Rachael Walker
Rachael has a PhD in Clinical Engineering from the University of Liverpool. She is currently head of Flow Cytometry at the Babraham Institute, which is just outside Cambridge. I have over 10 years experience with flow cytometry, including over 7 years running several flow cores at the University of Cambridge. She is a very active member of the cytometry world and is a member of ISAC, flowcytometryUK and the Royal Microscopical Society. In 2012 I was awarded a 5-year ISAC Scholarship.
Articles by Rachael Walker
Your reagents should do ‘Exactly what they say on the tin.’ This only happens though if you look after them in the way the manufacturer states on their data sheets. We have all been guilty of using reagents past their expiration date. Usually we can get away with it, but there are a few things…
A flow cytometer collects the events you are interested in, and also ‘sees’ every event that goes through. This includes debris and even bits in your buffers. As cytometrists, we gate our cells to exclude unwanted bits and to focus on the sub-populations that we are interested in studying. There are two main ways of gating…
It’s happened to us all, you are ready to run your samples on the cytometer and you can’t see your cells on the screen. Here are a few tricks to troubleshooting this: Cytometer vs. computer connection The different types of cytometers will need different orders for switching on the cytometer and computer. Some are cytometer…
Wow, you’ve done it! Your experiment worked and your boss asked you to write it up for publication in your favorite journal. Where to start with presenting your flow data? Take a deep breath, help is in hand in the form of the MIFloCyt Guidelines. As with other scientific techniques, there are ‘Minimum Information about…
If, like many people, you use fluorescent proteins to view your transfection efficiency or your CRISPR gene editing, you can also isolate cells with different expression levels of fluorescent proteins. Here are 5 ways to improve your sorting experiment.
Take a look at the dotplot below, are you happy with the way it’s presented? Do you think that you could recreate that experiment? If you were a reviewer, would you accept that figure? Sure, it’s flow plot, it shows 3 populations of which two are gated. Read many journals and you will see data…
I have been working and managing flow cytometry core facilities in Cambridge for 10 years and I would like to share with you some of my experiences. I have worked up the career ladder in the past 10 years and in 2012 I became the Head of Flow Cytometry at Babraham Institute. This means that…
If you use a Becton Dickinson (BD) cytometer in your lab, the chances are you are acquiring your data using ‘Diva’ software. Diva software is used to acquire your cytometry data on LSRII, LSRFortessa, CantoII and Aria cell sorters. As well as acquiring your data using Diva software, you can also analyse your data after…
Once you have been in the field of Flow Cytometry for a bit, the name Howard Shapiro will be familiar to you. However, for those who are new to Cytometry, you might not be aware of Dr Shapiro and his fabulous book ‘Practical Flow Cytometry’. Most Cytometrists have a paper copy of this bible of Flow…
If you are bringing cells to a core to be sorted there are a few things you can do to optimise your sorting and will help the core staff. Here are a few hints: 1) Know the size of your cells Do you know the size of your cells? Not many people do and its one of…
The golden rule of flow cytometry, especially cell sorting is: ‘Put good cells in and get good cells out’. When you sort you might not get good cells out and you may not get the numbers you were expecting. In my previous article I touched on a few reasons why your cell numbers might be…
If there are a million cells of interest in your sample and you pass them through a sorter, you might expect to get a million cells back. But you don’t – and here is why. Hardware aborts A hardware abort occurs when an instrument can’t process the information about an event because it is still…
Cell sorters do not operate by magic, even it looks that way. It’s about the application of physics, electronics, fast computers and formation of droplets. Whether you bring your cells to a flow core to be sorted or you sort them yourself, it important to know how the cell sorter works. Cells can be sorted…
Ever done a multicolour flow cytometry experiment, run all your controls, done your compensation and then started to analyse your data and realised that you can’t work out where to put your gates? To err is human… When acquiring data on a cytometer, there can be measurement errors due to counting statistics, errors in processing…
Here are a few handy hints for dealing with your flow cytometry core facility colleagues. They are an amazing resource and are the people with the power to get experiments done.
You are sitting in a seminar when you glimpse it: the figure that beats all other figures – a beautiful contour plot – and you realise that a similar figure is what you need to publish your paper in a high-ranking journal. You know the basics of flow cytometry, but admit you need a little…
For those of you who print out the results that you have acquired from the Flow Cytometer to stick in your lab book, did you know that inkjet printers and cytometers have a shared history? Flow Cytometry is less than 50 years old and machines today still use some of the same principles as the…