This EAGER proposal, augmenting basic materials and device research in integrated polymer/living tissue structures, opens an exciting new area in engineered materials. Upgrading from the planned inkjet printer to the new generation of materials plotters in this exploratory project will enable the rapid integration of organic structural, sensor, actuator and electronic components into fully functional devices at many scales. The applications for robotics and cyber-physical systems include 3D polymer MEMs with integrated organic electronics, neurons and even muscle tissue into polymer mechanical devices, variable-focus vision systems and new approaches to polymer muscles.
Broader Impacts: This equipment will advance discoveries in multiple materials and device studies in projects across a number of academic departments. The research will broaden participation by providing the critical hardware for three female PhD students in the PI's labs, two of which are funded by NSF GRFs. The equipment will be made broadly available through a new user-service facility, enhancing infrastructure in multiple disciplines.
The goals of this project were to investigate a new class of micro-device in which polymeric electro-mechanical systems are hybridized with living cells that function as high-performance actuators, sensors or decision-making elements. The specific tool funded was a "materials plotter" which was used to fabricate soft organic electronics. The primary outcomes were 1) demonstration of skeletal muscle cells co-fabricated with a soft-polymer hydrogel scaffold and 2) organic electrochemical transistors fabricated by a combination of standard lithography and the materials plotter. The first result uses optical tweezers to precisely position skeletal muscle precursor cells (or "myoblasts") and then harden the surrounding liquid into a polymer hydrogel. This "pick and place" of cells combined with a 3D printer enables complex polymer architecture to be created with integrated biological cellular function. The second result is a relatively new form of transistor that uses ions as an intermediate charge carrier. Ions are critical for charge mobility in conducting poylymers, making it relatively easy to modulate the electrical conductivity of these polymers by electrostatically injecting ions. These "iontronic" transistors are very good candidates for electrical/cellular interface because they are very sensitive and also because cells naturally use ions as control mechanisms. The ongoing research will combine these two results in order to electrically stimulate individual muscle cells or groups of muscle cells as a new form of micro-actuator.
