This IEEE Sensors paper by Truong, Handel, and Fraundorf examines quantum 1/f biochemical detection limits in THz signatures revealed by scanning tunneling microscopy currents. The research investigates using scanning tunneling microscope (STM) tunnel currents to detect terahertz vibrational signatures of biological molecules, analyzing how quantum 1/f noise in the tunneling current establishes fundamental detection limits for identifying biomolecules through their characteristic THz absorption fingerprints, with applications to single-molecule detection, protein identification, and nanoscale biosensing.