Tethered particle motion

Tethered particle motion (TPM) is a biophysical technique used to study molecular interactions, conformational changes, and dynamics at the single-molecule level. In TPM experiments, a biomolecule (such as DNA, RNA, or a protein) is typically attached (or "tethered") to a surface via one end while the other end is labeled with a fluorescent particle, usually a microsphere or quantum dot.