for Lysozyme Detection Using Electrochemical Impedance Spectroscopy

Abstract

This research develops a label-free aptamer biosensor (aptasensor) based on graphite-epoxy composite electrodes (GECs) for the detection of lysozyme protein using Electrochemical Impedance Spectroscopy (EIS) technique. The chosen immobilization technique was based on covalent bonding using carbodiimide chemistry; for this purpose, carboxylic moieties were first generated on the graphite by electrochemical grafting. The detection was performed using [Fe(CN)6]3−/[Fe(CN)6]4− as redox probe. After recording the frequency response, values were fitted to its electric model using the principle of equivalent circuits. The aptasensor showed a linear response up to 5 µM for lysozyme and a limit of detection of 1.67 µM. The sensitivity of the established method was 0.090 µM−1 in relative charge transfer resistance values. The interference response by main proteins, such as bovine serum albumin and cytochrome c, has been also characterized. To finally verify the performance of the developed aptasensor, it was applied to wine analysis.

FRET-Based Aptasensor for the Selective and Sensitive Detection of Lysozyme

“…Therefore, we went on to determine the selectivity of the lysozyme sensor by characterizing its performance in the presence of various biomolecules individually and in a mixture. For this purpose, we selected previously reported interfering biomolecules: bovine serum albumin (BSA), glucose, and cytochrome C (Cyt-C) separately and in a mixture [24][25][26]30]. To make this study relevant to the biological context, concentrations of each of the interfering biomolecules were kept similar to their biological concentrations [54][55][56].…”

“…A number of techniques have been demonstrated for the detection of lysozyme including classical analytical methods such as chromatography [21] and enzyme-linked immunosorbent assay (ELISA) [22,23]. Recent techniques for lysozyme analysis include electrochemical [2,[24][25][26], optical [27][28][29], colorimetric [5,30,31], and surface plasmon resonance (SPR) [32,33], some of which are highly sensitive with detection limits in the picomolar to femtomolar ranges [1,2,24,26,27]. Nevertheless, most of these detection methods suffer from one or more problems such as low-selectivity, complex sample pre-treatment, time-consuming immobilizing processes, slow response time, etc.…”

“…Nevertheless, most of these detection methods suffer from one or more problems such as low-selectivity, complex sample pre-treatment, time-consuming immobilizing processes, slow response time, etc. For example, the electrochemical detection typically requires time consuming electrode/surface preparation, complicated sensor immobilization processes, and/or labeling of the probe with a redox moiety such as ferrocene [25,26,34]. Other methods such as SPR usually require overnight or several days of surface fabrication and costly probes/reagents [32,33].…”

A 0.18 μm CMOS LDO Regulator for an On-Chip Sensor Array Impedance Measurement System

“…Many emerging sensor technologies, especially those based on bio and nano-materials, rely on Impedance Spectroscopy (IS) to evaluate their activity, i.e., the sensor information is obtained from its impedance extraction over a specific interval of stimulus frequencies [ 1 , 2 , 3 ]. However, despite the versatility and the promising applications of the newest impedance sensors—from environmental monitoring [ 4 ] to molecular diagnosis [ 5 , 6 , 7 ] or DNA or proteins microarrays [ 8 , 9 ]—their potential use outside the specialized laboratories is hindered by the lack of suitable on-chip electronic interfaces that allows preserving levels of resolution, accuracy and reliability comparable to those of the bulky laboratory instruments, but with a miniaturized system powered by limited energy sources.…”

Detection of Nonspecific Binding of <em>E. coli</em> O157:H7 on Reduced Graphene Oxide Screen-Printed Carbon Electrodes Using Electrochemical Methods

“…Owing to the need to distinguish pathogenic microorganisms from non-pathogenic ones, electrochemical biosensors can employ various biorecognition schemes such as DNA/RNA/PNA [2][3][4], antibody [5][6][7], aptamers [8][9][10], antimicrobial peptides [11][12][13], carbohydrate [14,15] and bacteriophages [16][17][18]. In bacteria detection, specificity to identify pathogenic bacteria strains that can cause illness is vital.…”