Exosomes/microvesicles are known to shuttle biological signals between cells, possibly by transferring biological signal components such as encapsulated RNAs and proteins, plasma membrane proteins, or both. Therefore exosomes are being considered for use as RNA and protein delivery vehicles for various therapeutic applications. However, living cells in nature secrete only a small number of exosomes, and procedures to collect them are complex; these complications impede their use in mass delivery of components to targeted cells. We propose a novel and efficient method that forces cells through hydrophilic microchannels to generate artificial nanovesicles. These mimetic nanovesicles contain mRNAs, intracellular proteins and plasma membrane proteins, and are shaped like cell-secreted exosomes. When recipient cells are exposed to nanovesicles from embryonic stem cells, mRNAs of Oct 3/4 and Nanog are transferred from embryonic stem cells to the target cells. This result suggests that mimetic nanovesicles can be used as vehicles to deliver RNA. This nanovesicle formation method is expected to be used in exosome research and to have applications in drug and RNA-delivery systems.