Biosensor Design

With the experiments detailed,  the translocation of EcoR124I has been successfully characterised and this allows its development and incorporation into various biosensing systems. The EcoR124I system can be used directly as a negative response sensor, with complex formation and translocation being directly affected by hydrophobic compounds, DNA-binding drugs, dioxins and other toxins.  In  addition the EcoR124I system will be incorporated into a more complex biosensing device as a nanoactuator single-molecule sensing system, which is the transducer of a generic biosensor. In conjunction with a molecular response element (MREs) this device will provide a generic biosensor for identification and quantification of specific molecules at very low concentrations (Figures 10 and 11). This work is funded by the BioNano-Switch Project (EC funding under the NEST Synthetic Biology scheme.  A model system that detects and quantifies thrombin concentrations has already been designed and tested.

 

Figure10    Biosensor Transducer

A view along a microchannel showing the electronic sensors on the floor of the channel (which detect the vertical movement of the magnetic bead) and above which the DNA substrate is surface attached.  The gold-coloured spheres are the magnetic beads attached at the other end of the DNA substrate (not to scale).  The EcoR124I molecular motor comprises a core DNA-binding unit (vertical green objects on the DNA) and the motor subunit (horizontal green objects), which readily assembles and disassembles from the DNA following translocation.  The motor ‘pulls’ the DNA toward itself and thus ‘pulls’ the magnetic bead toward the sensor providing an electronic output from a biological input (in the form of ATP – the fuel).