Microfluidic devices, along with methods of their fabrication, are provided. The microfluidic device can include a substrate defining a microchannel formed between a pair of side walls and a bottom surface and a plurality of nanotips positioned within the microchannel and proximate to each side wall such that a boundary layer is formed along each side wall between the plurality of nanotips and the side wall upon addition of a liquid into the microchannel.