Experiment Validation: In vitro ThT Assay

SUMMARY

# Experiment Validation: In vitro ThT Assay ## Background and Rationale The validation of computational models through experimental verification represents a critical juncture in contemporary neuroscience research, particularly in the study of protein aggregation disorders such as Alzheimer's disease. This in vitro Thioflavin-T (ThT) fluorescence assay serves as an essential bridge between sophisticated multiscale computational predictions and empirical reality, addressing one of the most pressi

METHODOLOGY NOTES

**Phase 1: Sample Preparation and Protein Purification (Days 1-3)** • Express and purify recombinant amyloid-β peptides (Aβ40 and Aβ42) using established protocols • Prepare monomeric peptide solutions in HFIP (1,1,1,3,3,3-hexafluoro-2-propanol) at 1 mg/mL • Lyophilize and store at -80°C until use • Prepare working solutions in PBS (pH 7.4) at concentrations: 10, 25, 50, 100 μM • Filter through 0.22 μm filters to remove pre-formed aggregates • Validate monomer purity using size exclusion chromatography and mass spectrometry **Phase 2: ThT Assay Setup and Kinetic Measurements (Days 4-11)** • Prepare ThT stock solution (1 mM in distilled water, filter sterilized) • Set up 384-well black plates with final concentrations: 20 μM ThT, peptide concentrations as above • Include controls: ThT alone, peptide alone, pre-formed fibril standards • Perform measurements in triplicate for each condition (n=24 wells per concentration) • Monitor fluorescence kinetics (λex=440 nm, λem=480 nm) every 10 m