3 hexafluoro 2 propanol

The composition of membranes used in this study is consistent with our previous study [14 (link)]. The desired amount of POPC, POPS, cholesterol and 0.5% (mol:mol) spin-labeled lipids in chloroform were mixed well and dried by N₂ flow. The mixture was evacuated in a vacuum drier overnight to remove any trace of chloroform. To prepare MLVs, the lipids were resuspended and fully hydrated using 1 mL of pH 7 or pH 5 buffer (5 mM HEPES, 10 mM MES, 150 mM NaCl, and 0.1 mM EDTA, pH 7 or pH 5) at room temperature (RT) for 2 hours. To reconstitute FP1 without GGGKKKK in membrane, the desired amounts of peptide were dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol (Sigma, St. Louis, MO) and well mixed with the lipids in chloroform. The mixtures were dried and fully hydrated to generate the MLVs. To prepare SUVs for CD and ITC measurements, the lipids were resuspended in pH 7 or pH 5 buffer and sonicated in an ice bath for 20 minutes or when the suspension became clear. The SUVs solution was then further clarified by ultracentrifugation at 13,000 rpm for 10 min.

Aβ was prepared as previously described (Puzzo et al., 2012 ; Ripoli et al., 2013 (link); Stine et al., 2003 (link)). Briefly, the lyophilized peptide American Peptide, Sunnyvale, CA, USA) was suspended in 1,1,1,3,3,3-hexafluoro-2-propanol (Sigma, St. Louis, MO, USA) to 1 mM. After the complete evaporation of 1,1,1,3,3,3-hexafluoro-2-propanol to allow complete monomerization, the Aβ film was dissolved in dimethyl sulfoxide (DMSO; Sigma), sonicated for 15 minutes, aliquoted, and stored at −20 °C. Different protocols were used to obtain preparations of Aβ42 or Aβ40 enriched in monomers mAβ42 and mAβ40) or oligomers (oAβ42 and oAβ40). For mAβ42 and mAβ40, the DMSO-Aβ solution was diluted in artificial CSF (ACSF) immediately before use to the final concentration (200 pM and 200 nM). For oAβ42 and oAβ40, the DMSO-Aβ solution was incubated in PBS at 4 °C for 12 hours and 1 week, respectively, to allow oligomerization. These oligomerized Aβ solutions were then diluted in ACSF to the final concentration, calculated based on the MW of the monomeric peptides. The oligomerization status of these solutions was routinely tested by western blot (WB) analysis. Scramble Aβ42 and Aβ40 (AnaSpec Inc, San Jose, CA, USA) were prepared following the same procedure.

Poly-ε-caprolactone (PCL, Mn: 50,000, CELLINK, Göthenburg, Sweden) was solubilized overnight in 1,1,1,3,3,3-hexafluoro-2-propanol (Sigma-Aldrich, St. Louis, MO, USA) at 100 mg/ml under stirring. PCL solutions were placed into a 5-ml plastic syringe (Becton, Dickson and Company, Franklin Lakes, NJ, USA) with a 27G metallic needle and electrospun into scaffolds at the following processing conditions; flow rate 2 ml/h, 20-cm distance and electrical voltage 18kV. The fibers were collected on an aluminum foil-covered rotating stainless-steel mandrel (120 rpm) at 25°C. After electrospinning, the scaffolds were kept under vacuum for 2 days to ensure solvent evaporation before SAP physical adsorption. SAP P₁₁-4 (Curodont Repair^™, Credentis AG, Windisch, Switzerland) solutions were prepared by resuspending the peptide in sterile deionized water (DI) at different concentrations, namely: 0.1 mg/ml, 1 mg/ml, 1.25 mg/ml, and 2.5 mg/ml. The desiccated fibrous scaffolds were cut (15×15 mm²) and immersed in the distinct P₁₁-4 solutions for 24 h at 37°C to allow the physisorption on the fibers’ surface. Next, the scaffolds were left to dry for 24 h, then assigned to the following groups: PCL-P₁₁-4 0.1 mg/ml, PCL-P₁₁-4 1 mg/ml, PCL-P₁₁-4 1.25 mg/ml, PCL-P₁₁-4 2.5 mg/ml, and non-modified/pristine PCL (control).