Real-time characterization of fibrillization process of amyloid-beta on phospholipid membrane using a new label-free detection technique based on a cantilever-based liposome biosensor.

The dynamic behavior of amyloid-beta protein (A beta) fibrillization on cell membrane is closely related to the progression of Alzheimers disease (AD). In this paper, we reports a new approach for real-time monitoring of the fibrillization process of A beta on lipid membrane using a miniaturized cantilever-based liposome biosensor, which contributes to the technology development of A beta label-free detection and the mechanism elucidation of A beta fibrillization on cell membrane. 1,2-Dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposome as model cell membrane was immobilized on the cantilever surface and A beta(140) was selected as a target protein in this work. Liposome-A beta interaction is evaluated by detecting the resistance change rate of the strain gauge embedded in the cantilever, which is directly proportional to the deflection of cantilever. 24-h real-time monitoring result clearly shows chronological change in the resistance with the progress of A beta fibrillization on liposomes. Moreover, it is found that the extent of liposome-A beta interaction is closely dependent on the aggregate state and concentration of A beta but is less dependent on the type of used solvent (water or serum). It is indicated that DPPC liposome shows sufficient affinity and selectivity to A beta even in serum. In particular, a concentration of A beta as low as 1 mu M can be detected using the cantilever-based liposome biosensor. Furthermore, it is confirmed that this biosensor has a potential of recognizing different states of A beta. We expect that the cantilever-based liposome biosensor becomes an effective tool for accelerating amyloid related research and developing the early diagnosis approach of AD. (C) 2016 Elsevier B.V. All rights reserved.