Researchers at Berkeley and National Chiao Tun University in Taiwan released the results of their experiments with 3D printing electronics. They worked with polymers because of their flexibility but because polymers are notoriously poor conductors of electricity, they created a process whereby a polymer is printed with wax 'spacers' that can then be removed and injected with metal. By varying the shape of the metal components, they are able to create different electronics. In a first bid to create a useful application, the team printed a 'smart cap' for a milk bottle which used the electrical impulses produced by growing bacteria in order to wirelessly detect the spoilage of the milk in the container.

Read and see more at: http://3dprint.com/82760/3d-printing...lk-is-spoiled/