PiF

PiF (300 μM/250 μL; tail vein injection; single administration) selectively stains pancreatic β cells and enables detection of reduced β cell mass in Streptozotocin (HY-13753)-induced type 1 diabetic mice. Compared with the pancreas of diabetic mice, the pancreas of control mice shows a fluorescence intensity over 5 times higher, an islet count 3.4 times greater, and a single islet intensity over 2 times higher^[1].
[¹⁸F]PiF (~7.4 MBq; intravenous injection; single administration), as the PET tracer form of PiF, selectively accumulates in pancreatic β-cells of healthy ICR mice, reaching a peak uptake of 16.1 %ID/g at 30 minutes post-injection, and its specific uptake is confirmed by blocking experiments^[1].
Guidelines (The following is our recommended protocol, which serves only as a guideline and should be modified according to your specific needs).

Rapid Visualization of β Cells/Islets in Mouse Pancreatic Tissue
1. Reagent Preparation: Prepare PiF stock solution (dissolved in DMSO), and dilute it to 300 μM with PBS containing 2% BSA prior to use.
2. Procedure:
2.1 In Vivo Injection: Inject PiF working solution (300 μM, 250 μL) into mice via the tail vein.
2.2 Incubation and Tissue Harvest:
Incubate for 1 hour to allow the probe to circulate and specifically accumulate in pancreatic β cells.
Euthanize the mice and rapidly harvest the pancreatic tissue.
2.3 Tissue Freezing (No Fixation/Dehydration Required):
Place the freshly harvested pancreatic tissue directly into Tissue-Freezing Media (TFM/OCT) and freeze it on dry ice.
This optimized protocol skips the traditional steps of 4% paraformaldehyde fixation and 30% sucrose dehydration.
2.4 Sectioning:
Use a cryostat to cut the tissue into 20 μm-thick frozen sections and mount them on glass slides.
2.5 Direct Staining and Observation:
Place the TFM/OCT-covered sections directly under a fluorescence microscope and observe using a TRITC filter (Ex 535 nm / Em 565 nm). PiF-stained islets (core of β cells) show strong red fluorescence.
Optional Washing: To remove the background from the embedding medium, add PBS dropwise onto the sections for incubation/rinsing before observing the PiF-specific signal.