Identification of peptide coatings that enhance diffusive transport of nanoparticles through the tumor microenvironment

Rashmi Mohanty; Xinquan Liu; Jae You Kim; Xiujuan Peng; Sahil Bhandari; Jasmim Leal; Dhivya Arasappan; Dennis C. Wylie; Tony Dong; Debadyuti Ghosh

One hundred nanometer diameter yellow-green carboxylate polystyrene nanoparticles (ThermoFisher Scientific) were surface modified with either peptide or poly(ethylene) glycol (PEG) coating. C-terminal amidated P4 and iRGD peptides (LifeTein) and methoxy-PEG 1kamine (Alfa Aesar) were covalently conjugated to the COOH functional group of the nanoparticle at a molar ratio of 5:1 using standard carbodiimide chemistry with (1-ethyl-3-[3dimethylaminopropyl]carbodiimide hydrochloride) (EDC) (Thermo Fisher Scientific) and Sulfo-(N-hydroxysulfosuccinimide) (Sulfo-NHS) (Thermo Fisher Scientific), following manufacturer's protocol. After conjugation, we performed dialysis for 24 hours against 1× PBS using 100 kDa molecular weight cut-off dialysis membrane (Spectrum Labs) for buffer exchange and to remove unconjugated PEG/peptide. Size and the zeta potential of the uncoated and peptide/PEG conjugated nanoparticles were measured by suspending the particles in 10 mM NaCl at 25 °C. The nanoparticle formulations were stored at 4 °C for particle tracking experiments.