Electrochemically Active Alginate: Development, Fabrication and Application

The work presented here develops a new type of electrochemically active hydrogel based on alginate. By oxidizing a copper electrode in the presence of alginate, it is shown that the alginate will become cross linked at the electrode surface. By modulating the growth time or growth potentials, the mechanical properties of the gels can be modulated, with time being the easiest to control. It was also shown that with the reduction of the copper ions in the gel, the structure can be de-cross linked. This mechanism was harnessed to provide fluidic delivery of a small molecule representing a drug, with the optimum growth conditions for this applications found to be the application of a 2.5 V potential difference for one hour versus an aluminum counter electrode. Constructing a device from this gel, it was shown that the rate of fluidic release can be modulated by varying the potential between 1 and 5 volts potential difference. Finally, this process was further developed into a new printing technique, allowing for the printing of gradient structures with a continuum of densities throughout the structure.