TEM of Uptake Control SmartFlares after uptake

Following on from the last post, the Uptake Control SmartFlares were loaded into cells, prepared and taken to the Electron Microscope.

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TEM of VEGF SmartFlares after uptake

Throughout all of the fluorescent microscopy experiments, we’ve been seeing SmartFlare fluorescence in punctate structures. Using these techniques, it’s very difficult to say with certainty that the SmartFlares are within vesicles or (for example) aggregated/agglomerated in the cytosol. As this is pertinent to the current investigation, we took cells loaded with SmartFlares to the electron microscope which has the resolution to discern membrane structures as well as the gold particles.

Source of chloroquine-induced vacuoles

In a recent post, I was musing about why the SmartFlares weren’t in the swollen chloroquine-induced vacuoles. Out of interest more than anything, I did a quick experiment to see what would happen if I pre-labelled the endocytic pathway with one coloured dextran, then added in a second with the chloroquine.

Here’s what happened:

Discussion Points from SmartFlare Group Meeting

I recently discussed the SmartFlare project at a joint Sée and Lévy Group Meeting, partially extolling the virtues of Open Science but mostly focussing on the data acquired so far and some of the proposed experiments.

By Andreas E. Neuhold[CC BY 3.0], via Wikimedia Commons

Regarding the SmartFlare project, the three big questions that formed the basis of the talk were:

• Why do only some cells take up SmartFlares?
• Where are the SmartFlares?
• Why are the VEGF and Scrambled SmartFlares fluorescent in puncta?

Below are some of the interesting points that were made during the meeting. Replies at the time (as best as I can remember them) in green:

Effect of Chloroquine on SmartFlare Distribution and Intensity

In order to investigate why the SmartFlares seem to be fluorescent in puncta within the cells, we designed an experiment to try to inhibit endosomal maturation, thus (hopefully) preventing SmartFlare processing and release of fluorescence.

Discussion Points from Honours Project Report

With the Undergraduate project reports now marked, Gemma has kindly agreed to post her project report on the blog. You can find a pdf of the report here.

As most of the methods and results are already on the blog, a slightly abridged and edited version of the discussion section is replicated below: