Metal microneedle fabrication using twisted light with spin.

Microneedle fabrication on a metal surface based on laser ablation using twisted light with spin was demonstrated, for the first time. The resulting needle showed a height of at least 10 microm above the target surface and a tip diameter of less than 0.3 microm. We also demonstrated the fabrication of a two-dimensional 5 x 6 microneedle array. The needles were uniformly well shaped with an average length and tip diameter of about 10 and 0.5 microm, respectively.