Invitrogen Corp. of Carlsbad has purchased Quantum Dot Corp. of Hayward, both in California, and the BioPixels business unit of BioCrystal Ltd. of Westerville, Ohio. The acquisitions strengthen Invitrogen’s Molecular Probes business in advanced labeling and detection technologies.The company also has reached an agreement with Georgia Tech Research Corp. of Atlanta to exclusively license its metal nanocluster technology. The photostable nanoclusters offer up to 10 times the fluorescence of semiconductor nanocrystals.The combination of activities will enable Invitrogen to create products for the enhanced visualization and understanding of cellular processes, molecular interactions and other factors that are important in diagnosing and treating diseases. Terms of the acquisition and license were not disclosed.In other news, Invitrogen has completed its acquisition of Biosource International Inc. of Camarillo, Calif., augmenting its growing collection of protein and primary antibody products.