A possible application of the Hrp system is in the biofilm detector system. According to the specifications of the detector, the AHL levels processed will be around 0.1nM. Without the Hrp system, i.e. simply having a pLux promoter, only basal levels of expression of reporter will be achieved. With the amplification provided by the Hrp system (as demonstrated by Device 1 ) even this low input will provide high expression levels of the detector. This is illustrated in the graphs below.
The Biofilm system focuses on detecting biofilm formation on medical equipment usually indicating the presence of a pathogenic organism. Therefore, apart from responding to low levels of AHL, the system must also have a fast response time otherwise its use will be fairly limited. This is another area that can be enhanced with the use of Hrp. Being based on sigma factor kinetics, it is much faster than the average biological component. Hence by inlcuding Hrp, we decrease significantly the repsonse time of our overall system. The way that this is incorporated in the design of the Biofilm system is shown below.