Abstract: Compositions and methods are provided for genetically modifying cells to guide in situ chemical synthesis of electroactive, conductive, or insulating polymers on plasma membranes, organelle membranes, or subcellular surfaces of cells. In particular, compositions and methods are provided for genetically modifying excitable cells such as neurons, muscle cells, and endocrine cells to guide in situ chemical synthesis of polymers on the extracellular side of the plasma membrane. The subject methods can be used in various applications, for example, to assemble polymers in vivo at targeted locations to modulate electrical conduction and create new electrical conduction pathways, allow cell-type-specific neuromodulation, provide a conductive structure on cells for connection to electrodes, sensors, or other external electronic and electrochemical devices, and create a durable structure to replace damaged tissue for use in regenerative medicine.

Abstract: Three-dimensionally (3-D) shaped interpenetrating double network (IPN) hydrogel based on a first network and a second network are provided. The 3-D shape is characterized by a non-uniform distribution of the second network (e.g. carboxylic acid groups) when in hydrated state. The 3-D shape can further be characterized by changes in the radius of curvature of the shape. The 3-D IPN hydrogel is created by applying a non-uniform illumination pattern to polymerize the second network of monomers within a layer of a first network. In hydrated state, the second network causes a swelling force that is resisted by the first network. The non-uniformal distribution of the second network with the first network is responsible for the 3-D of the resulting IPN. The invention can find use in ophthalmic applications as well as non-ophthalmic applications.