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

摘要

The dynamic behavior of amyloid-beta protein (Aβ) fibrillization on cell membrane is closely related to the progression of Alzheimer's disease (AD). In this paper, we reports a new approach for real-time monitoring of the fibrillization process of Aβ on lipid membrane using a miniaturized cantilever-based liposome biosensor, which contributes to the technology development of Aβ label-free detection and the mechanism elucidation of Aβ fibrillization on cell membrane. l,2-Dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposome as model cell membrane was immobilized on the cantilever surface and Aβ(1-40) was selected as a target protein in this work. Liposome-Aβ 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 Aβ fibrillization on liposomes. Moreover, it is found that the extent of liposome-Aβ interaction is closely dependent on the aggregate state and concentration of Aβ 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 Aβ even in serum. In particular, a concentration of Aβ as low as 1 μM can be detected using the cantilever-based liposome biosensor. Furthermore, it is confirmed that this biosensor has a potential of recognizing different states of Aβ. 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.