Bioassay of proteins in stable solution state using a novel cantilever-based liposome biosensor

We have developed a micro-cantilever biosensor with embedded NiCr thin film strain gauge. Meanwhile, DPPC liposomes have been selected as sensing biomolecules to be immobilized on the surface of the micro-cantilever. The liposome-protein interaction was detected by measuring the resistance change rate of the strain gauge. In this work, a PDMS-based sealed reservoir structure was newly fabricated and added on the sensor to keep the target solution stable, where a long-time stable detection was achieved. The resistance of the cantilever-based biosensor increased with time in lysozyme or carbonic anhydrase from bovine (CAB) aqueous solution, and the characteristic of chronological resistance change varied with the concentration and kind of the proteins. It is expected that the micro-cantilever sensor with droplet-sealing structure can be used for bioassay of various proteins in future.