PTO-41 

PTO-41 is a blood-brain barrier-permeable near-infrared fluorescent probe that targets β-amyloid oligomers (Aβ Oligomers, AβOs) with a K_d of 349 nM. PTO-41 exhibits low cytotoxicity, high sensitivity to β-amyloid oligomers in in vitro phantom imaging, and can be rapidly cleared from the brain. PTO-41 is applicable to the research of Alzheimer's disease (Ex/Em = 538 nM/680 nM)^[1].

PTO-41 (25 μM) selectively binds to Aβ42 oligomers in a brain-relevant biological environment, producing a significantly higher near-infrared fluorescence signal than with Aβ42 monomers or aggregates^[1].
PTO-41 (0.1-10 μM; 24 h) shows negligible cytotoxicity towards SH-SY5Y human neuronal cells at concentrations up to 10 μM after 24 h incubation^[1].

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

PTO-41 (4 mg/kg; intravenous injection; single bolus) can cross the blood-brain barrier and specifically label β-amyloid oligomers in 4-month-old APP/PS1 mice; at 30 min post-injection, the NIRF signal in transgenic mice is 1.30-fold higher than that in wild-type controls^[1].
PTO-41 (intravenous injection) exhibits efficient blood-brain barrier penetration and rapid brain clearance in healthy ICR mice, with an initial brain uptake of 9.04 % ID/g at 2 min post-injection and a clearance rate of 5.0^[1].

Guide (The following is our recommended experimental protocol. This protocol serves only as a reference guide, and specific operations should be adjusted according to your actual needs).
1. Preparation of PTO-41 Stock Solution
Weigh PTO-41 and dissolve it in DMSO to prepare a 25.0 μM stock solution. Store the solution at -20℃ away from light.
2. Fluorescence Binding Assay for Aβ Species
2.1 Dilute PTO-41 with PBS (pH 7.4) to a final concentration of 500 nM in a quartz cuvette.
2.2 Add pre-prepared Aβ42 monomers/oligomers/aggregates (final concentration 1.5 μM, i.e., probe:Aβ ≈ 1:3).
2.3 Mix well and incubate at room temperature for an appropriate period of time (usually several minutes until equilibrium is reached).
2.4 Measure fluorescence: Ex = 570 nm, Em scan = 600-800 nm (record the intensity at 680 nm).
2.5 Use PTO-41/PBS without Aβ as the blank for calibration.
3. In Vivo NIR Fluorescence Imaging in Mice
3.1 Reagent Preparation (Injection Solution):
Solvent system: 15% DMSO + 15% Cremophor EL + 70% PBS
The final concentration of PTO-41 is calculated based on 4 mg/kg body weight (100 μL is typically used for mice)
Prepare immediately before use, shake well and let stand for 20 min to ensure stable dissolution
3.2 Animal Imaging
3.2.1 Use 4-month-old female APP/PS1 transgenic mice and age-matched WT control mice (n=3-4).
3.2.2 Shave the head hair before the operation to reduce background interference.
3.2.3 Inject 100 μL of PTO-41 solution via tail vein.
3.2.4 Image acquisition using the IVIS Spectrum system:
Ex = 570 nm / Em = 680 nm
Time points for acquisition: before injection, 30, 60, 120, 240, 360 min
Draw ROIs on the brain in the software (Living Image 4.2.1) for quantitative analysis.

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

465.34

C₂₇H₃₀BF₂NO₃

2408913-88-0

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Room temperature in continental US; may vary elsewhere.

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

• [1]. Zeng F, et al. Versatile near-infrared fluorescent probe for in vivo detection of Aβ oligomers. Bioorg Med Chem. 2020;28(13):115559.