Portal de Periódicos da CAPES

Picogram Mass Sensor Using Piezoresistive Cantilever for Biosensor

2004; Institute of Physics; Volume: 43; Issue: 7S Linguagem: Inglês

10.1143/jjap.43.4663

1347-4065

Hayato Sone, Haruki Okano, Sumio Hosaka,

Advanced MEMS and NEMS Technologies

A harmonic vibrator using a piezoresistive cantilever has been developed for a picogram mass biosensor. We constructed a prototype vibrator sensor using the cantilever, Wheatstone bridge circuits, positive feedback controller, a piezoactuator and a phase-locked loop (PLL) demodulator. As experimental results, a mass sensitivity of 2.2 pg/Hz was obtained from water molecular adsorption on the cantilever. We confirmed that the mechanism of water molecular growth has 2 modes, island growth and layer growth. The critical point of the mechanism change was a humidity of about 42%. At the critical point, the adsorbed mass corresponds to the water layer of about 13 monolayers.