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

The uptake of the hydrophilic, net neutral C5 clone was compared to the negative control clone following the protocol as described by Bajpayee et al. 80 . Briefly, the tumor slices were preequilibrated with 1× PBS supplemented with protease inhibitors (Complete ULTRA Tablets, Roche Applied Science) for 24 -48 hours in a 37°C, 5% CO2 incubator. Tumor slices were then incubated with 300 µL of 10 6 pfu/µL P4 or control-phage supplemented with protease inhibitors in a 96-well plate. The 96-well plate was incubated at 37°C, 5% CO2 for five days. Ten microliter samples from the bath were collected every day, and the bath titer of the clones were calculated using standard double-layer plaque assay. The number of phage were in the tumor slice was calculated based on the difference between the initial and final bath titer. At the end of 5 days, the tumor slice surfaces were blotted with Kimwipes, and wet weight of the tissue was measured. The slices were then lyophilized for 24 hours, and dry weight was measured; the water weight inside the tissue was calculated by subtracting the dry tissue weight from the wet tissue weight. The clone uptake ratio was calculated based on the clone titer inside the tissue to that of the clone titer in the bath at that given time point.