The wide success of PGMs is largely due to their portable ‘pocket’ size, low cost, reliable quantitative results and simple operation. With their recent integration into mobile phones (for an example of a glucose meter integrated with the Apple iPhone, see http://ibgstar.com/web/ibgstar), PGMs are likely to find an even wider base of users. Although a number of other methods have been developed to quantitatively detect targets of interest using simple instruments, most such sensing devices have not been able to match the PGM in its wide commercial availability to the public. However, the PGM is still limited in that it can detect only a single target, glucose.