A multiplex hand-held diagnostic biosensor, using two inflammatory salivary biomarkers, Human Neutrophil Elastase (HNE) and Cathepsin-G, was constructed made to potentially detect Periodontitis at an early stage is described. The use of magnetic nanoparticle biosensor method used as a device was based on the measurement of proteolytic activity using specific proteases probes. The magnetic nanoparticle biosensor device is capable of specific and quantitative detection of HNE and Cathepsin-G in solution and in spiked saliva samples with a lower detection limit of 1 pg/mL and 100 fg/mL for HNE and Cathepsin-G, respectively.