A nanofibrillar structure for cell culture and tissue engineering is disclosed. The cross-linked metal complex may be formed by cross-linking a cross-linkable iridium complex, which comprises a set of ligands coordinated to a central iridium atom. These properties are possible by incorporating a filter dye having a \u03bbmax of from about 300 to about 500 nm into the imageable layer of the imageable elements. A large electric power accumulator is provided to store electric power when the generator is able to produce excess power and the accumulator may deliver power along with the generator to drive the rods and deliver acoustic energy.