From The Editor | January 22, 2025

Biophotonics: Keeping Astronauts Safe And Diagnosing Sleep Apnea

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By John Oncea, Editor

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Biophotonics is used in imaging, sensing, and therapy to diagnose disease, reduce the risk of infection, and observe brain activity. Now it is being used to keep astronauts healthy and diagnose and treat sleep apnea.

Biophotonics is the study of how light interacts with biological systems, and the use of light to examine and manipulate them. It’s a multidisciplinary field that combines biology with photonics, the physical science of light.

Biophotonics is used to create images of cells, tissues, and organs. For example, fluorescent markers can be injected into a biological system to track cell dynamics. It is also used to sense biological systems, such as identifying bacterial and fungal infections, as well as to develop new therapies, such as non-invasive treatments that use light to stimulate the body's natural repair mechanisms.

Medicine and dentistry are two areas in which biophotonics are applied to diagnose diseases, assess tissue tumors, identify antibiotic resistances, and reduce the risk of infection. It also can be used to observe and control brain activity, which may help understand conditions like Parkinson’s disease.

Two lesser-known uses of biophotonics have emerged recently: its ability to help evaluate the health of astronauts and as a tool to diagnose sleep apnea.

Biophotonics In Space

Biophotonics plays a pivotal role in advancing space exploration and keeping astronauts healthy. By leveraging light-based technologies, biophotonics offers innovative solutions for medical diagnostics, therapeutic applications, and biological research in the unique environment of space, notes the Mars On Earth Project.

One significant application of biophotonics in space is photobiomodulation therapy. According to Springer Nature, this technique utilizes specific wavelengths of light to stimulate cellular processes, promoting tissue repair and mitigating common pathologies associated with space travel, such as muscle atrophy and delayed wound healing. The beneficial effects of photobiomodulation have been demonstrated in various studies, highlighting its potential to enhance astronaut health during long-duration missions.

In addition to therapeutic applications, biophotonics facilitates advanced biological experiments in space, adds Photonics. Researchers have developed photonic devices capable of cultivating microorganisms under microgravity conditions.

For instance, a modular, self-contained device employing LEDs and photodiode sensors has been designed to monitor bacterial growth with minimal human intervention. Such innovations enable scientists to conduct biological research in outer space, providing valuable insights into microbial behavior and potential implications for human health during space missions.

Moreover, biophotonics contributes to the development of compact and efficient diagnostic tools essential for space travel. Techniques like fluorescence imaging and Raman spectroscopy offer non-invasive methods to monitor astronauts’ health, ensuring timely detection and treatment of medical conditions. The integration of these optical technologies into portable devices aligns with the constraints of space missions, where equipment size and reliability are critical factors.

Currently, ultrasound devices are used in space to diagnose and monitor medical issues that occur in astronauts, the Mars On Earth Project writes. Uses of ultrasound devices in space include monitoring of musculoskeletal health that might deteriorate due to low gravity, cardiovascular function, and soft tissue injuries.

Another application is the use of two-photon microscopy to detect bone loss, one of the more serious side effects of extended space flight which is accelerated bone loss because of microgravity. The Mars On Earth Project notes bone loss in hips and the spine can be up to 1% per month, a condition that can be monitored with two-photon microscopy, a powerful imaging technique that utilizes two photons of lower energy to excite fluorophores within a specimen simultaneously, leading to fluorescence emission.

“This process allows for deeper tissue penetration and reduced phototoxicity compared to traditional fluorescence microscopy techniques,” writes the Mars On Earth Project. “Two-photon microscopy can provide high-resolution imaging of bone microstructure, allowing researchers to study changes in bone architecture and mineralization associated with bone loss in microgravity. This technique enables visualization of individual bone cells, such as osteoblasts, and osteoclasts, as well as their interactions within the bone matrix.”

Biophotonics serves as a cornerstone in the advancement of space exploration, providing essential tools for medical care and biological research. Its applications not only enhance the well-being of astronauts but also pave the way for more sustainable and longer-duration missions beyond Earth.

Diagnosing Sleep Apnea

“Obstructive sleep apnea (OSA) is a common sleep disorder characterized by intermittent airway blockages during sleep, leading to disrupted breathing,” writes Medical Xpress. “Despite advances in diagnostic tools, current methods for assessing the condition remain limited, often unable to provide a complete picture of the airway obstructions that occur during sleep. This has prompted the search for a more accurate, less invasive way to diagnose OSA and guide treatment decisions.”

In a recent study reported in Biophotonics Discovery, researchers revealed that they developed an innovative approach using swept-source optical coherence tomography (OCT), a technology traditionally employed in eye care, to obtain highly precise visualizations of the upper airway. By integrating a specialized device into the OCT system, they extended its range, enabling the capture of detailed, high-resolution images of the airway in both awake and sleep states.

The study focused on a 28-year-old individual with sleep-disordered breathing. With the enhanced OCT system, researchers created 3D reconstructions of the upper airway, revealing notable differences between awake and sleep conditions. The most severe airway obstruction was identified in the oropharynx – the area at the back of the mouth – commonly implicated in obstructive sleep apnea (OSA).

In addition to imaging, the study utilized computational fluid dynamics (CFD) to simulate airflow through the airway, highlighting areas of turbulence that signal obstruction. This combination of OCT imaging and CFD provided precise identification of the regions with the most significant blockages during sleep.

By delivering detailed visualizations of the airway structure and airflow dynamics, this innovative method has the potential to transform OSA diagnosis and treatment. Offering a deeper understanding of airway functionality, it can improve surgical planning and enhance outcomes for patients with OSA, paving the way for more effective and individualized therapeutic approaches.