A method is provided to prepare one or more microfluidic channels on a receptive material by applying an image-forming material to a heat sensitive thermoplastic receptive material in a designed pattern and heating the material under conditions that reduce the size of the thermoplastic receptive material by at least about 60%. In an alternative aspect, the microfluidic channels on receptive material are prepared by etching a designed pattern into a heat sensitive thermoplastic material support and then heating the material under conditions that reduce the size of the thermoplastic receptive material by at least about 60%.