Microfluidic systems and methods. A microfluidic device for in vitro fertilization comprises a substrate and a plurality of microchannels disposed in the substrate, including an inlet of at least two of the plurality of microchannels arranged on the substrate to align with a fluid-handling device. Another microfluidic system for assaying a plurality of cells comprises a substrate and a plurality of microfluidic channels comprising a source channel, a sink channel, and a cell chamber. An insert for a microfluidic system comprises a substrate configured to be inserted into a dish and a plurality of microscale wells disposed in the substrate. A microfluidic channel comprises a substrate and at least one microchannel having an open inlet, an open outlet, a channel, and an opening in the substrate disposed over a portion of the channel. A device for providing an amount of fluid for a fluidic system comprises a main reservoir, an aspiration well, tubing coupling the reservoirs, and a seal closing the main reservoir. Air tubing having a hydrophobic end extends into the at least one aspiration well.
