In this study, we show that synthetic sapphire (Al2O3), an established implant material, can also serve as a platform material for biosensors comparable to nanocrystalline diamond. Sapphire chips, beads, and powder were first modified with (3-aminopropyl) triethoxysilane (APTES), followed by succinic anhydride (SA), and finally single-stranded probe DNA was EDC coupled to the functionalized layer. The presence of the APTES-SA layer on sapphire powders was confirmed by thermogravimetric analyis and Fourier-transform infrared spectroscopy. Using planar sapphire chips as substrates and X-ray photoelectron spectroscopy (XPS) as surface-sensitive tool, the sequence of individual layers was analyzed with respect to their chemical state, enabling the quantification of areal densities of the involved molecular units. Fluorescence microscopy was used to demonstrate the hybridization of fluorescently tagged target DNA to the probe DNA, including denaturation- and re-hybridization experiments. Due to its high thermal conductivity, synthetic sapphire is especially suitable as a chip material for the heat-transfer method, which was employed to distinguish complementary- and non-complementary DNA duplexes containing single-nucleotide polymorphisms. These results indicate that it is possible to detect mutations electronically with a chemically resilient and electrically insulating chip material. ; This work is supported by the Life-Science Initiative Limburg and the Research Foundation Flanders FWO (Projects G.0829.09, Synthetic diamond films as platform materials for novel DNA sensors based on electronic detection techniques and G.0B62.13N, Exploration of heat conductivity effects for applications in bio- and chemosensors), and the Methusalem project NANO (Antwerp-Hasselt). The authors like to thank Guy Reggers for the TGA measurements, Huguette Penxten for the FT-IR measurements, Kathia L. Jimenez Monroy for the AFM measurements, Matthias van Gompel for providing the Al 2 O 3 chips and Bart Ruttens for sample characterization with Xray diffraction. ; synthetic sapphire; nanocrystalline diamond; heat-transfer method; fourier-transform infrared spectroscopy; thermogravimetric analysis; X-ray photoelectron spectroscopy; confocal fluorescence microscopy; single-nucleotide polymorphisms in DNA