1 4 bis 2 hydroxyethyl piperazine

1,1,1,3,3,3-Hexafluoro-2-propanol (HIFP, 99.99%), 1,4-Bis(2-hydroxyethyl)piperazine (HEP, 99%), 1,6-hexanediol (HD, 99%), 4,4′-Methylenebis(phenyl isocyanate) (MDI, 98%), anhydrous 1,2-dichloroethane (DCE, 99.8%), anhydrous diethyl ether (>99%), anhydrous N,Ndimethylformamide (DMF, 99.8%), dibutyltin dilaurate (DBTDL, 95%), dimethyl sulfoxide (DMSO, ≥99.5%), propylene glycol (PG, >99.5%), and tetrahydrofuran (THF) were purchased from Sigma-Aldrich (St. Louis, MO, USA). Polyethylene glycol (Mw = 6,000) was purchased from EMD Chemicals (Mississauga, ON, Canada). Visiblex TM color-dyed polystyrene nanoparticles (PSNs, 200 nm, COOH on its surface, media: 0.1% Tween 20 in deionized water) was purchased from Phosphorex Inc. (Hopkinton, MA, USA). C 12 -HPC(2-(4,4-Difluoro-5-Methyl-4-Bora-3a,4a-Diaza-s-Indacene-3-Dodecanoyl)-1-Hexadecanoyl-sn-Glycero-3-Phosphocholine) was purchased from Thermo Fisher Scientific (Asheville, NC, USA). Vaginal fluid simulant (VFS) was prepared by dissolving 1.0 g acetic acid, 0.018 g bovine serum albumin, 0.222 g Ca(OH) 2 , 0.6 g glycerol, 5.0 g glucose, 1.4 g KOH, 2.0 g lactic acid, 3.51 g NaCl, and 0.4 g urea in 1 L of distilled water. The pH of VFS was adjusted by adding 0.1 N HCl or 0.1 N NaOH solution [31] .