October 10, 2019
by Carol Lynn Alpert
Participating: Jessica, Peter, Abhijit, Faiz, Elizabeth, Carol Lynn.
News: Abby has graduated! She is temporarily working for Core Quantum while looking for a job in Bay Area. Her paper is in press now at the Journal of Chemical Physics.
Current Goals: (1) Apply the “strand-invasion technique” to both DNA-caged QDot micelles, and to compact uncaged QDot-DNA conjugates in a flow cell set-up on the STORM scope with U87 cells. (2) Complete light sheet illumination set-up with the microscope. (3) Explore the holographic technique again, this time using non DNA-conjugated QDots to be supplied by QDot team.
Report: Optics Team – Georgia
In his post this month Abhijit describes a breakthrough in imaging fruit fly myopodia in neuromuscular junctions. Daichi Kamiyama applied a new CF568 dye which attached better to the primary antibody and thus reduced noise from background light. They moved on to performing two-color sequential imaging of the growth-cone. Peter and Abhijit finalized the design for the light-sheet add-on to the STORM setup, and have begun ordering the parts. They also acquired flow channel slide samples for imaging under the STORM objective. The holography paper has been submitted to Optics Letters and is being sent out for review.
Report: QDot Team – Ohio
Faiz reported a temporary setback achieving water solubility with the NN Labs QDots. Comparing notes with undergraduate researcher Thomas Porter, they discovered that the TMAH reagent Faiz was using was old and contaminated and not performing properly. As Faiz wrote, "A trivial issue of chemical impurity bottlenecked our further photoswitching experiments." In another setback, Elizabeth Jergens reported that the new DNA-azo sequence was not conjugating well to gold nanoparticles. She’s ordered more gold NPs to continue the testing. Elizabeth also explored labelling HepG2 cells with DNA cages, but the results indicated too much non-specific binding. She is now switching to U87 cells, a glioma cell line. Catch up on the details here.
Report: Communications Team – Boston
Carol Lynn reported making contact with Kner lab collaborators Daicho Kamiyama and Melissa Inal to schedule time to discuss their research into neuromuscular junctions in fruit flies. We will have a phone conference next Thursday to learn more about how STORM imaging is aiding their investigations. The Communications Team will soon be posting the film of The 2019 Quantum Matters™ Science Communication Competition Finals. The winning talk was on quantum dots.
We discussed how to proceed, in light of the setbacks, with the grant scheduled to end April 30. It may be possible to get a second no-cost extension for MOS to allow more time for filming implementation of STORM-AO with QDots in Georgia. It's difficult to predict when the problems will be solved; Jessica said it could take from 1-6 months. Peter remarked that he was most excited about getting the holography technique working, since that would be a breakthrough for the field. Jessica offered to supply QDs conjugated to antibodies, without DNA, so that Peter and Abhijit could at least test the holographic technique with stronger fluorophores in a particle tracking experiment rather than with a full STORM setup. Peter and Abhijit thought this was a good idea, since their prior holography experiments had been plagued with excessive background noise caused by the combination of low photon counts and scattered laser light. The QDots would increase the photon density, and thus improve the signal/noise ratio. We decided to add this to our agenda.
All: Please check for errors in this post and alert the author. Please post any new publications, posters, talks, inventions in the Pubs section.
QDot Team: next steps:
1. For the effort to apply the strand invasion technique on PC3 treated compact QDots, Abby and Thomas need to conjugate them to an antibody-binding DNA and test in U87 cells.
2. For the QDot caging method, Elizabeth will pursue optimizing the protocol to reduce non-specific binding.
3. To aid the Kner lab in their holography experiments, supply PC3-treated QDots conjugated to any type of antibody, without DNA
1. Acquire a complete set of imaging data on the myopedia in neuromuscular junctions.
2. Construct the light sheet add-on to the STORM setup.
3. Attempt holography on QDot-antibody conjugates to be sent from Ohio, in a particle tracking experiment.
Our next meeting is set for Wednesday, November 6, at 3 pm.