There is an urgent need to develop highly selective, sensitive and reproducible miniaturized bio-sensing platforms based on reliable interfaces is compatible with microfabrication processing. Our objective is to first create pyrolyzed carbon micropillar arrays with high surface area as bio-sensing electrodes, second to develop functionalization methods in order to improve the biomolecule immobilization efficiency and finally to understand the electrochemical phenomena occurring at the biomolecule/carbon interface. The carbon micropillar arrays with high aspect ratios and hierarchical porous surface have been fabricated by carbon microelectromechanical systems (C-MEMS). Nanomaterials have been integrated onto the micropillar arrays to further increase the accessible surface area and in order to achieve efficient covalent immobilization of biomolecules, various functionalization methods have been investigated. The developed bio-sensing platform was then applied to several applications including DNA sensors; H2O2 sensors, aptamer sensors and HIV sensors.