A sample probe includes a tip including a distal end for penetrating a cellular membrane, an opening located at or proximal to the distal end, and tip microchannels extending through the tip and communicating with the opening; and a body adjoining the tip and including body microchannels, wherein at least one of the body microchannels communicates with at least one of the tip microchannels. A method for sampling intracellular material includes inserting a probe tip through a cellular membrane; aspirating intracellular material from the cell, through an opening of the tip, and into a first microchannel of the tip; flowing isolator fluid from a second microchannel of the tip into the first microchannel to form a plug of intracellular material; and aspirating the plug and the isolator fluid through the first microchannel.