Nanoporous protein matrix made of amyloid fibrils of β2-microglobulin

Amyloid fibrils are considered as novel nanomaterials because of their nanoscale width, a regular constituting structure of cross β-sheet conformation, and considerable mechanical strength. By using an amyloidogenic protein of β(2)-microglobulin (β(2)M) related to dialysis-related amyloidosis, nanoporous protein matrix has been prepared. The β(2) M granules made of around 15 monomers showed an average size of 23.1 nm. They formed worm-like fibrils at pH 7.4 in 20 mM sodium phosphate containing 0.15 M NaCl following vigorous nondirectional shaking incubation, in which they became laterally associated and interwound to generate the porous amyloid fibrillar matrix with an average pore size of 30-50 nm. This nanoporous protein matrix was demonstrated to be selectively disintegrated by reducing agents, such as tris-(2-carboxyethyl) phosphine. High surface area with nanopores on the surface has been suggested to make the matrix of β(2) M amyloid fibrils particularly suitable for applications in the area of nanobiotechnology including drug delivery and tissue engineering.