Unblenders, Dremelfuges, and Optical Tweezers

Lina Nilsson
Fabbed Lab: The DIY science group Tekla Labs, founded by the author, creates free instructions on making “standard laboratory equipment using locally available supplies.”

Two of the most useful DIY projects I know of are a modified record player that doesn’t make a sound and a kitchen blender that unmixes its contents. Both are research-grade science equipment. Scientists, both amateur and professional, build equipment to do real and important experiments. The instruments range from simple modifications of $10 gadgets to $100,000 precision instruments built from scratch. DIY equipment is an alternative that can save money and be easier to repair than closed-box commercial versions of standard equipment. But at the same time, some of the most cutting-edge research done today is possible only through novel DIY instruments.

stirrer   centrifuge   magnetic stirrer

(Left to right) This sample rotator uses a DC motor to provide continuous mixing of lab samples. Centrifuge made from a hand-held eggbeater. This $30 DIY magnetic stirrer does the job of its $250–$1,000 commercial counterpart.

Standard methods for identifying proteins and DNA with dyes require an overnight destaining step on a sample rotator. Growing a variety of single-celled organisms is done with similar agitation. Rather than buying a commercial rotator for $500, either pro-cedure can be completed by modifying a gramophone to spin sample containers rather than LPs. By adding an adapter to hold test tubes, your kitchen blender can become a centrifuge for separating samples such as bacteria cultures or blood components.

The centrifuge is a workhorse of the research biology lab, and there are many research-grade DIY options. One example is a small centrifuge that requires no more than 30 minutes of simple modifications to a handheld eggbeater. Doesn’t sound like a research-grade instrument? Think again. It was designed by one of the world’s most well-known chemists, George Whitesides, at Harvard. In order to use such simple DIY equipment — or any equipment — with controlled research studies, the performance has to be quantified and documented. Whitesides’ eggbeater design has been published with both mathematical calculations and experimental performance tests.

Moving out of the kitchen and into the garage for inspiration, we get higher performance (faster spinning) with Cathal Garvey’s “Dremelfuge,” a 3D-printed centrifuge rotor attached to the popular handheld rotary tool. Garvey has used the Dremelfuge attached to a standard drill for small-scale isolation of plasmid DNA from bacteria, an important step in many studies of genes and proteins.

To sterilize tools before experiments, scientists use an autoclave, an instrument that is essentially a large and sophisticated pressure cooker. For many applications, borrowing the latter from your kitchen will work just as well, assuming you can work with smaller batches and are willing to wait a little longer (pressure cookers operate at a lower pressure than autoclaves and for obvious reasons also are not designed with a built-in drying cycle at the end). Just as for a commercial autoclave, you can test that the pressure cooker did its job by adding autoclave tape on whatever you’re sterilizing — if black stripes appear, the temperature got high enough (typically 121°C).

Keeping things sterile and preventing contamination is important for biological experiments. For this reason — and also because nobody wants to continuously stir a liquid for hours on end — a laboratory device called a magnetic stirrer is commonly used to mix and prepare liquids. The stirrer platform relies on a rotating magnetic field to continuously and evenly spin a small magnetic bar that is put inside the liquid container. A basic commercial version costs $250–$1,000, but university researcher Malcolm Watts has built a DIY version for well under $30 that is so elegant my university colleagues don’t even realize it’s home-built (see teklalabs.org for the design). Unlike any commercial version I know of, Watts’ magnetic stirrer runs off of a battery, so I can easily move it around the lab as needed and researchers can use it in remote field locations or developing countries without access to wall power.

In addition to the flexibility and affordability of DIY, researchers make their own instrumentation to be able to make repairs in-house. Indeed, not too long ago, in-house instrumentation repair and design was common at research institutions, but you’ll be hard-pressed to find an equipment designer or scientific glassblower at my work today. Brian Millier, an instrumentation engineer at Dalhousie University, says, “30 years ago I performed about 95% of all of the repairs needed on our commercial instruments.” Today, commercial equipment is more complex, and parts are miniaturized and not readily sourced or replaced. The instrumentation is simply not meant to be repaired in-house. Millier claims, “I can now perform less than 50% of the required repairs, even though I have 30-plus years’ experience in this field.”

With less work on commercial equipment, Millier has turned to making his own equipment for university researchers and teaching labs. For example, Millier has built a $150 photometer that uses an RGB LED for the light source and a low-cost RGB light sensor to detect colors in experimental solutions. In the lab, one of the many uses of photometers is the detection and quantification of proteins that have been tagged with fluorescence markers (see Nobel Prize in Chemistry 2008).

While commercial spectrophotometers, which cost thousands of dollars, have full spectrum capabilities, Millier’s version measures absorption only at three distinct wavelengths, corresponding to green, red, and blue. Indeed it is common for DIY equipment to have more restrictive functionality than their commercial counterparts, but for many routine assays, this core functionality is sufficient. For protein tagging, most researchers focus on the limited set of green, red, and blue wavelengths of common tags.

Instruments used to copy DNA start at around $5,000 and can get significantly more expensive. While these PCR machines (see Nobel Prize in Chemistry 1993) can do other fancy tricks, their key function is to cycle the sample temperature. Millier built a PCR machine for researchers at his university using a custom controller and a toaster oven. For the ultimate low-tech DIY, the original method of manually moving your sample between tubs of temperature-controlled water can also give you the same result.

Not all DIY equipment solutions are low-tech. Many high-end commercial instruments started out as projects by single scientists and engineers and were later commercialized. This driving force of building-it-yourself remains today. For example, optical tweezers are sophisticated instruments that use laser light to very precisely move small particles, such as proteins, within a three-dimensional space. There are currently a handful of commercial options, but not only are they more expensive, they are not easily modified and will in general have inferior experimental performance. So, the vast majority of researchers build their own. Indeed, if you have $100,000 for optical parts and a few months of free time, you can build your own optical tweezer setup to mechanically manipulate proteins withsub-nanometer (10-9 meter) and 0.1-second resolution. Commercial designs will catch up and perhaps eventually surpass these DIY designs, as they did for other high-end instruments such as electron microscopes. But at least for now, DIY reigns supreme.

I regularly meet scientists who have designed their own instruments, from eggbeater centrifuges to high-precision optical tweezers. However, unlike the many other DIY forums, research-grade science equipment does not have an active community for sharing innovations. If we’re serious about open science, we need to not just change how we share results but also ease access to laboratory infrastructure and experimental inputs. We need to start sharing our equipment designs. Help me at teklalabs.org.

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