Linker chemistry dictates the delivery of a phototoxic organometallic rhenium(i) complex to human cervical cancer cells from core crosslinked star polymer nanoparticlesElectronic supplementary information (ESI) available: Experimental and additional data. See DOI: 10.1039/c8tb02464b

We have investigated core-crosslinked star polymer nanoparticles designed with tunable release chemistries as potential nanocarriers for a photoactive Re( i ) organometallic complex. The nanoparticles consisted of a brush poly(oligo-ethylene glycol)methyl ether acrylate (POEGA) corona and a cross-linked core of non-biodegradable N , N ′-methylenebis(acrylamide) (MBAA) and either pentafluorophenyl acrylate (PFPA), 3-vinyl benzaldehyde (VBA) or diacetone acrylamide (DAAM). Each star was modified with an amine functionalized photodynamic agent ( i.e. a rhenium( i ) organometallic complex) resulting in the formation of either a stable amide bond (POEGA- star -PFPA), or hydrolytically labile aldimine (POEGA- star -VBA) or ketimine bonds (POEGA- star -DAAM). These materials revealed linker dependent photo- and cytotoxicity when tested in vitro against non-cancerous lung fibroblast MRC-5 cells and HeLa human cervical cancer cells: the toxicity results correlated with final intracellular Re concentrations. Release of a photoactive Re( i ) complex from a polymer star via ketimine linkages gives improved phototoxicity.