3D Printed Lab-On-Chip Breakthrough Achieved by USC Researchers

The 3D printing sector has obviously gone through a drastic evolution in the past several years. Nevertheless, there’s still ample reason to believe that neither the technology nor the industry will start to reach their full potential until additional, similarly significant progress is made in automation. One of the best examples bearing this out is the shift in strategic focus from hardware to software, which some of the industry’s most important companies are currently making. More and better automation is the main underlying goal of improving the software platforms used for operating 3D printers.

The size of the object produced is probably the key factor determining how urgent of a priority it is, to automate the processes involved in 3D printing that object. As is also true of conventional manufacturing, this is simply because the most expensive and time-consuming items to produce tend to be those that are extremely large — or extremely small. One area in which 3D printing may inherently have the edge over conventional manufacturing, both in general as well as specifically in terms of automation, is in 3D nanoprinting.

In the field of microfluidics — especially concerning any object referred to as a “lab on a chip” (LOC) — manufacturing the end-product requires a precision that should make 3D printing the ideal solution. Yet, at least with regards to vat polymerization, low-cost versions of the technology aren’t precise enough at this point to build layers of liquid resin at the 10-micron level required for microfluidic medical testing devices. A recent article published in the journal Nature Communications, however, documents a potential solution to this problem, developed by a research team at the University of Southern California’s (USC’s) Viterbi School of Engineering.

LOC devices depend on tiny networks of internal channels, designed for the minuscule amounts of liquid that they collect to flow through. During the production process, while the surrounding surfaces harden into solids, the center — the internal channels — need to be left in the liquid state, so they can be flushed and left hollow during the post-processing phase. The primary issue with using vat polymerization for these devices is that the resin used in printing them is usually transparent, since the devices and their contents (blood or some other human bodily fluid) are generally meant to be looked at through microscopes. Although some opaque resins can be kept liquid at this scale, the clear liquids used for LOCs allow more light to pass through, leading to narrower than desired channels, which would become clogged if used.

The solution developed by the research team at USC, led by Professor of Aerospace and Mechanical Engineering and Industrial and Systems Engineering Yong Chen, is ingenious in its simplicity. At the stage of the printing process in which the layers have to remain liquid, an auxiliary platform moves to momentarily block the light from solidifying the channels. The standard commercially available vat polymerization 3D printer, according to Professor Chen, can, at best, print at the 100-micron level with poor accuracy.

Professor Chen said that the solution his team developed allowed them to print their end-product within 10-micron ranges, “…and we can control it really accurately, to an error of plus or minus one micron. This is something that has never been done before, so this is a breakthrough in the 3D printing of small channels.” Professor Chen said the team is currently filing a patent application for the method written about in Nature Communications, in addition to its seeking partners for commercializing the technique.

If this technique leads to automated 3D-printing of LOCs, it’s easy to imagine that the market it creates would almost certainly lead to the development of entire end-to-end platforms designed for the process. The most noteworthy thing about the USC team’s solution, though, is that it wasn’t created by developing an entirely new 3D printer, but rather by coming up with a slight modification that could work for many different printers. In this sense, it illustrates how much the potential for automating 3D printing processes — and thereby, contemporary industrial processes in general — will be opened up, simply by an increasing number of users adopting the technology.