High-throughput analysis of Alzheimer's [beta]-amyloid aggregation using a microfluidic self-assembly of monomersf

The principal histopathological feature of Alzheimer's disease is the presence of [beta]-amyloid (A[beta]) aggregates in the gray matter of the brain, and researchers believe that various environmental factors play significant roles in the conformational change and self-assembly of A[beta] peptides. Therefore, discovering a rapid and convenient analytical method of evaluating the environmental factors on A[beta] aggregation would have a considerable impact. Herein we report our development of a novel microfluidic screening system enabling high-throughput analysis, low-consumption of reagents, and short analytical time. Microchannels with a cross-sectional dimension of 100 [micro]m x 100 [micro]m were immobilized with A[beta] monomers via N-hydroxysuccinimide ester activation of the internal surfaces, and then a fresh A[beta] monomer solution mixed with different small molecules or metal ions was continuously introduced into the microchannels to induce A[beta] aggregation. In this work, we investigated (1) the temporal evolution of A[beta] aggregation within microchannels, (2) the high-throughput screening of the inhibitory effect of 12 small molecules against A[beta] aggregation, and (3) the effect of different metal ions ([Fe.sup.3+], [Cu.sup.2+], [Zn.sup.2+], and [A1.sup.3+]) on A[beta] aggregation by using thioflavin T (ThT)-induced fluorescence microscopy and ex situ atomic force microscopy. The microfluidic system should contribute to a simultaneous analysis of multiple environmental factors affecting amyloid aggregates in a parallel manner and to screen therapeutic small molecules prior to their in vivo evaluation.