A conformal coating technique with nanocarbon was developed to enhance the surface properties of alumina nanoparticles for bio-applications. The ultra-thin carbon layer induces new surface properties such as water dispersion, cytocompatibility and tuneable surface chemistry, while maintaining the optical properties of the core particle. The possibility of using these particles as agents for DNA sensing was demonstrated in a competitive assay. Additionally, the inherent fluorescence of the core alumina particles provided a unique platform for localization and monitoring of living organisms, allowing simultaneous cell monitoring and intra-cellular sensing. Nanoparticles were able to carry genes to the cells and release them in an environment where specific biomarkers were present.