Total protein content measured was observed to be the highest following a 24-hour incubation for amine-modified nanoparticles, carboxylate-modified and unmodified nanoparticles in descending order of detected protein content. There was no statistically significant difference observed between the protein content measured for 2-hr incubation samples versus 24-hour incubations for carboxylate-modified nanoparticles with only unmodified (half protein content at 24h vs 2h) and amine-modified (8-fold increase in measured protein content at 24h vs 2h) nanoparticles showing a significant change in protein content following 24-hr incubation (Figure ).