In this work we report on the optical properties of specific synthetic carbon nano-dots (CDs) and their suitability for the development of optical biosensors. We examine the photoluminescence behavior of these CDs under different conditions, in their native form, as well as when conjugated to the catalytic protein glucose oxidase (GOx) for the construction of optical glucose biosensors. The effect of pH and hydrogen peroxide on the observed spectra is examined as the basis for the biosensor development. The CDs examined here have inherent surface amino functional groups which allow for easy conjugation to biomolecules via EDC-NHS, providing a well defined platform for biosensing applications. We conclude that the well controlled, stable, and highly efficient fluorescence behavior of the CDs in solution or in conjugate, provides the grounds for this class of materials to be used in a variety of arrangements for the development of optical and optoelectrochemical detection systems.