Once 3-D printers became popular, laboratory-grade microscopes were some of the first designs researchers capitalized on. Given how ubiquitous microscopes are to any lab, it makes sense. Throughout the years, there have been many designs for low-cost microscopes.
So, Joel Collins and Richard Bowman’s OpenFlexure Microscope is not exactly novel, but it is unique.
“The big thing is the mechanical stage,” Bowman, a physics professor at the University of Bath (UK), told Laboratory Equipment. “It features a very precise stage that can make 50 nm steps in X, Y, and Z under computer control, meaning that it’s suitable for automated experiments even using oil immersion objectives. We paid attention to the stability of the stage over time, so the drift is relatively low. There are a lot of low-cost microscope designs now, but often there’s more focus on the optics than on the stage. If anything, the OpenFlexure Microscope is about the stage rather than the optics.”
An OpenFlexure Microscope can be constructed for as little $18, including the cost of the printed plastic, a camera and fastening hardware. A top-end version would cost a couple hundred dollars to produce, and would include a microscope objective and an embedded Raspberry Pi computer.
The “basic” version of the imaging system is traditional, with a webcam-based lens that works best in bright field to imaging thin transparent samples—like the blood smears the researchers are working with to further their malaria diagnostic research.
However, the microscope is highly customizable. In fact, that was one of the main motivations for designing the OpenFlexure Microscope in the first place.
“I did my Ph.D. in optical tweezers and was always really frustrated that we ended up buying complete microscopes then breaking them apart to modify the optics,” explained Bowman. “The OpenFlexure Microscope is a microscope you build yourself, so you don’t have to build any parts you don’t need.”
Recently, Bowman and Collins have implemented epifluorescence, polarization contrast, reflected light bright-field, and even modulated LEDs to digitally approximate differential interference contrast DIC) microscopy, which works well to image phase objects like unstained cells.
Another benefit of building a microscope from an open design platform is that it’s easy to send around the world. In Collins and Bowman’s case, they can send the designs to their Tanzanian partners, STICLab, where those researchers can modify the design to better suit their local market. In fact, to date, more than 100 OpenFlexure microscopes have been printed in Tanzania and Kenya, demonstrating the viability of a complex piece of hardware being conceptualized in one part of the world and manufactured elsewhere.
Bowman has had an OpenFlexure Microscope running in his office for about 5 months of continuous operation. He said he replaced a couple screws that wore out, but other than routine maintenance, it is still working well. In fatigue tests conducted in Tanzania, the microscopes run for 3 to 4 months of continuous operation.
“We expect this to be much longer if they are not operated constantly,” Bowman said. “And now that we know the weak points, we can refine the design so it lasts even longer.”
Bowman’s ultimate goal with the OpenFlexure Microscope, a project that has taken five years to complete, is for it to serve as a platform for other researchers. Already, that dream is becoming a reality. Last year, three separate papers were published from research groups at Strathclyde University and University of Cambridge that utilized the OpenFlexure Microscope for phase imaging and localization-based super-resolution, as well as an optical projection tomography system,
“I hope the OpenFlexure Microscope opens up automated microscopy to a whole new set of people, and frees up a cohort of Ph.D. students from repetitive experiments to focus on their exciting science,” Bowman said.
Photo: The 3D-printed OpenFlexure Microscope. Credit: Joel Collins/University of Bath