Zinc detection in the islet of Langerhans by SIMS

We have performed the TSQ (a Zn ²⁺ fluorescent probe) staining of the rat pancreas. TSQ fluorescent images correlated with the anti-insulin positive area, islet of Langerhans. Ion microscopy of the freeze-dried and fresh-frozen ultra-thin section (100 nm) of isolated islets disclosed specific existence of zinc (Zn) as the zinc ion images ( ⁶⁴ Zn) and the cesium-zinc cluster ion images ( ⁶⁴ Zn ¹³³ Cs). However, in the semi-thin section (10 μm), the ⁶⁴ Zn and the ⁶⁴ Zn ¹³³ Cs were not restricted to the islet without any coating by SIMS. The incinerated semi-thin section were investigated to obtain high detection sensitivity for the ⁶⁴ Zn ion by ion microscopy. The clear images of ²³ Na and ³⁹ K, as the morphological convenient check, were got as strong signals on the burned specimen. Signals of the ⁶⁴ Zn and the ⁶⁶ Zn ion were observed over the islet and acini. The ⁶⁸ Zn isotope ion image was restricted to islet cells as observed by TSQ. Our finding suggests that the method of incineration may be a simple and highly sensitive method for the Zn detection in the islet of Langerhans as well as the acini.