The r-SiPcBOA probe concentration and, consequently, molar ratio were incorrectly reported in the article entitled “High payload delivery of optical imaging and photodynamic therapy agents to tumors using phthalocyanine-reconstituted low-density lipoprotein nanoparticles” by Li published in the Journal of Biomedical Optics, Volume 10(4), 041203 (July∕August 2005). In Figs. 4(i) and 4(j), $\mathrm{Hep}{\mathrm{G}}_2$ cells were effectively incubated with $66\mu \mathrm{g}∕\mathrm{ml}$ SiPcBOA, equivalent to the probe concentration in $85\mu \mathrm{g}∕\mathrm{ml}$ r-SiPcBOA-LDL protein. Instead of a $50\mu \mathrm{g}∕\mathrm{ml}$ r-SiPcBOA-LDL exposure, cells were exposed in the clonogenic assay to $5.8\mu \mathrm{g}∕\mathrm{ml}$ . Additionally, the actual SiPcBOA to LDL molar ratio is 400:1. Hence, the considerable PDT efficacy we reported for r-SiPcBOA-LDL was, in fact, achieved at a nearly 10-fold lower probe concentration.