Jennifer Lewis, Sc.D. of the Wyss Institute for Biologically Inspired Engineering at Harvard University and her lab partnered with J. Daniel Berrigan, Ph.D. and Michael Durstock, Ph.D. at the US Air Force Research Laboratory to develop a new 3D printing technique for soft electronics, called Hybrid 3D printing. The technology basically involves shaping of the wearable electronics according to the user. For this, it involves use of conductive, stretchable 3D printing material made from TPU mixed with silver flakes. Other electrical components included parts like LEDs, resistors and micro-chips.
Source: http://onlinelibrary.wiley.com/doi/10.1002/adma.201703817/full