An improved technique for updating a memory in digital pixel sensors in which a memory update may be directed to only some of the locations or cells in the memory is disclosed. The energy generated from tissue displacement is stored and made available for use as a cardiac pacing charge to be delivered by the device when a triggering condition, such as an arrhythmia is detected. In one embodiment, methods of making the modified neurotoxin include using recombinant techniques. The liquid crystal layer comprises a liquid crystal composition having an electronic carrier-transporting function and comprising at least two compounds including at least one electron-donating compound or electron-accepting compound having a -electron conjugated structure.