Photoacoustic microscopy is allowing researchers and clinicians an unprecedented view — based on the technique’s ability to reveal information about the circulation of cells throughout the body — of the origins of disease. It is also opening a window into the innate abilities of animal species to adapt to their environments. For example, photoacoustic microscopy has revealed the ability of glass frogs to camouflage themselves by becoming nearly transparent, even while they sleep or rest.
The photoacoustic microscopy technique involves using a laser beam that is absorbed by tissue, and the resulting effect is then converted into ultrasonic waves. Scientists used the technique to study the glass frogs, which are native to the rainforests of Central and South America. The study revealed that the frogs can conceal their circulating red blood cells while sleeping. The frogs’ skin is transparent, but the red blood cells in their circulatory systems ordinarily absorb green light while reflecting red light, making the frogs highly visible. Thanks to the noninvasive nature of photoacoustic microscopy, the scientists were able to place the tiny creatures upside down in a petri dish to mimic how the animals sleep on leaves in the wild. What the technique then revealed to them was surprising. Red blood cells were almost entirely absorbed into the animals’ livers, with no apparent side effects, while they rested.
Photoacoustic imaging also has genuine potential in clinical settings because it has been shown to effectively capture circulating tumor cells well before cancer could be officially diagnosed. This was the conclusion of authors Junjie Yao and Van Tu Nguyen in our cover story in this edition of BioPhotonics. Learn about the evolution of this technique here.
Elsewhere in this issue, author Jeffrey Weiss writes about the potential for early diagnosis, with the use of dynamic light scattering to capture the early signs of Alzheimer’s disease. Dynamic light scattering measures the scattered light intensity fluctuations from random thermal movement, and the method is already used to diagnose cataract formation. According to Weiss, other optical technologies capture the thinning of the retinal tissue at a much later stage of Alzheimer’s. Read about how dynamic light scattering could be an important diagnostic tool here.
Also in the hunt for early and accurate diagnoses, authors Najeeb Khalid, Ilias Hurley, and Alexander Novikov are using aptamers, or short sequences of DNA or RNA, which bind to specific molecules while enhancing fluorescence. This process could allow clinicians to pinpoint trace amounts of a particular disease or pathogen before it has manifested itself as dysfunction within the body or in obvious symptoms. Find out how aptamer molecular photonic beacons function here.
Author Emily Bishop focuses on the instrumentation inherent in Raman spectroscopy, in which the lasers, filters, mirrors, and other components can enable sensitive readings that are valuable for observing cellular changes, even within the brain. Learn more about these advancements here.
Finally, in “Biopinion,” Alexander Scheeline discusses the differing priorities of academia and industry in biomedical optics, and how scientists can take these differences into account when considering their own career paths. Read what he has to say here.
