Just over a decade ago, renowned chemist Dr. Joseph DeSimone introduced a groundbreaking technology that would form the foundation of the company Carbon, where he served as Co-Founder and CEO. This technology, known as Continuous Liquid Interface Production (CLIP), transformed resin 3D printing by drastically increasing both its speed and efficiency. Now, DeSimone and his team of researchers at Stanford University have advanced the technology even further with the development of Injection CLIP (iCLIP). This innovation serves as the basis for PinPrint, a new company DeSimone is co-founding. PinPrint’s mission is to reimagine the patient experience in the realms of vaccinations and drug treatments. Here, we’ll explore the technology and vision behind PinPrint, insights from DeSimone on what drove Carbon’s success and his advice for aspiring leaders in science and additive manufacturing.
PinPrint’s first target is microneedle patches, which offer a pain-free alternative to conventional needles. They can be used for vaccine and drug administration for both therapeutic and cosmetic use cases, as well as for collecting interstitial fluid samples. Compared to needles, microneedle patches are easy to apply, less hazardous and minimally invasive. This means they can easily be administered in homes or non-clinical settings, in addition to clinical ones. Furthermore, these patches carry less potential for microbial infection, and they are easier to dispose of than regular needles. These devices have been around for decades and are easy to manufacture using traditional methods. However, PinPrint is leveraging additive manufacturing to achieve highly complex geometries, enabling the creation of microneedles with microfluidic channels and negative spaces that would be impossible to incorporate through conventional manufacturing.
A standard microneedle patch, without microfluidic channels (Photo Credits: MyLife Technologies)
Solving the Problem of Overcuring: CLIP vs. iCLIP
Accomplishing such geometries in microneedle patches could only be done if a fundamental problem with resin 3D printing was addressed: overcuring. Overcuring refers to the unintended closing of negative spaces. This happens when UV light reaches previously cured layers, causing curing to occur in spaces that were supposed to be negative space, lowering the resolution of the Z axis. DeSimone and the Stanford lab wanted to address this issue and achieve superior resolution not only in the XY plane, but in the Z axis as well.
To understand the team’s solution, we first have to look at CLIP technology. Like other VAT photopolymerization technologies, it involves curing resin with UV light. The key addition here is a special window located below the resin that’s transparent to light, but also permeable to oxygen. CLIP controls the oxygen flux through this window, creating a “dead zone” in the resin pool just tens of microns thick, where photopolymerization won’t occur. This gap creates suction that causes the resin to flow continuously as the build plate is raised. So, instead of being printed layer-by-layer, an object is grown within the vat of resin, just above the dead zone, allowing printing to occur 100 – 1000 times faster than conventional 3D printing methods. This method achieved remarkable resolution in the XY plane, but left the Z axis challenged by overcuring.
Nearly ten years later, DeSimone and a team from Stanford introduced iCLIP to address this issue, publishing their landmark study in the Proceedings of the National Academy of Sciences (PNAS) in September 2024. The technique involves constantly pumping naturally oxygenated (inhibited) resin through all the negative space, whether that be channels or lattices, flushing out any residual resin that could become overcured. Therefore, the process mechanically pushes resin into the gap, instead of relying on suction to draw it. This advancement enabled the creation of microchannels with smaller diameters and heights, greatly enhancing functionality, now printing features with high-resolution pixels down to 10 to 25 microns. Generally, the lab is focusing on manufacturing with light, looking into achieving single-digit micron resolution in all three Cartesian coordinates.
Diagrams illustrating microfluidic channels created with iCLIP technology (Photo Credits: I.A. Coates, et al./PNAS)
How Can PinPrint Microneedle Patches Be Used?
With a solution for overcuring in tow, DeSimone and his team began the journey to improve microneedle patches, integrating them with microfluidics. PinPrint’s microneedle patches are not yet available on the market, but the company is currently testing its patches on humans. Once ready for distribution, one of the first drugs PinPrint will work with is lidocaine, a local anesthetic medication that numbs the area where it’s applied. DeSimone envisions these lidocaine patches being sold to dermatological clinics to instantly numb people, instead of waiting 30 minutes for a numbing cream to kick in. He compared this business approach to bowling: “What is the first pin you want to knock over that knocks over additional pins? For us, that first pin is lidocaine.”
What are the other “bowling pins” PinPrint hopes to knock down? DeSimone sees potential for using the patches to collect interstitial fluid. “Imagine walking into a Walmart, putting a patch on, doing your shopping, leaving a patch at the counter, and getting molecular information instead of doing a venous puncture and a blood draw,” he said. Another use case could be pharmaceutical companies purchasing the patches and filling them with one (or multiple) vaccines.
A visual comparison of microchannels created with iCLIP and a penny (Photo Credits: I.A. Coates, et al./PNAS)
An Entrepreneurial Perspective
Over the last few years, the additive manufacturing industry has faced a more somber market, marked by major acquisitions and layoffs. Despite this, DeSimone shared that Carbon hasn’t really felt an impact. “I think that perhaps it is because we have relentlessly focused on manufacturing and how to take 3D printing into real-world manufacturing,” he said, citing Carbon’s early partnerships with adidas and Invisalign. “Living at the intersection of all three: hardware, software and materials, has been the key to that.”
He further credited some of Carbon’s success to the company’s subscription model: “We have a subscription model and there’s no other piece of manufacturing hardware that I’m aware of that is subscribed to in any industry sector. In the beginning, even our own investors were concerned about whether we could get three-year subscriptions versus one-year subscriptions, and now, because we’re in manufacturing, it’s actually turning to be five-year subscriptions. So we have tremendous visibility on revenue: it’s contractual.”
Where Should We Be Directing Energy?
When asked about what advice he would give to young scientists and engineers looking to make a difference in the industry, DeSimone brought up an idea that might be surprising: “I think one can make a pretty compelling argument that, in many ways, no more research is needed in green, sustainable polymers as an example,” he began. “You could snap the chalk line today and say, OK, no more, but implement what you’ve got…There’s a lot of great stuff out there that’s not getting used. Why is that?” His point was clear—there’s a wealth of untapped potential that could be leveraged right now, if only it were brought into practice.
For those looking to bring disruptive technology to the marketplace, DeSimone recommends Geoffrey Moore’s book, Crossing the Chasm. “That our book was our Bible at Carbon. It’s our Bible at PinPrint,” he said, underscoring the ongoing relevance of Moore’s insights.
Carbon offers to scale production for its partners with its fleets of 3D printers (Photo Credits: Carbon)
More broadly, DeSimone acknowledged the crucial role of both businesses and policy in driving progress. “It takes entrepreneurs and policy changes, and there’s a huge opportunity now to be focused on vertical integration and taking things forward…Young people should be thinking about where they want to play,” he urged, pointing to the tremendous potential for emerging leaders in the field.
DeSimone also touched on an issue unfolding in the United States: “We’re in the midst of a challenge in the United States right now with the war on universities, and our technology arguably spun out of that kind of setting,” he remarked. “Don’t get me wrong, I think changes need to happen in academic research, but I worry about whether the community is ready to make those hard decisions about what needs to be funded and what doesn’t.” He expressed hope that a better understanding of commercialization could guide not all, but some, of these difficult decisions. Ultimately, DeSimone emphasized that for a tech business to succeed, it requires both a strong business strategy and a solid technological foundation. With PinPrint, the combination of strategic vision and innovative technology holds promise, and we’ll be watching to see how the technology is received in the healthcare space.
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*Cover Photo: Microneedle patches created with iCLIP technology. Credits: I.A. Coates, et al./PNAS