James Clerk Maxwell originally conceived his thought experiment as a hypothetical being able to capture information about a system, apparently against the second law of thermodynamics. Later on, his demon was “exorcised” when theoretical work suggested that it cannot use the information gained on the system without memorizing it and that the erasure of this information to reset the measurement device comes at an energetic cost, so as to preserve the laws of physics. Today, physicists and chemists try to prove the physical dimension of information by quantifying the relationship between information and energy and try to implement concrete information-driven devices.
For an application of Maxwell’s demon to biological problems, see:
Binder P, Danchin A (2011) Life’s demons: information and order in biology. What subcellular machines gather and process the information necessary to sustain life? EMBO Reports 12: 495–499
For a deeper incursion into the relationships between information and energy and the possibility to create molecular devices making use of information, see:
Serreli V, Lee CF, Kay ER, Leigh DA (2007) A molecular information ratchet. Nature 445: 523–527
Lutz E, Ciliberto S (2015) Information: from Maxwell’s demon to Landauer’s eraser. Physics Today 68: 30