Fig. 6
Interactions of PS-PEG micellar QDs (prepared by using sonication 30 s in the interfacial instability method) with biological cells. a PS-PEG micellar QDs were fairly biocompatible judging from the MTT cytotoxicity assay results. The concentrations were based on the amounts of QDs used. b Tat peptide-conjugated PS-PEG micellar QDs can be internalized by live cells. c RGD peptide-conjugated PS-PEG micellar QDs can specifically recognize and bind with the α v β3-integrin molecules over-expressed on U87MG cells (right image). In comparison, in the absence of α v β3-integrin over-expression (MCF-7 cells, left image) or Tat peptide (PS-PEG-COOH micellar QDs, middle image), no significant binding (QD fluorescence) was observed. The red fluorescence was from QDs. The cell nucleus was stained by the blue fluorescent dye Hoechst 33342. Cell periphery is shown by white line (from the corresponding bright field microscopy images)