text: Copper is a biologically important metal to detect. It has many sensors developed for it including:
  *CTAP-1, a sensor that shows a response in the UV region when Cu(I) binds to an azatetrathiacrown motif that in turn excites a pyrazoline-based dye that is attached. To use the probe, one excites it at 365 nm. If it is bound to Cu, then it will increase its fluorescence intensity. CTAP-1 is effective as it has a large modulation in its spectrum upon binding Cu, and is selective for the binding of Cu over other metals.
  *Coppersensor-1 (CS1) that comprises a thioether rich motif that binds to Cu(I) causing the excitation of a boron-dipyrromethene (BODIPY) dye in the visible region. The probe has good selectivity for Cu(I) over alkaline earth metals, Cu(II), and d-block metals.