Loading...
Publication
Development of biosensors for molecular analysis
| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 4.08 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
This thesis deals with the application of piezoelectric sensors, namely quartz crystal
microbalances (QCM), for the study of molecular interactions and for biomedical purposes.
Piezoelectric transduction allows the detection of biorecognition events and its operation
depends on the mechanical vibration of the crystal whose resonance frequency is sensible to
surface mass changes. But in liquid medium these sensors also respond to the properties of
solutions and adsorbed films. Thus, a major aspect explored in this thesis is the expansion of
the physical understanding of the behavior of these sensors in liquid medium and also how
organic or biological layers can affect the results and their interpretation. This was achieved
using impedance analysis where the behavior of the piezoelectric sensor is interpreted with
the help of equivalent electric RLC circuits. The potential electroacoustic interference of
charged species in solution was particularly studied and a new equivalent circuit is proposed
in order to detect and quantify these effects with the assistance of impedance analysis.
The efficiency of the key steps taken for the development of our QCM system, was
experimentally demonstrated with the qualitative and quantitative analysis of the process of
ii
11-hydroxy-1-undecanothiol SAMs (self-assembled monolayers) formation and the
recognition of streptavidin in aqueous medium using biotin modified sensors.
Finally the work was focused on the development of a new detection tool for the HIV1 virus
using piezoelectric immunosensors based on recombinant antibodies to detect the Vif
molecule (virion infectivity factor). The developed immunosensors selectively detected Vif in
aqueous solutions and presented specificity and good sensibility when detecting the target
protein in complex samples like mixtures of proteins and cell extracts.
Description
Tese dout., Ciências Biotecnológicas, Universidade do Algarve, 2007
Keywords
Teses Biotecnologia Bio-sensores