as molecular recognition species toward many analytes. For a receptor to recognize a specific target, its immobilization on a solid support must not interfere with molecular recognition. Although a variety of immobilization methods have been adapted from standard chromatographic support modifications, many sophisticated immobilization techniques have been developed recently. [3] Knowledge of the basic mechanisms by which the reactive groups couple to target functional groups provides the means to design a conjugation strategy. Since the development of Clark's oxygen-sensing electrode in the midtwentieth century, numerous strategies for biosensor designs have emerged. New avenues with various approaches exploiting ongoing discoveries in biology, electronics, physics, and chemistry have significantly expanded the opportunities for biosensor applications. Miniaturization and implantable devices are still significant challenges facing biosensor technology, although progress is being made toward these goals. The application of miniaturization techniques to optical molecular sensors has resulted in their potential use for inaccessible, difficult, or dangerous locations, for example, in vivo sensors for arterial use. In this Highlight, we will present a new detection modality based on terahertz time-domain spectroscopy (THz-TDS). We concentrate on a THz biodetection approach that expands over many disciplines and applications. The uniqueness, limitations, and potential capabilities of the THz biosensor will be reviewed in light of recent developments. [4, 5]