Molecular machines are tiny structures made up of molecules that can perform specific tasks at the nanoscale. They operate similarly to mechanical machines but are much smaller, often found in biological systems. Examples include motor proteins that help transport materials within cells and DNA nanomachines that can change shape in response to environmental signals. These machines can be engineered for various applications, including drug delivery and nanotechnology. Researchers are exploring how to design and control these molecular systems to create new technologies, such as smart materials that respond to stimuli or biological sensors that detect diseases.