In-plane microneedle chip fabricated by crystalline wet etching of (110) silicon wafer

In this research, simple crystalline wet etching of (110) silicon is employed to fabricate an in-plane silicon microneedle chip, which is composed of microneedle tips, microchannels and reservoir. The required penetration forces to insert the fabricated microneedles into the skin of chicken breast flesh without failure were 70 mN (500 µm in displacement) and 250 mN (2 mm in displacement) for a single tip and five tips, respectively.