Once viewed solely as a tool to analyse biomolecular interactions, biosensors are gaining widespread interest for diagnostics, biological defense, environmental and quality assurance in agriculture/food industries. Advanced micro fabrication techniques have facilitated integration of microfluidics with sensing functionalities on the same chip making system automation more convenient1. Biosensor devices relying on lab-on-a-chip technologies and nanotechnology has attracted much of attention in recent years for biological defense research and development. However, compared with the numerous publications and patents available, the commercialization of biosensors technology has significantly lagged behind the research output. This paper reviews the reasons behind the slow commercialisation of biosensors with an insight to the critical stages of a biosensor development from the sensor chip fabrication to surface chemistry applications and nanotechnology applications in sensing with case studies. In addition, the paper includes the description of a new biodetection platform based on Real-time Electrochemical Profiling<sup>TM</sup> (REP<sup>TM</sup>) that comprises novel electrode arrays and nanoparticle based sensing. The performance of the REP<sup>TM</sup> platform has been tested for the detection of Planktothrix agardhii, one of the toxic bloom-forming cyanobacteria, usually found in shallow fresh water sources that can be used for human consumption. The optimised REP<sup>TM</sup> assay allowed the detection of P. agardhii DNA down to 6 pM. This study, showed the potential of REP<sup>TM</sup> as a new biodetection platform for toxic bacteria and hence further studies will involve the development of a portable multi-analyte biosensor based on REP<sup>TM</sup> technology for on-site testing.