Phosphorylation is a common reversible post‑translational modification that plays a regulatory role in many biological processes, such as cell signaling, and is therefore of great importance in the study of many diseases, including cancer. Understanding phosphorylation helps us to understand disease pathogenesis. Phosphoproteins and phosphopeptides are typically present at very low concentrations and are poorly ionized, making them difficult to detect by mass spectrometry (MS). Therefore, enrichment techniques that can specifically enrich phosphopeptides and are compatible with MS analysis are urgently needed.
Titanium dioxide (TiO₂) has selective affinity for enriching phosphoserine (pSer), phosphothreonine (pThr), and phosphotyrosine (pTyr) residues. TiO₂ magnetic beads are proprietary magnetic microparticle carriers that enable simple, convenient, efficient, highly specific, and highly reproducible enrichment of phosphopeptides from protein digests of complex biological samples. The TiO₂ nanoparticles on the bead surface show no obvious preference for mono‑phosphopeptides versus multi‑phosphopeptides, making them very suitable for single‑step enrichment of phosphopeptides for MS‑based proteomics analysis. In addition, TiO₂ magnetic beads can also be used to isolate extracellular vesicles (EVs) such as exosomes by binding to phospholipid bilayers. TiO₂ captures small EVs (sEVs) by forming a bidentate structure with the phosphate groups of the EV bilayer phospholipids, and the magnetic core further separates the magnetic bead‑sEV complexes. The binding between beads and EVs is reversible; captured sEVs can be eluted and collected by washing with an alkaline solution.
Aladdin's 5 μm Titanium Dioxide Magnetic Beads (thin shell layer) are monodisperse, micron‑sized magnetic beads with uniform size. The surface has a nanoscale rough island‑like structure, offering advantages such as high specific surface area, strong saturation magnetization, and fast magnetic response time. TiO₂ magnetic beads combine the rapid external magnetic field response of magnetic materials with the stability of metal oxides, feature a very high specific surface area, simplify the phosphopeptide enrichment process, and increase enrichment throughput.
Figure 1. SEM image of 5 μm titanium dioxide magnetic beads (thin shell layer)
| Cat. No. | T1520787 |
|---|
| Product Name | 5 μm Titanium Dioxide Magnetic Beads (thin shell layer) | | Size | 5 ± 0.2 μm | | Surface Potential | Approx. -20 mV | | Magnetic Content | Approx. 10%–15% | | Solvent | Purified water | | Concentration | 25 mg/mL |
|
Product Features
High specificity for phosphopeptides
No obvious preference for mono‑phosphopeptides vs. multi‑phosphopeptides
Fast magnetic response (<30 seconds) reduces sample loss and is more suitable for automation
Antioxidant properties reduce the risk of sample contamination
Exosome Extraction
TiO₂ magnetic beads are stored in purified water at 25 mg/mL. Before use, the beads should be washed and equilibrated (allow to return to room temperature). The amount of beads can be scaled up or down as needed.
Vortex the TiO₂ magnetic beads to ensure uniform dispersion.
Transfer 200 μL (5 mg) of TiO₂ magnetic beads to a 2 mL centrifuge tube.
Place the tube on a magnetic separator for 30 seconds, then remove the supernatant.
Gently wash the beads with 200 μL of 10 mM PBS (e.g., intermittent vortex mixing) for 5 minutes.
Place the tube on the magnetic separator for 30 seconds and remove the supernatant.
Repeat steps 4 and 5.
Add 100 μL of sample (serum containing exosomes) to the beads and co‑incubate at 4 °C for 5–10 minutes.
Place the tube on the magnetic separator for 30 seconds, remove the supernatant by magnetic separation, and wash 2–3 times with 10 mM PBS (pH 7.4).
Remove the magnetic field, add PBS containing 10% ammonia water to the bead‑exosome complex, and co‑incubate at 4 °C for 5–10 minutes to release exosomes from the beads.
Place the tube on the magnetic separator for 30 seconds, collect the supernatant (exosome suspension). Further adjust the pH of the exosome resuspension by ultrafiltration if needed.
Note: Ammonia water is corrosive. Please follow the safety instructions for use.
Notes
Titanium dioxide magnetic beads will settle upon prolonged standing. Use after thorough stirring or vortexing to disperse evenly.
Store sealed at 2 °C–8 °C in a refrigerator. Avoid drying into a solid mass.
ZJ26F0838159