February 4, Allison Dennis, Los Alamos National Laboratory

DennisMSE Seminar: 2:30 PM, 15 St. Mary’s Street, Room 105

Quantum Dots and their Application in Förster Resonance Energy Transfer (FRET) Sensors

Abstract: Semiconductor quantum dots (QDs) are fluorescent nanoparticles that have been utilized in biomedical imaging, biosensing, energy applications, and telecommunications. In my talk, I will discuss traditional applications of QDs in fluorescence resonance energy transfer (FRET)-based biosensing, the synthesis and characterization of some next-generation QD chemistries, and the ways in which these new nanomaterials can be exploited in creative energy transfer schemes to produce next-generation fluorescent biosensors.

Specifically, I will describe a quantum dot-fluorescent protein (QD-FP) device utilizing a pH-sensitive fluorescent protein acceptor to produce a long-lived pH sensor for intracellular imaging. Furthermore, I’ll discuss how the manipulation of QD semiconductor composition and the incorporation of a super-thick shell to form so-called ‘giant’ nanocrystal quantum dots (g-NQDs) facilitates blinking suppression, improved chemical stability, bandgap engineering, and color tuning. I have developed novel g-NQD compositions based on InP cores and a variety of shell materials, yielding a range of electronic structures, from Type I to Type II, producing photoluminescence emission wavelengths spanning from the blue into the NIR. I will elaborate on recent observations of the first non-blinking QDs emitting in the NIR (InP/CdS g-NQDs) and other unpublished QD chemistry. Novel FRET biosensor concepts enabled by the development of ultra-thick-shelled g-NQDs will be introduced.

Biography: Allison Dennis studied Bioengineering and German at Rice University before joining the Pharmaceutical Technology group at the University of Regensburg in Bavaria as a Fulbright Scholar. She earned her Ph.D. in Bioengineering from Georgia Tech in 2009 and subsequently joined the nanomaterials chemistry lab at the Center for Integrated Nanotechnology (CINT) at Los Alamos National Laboratory (LANL). Dr. Dennis’s research goals combine her expertise in fluorescent biosensor design and the synthesis of novel quantum dot nanomaterials to develop QD-to-QD energy transfer-based biosensors exhibiting dramatic photostabilty and chemical robustness for long-term, repetitive, and multiplexed fluorescent sensing.

Faculty Host: Mark Grinstaff