Conjugation of Antigen or Fluorophore onto PLG Nanoparticles

PLP_139–151 and Eα_52–68 were purchased from GenScript, and OVA_323–339 was purchased from Celtek Peptides. FITC-cadaverine was purchased from Thermo Fisher Scientific. Lyophilized PLG nanoparticles were washed three times using PBS at pH 7.4. Approximately 4 mg of PLG nanoparticles was recovered and activated using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC), purchased from Sigma-Aldrich, at 16 mg/mL. Peptide or fluorophore was immediately added at the appropriate concentration to achieve desired higher or lower conjugation levels. The coupling reaction proceeded for 1 hr under constant agitation. Uncoupled peptide was removed with three PBS washes. Total peptide conjugation was measured using the Micro BCA Protein Assay Kit manufactured by Pierce Biotechnology.