(444e) Effect of Entanglements in Lipid- and Polymer-Planar Membranes on Nucleation of Amyloid ? and Its Fibril Growth Behavior
AIChE Annual Meeting
Wednesday, October 31, 2018 - 9:00am to 9:15am
Design of biosensor to detect amyloid Î² peptide (AÎ²) from Alzheimerâs disease requires the biocompatible materials with high affinity to AÎ². We then used the biocompatible polymers polymetyl methacrylate (PMMA), polysulfone (PSf), poly(L-lactic acid) (PLLA), and polyvinylpyrrolidone (PVP), together with phospholipid from biomembranes such as 1,2-dioleoyl-phosphatidylcholine (DOPC) and 1,2-dipalmitoyl-phsphatidylcholine (DPPC). Phospholipid- and polymer-based membranes were prepared on the surface of Au electrode of the quartz crystal microbalance (QCM). The accumulated amount of AÎ² based on the frequency change of QCM was in order of PSf > PLLA > DOPC > PMMA ~ PVP ~ DPPC. Generally, the accumulation of AÎ² results in its fibrillation via a nucleation. The fibrillation behavior of AÎ² on these planar membranes was then examined by using a total internal reflection fluorescence miscroscopy combined with a fluorescence probe thioflavin T (ThT). Because ThT can specifically bind to amyloid of AÎ². The nucleation rate of AÎ² on planar membranes was determined from the reciprocal of lag time measured by ThT fluorescence intensity. Nucleation rate of AÎ² was negatively correlated with the molecular weight of polymers. The slope of nucleation rate to molecular weight in the range of more than 100,000 was larger than that in the range below 100,000. This strongly suggested that the entanglements of polymers inhibited the nucleation process of AÎ². The entanglements within planar membranes is a key factor for regulating the formation of AÎ² assemblies on membrane interfaces.