Speeding up sensor response times by modifying the geometry of the fluidic channel of a disposable array compatible sensor housing for surface acoustic wave biosensors

Abstract

We describe an array compatible sensor housing for surface acoustic wave (SAW) based biosensors. The sensor housing is produced by injection molding as a mass market compatible production technology and embedded into this sensor housing by a fully automated assembly unit. A major advantage of our sensor housing is the fact that the sensitive sensor surface remains accessible for surface modification even after the embedding of the sensor into the housing. Single sensor housings can be combined to flexible sensor arrays by means of a second component, the fluidic cover. In order to speed up sensor response times we will demonstrate a design feature of this setup that allows us to easily decrease the height of the flow channel above the sensor by a slight geometric modification of the fluidic cover. We will compare five different modifications of our setup, each featuring a different sample channel height. Reducing the flow channel's height significantly reduces diffusion effects due to a reduced thickness of the Nernst diffusion layer above the sensor. This directly translates into decreasing sensor response times. The reduction of the flow channel's height allows furthermore the significant reduction of the effective sample volume above the sensor from 4.8 μl (former flow cell setup) down to 160 nl. We will compare these modifications with the initial housing setup and with a formerly used setup featuring a flow cell with respect to effective sample volume and sensor response times. © 2009 Springer-Verlag.