Faster and Cheaper
(December 16th, 2014) No money, little time but lots of ideas and DIY attitude. PhD student Adam Lynch constructed his very own microscope (using USB microscopes and kitchen unit legs) to be able to visualise primary hemocytes of a freshwater snail.
When confronted with the decision to either spend a lot of money to buy automated equipment to speed up his research or spend a lot of time using a single microscope, Adam Lynch, PhD student based at Brunel University, UK came up with a third option: save time and money by making minor tweaks to several cheap USB microscopes and develop an entirely new system to conduct parallel cell motility assays fast and by keeping to the budget. He called it Low-Cost Motility Tracking System or LOCOMOTIS for short.
This new system was born out of the necessity to understand how certain phagocytic immune cells (hemocytes) from the freshwater snail Biomphalaria glabrata react to invading schistosomes. This field has become an important area of research as infected snails can, in turn, cause the intestinal disease schistosomiasis, an often neglected but serious tropical disease in humans. “As part of my PhD project,” explains Lynch, “I was looking at whether pollution in the aquatic environment of the snails affects their immune system and whether they are more likely to be infected or change the infection process which would lead to alterations in the human infection.”
The stumbling block was finding a suitable way to assess cell motility. At the time, the options were limited: time consuming time-lapse imaging on a single microscope; high throughput assays - but they don’t allow direct visualisation of moving cells; or expensive automated systems. For Lynch, the alternative was to get multiple microscopes working without spending lots of money. “I decided to try and see if I could use these much cheaper USB microscopes because we could afford several of them and in fact, we were able to see cells by making some fairly simple adjustments.”
To improve on manufacturers’ claims, Lynch simply turned three microscopes upside-down, switched off the microscopes’ inbuilt lighting, replacing it with an LED strip desk lamp and placed the entire device inside a heated incubation chamber. Pixel resolution was set at 640x480, which was actually not the maximum resolution possible, but was selected as time-lapse experiments generate a large number of files, especially when running three microscopes simultaneously.
At this stage, an unexpected characteristic of most USB devices almost stopped the process: as all three microscopes were the same make and model, there was nothing to distinguish them from each other and the computer was only registering images from one microscope. However, this issue was promptly solved with a purpose-built software application, allowing the capture of images from three microscopes onto the same computer.
The entire process from the idea to develop a new system to the published article took about a year to complete, with several abandoned approaches along the way. “I wanted to test several doses of different chemicals and obviously do several replicates, so doing one at a time wasn't really an option. That’s how the microscope came about,“ says Lynch.
In addition to his own work with freshwater snails, Lynch also tested his new system using different types of cells. He investigated cell tracking and scratch assays on mouse Sertoli cells and human breast cancer epithelial cells, and took images of shrimp from the genus Artemia in various stages of development. All results were comparable to standard techniques using inverted microscopes.
According to Lynch, this is just a working model and it could be made cheaper by, for example, sourcing the parts – like camera and lenses - directly from the manufacturer rather than buying the full microscope. Lynch also believes it could be made a lot smaller and potentially using more cameras, ideal for non-specialist research centres or labs with a limited budget. “There seems to be some possible demand for improvements and there are many ways that it could be improved,” concludes Lynch, “given the interest, it's definitely something I will consider taking further.”
Images: Lynch et al. PLoS ONE