A Three-Dimensional Enormous Surface Area Aluminum Microneedle Array with Nanoporous Structure

Figure 2

The AAO surface area and SEM images; (a) evaluated curves of AAO surface area based on a 1 cm² substrate, (b) AAO with 15 nm pore size, (c) AAO with 60 nm pore size, and (d) AAO with 500 nm pore size.

(a)

(b)

(c)

(d)