PiF 

PiF is a fluorescent probe with high specificity for pancreatic β-cells (Ex/Em = 535 nm/565 nm), and its fluorescence signal increases significantly with elevated insulin concentrations in in vitro experiments. PiF enables visualization of rat and human islets transplanted via the portal vein in mouse livers with low liver background signals. The fluorine atom of PiF can be replaced by radioactive ¹⁸F to prepare a PET tracer. PiF can be used for research on type 1 diabetes^[1].

PiF (0.5 μM; 30 min) shows a dose-dependent fluorescence response to bovine insulin in a cell-free 20 mM HEPES buffer system (pH 7.4) after 30 min of incubation^[1].
PiF (1 μM; 30 min) is highly selective for insulin over glucagon and human serum albumin in a cell-free 20 mM HEPES buffer system (pH 7.4) after 30 min of incubation^[1].
PiF (1 μM; 1 h) selectively stains pancreatic β-cells (not α-cells) in isolated mouse islets after 1 h of incubation, as confirmed by co-staining with cell-specific markers and gene expression analysis of sorted cell populations^[1].
PiF (0.25-2 μM; 1 h) selectively stains isolated rat islets in a concentration-dependent, non-toxic manner after 1 h of incubation, with a linear correlation between fluorescence intensity and probe concentration^[1].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

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.

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

554.55

C₂₆H₂₆F₄N₂O₅S

2688758-23-6

COC1=C(C=C(C=C1C)C2=C3C=CC(C=C3OC4=C2C=CC(N(CCF)C)=C4)=N)C.O=S(C(F)(F)F)(O)=O

Room temperature in continental US; may vary elsewhere.

Please store the product under the recommended conditions in the Certificate of Analysis.

• [1]. Kang NY, et al. Multimodal Imaging Probe Development for Pancreatic β Cells: From Fluorescence to PET. J Am Chem Soc. 2020;142(7):3430-3439.