Opinions on the State of the Art

Passing DNA through a silica column twice does not increase yield – A cautionary tale of cognitive bias

Scientists are stereotyped as objective thinkers, putting hard facts above our own subjective experience. If you’re being honest though, as a group of people we’re particularly vulnerable to a host of cognitive biases including magical thinking, confirmation bias, etc. Why the maudlin tone??? Well, I challenged my own magical thinking, and it turns out I was wrong. Not just a little wrong, but pretty definitively wrong. Oh well, better to don the dunce cap for one day, than be a dunce forever.

PSA: Your thermal cycler is NOT a refrigerator (Don’t hold below ambient!)

Published: June 10th, 2019 Last Modified: August 27th, 2019

One of the most precious machines in the molecular biology lab is the thermal cycler, often called the PCR machine. They dutifully cycle between the temperatures you set, amplify your DNA and never complain. We’ve got quite a herd ourselves and we love them all dearly. We’ve got Rowan, Cycler #2, Chad, River, Ol’ Red and Greybeard.

Unfortunately, these machines are often not treated with the respect of a 20,000$+ piece of gear and are instead used as a glorified mini-fridge. What do I mean by that? After your PCR is finished, do YOU set it to hold at 4C? Do you let it hold 4C overnight? Do you let it hold at 4C on a Friday and only turn off the machine Monday? Do you compromise and let it hold at 10C or 16C? Stop! Just stop!

There’s NO advantage to holding your PCR reaction at anything below ambient for any length of time! Let me try to convince you so you can SIGNIFICANTLY extend the lifetime of your machine.

This message is brought to you by the People for the Ethical Treatment of Thermal Cyclers (PETTC)

3D Printing stuff for your lab, hype and realities

Published: April 11th, 2016 Last Modified: June 16th, 2017

3D printing as a technology has been around for decades, with makers and hackers making 3D printers economical for consumers only in the last 5 years or so. There’s more than one way to frikassee a cat, just as there’s more than one way to 3D print an object. Rather than cover the plethora of emerging 3D printing technologies, I will talk about what is known as fused deposition modeling (FDM). Essentially, you have a plastic filament pulled into a heated nozzle (Think of an arts and crafts glue gun) which is able to move in the X, Y and Z axis. The movement of the nozzle is controlled by a computer interface where you put your digital 3D model. Software converts the 3D model into X, Y and Z movements the printer can understand and off it goes!

There’s been a bit of buzz about 3D printing lab equipment and I thought I’d weigh in with my experiences, both good and bad so that you can decide whether it’s worth getting one for your lab.

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