All chemicals used for SPIO synthesis, including iron salts and 15−25 kDa dextran, were purchased from Sigma-Aldrich (Saint Louis, MO). Purified human complement component C3 and iC3b was purchased from Quidel Corporation (San Diego, CA), aliquoted and stored at −80 °C. Goat anti-human complement C3 polyclonal antibody that recognizes most of the C3 cleavage products was purchased from MB Biomedicals (Solon, OH). A C5a ELISA kit was purchased from Sino Biological Inc. (Beijing, China) and used according to the manufacturer’s instructions. IRDye 800CW-labled secondary antibody (anti-goat) was from LI-COR Biosciences (Lincoln, NE). Feraheme, LipoDox, and Onivyde were obtained from the University of Colorado Hospital’s pharmacy. Human sera (total 47 donors) were obtained within a 2 week period from consented healthy donors at the University of Colorado Blood Donor Center (under the Center’s Institutional Review Board protocol for anonymous collection; only age and gender were made available to the investigators), according to the previously described protocol.43 (link) Briefly, blood was collected into Vacutainer Z (Beckton Dickinson), left to clot for 1 h at room temperature, and then centrifuged at 2500g for 15 min to separate serum from blood clots. Serum was aliquoted and stored at −80 °C. Each aliquot was thawed and frozen no more than twice.