Detection of Low Density Lipoprotein-Comparison of Electrochemical Immuno- and Aptasensor.

Daria Rudewicz-Kowalczyk,Iwona Grabowska

doi:10.3390/s21227733

Abstract

An elevated level of low density lipoprotein (LDL) can lead to the cardiovascular system-related diseases, such as atherosclerosis and others. Therefore, fast, simple, and accurate methods for LDL detection are very desirable. In this work, the parameters characterizing the electrochemical immuno-and aptasensor for detection of LDL have been compared for the first time. An immunosensor has been designed, for which the anti-apolipoprotein B-100 antibody was covalently attached to 4-aminothiophenol (4-ATP) on the surface of the gold electrode. In the case of an aptasensor, the gold electrode was modified in a mixture of ssDNA aptamer specific for LDL modified with –SH group and 6-mercaptohexanol. Square-wave voltammetry has been used for detection of LDL in PBS containing redox active marker, [Fe(CN)6]3−/4−. Our results show the linear dependence of [Fe(CN)6]3−/4− redox signal changes on LDL concentration for both biosensors, in the range from 0.01 ng/mL to 1.0 ng/mL. The limit of detection was 0.31 and 0.25 ng/mL, for immuno- and aptasensor, respectively. Whereas slightly better selectivity toward human serum albumin (HSA), high density lipoprotein (HDL), and malondialdehyde modified low density lipoprotein (MDA-LDL) has been observed for aptasensor. Moreover, the other components of human blood serum samples did not influence aptasensor sensitivity.

Highlights

Low-density lipoproteins (LDL) transfer cholesterol and lipids from the liver to other organs within the plasma
There is no doubt that low density lipoprotein (LDL) particles are the direct cause of atherosclerosis cardiovascular diseases (ASCVDs) [2,3]
50 -ACCTCGATTTTATATTATTTCGCTTACCAACAACTGCAGA-30 with 30 -SH group modification was synthesized by Biomers (Germany). 4-aminothiophenol (ATP), N-(3Dimethylaminopropyl)-N0 -ethylcarbodiimide hydrochloride (EDC), N-Hydroxysuccinimide (NHS), bovine serum albumin (BSA), phosphate buffer saline tablets: 0.01 M phosphate buffer, 0.0027 M potassium chloride, and 0.137 M sodium chloride, pH 7.4 at 25 ◦ C (PBS), 6-mercapto-1-hexanol (6MHol), low density lipoprotein (LDL), human serum albumin (HSA), 4-mercaptobenzoic acid (4-MBA), K2 Fe(CN)6, K3 Fe(CN)6, were purchased from

Summary

Introduction

Low-density lipoproteins (LDL) transfer cholesterol and lipids from the liver to other organs within the plasma. They consist of triglycerides, cholesteryl esters, phospholipids, un-esterified cholesterol, and apolipoprotein B (apoB-100). These particles assume a spherical shape with an average diameter of 22 nm in which an amphipathic shell surrounds a hydrophobic lipid core. This outer shell comprises phospholipids, majority of un-esterified cholesterol and single copy of apoB-100. There is no doubt that LDL particles are the direct cause of atherosclerosis cardiovascular diseases (ASCVDs) [2,3]. Reliable and fast detection of ASCVDs biomarkers, such as LDL is extremely important in order to start treatment as early as possible [5]

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Results

Conclusion