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

<table>The schematic diagram of aluminum needle formation; (a) aluminum column formation by mechanical cutting, (b), (c) trapezoid-shaped formation by a short time of electropolishing, (d) needle-shaped formation by a long time of electropolishing.</table>

Journal of Nanomaterials

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Figure 3

Figure 3: A Three-Dimensional Enormous Surface Area Aluminum Microneedle Array with Nanoporous Structure 