The Uppsala team was able to upgrade a standard inverted microscope to a time-lapse cell imaging system, using a smartphone and 3-D-printed parts. [Image: Linda Koffmar]
A research team the department of medical cell biology at Uppsala University, Sweden, has built a live-cell, time-lapse imaging system from an ordinary inverted microscope, a smartphone, and some 3-D printed parts and off-the-shelf electronics (PLOS One, doi: 10.1371/journal.pone.0167583). The scientists believe that the setup, the parts for which (excluding microscope and smartphone) retail for less than US$280, could bring the capability for time-lapse imaging within reach of a wide variety of small research labs, including those in low-resource settings.
Time-lapse imaging, which allows scientists to study the dynamics of cells and their response to environmental and chemical changes, crops up in a wide range biological studies. But the equipment for such imaging tends to be expensive. That’s not so much because of a need for sophisticated optics as because fairly strict environmental controls are needed to ensure that the cells behave normally across the (often lengthy) imaging period. That means that expensive equipment needs to be added to the imaging system to protect the cells from pH changes, temperature shifts, evaporation and even the harmful effects of light (phototoxicity).
The Uppsala team got around those limitations with a bit of hardware hacking. The scientists started with two items that are common fixtures in biomedical research labs: An ordinary inverted microscope (a technology dating from the mid-1800s) and a smartphone.
They then bolted a variety of components onto the microscope: a 3-D printed structure to hold the smartphone in place in front of the microscope objective; a 3-D printed incubator chamber for environmental control of the cell culture; a hand-built, servo-motor-operated shutter disk (to minimize light exposure); and a control unit built off of an Arduino board (an inexpensive programmable circuit board popular among hobbyists). An improvised heating unit and a commercially available power supply rounded off the setup—which the scientists dubbed the affordable time-lapse imaging and incubation system (ATLIS).
Testing the system
The Uppsala scientists tested ATLIS with human kidney cells in a 12-hour time-lapse experiment. They found that the cells proliferated normally, and that “a five-megapixel smartphone camera was … capable of producing high-resolution images comparable to those taken by microscope-dedicated cameras present in commercial live cell imaging systems.”
Imaging cells in an evaporation-sensitive setting, such as might be found in cells cultured in a microfluidic biochip system, proved a bit more of a challenge to ATLIS, as the media-filled channels tended to dry out over the imaging time frame. The team overcame that challenge by adding a humidification module—essentially a water reservoir that boosted the moisture content of the air flowing from the heating unit to the incubation chamber.
New lab equipment paradigm?
The total cost of the system, excluding microscope and smartphone, was around US$277, according to the researchers. That’s well within reach of most research labs that already have an old inverted microscope and smartphone on hand.
Indeed, the senior author of the study, Johan Kreuger, notes that while what his team did “isn’t rocket science,” it points to a lab paradigm that may become increasingly important. “In the future, it will be much more common that scientists create and modify their own research equipment,” says Kreuger. “This should greatly propel technology development.”