TyroSphere nanoparticles consisting of the triblock polymer [poly(ethyleneglycol)-block-oligio(desaminotyrosine octyl ester suberate)-block -poly(ethyleneglycol)] aggregates were loaded with amphiphilic porphyrins as reported by Tsubone, et al. Meso-cis-di(N-methyl-4-pyridyl)diphenylporphine dichloride Cat. No: D40922 , which is a positively charged porphyrin and meso-cis-di(4-sulfonatophenyl)-diphenylporphine dihydrochloride Cat. No: T40637, a negatively charged porphyrin were used. The photophysical properties of both porphyrins were improved when loaded onto the nano-particles, along with a greater yield of single oxygen generation and decrease in aggregation were noted. The effects of these porphyrin nano-particles were investigated in HeLa cells as a model for photodynamic therapy applications demonstrating a 3X increase in cell death when compared to the free porphyrins.