Biosensors group has extensive know-how and experience in laboratory research with acoustic wave sensors (Surface Acoustic Wave (SAW) and QCM). The Love wave biosensor, a SAW-based waveguide device originally developed by Prof. E. Gizeli (Sensor Actuat 1992, Patent WO9201931), is a system routinely used for the propagation and detection of shear acoustic waves in a frequency range of 100 to 300 MHz. Today, the lab is also using a plethora of different commercially available or home-made devices to test novel concepts on acoustic sensing and develop integrated platforms. An ongoing research interest involves the design and manufacturing of acoustic wave devices both in a single and multi-channel array format. Devices in an array format are desirable since they will require low volumes of consumables, thus, creating the potential for multiple testing. Acoustic SAW-type biochips are currently developed in collaboration with Dr JM. Friedt from Femto-ST Institute and the Franche-Comté University, France and our industrial partner Senseor, France.
Novel device geometries
In addition to the Love wave devices, a new project involves the design and fabrication of Lamb acoustic wave biosensors. The goal of this work is the fabrication of novel acoustic chips using materials such as Si, GaN and AlN (Appl Phys Lett 2010); this choice of materials will make the sensors compatible with compound semiconductor processing techniques, in contrast to the standard piezoelectric (quartz and lithium niobate etc) materials applied so far. This means that the sensor may serve as an element to a larger system (i.e., a Lab-on-a-Chip). This approach, developed in collaboration with Dr G. Konstantinidis from the Microelectronics Research Group, IESL-FORTH, Greece offers the advantage of providing a fully monolithically integrated system easily applicable to biodetection and point-of-care diagnostics.
Microfluidics-on-SAW and integrated diagnostic platforms
The future of biomedicine is strongly associated with the development of sensitive detection tools that take advantage of current advancements in engineering. The field of biomedical engineering builds upon mathematics, physics and biochemistry in order to provide solutions to medicine and the biomedical sciences. Among the research interests of our lab is the development of highly integrated and user-friendly systems that are based on a lab-on-a-chip concept and are capable of generating faster and more sensitive results. We have revolutionized acoustic sample detection by introducing the microfluidic-on-SAW (μF-on-SAW) concept; instead of carrying out the traditional “one-sample-per-sensor” detection strategy, we designed and developed a special microfluidic module, which results in a parallel multi-channel configuration (J MEMS 2008). The advantage of this approach, developed in collaboration with Dr A. Tserepi from NCSR-Demokritos, is that, in a standardized and cost-effective way, the number of microchannels on each SAW device can vary from 4 to 10 according to the desired application, reaching the “many-samples-per-sensor” regime. The potential of the μF-on-SAW platform has been demonstrated during the fast, sensitive and reproducible detection of four cardiac markers (Anal Chim Acta 2011). Combination of the μF-on-SAW with Dip Pen nanolithography also resulted in the fast and efficient pre-functionalization of the microfluidic areas (Analyst 2012). The development of efficient microfluidic modules on SAW is an ongoing effort in our lab, currently carried out in collaboration with our industrial collaborator Jobst Technologies, Germany.