LysoSensor PDMPO 

PDMPO, a lysosome pH indicator, is an excellent fluorescent acidotropic reagent for fluorescence imaging. PDMPO is a potent tool with which to study acidic organelles of live cells. PDMPO exhibits pH-dependent dual-excitation and dual-emission spectral peaks. PDMPO produces a blue fluorescence in weakly acidic organelles and shifts to yellow in more acidic lysosomes. (Abs=329 nm; Em=440/540 nm)^[1].

Guide (The following is a recommended protocol. This protocol is provided as a guide only and should be modified to suit your specific needs).
1. Preparation of Stock Solution^[1]
1.1 Dissolve LysoSensor PDMPO in 50 μL of anhydrous DMSO at a concentration of 1 mM to prepare the stock solution.
1.2 Aliquot the stock solution to avoid repeated freeze-thaw cycles.
2. Preparation of Working Solution
2.1 Dilute the 1 mM stock solution to a working concentration of 1-200 μM in antibiotic-free DMEM medium (the recommended initial concentration is 1 μM).
Note: Prepare the working solution freshly before use. Thaw the aliquoted stock solution at room temperature prior to use and protect from light.
3. Staining Procedure
3.1 Fixed Cell Imaging
3.1.1 Incubate the cells with LysoSensor PDMPO working solution at 37°C and 5% CO₂ for 5 min.
3.1.2 Discard the staining solution and wash the cells 3 times with pre-chilled PBS to remove unbound dye.
3.1.3 Fix the cells with 4% PFA at room temperature in the dark for 15 min.
3.1.4 Discard the PFA and wash the cells 3 times with PBS.
3.1.5 Imaging detection.
3.2 Live Cell Imaging
3.2.1 Incubate the cells with LysoSensor PDMPO working solution at 37°C and 5% CO₂ for 5 min.
3.2.2 Discard the staining solution and gently wash the cells 3 times with PBS.
3.2.3 Place the cells in a live-cell imaging system, and acquire images at a rate of 1 frame/30 s for 1 h.

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

366.41

C₂₀H₂₂N₄O₃

531

333

Solid

White to off-white

O=C(NCCN(C)C)COC(C=C1)=CC=C1C2=CN=C(O2)C3=CC=NC=C3

Room temperature in continental US; may vary elsewhere.

-20°C, protect from light

*In solvent : -80°C, 6 months; -20°C, 1 month (protect from light)

* Please refer to the solubility information to select the appropriate solvent. Once prepared, please aliquot and store the solution to prevent product inactivation from repeated freeze-thaw cycles.
Storage method and period of stock solution: -80°C, 6 months; -20°C, 1 month (protect from light). When stored at -80°C, please use it within 6 months. When stored at -20°C, please use it within 1 month.

• [1]. L V Albrecht, et al. Protocol for Probing Regulated Lysosomal Activity and Function in Living Cells. STAR Protoc. 2020 Oct 17;1(3):100132.  [Content Brief]

  [2]. Patricia Merdy, et al. PDMPO: a specific silicon or silica, pH sensitive fluorescent probe? RSC Adv. 2020 Aug 21;10(51):31003-31011.  [Content Brief]