In the past few years, quantum dots have attracted great attention owing to their unique photoluminescent properties. One of the most promising fields of application for QDs is biomedicine, but for any application in this area, the nanocrystals have to be water soluble, biocompatible and should emit in the near-infrared region. As “traditional” QDs preparations rely on wet chemistry reactions on non-polar solvents, an extra step must be introduced to render the nanocrystals soluble in the aqueous media. This extra step can reduce the quality of the final QDs. Direct preparations of CdTe-based QDs in water are developed to overcome this problem. Here, the preparation in water of red-emitting CdTe-based QDs coated with different organic ligands, including sugar conjugates is presented. The viability of human cell lines in their presence is assessed. A red-emitting QD is further functionalized with proteins and antibodies to demonstrate their in vitro potential for targeting and killing cancer cells.