SUMMARY
# s:**
- Compare uptake with/without magnetic particles using tight junction integrity markers
- Test whether clustering occurs at BBB-relevant TfR expr
## Background and Rationale
# Magnetic Particle-Enhanced Transcytosis at the Blood-Brain Barrier: A Falsification Study of Tight Junction Integrity and Transferrin Receptor Clustering
The blood-brain barrier (BBB) represents one of the most significant obstacles to effective neurotherapeutic delivery, with tight junction (TJ) proteins forming t
METHODOLOGY NOTES
**Phase 1: Cell Culture Preparation (Days 1-7)**
• Culture brain microvascular endothelial cells (hCMEC/D3 or bEnd.3) on Transwell inserts (0.4 μm pore, 24-well format)
• Maintain cells in EBM-2 medium with 2.5% FBS and growth supplements
• Allow monolayer formation for 5-7 days until TEER >150 Ω·cm²
• Confirm tight junction integrity using immunofluorescence for ZO-1, claudin-5, and occludin
• Validate TfR expression levels via Western blot and flow cytometry (target: 50,000-100,000 receptors/cell)
**Phase 2: Magnetic Nanoparticle Preparation (Day 6)**
• Prepare transferrin-conjugated magnetic nanoparticles (50-100 nm diameter)
• Synthesize control transferrin without magnetic core
• Characterize particle size, zeta potential, and transferrin conjugation efficiency
• Prepare fluorescently-labeled molecular tracers: FITC-dextran (4 kDa, paracellular) and Alexa647-transferrin (transcytosis)
• Sterilize all preparations via 0.22 μm filtration
**Phase 3: Transport Assay Setup (Day 7)**