Analysis: how 3D printing could help make testing for health conditions accessible to everyone, everywhere
This could reduce dependency on traditional lab tests for screening, on the global supply chain, storage of single-analysis tests, and reduce wait times for health monitoring or diagnosis.
Imagine you are not feeling well and go to the GP, who examines you and recommends some tests to rule out certain conditions, or maybe to check part of an underlying health condition. Imagine getting tested and having results that same day. This may, someday, become a reality. But how? Such testing requires a well-equipped lab, with highly trained staff, but, this can't be expected to be everywhere.
We need to do two things to make sure such testing (preliminary testing, at least) can be accessible to everyone, everywhere: We need to miniaturise the lab and to make it portable. We can do this by using micro-fluidics (devices capable of using 1/1000 of a litre), and new manufacturing techniques, such as 3D printing.
Why 3D printing?
3D printing is something we’ve all heard about, and can even purchase for use at home, but we might not all be familiar with how they work. A 3D printer is a device that houses a type of mixture (either a liquid resin or a solid), that can be reacted with light or heat to form solid structures, using metals or plastics. You can build a whole range of structures, shapes and geometries with these printers, creating models and tools, using a digital blueprint. In 3D printing, you can be quite creative with designs, as the printer can build structures in 3 dimensions (up, down, side-to-side), using a range of sizes and geometries.
From Product Design Online, how does 3D printing work?
Unlike traditional manufacturing like injection moulding, 3D printing can be used to build something with a range of sizes and geometries within a single piece. This lowers the cost and time required for manufacturing. The 3D printer can project your digital blueprint in a liquid bath filled with a plastic pre-cursor and pixel by pixel will build that structure using light in a method called digital light projection, or using heat to melt and extrude a filament, which is called fused deposition modelling. Both technologies are used to make game models, ornaments, useful tools for the home (and in space!), but we don't see too much of it in the lab, yet.
Overall trend
Analytical chemistry is a mixture of chemistry and the analysis of molecules; we investigate how molecules interact, and we can use that to test for one type of molecule or another. A method called chromatography uses molecular interactions to separate components of a mixture, such as pollutants from water in environmental testing, or proteins or disease markers in blood samples. This technology is highly specialised, requiring specific equipment, chemicals, biomolecules etc, but our access to these can be limited.
Miniaturisation and portability of tests means that analysis is taken out of the lab and into different environments. The idea of bringing testing home, or to remote areas is called point-of-care, where samples can be collected and ideally analysed away from the lab. This could be useful in screening tests, as well as health monitoring. As 3D printing has gained popularity, and polymer printing is very accessible, scientists have been looking at how best to integrate these technologies. One of the benefits of 3D printing is that we can be more creative and build in 3-dimensions; so rather than building a flat plate with limited pathways for holding test materials (such as a 2D device), we can build a sphere (for example) or other geometry, with lots of different routes for liquids/tests to run through. Colleagues in the Netherlands have been working on this concept for several years.
Microfluidic devices can be portable (< 2kg), so can be taken into the field for environmental testing, or into the home for medical tests such as a glucose monitor for diabetic patients, or our COVID-19 home tests. Devices for microfluidics can be manufactured for this type of testing using 3D printing, however there are some hurdles.
Why do we need to change materials?
Ideally, this type of technology would be easy to apply to lab testing, and could shorten test times, or even house multiple tests in a single printed-device. While 3D printing offers many benefits, and flexibility in terms of design, our research has shown that the composition of commercial 3D printing resins can have an impact on the final surface of the 3D printed material, where unintended interactions between your molecule of interest, and the printed polymer might happen.
We've also seen the use of lab or test conditions, such as temperatures cycles from hot-cold, or even the use of certain solvents, can weaken the printed polymer. By changing the surfaces of these materials we can make them stronger for analysis and more inert so we can use them in testing; it’s difficult but not impossible. We’ve been experimenting with both chemical and physical methods (heat/plasma) to improve the control over surface chemical groups. Using chemistry, engineering, and polymer science we have introduced new chemistries to printed materials, for example, adding another active layer to the printed device, to allow new chemistries on the device surface for specific tests, like chromatography.
From BBC, could 3D printing be the future of organ transplants?
While limited, it demonstrated the importance of changing the chemistry of a material to suit the application. Without the modification, the printed device leaked when used with a flow of liquid, and the material used for chromatography was not stable. Other groups have bypassed this step altogether and are focussing on developing resins, capable of direct use in these fields, as highlighted in this video with Dr Simone DiMartino and even for use in the extraction of DNA.
Plastics or polymers that are protein or biomolecule friendly, and that don't remove our test molecules, need to be developed before we can bring this technology to the lab, or even to your GPs office. This could reduce dependency on traditional lab tests for screening, on the global supply chain, storage of single-analysis tests, and reduce wait times for health monitoring or diagnosis. All waiting to be unlocked with the right recipe of polymers.
The views expressed here are those of the author and do not represent or reflect the views of RTÉ
