We’ve been selecting aptamers in the lab for the last year. Having a qPCR on the bench has really helped, and so we wrote up a methods paper in ACS Combinatorial Science. The company that made our qPCR instrument has put up a blurb about it, too.

The qPCR function is great for cycle course optimization, and we have been using the melt curve analysis function of the Open qPCR (thermofluorimetry) to do a binding assay. It works pretty well. We put a dye in with the aptamer and measure the temperature at which the dye dye-DNA complex melts. The bound aptamer has a different melt temperature, so it gives a specific signal. We plot that specific signal as a function of concentration and to determine the binding constant. It’s based on the Easley lab’s method paper from 2015 with low-cost equipment.

The instrument simplifies some of the more touchy parts of the aptamer selection. Undergrads have been turning rounds pretty efficiently this year with the help of the open qPCR instrument.

We have also been using graphene oxide to try some selections. I have only heard of graphene oxide SELEX recently, but it grabs unstructured DNA to separate them from aptamers bound to target. It’s looking good. I hope to report on that soon.