WSU team 3D prints drug-delivering contact lenses

Just weeks after Newcastle University researchers made headlines for their world-first 3D printed corneas, it appears a team at Washington State University (WSU) has also been keeping its eye on 3D printing’s potential in making medical treatments for the visually impaired.

After receiving an 18 month exploratory research grant, WSU researchers have created a kind of 3D printed contact lens that could be used as a cheaper alternative to laser eye surgery.

Alternative eye therapies needed

According to recent estimates from the U.S. National Eye Institute (NEI) over 35 million people in America were affected by age related eye disease in 2010. By 2050, the institute expects this figure to double.

Diabetic retinopathy, which will affect around one third of world’s diabetics in their lifetime, is one example of such diseases. In people aged 65 and over, the condition affected around 7.7 million people in 2010.

The estimated number of American citizens over the age of 65 affected by diabetic retinopathy in 2010 and 2050. Image via the National Eye InstituteThe estimated number of American citizens over the age of 65 affected by diabetic retinopathy in 2010 and 2050. Image via the National Eye Institute

Introducing: microneedle arrays

It is always challenging to treat such delicate conditions. At WSU, researchers propose a direct treatment method using microneedle arrays.

A technology that has been around in medicine for some time, microneedle arrays have been proven as an effective means of controlling drug delivery into the body.

Unlike a hypodermic needle, microneedles create small, shallow invasions in the skin. As an array, in this case of around 25, the microneedles are created to gradually deliver drugs into the body over an extended period of time. Treatment this way improves drug effectiveness, and reduces the risk of side effects.

Insertion of a hypodermic needle vs. microneedle array. Image via Clinical and Experimental Vaccine Research 2014/Korean Vaccine Society.Insertion of a hypodermic needle vs. microneedle array. Image via Clinical and Experimental Vaccine Research 2014/Korean Vaccine Society.

Controlled drug delivery

WSU researchers propose to make their eye microneedle arrays using 3D printing, meaning that each one could, in effect, be custom-made for specific patients and conditions.

To achieve the fine resolution required for these devices, a vat photopolymerization technique, such as SLA, DLP or even nanolithography, is likely the best route of fabrication.

The plan is to apply the drug-loaded arrays directly to a patient’s eye. The microneedles would be left there potentially for up to a month. Then, thanks to the WSU assistant professor Kuen-Ren “Roland” Chen’s  “locking” and “unlocking” technology, they would be removed afterwards causing minimal damage and discomfort.

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Featured image shows a 3D printed prototype of a programmable microneedle array for the eye. Photo via WSU

World's first 3D LED printer could print HUD contact lenses

Researchers at Princeton University have developed a 3D printer that can print LEDs in layers — and it could one day print contact lens HUDs.

Illustration depicting the layers of the LED device.
Kong et al, Nano Letters

Here’s a hypothetical question: would you rather have a HUD on glasses or a contact lens? If you answered “contact lens”, the bad news is that you may be waiting some time… but the good news is that it just got a little more feasible, with the invention of the world’s first 3D printer that can print LEDs.

The team, led by Michael McAlpine at Princeton University’s McAlpine Research Group, has successfully used its printer to 3D-print quantum dot LEDs — LEDs that are considered the next step up from OLED. QLEDs shine brighter and with purer colour, at a lower power consumption rate, using cadmium selenide nanocrystals. They’re also ultrathin, flexible and transparent — like, for instance, contact lenses.

“The conventional microelectronics industry is really good at making 2D-electronic gadgets,” McAlpine said. “With TVs and phones, the screen is flat. But what 3D printing gives you is a third dimension, and that could be used for things that people haven’t imagined yet, like 3D structures that could be used in the body.”

McAlpine and his team printed the LED in five layers. A ring made of silver nanoparticles on the bottom layer is the metal conduit for a mechanical circuit. Two polymer layers follow to supply and transfer the electrical current to the next layer, consisting of cadmium selenide nanoparticles (the quantum dots) contained in a zinc sulphide case. The top and final layer is the cathode, made of eutectic gallium indium.

The printer cost around $20,000 and took two years to develop.
Kong et al, Nano Letters

“What we have presented here is an additional method to integrate electronics that can take into consideration the three-dimensional geometry of an object,” said study lead co-author Yong Lin Kong. He also noted that this is the first example of a fully 3D printed, fully functional electronic device.

Potential applications for the technology include wearables, such as the aforementioned contact lens — if the team can figure out a way to include an on-board power supply. The team is also going to be investigating the inclusion of a 3D-printed transistor for added functionality.

You can find the full study online in the journal Nano Letters.