In-plane silicon microneedles with open capillary microfluidic networks by deep reactive ion etching and sacrificial layer based sharpening

•The deep reactive ion etching (DRIE) of in-plane silicon microneedles is presented.•A needle sharpening process is developed using sacrificial layers (remaining unetched silicon).•The wedge-shaped needle is sharpened to conical structure tapering from the base to the apex.•The sharp microneedles have been demonstrated to be sufficiently robust for skin penetration.