QCM Immunosensor Based on Polyamidoamine Dendrimers

Abstract

The poly(amidoamine)(PAMAM) dendrimers of fourth generation (G4) and 1-hexadecanethiol (HDT) has been used for formation of self assembled monolayers on a gold surface for preparation of quartz crystal microbalance (QCM) immunosensor for detection of human IgG. The anti-IgG antibodies were immobilized on a surface of G4-HDT layers or those covered by Protein A. In later case the oriented immobilization of anti-IgG takes place due to preferred interaction of F c portion of antibodies with the Protein A. The detection limit in a flow mode was 7 nM both for biosensor with and without Protein A. However, in the case of Protein A the number of bounded Ab was 1.4 times lower in comparison with those without Protein A. Thus, the sensitivity of the Protein A based sensor was higher due to orientation effect in comparison with randomly oriented Ab at a dendrimer surface without Protein A. Increased concentration of IgG and formation of Ab-Ag complexes resulted in increase of motional resistance, that suggest increased contribution of viscoelasticity, as revealed from impedance analysis. The most important property of the immunosensor was its ability for regeneration using 0.1 M glycine-HCl.

EQCM Biosensors Based on DNA Aptamers and Antibodies for Rapid Detection of Prions

“…In this work we analyzed freshly prepared biosensors. In principle regeneration of aptasensor is possible using high ionic strength (2 M NaCl) [31][32][33], while for antibodies, 0.1 M glycine-HCl may be used [34]. However, success in regeneration depends also on the supporting layers and on the method of immobilisation of biopolymers.…”

Detection of Protein–Aptamer Interactions by Means of Electrochemical Indicators and Transverse Shear Mode Method

“…Although the detection limit was similar in the two cases, the advantage of the aptasensor was its possibility of surface regeneration, which was impossible for an antigen-based biosensor. However, recently it has been shown that immobilization of anti-IgE on the dendrimer surface also allows us to regenerate an immunosensor (Svobodová et al, 2006). The QCM method was recently compared with the electrochemical biosensor assay of thrombin detection .…”

Detection of Abasic Sites in DNA by Electrochemical, Immunoelectrochemical and Acoustic Methods Using OsO4, 2,2′‐bipyridine as a Probe for Unpaired Thymine Residues

“…The acoustic sensor was prepared as follows. The 8 MHz AT-cut quartz crystal (CH Instruments, USA) was first cleaned as reported previously [19] and then incorporated into a flow through system. The cell was previously described in detail [20].…”