Lysozyme aptasensor based on a glassy carbon electrode modified with a nanocomposite consisting of multi-walled carbon nanotubes, poly(diallyl dimethyl ammonium chloride) and carbon quantum dots

Abstract

An aptamer-based method is described for electrochemical determination of lysozyme. A glassy carbon electrode was modified with a nanocomposite composed of multi-walled carbon nanotubes, poly(diallyl dimethyl ammonium chloride), and carbon quantum dots. The composition of the nanocomposite (MWCNT/PDDA/CQD) warrants good electrical conductivity and a high surface-to-volume ratio. The lysozyme-binding aptamers were immobilized on the nanocomposite via covalent coupling between the amino groups of the aptamer and the carboxy groups of the nanocomposite. The modified electrode was characterized by electrochemical impedance spectroscopy, cyclic voltammetry and differential pulse voltammetry. The use of this nanocomposite results in a considerable enhancement of the electrochemical signal and contributes to improving sensitivity. Hexacyanoferrate was used as an electrochemical probe to study the dependence of the peak current on lysozyme concentration. In the presence of lysozyme, the interaction of lysozyme with immobilized aptamer results in a decrease of the peak current, best measured at +0.15 V vs. Ag/AgCl. A plot of peak current changes versus the logarithm of the lysozyme concentration is linear in the 50 fmol L to 10 nmol L concentration range, with a 12.9 fmol L detection limit (at an S/N ratio of 3). The method is highly reproducible, specific and sensitive, and the electrode has a rapid response. It was applied to the determination of lysozyme in egg white, serum, and urine. Graphical abstract Schematic of a nanocomposite composed of multi-walled carbon nanotubes (MWCNTs), poly(diallyldimethyl ammonium chloride) (PDDA), and carbon quantum dots (CQDs) for use in a lysozyme aptasensor. The aptamer was immobilized on the surface, and bovine serum albumin (BSA) was applied to block the surface. The changes of peak current for the electrochemical probe hexacyanoferrate (Fe(CN)) in the presence and absence of lysozyme was traced.

Electric Field-Induced Chemical Surface-Enhanced Raman Spectroscopy Enhancement from Aligned Peptide Nanotube–Graphene Oxide Templates for Universal Trace Detection of Biomolecules

“…4c,d and S23); all bands detected are in a good agreement with literature values). [45][46][47][48][49][50] These molecules are commonly used in biomedical assays and the results show the potential applicability of the FF-PNT/GO substrates to medical assay technology. Another molecule of interest in the pharmaceutical industry is nitrophenol (4-NIP) and its derivatives.…”

Electrochemical Cloth-Based DNA Sensors (ECDSs): A New Class of Electrochemical Gene Sensors

“…First, the combination of CdTe-MWCNTs to the WE increased the surface-to-volume ratio of the electrode and improved the immobilization of the CP. 29 Thus, more signal probes were immobilized on the electrode surface. Second, the DPV detection involved a great many of electroactive substances that might be more sensitive to the improvement of electron transfer rate on the CdTe-MWCNTs-modified electrode surface.…”

“…This may be due to the following two reasons. First, the combination of CdTe-MWCNTs to the WE increased the surface-to-volume ratio of the electrode and improved the immobilization of the CP . Thus, more signal probes were immobilized on the electrode surface.…”

“…It has been reported that a modified electrode based on a QDs/CNTs nanocomposite responded even more sensitively than an electrode modified only by QDs or CNTs. 27 To date, EC sensors based on QDs/ CNTs nanocomposite-modified electrodes have been applied to detect specific biomolecules, such as glucose, 27 insulin, 28 lysozyme, 29 phenylethanolamine A, 30 and the anti-HIV drug Rilpivirine. 31 However, thus far, such EC sensors have not been used for DNA detection.…”

Recent Progresses in Development of Biosensors for Thrombin Detection

“…These materials render mechanical constancy, a great surface-to-volume ratio, low cost, electrocatalytic characteristics etc. [ 56 , 57 , 58 , 59 , 60 ]. Specifically, Jamei et al fabricated an ultra-sensitive aptasensor based on polymer quantum dots and a C60/MWCNT polyethyleneimine (PEI) nanocomposite modified on the SPCE electrode surface to analyze TB ( Figure 3 ).…”