In the realm of biomedical imaging, optical coherence tomography (OCT) has become an indispensable tool, particularly for routine eye examinations worldwide. This technology leverages near-infrared light waves to non-invasively capture high-resolution cross-sectional images of the retina, enabling clinicians to diagnose and monitor various ophthalmic conditions with unprecedented clarity. Despite its widespread adoption, OCT devices are often encumbered by intricate mechanical components which, while crucial for image scanning, present reliability challenges and limit the miniaturization of instruments. Addressing these hurdles, a pioneering research team at the University of Colorado Boulder has unveiled a groundbreaking OCT device that operates without any mechanical scanning parts, thereby promising enhanced durability, reduced power consumption, and a pathway to more compact, versatile bioimaging systems.
Traditionally, OCT systems rely on scanning mirrors that oscillate to sweep the incident light beam across the sample, building detailed two-dimensional or three-dimensional images layer by layer. These moving parts, however, are prone to wear and can contribute to device malfunctions, especially in compact or portable units. The innovative approach introduced by the Colorado team circumvents these mechanical elements entirely by employing an electrowetting beam-scanner, a technology that manipulates the curvature of a liquid interface through electric potential differences. This liquid lens mechanism dynamically alters its shape at high speeds to direct the light beam, enabling precise and rapid scanning without the drawbacks inherent in mechanical movement.
One of the core advantages of this electrowetting method is its ultra-low power requirement compared to conventional scanning mirrors. By electrically controlling the wettability of a liquid in a small cell, the researchers achieved the modulation of optical pathways with minimal energy expenditure. This reduction in power not only extends the operational lifetime of the device but also facilitates integration into portable, wearable, or implantable systems, where energy efficiency and compactness are paramount. The absence of mechanical parts further enhances reliability, removing potential points of failure and reducing maintenance needs, a critical consideration for medical devices intended for widespread clinical deployment.
The research, recently published in Optics Express, details the design and characterization of this nonmechanical spectral domain OCT system. Under the guidance of lead author Samuel Gilinsky, the team rigorously tested the imaging capabilities of their device using biological samples, notably the eye of the zebrafish. Leveraging this aquatic model organism, which shares striking anatomical and optical similarities to the human eye, allowed the validation of the system’s resolution and imaging performance in a living tissue context. The cross-sectional images captured revealed distinct layers of the cornea and iris, affirming the system’s ability to resolve fine structural details crucial for accurate diagnostics.
Achieving axial resolution on the order of 10 microns and lateral resolution near 5 microns, the team’s imaging system surpasses the benchmark for identifying subtle features within the eye’s anatomy. Such precision is essential for early detection of degenerative eye conditions, including age-related macular degeneration and glaucoma, which often manifest as slight morphological changes undetectable by lower-resolution methods. By refining the optical pathways through electrowetting control, the device offers unprecedented image sharpness and contrast, facilitating better interpretation of tissue health by practitioners.
Beyond ophthalmology, this technological leap holds significant potential for cardiovascular diagnostics. Gilinsky and colleagues highlight that the methodology could be extended to visualize and characterize human coronary features non-invasively. Given that heart disease remains the leading cause of mortality globally, improvements in coronary imaging tools could revolutionize early detection and intervention strategies. The electrowetting-based scanning mechanism can enable smaller, more flexible endoscopic systems capable of navigating intricate bioanatomical pathways with minimal discomfort, expanding the frontiers of in-vivo imaging.
The team’s expertise in both electrical and mechanical engineering underpinned the multidisciplinary nature of this breakthrough. Collaborators included Professor Juliet Gopinath and Associate Professor Shu-Wei Huang from electrical engineering, alongside Professor Victor Bright from mechanical engineering. Their combined efforts brought together precise electrowetting lens fabrication, system integration, and mechanical design to realize a fully functional prototype. PhD graduates Jan Bartos and Eduardo Miscles, as well as doctoral candidate Jonathan Musgrave, contributed significantly to the experimental validation and refinement of the device’s performance.
In addition to the technological innovation, the researchers meticulously accounted for safety and biocompatibility, essential criteria for any biomedical device intended for clinical use. Compactness and lightweight form factors were achieved without compromising optical quality, ensuring the device could be comfortably used in human subjects for retinal imaging as well as endoscopic procedures. Such considerations pave the way for future commercialization and broad adoption in diverse medical settings.
The selection of the zebrafish as a model organism for validation was deliberate and strategic. Zebrafish eyes exhibit transparent and structurally analogous components to human eyes, allowing for the direct translation of imaging advancements. Moreover, their genetic tractability and established role in biomedical research make them ideal for testing new diagnostic tools. The bioimaging device successfully delineated the cornea and iris layers with distinct clarity, a promising step towards capturing similar or superior images in human applications.
Potential clinical advantages extend into early disease detection and monitoring, addressing a critical need in personalized medicine. With more precise imaging modalities, practitioners can monitor disease progression or treatment efficacy in real time, adjusting interventions proactively. Furthermore, the potential for miniaturization and integration into handheld or implantable devices opens avenues for telemedicine and at-home diagnostics, significantly enhancing patient care accessibility.
Looking forward, the research team envisions the electrowetting OCT technology playing a vital role in revolutionizing endoscopy by enabling smaller diameter optics without sacrificing image quality. This advancement not only reduces patient discomfort but also facilitates access to previously challenging anatomical regions. Such enhancements could transform diagnostic procedures for a multitude of organs beyond the eye and heart, thereby elevating the standard of care across numerous medical disciplines.
This development was made possible with funding support from prestigious institutions including the Office of Naval Research, the National Institutes of Health, and the National Science Foundation. These bodies recognized the project’s potential to bridge fundamental physics, cutting-edge engineering, and translational medicine, underscoring its multidisciplinary and impactful nature. The work exemplifies how innovative optical engineering can lead to transformative healthcare technologies.
As the medical field continues to embrace optical technologies for non-invasive diagnostics, this research stands out as a landmark achievement. By eliminating mechanical complexity and enhancing performance through electrowetting beam scanning, the University of Colorado Boulder team has charted a promising course toward smarter, more reliable, and more accessible bioimaging devices. Their vision is clear: to empower clinicians worldwide with superior tools that improve health outcomes and ultimately save lives.
Subject of Research: Development of a nonmechanical spectral domain optical coherence tomography device using electrowetting beam-scanner technology for biomedical imaging applications.
Article Title: Nonmechanical spectral domain optical coherence tomography using an electrowetting beam-scanner
Web References:
- https://opg.optica.org/oe/fulltext.cfm?uri=oe-33-17-35604&id=575535
- http://dx.doi.org/10.1364/OE.565684
References: Gilinsky et al. 2025, Optics Express
Image Credits: Gilinsky et al. 2025, Optics Express
Keywords
Optics, Optical devices, Physics, Applied sciences and engineering, Engineering, Electrical engineering, Eye
