In this work, we demonstrate the immobilization of carboxylic acid moieties on the surface of ZnO nanowires and its potential for biosensing applications. ZnO nanowires were synthesized via Chemical Vapor Deposition (CVD) technique and appropriately characterized. Vibrational spectroscopic techniques were used to determine nature of bonding and orientation of oleic acid molecule at nanowire surface, which is used as model system. Furthermore, on the basis of photoluminescence data on modified- and unmodified ZnO nanowires with oleic acid, a generic approach to sense biomolecules along with mechanism of sensing is proposed.