Packaging of surface acoustic wave (SAW) based biosensors: an important issue for future biomedical applications

SAW devices, based on horizontally polarized surface shear waves (HPSSW) enable label-free, sensitive and cost-effective detection of biomolecules in real time. Early results have shown the importance of small sampling volumes with low inner surface areas as well as minimal mechanical stress arising from scaling elements of miniaturized sampling chambers. In this paper, we present a new way to integrate SAW devices with the sampling chamber: the sensor device is completely packed within a polymeric housing produced by stereo lithographic methods. The resulting polymer chip serves as a tight, durable but still disposable package for HPSSW biosensors which are completely encapsulated within the polymer chip. It includes a small sampling channel with a sample volume of only 374 nl per chip. Several preliminary experiments with these chips are shown to characterize the performance for their future application as a generic bioanalytical micro device.