Dimethylformamide

FDG-MNPs were prepared as described previously.²⁵ Briefly, for the synthesis of mannose triflate-cysteamine, 19.21 mg of mannose triflate (Fluka) was dissolved in 200 μL of distilled water at 90 °C. Separately, 84.85 mg of cysteamine (2-aminoetanethiol; Sigma, Istanbul, Turkey) was dissolved in 70 μL of pure water and adjusted to a pH of 7.5 prior to the addition of 40 mg of NaCNBH₃ (Fluka). Both solutions were mixed and heated for 1 hour at 90 °C prior to being precipitated, dried overnight at 65 °C and dissolved in dimethyl formamide (Merck). Next, 100 μL of Kryptofix (Merck) solution (2.0 mg/mL in dimethyl formamide), 200 μL of K₂CO₃ (Fluka) aqueous solution (2.0 mg/mL), 100 μL of dimethyl formamide (Merkc) and 200 μL of 16 mM NaF (Merck) were added to 1 ml of the prepared mannose triflate-cysteamine (35 mM) and heated for 20 minutes at 90 °C in a water bath. For purification, the product was passed sequentially through a Dowex 50 cation exchange resin column (Sigma), Ambersep 900 quaternary ammonium anion exchange resin (Fluka), Amberlite anion exchange resin (Sigma) and finally a C18 pre-cartridge (Sigma).