INTERPLAY OF MULTIVALENCY AND OPTICAL PROPERTIES OF QUANTUM DOTS. IMPLICATIONS FOR SENSING AND ACTUATION IN LIVING CELLS

JARES-ERIJMAN, E.; ROBERTI, M. J.; MENENDEZ, G.; PIETRASANTA, L. AND JOVIN, T

Bariloche, Argentina

Workshop; Workshop on nanomaterials. NANOMAT; 2009

Quantum dots (QDs) are unique probes due to their special properties (brightness, photostability, narrowband emission and broadband absorption), and excellent bio(chemical)compatibility for imaging structures and functions of living cells. When functionalized with ligands, they enable the recognition of specific targets and the tracking of dynamic processes for extended periods of time, detecting biomolecules with a sensitivity extending to the single molecule level. Thus, devices and probes based on such nanoparticles are a very powerful tool to study the essential processes underlying the functions and regulation of living cells.Here we present nanosensors and nanoactuators based on quantum dots in which the multivalency of these particles plays an essential role in the functionality and sensing characteristics of the nanodevices. Two examples will be presented, one of them being pH nanosensors [1] relying on the interplay of the multivalency and energy transfer between de nanoparticles and small molecules on their surface and the second one nanoactuators where controlled number of the amyloid protein α-synuclein (AS) regulate the aggregation of a fluorescently labeled bulk AS protein [2] specifically both in vitro and in live cells.References: [1] Menendez et al. 2009, In preparation. [2] Quantum dots as ultrasensitive nanoactuators and sensors of amyloid aggregation in live cells M. Julia Roberti, M. Morgan, LI. Pietrasanta, TM. Jovin, EA. Jares Erijman, 2009, submitted.[3] Shedding light on Parkinson’s disease: tetracysteine-tagged α-synuclein, a probe for amyloid-protein formation in living cells. Maria J. Roberti, Carlos Bertoncini, Rodolfo Rassia, Reinhard Klement, Elizabeth Jares-Erijman and Thomas M. Jovin, Nature Methods (2007) 4, 345 – 351.Acknowledgments. E.A.J.-E. is funded by the Max Planck Society (Partner Group grant), ANPCyT, CONICET, UBACyT, DFG Center for Molecular Physiology of the Brain (DFG CMPB), Cluster of Excellence 171 of the CMPB, in Göttingen, Germany, and the Max Planck Society (Toxic Protein Conformation project).