Carboxybetaine Modified Interface for Electrochemical Glycoprofiling of Antibodies Isolated from Human Serum

Abstract

Impedimetric lectin biosensors capable of recognizing two different carbohydrates (galactose and sialic acid) in glycans attached to antibodies isolated from human serum were prepared. The first step entailed the modification of a gold surface by a self-assembled monolayer (SAM) deposited from a solution containing a carboxybetaine-terminated thiol applied to the subsequent covalent immobilization of lectins and to resist nonspecific protein adsorption. In the next step, Sambucus nigra agglutinin (SNA) or Ricinus communis agglutinin (RCA) was covalently attached to the SAM, and the whole process of building a bioreceptive layer was optimized and characterized using a diverse range of techniques including electrochemical impedance spectroscopy, cyclic voltammetry, quartz crystal microbalance, contact angle measurements, zeta-potential assays, X-ray photoelectron spectroscopy, and atomic force microscopy. In addition, the application of the SNA-based lectin biosensor in the glycoprofiling of antibodies isolated from the human sera of healthy individuals and of patients suffering from rheumatoid arthritis (RA) was successfully validated using an SNA-based lectin microarray. The results showed that the SNA lectin, in particular, is capable of discriminating between the antibodies isolated from healthy individuals and those from RA patients based on changes in the amount of sialic acid present in the antibodies. In addition, the results obtained by the application of RCA and SNA biosensors indicate that the abundance of galactose and sialic acid in antibodies isolated from healthy individuals is age-related.

Stable mesoporous ZnFe2O4 as an efficient electrocatalyst for hydrogen evolution reaction

“…Electrochemical impedance spectroscopy (EIS) was also presented to discuss electron-transfer kinetics in HER, and it was performed at an overpotential of -100 13 mV vs. RHE. The obtained Nyquist plots of ZFO-EN-700 and ZFO-700 are shown in Fig.…”

“…Nickel complexes containing proton relays or redox-active pincer ligand were proved to exhibit excellent catalytic performance [10,11]. In recent reports, some peptides, proteins and some carbohydrates have also been applied in HER [12,13].…”

Recent Progress in Electrochemical Biosensors for Glycoproteins

“…According to this protocol, various lectins including Sambuccus nigra agglutinin (SNA), Maackia amurensis agglutinin, and Ricinus communis agglutinin (RCA) have been covalently immobilized on carboxyl-terminated SAM-modified electrodes to prepare glycoprotein sensors [67,68,69,70]. The SNA-immobilized sensors show ultrasensitive detection limits as low as 0.33 fM for fetuin and 0.54 fM for asialofetuin in impedimetric measurements [67].…”

“…Carboxybetaine thiols are also effective for the preparation of SAMs to which lectins can be covalently immobilized. Impedimetric sensors prepared using carboxybetaine SAM with SNA have been used for glycoprofiling of antibodies isolated from the human sera of rheumatoid arthritis patients (RA) and healthy subjects (Figure 4) [69]. …”

Novel Analysis of Glycan Structures: Nanoscale Approach

“…Moreover, using SAMs allows to control a biorecognition element´s density, orientation and anti-fouling properties of our surfaces. [6] Using nanomaterials like gold nanoparticles of different size or graphene oxide flakes leads to improved characteristics of prepared deviceselectrochemical and impedimetric biosensors in this case. Electrochemical devices, mainly in combination with different nanostructures, provide cheap, highly reliable and sensitive platform for glycomic analyses.…”