Adelaide-based researchers have created a tiny, 3D-printed micro-lens that can peer inside blood vessels and therefore might help prevent heart attacks.
“We 3D-printed this micro-lens, with a diameter of less than 0.26 mm, directly on an optical fibre in a single step,” says Jiawen Li, who leads the intravascular imaging program at the Institute of Photonics and Advanced Sensing (IPAS) at the University of Adelaide.
Jiawan award edited
Jiawen Li accepts her award at the Sony Women in Technology Award with Nature in Tokyo. Credit: Masayuki Nakano, Sony Group Corporation
Li recently received an international award for her invention of 3D-printed hair-thin endoscopes that can see inside the human body in a minimally invasive way. These tiny imaging devices were made possible by the development of micro 3D-printing technology, in collaboration with a German company Nanoscribe and the University of Stuttgart.
The devices provide real-time physiological data that has many clinical uses. For example, they can detect and diagnose coronary artery disease (CAD). This disease is characterised by the build-up of plaques on the walls of blood vessels, which can lead to life-threatening heart attacks.
While some technology is currently commercially available to detect and image these plaques, they are based on traditional Gaussian beam optics. A Gaussian beam is a projection of light that concentrates energy (for example, most lasers are Gaussian beams). However, the beam is diffracting, which means it spreads out when it hits an object or passes through an aperture, which reduces image resolution and causes blurring. This property leads to limitations when Gaussian beams are used to image blood vessels.
3d printed micro-lens
Now, a paper just published in Advanced Photonics details the development of an ultrathin lens that overcomes many of these limitations. Just 0.26 mm thick, the lens has a long focal depth and small focus diameter, and is 3D-printed directly onto an optical fibre for use as an endoscope.
Instead of a Gaussian beam, it uses a ‘needle beam’, or a Bessel beam. Li explains that this “stays tightly focused over a long distance without spreading much. Thus, its imaging resolution stays great, and the images remain sharp and clear for a longer distance.
“By overcoming the limitations of traditional optics and enables exceptional image quality, this device could provide greatly improved imaging capability of high-risk plaques that cause heart attacks.”
The device has undergone testing by cardiologists in preclinical models, imaging inside narrow coronary arteries. The results showed that the images have better spatial resolution and depth of focus than standard imaging probes.
“Now we are preparing for the ethics application for a small clinical trial at the Royal Adelaide Hospital,” Li says. “The aim is to utilise the 3D-printed new lens to accelerate decision-making in selecting the high-risk patients for treatments, to reduce heart attacks, hospitalisation, and/or death in future.”
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