Schematic showing experimental design. (a) DHLA capping of CdSe-ZnS (QD564) and subsequent conjugation of (His6)-Cyclin E (modified from ). (b) Microinjection of (QD564)-His6Cyclin E into 2-cell Xenopus embryos and (c) confocal imaging of microinjected pre-MBT and MBT Xenopus embryos. In (a) the DHLA molecule contains a bidentate thiol moiety on one end, allowing its stable attachment to the inorganic QD surface. Coupling of (His6)-Cyclin E to QD is achieved via strong metal affinity between the histidine tag of the protein and Zn+2 atoms on the QD surface. The schematic is not to scale.