From the Hubble Space Telescope capturing celestial bodies in distant galaxies, to smartphone cameras snapping moments of daily life, optical imaging plays a vital role in understanding both our world and our universe. Similarly, medical tools like endoscopes offer physicians an intimate look inside the human body.
Miniaturised scanners, small enough to nestle on the tips of endoscopes, allow for their insertion without significant discomfort or large incisions while capturing high-resolution images of tissues and organs.
“These specialised scanners bypass the need for a bulky camera sensor to obtain images, though they can be expensive and challenging to fabricate,” said Kaicheng Liang, Principal Investigator and Senior Scientist at A*STAR’s Institute of Molecular and Cell Biology (IMCB) and Institute of Microelectronics (IME). Safety regulations also limit their use in medical imaging devices like endoscopes, mandating operation at lower voltages that result in limited scan coverage.
To address these challenges, Liang and first author, Rachel Tan, proposed replacing complex and costly actuators with a simpler mechanism. Their innovation employs a single component that oscillates back and forth, much like a wiper blade. During their experiments, the vibrating optical fibre tip, powered by a piezoelectric bending actuator, traced an unexpected elliptical rather than a straight path due to a phenomenon known as 'whirling'.
By carefully adjusting the forces acting on the actuator, the researchers harnessed this effect to their advantage. It enabled the actuator to perform two-dimensional (2D) scanning using just one-dimensional (1D) movement. This breakthrough simplified the device's design and broadened the scanning area, allowing for simultaneous multiple views and significantly enhancing imaging capabilities.
The new system yielded high-resolution depth-multiplexed images of biological samples and demonstrated the ability to mosaic fields to achieve larger images, substantially boosting the scanning area.
"We are the first to exploit and enhance the whirling effect to produce a practical imaging function with state-of-the-art performance at an unprecedentedly low cost,” Liang stated. “Essentially, we turned a bug into a feature." Utilising a piezoelectric bender rather than the more intricate piezo tubes traditionally needed for 2D imaging also slashed production costs by nearly 50 times while expanding imaging coverage.
The technology, for which the team has a patent pending, holds promise for applications in endoscopes, headsets and miniaturised microscopes vital for medical diagnostics and biological research. They are currently collaborating with the National Neuroscience Institute on proof-of-concept imaging studies in clinical settings, and are working to streamline the manufacturing process for large-scale production and enhance the scanner's robustness to environmental factors.
The A*STAR-affiliated researchers contributing to this research are from the Institute of Molecular and Cell Biology (IMCB) and Institute of Microelectronics (IME).
