Overview of Piezoelectric Biosensors, Immunosensors and DNA Sensors and Their Applications

Abstract

Piezoelectric biosensors are a group of analytical devices working on a principle of affinity interaction recording. A piezoelectric platform or piezoelectric crystal is a sensor part working on the principle of oscillations change due to a mass bound on the piezoelectric crystal surface. In this review, biosensors having their surface modified with an antibody or antigen, with a molecularly imprinted polymer, with genetic information like single stranded DNA, and biosensors with bound receptors of organic of biochemical origin, are presented and discussed. The mentioned recognition parts are frequently combined with use of nanoparticles and applications in this way are also introduced. An overview of the current literature is given and the methods presented are commented upon.

Keywords: QCM; acoustic sensor; affinity; anisotropy; biosensor; immunosensor; label free; oscillation; piezoelectric; quartz crystal microbalance.

Figure 1

Piezoelectric immunosensors for the determination of an antigen (a) or an antibody (b). A piezoelectric crystal is depicted as a blue disc. The antibodies are shaped like Y letter because of typical appearance of common immunoglobulins; an antigen is drawn as a red ball.

Figure 2

Photograph of a commercially available Quartz Crystal Microbalance sensor with silver electrodes. Scale in millimeters is in the bottom of the photograph.

Figure 3

Piezoelectric immunosensors for the determination of an antigen (red ball) and increase of oscillations by application of a nanoparticle (yellow ball) covered with immunoglobulins (Y shaped). Blue disc represents a piezoelectric crystal.

Figure 4

Covering of crystal with a Molecularly Imprinted Polymer and following assay of an analyte chemically identical or close to the template.

Figure 5

Principle of a DNA piezoelectric biosensor. The picture represents an idealized biosensor, real biosensors can be modified in their principle. In the first step, double stranded DNA in a sample is denatured by, for example, heat. In the second step, single stranded DNA hybridizes with complementary DNA strand immobilized on a piezoelectric sensor. The hybridization results in decrease of oscillation frequency.

Figure 6

Principle of a DNA piezoelectric biosensor that use a DNA probe labelled with nanoparticles for signal amplifying. In the first step, double stranded DNA in a sample is denatured by, for example, heat. In the second step, single stranded DNA hybridizes with complementary DNA strand immobilized on a piezoelectric sensor. The hybridization results in decrease of oscillation frequency. In the second step, a DNA probe labeled by a nanoparticle is applied and the frequency of oscillations drop again.