Researchers at The Grainger College of Engineering at University of Illinois Urbana-Champaign are using the butterfly as a way to help scientists detect cancer.
Our planet is home to a variety of creatures with senses that outmatch those of humans. For instance, turtles can sense the magnetic field of the Earth, mantis shrimp can spot polarized light, elephants can pick up on sound frequencies too low for us to hear, and butterflies have the capacity to observe more colors, such as UV light.
A research team, motivated by the better vision of the Papilio xuthus butterfly, has come up with a sensor that can detect ultra-violet radiation which is not visible to the human eye. The sensor is made up of layered photodiodes and perovskite nanocrystals (PNCs) which can perceive different wavelengths in the UV range. This new imaging technology is also able to distinguish between cancer cells and healthy cells with an accuracy of 99%.
Viktor Gruev, a professor of electrical and computer engineering at the University of Illinois Urbana-Champaign, and Shuming Nie, a bioengineering professor, headed up this research which was recently printed in Science Advances.
Minor Modifications
It is amazing how minuscule changes can have considerable effects. Even relatively small alterations can create large shifts in outcomes. This is especially true when it comes to the world of technology. Even the slightest variations can lead to drastically different results.
Gruev points out that their new camera design is based on the visual system of butterflies, which can observe many different parts of the UV spectrum. To replicate this, they utilized brand-new perovskite nanocrystals with silicon imaging technology. This camera can recognize multiple UV regions.
Electromagnetic radiation that has a shorter wavelength than that of visible light (but longer than X-rays) is known as UV light. This type of radiation is commonly known for being emitted from the sun and its potential harmful effects on humans. UV radiation is categorized into three different regions – UVA, UVB and UVC – based on the range of their wavelengths. Since humans cannot detect UV light, it can be difficult to differentiate between the three regions and capture the relevant information.
Butterflies, however, have the ability to observe the small changes in the UV spectrum, just like humans can perceive shades of green and blue. Gruev remarked, “It is quite stunning that they can detect those slight alterations. UV light is highly absorbent, and yet butterflies have succeeded in doing this with remarkable success.”
The Game of Copying
This particular game requires players to imitate the behavior and actions of others. It is a popular pastime that is often used to test a person’s ability to follow instructions and to see how well they can match the same actions.
Humans possess trichromatic vision, meaning they can see three colors: red, green and blue. But the Papilio xuthus, a yellow Asian swallowtail butterfly, has more than just those three photoreceptors. In addition to red, green and blue, it has violet, ultraviolet and broadband receptors. Furthermore, this species also has fluorescent pigments that let them transform UV light into visible light that can be sensed by their photoreceptors. Consequently, this gives them the capacity to detect a broader range of colors and details in their environment.
The Papilio xuthus butterfly has a greater number of photoreceptors and a distinct tiered structure to them. To reproduce this UV sensing ability, the University of Illinois Urbana-Champaign team used a thin layer of PNCs and a layered array of silicon photodiodes.
Semiconductor nanocrystals, known as PNCs, boast properties that are similar to quantum dots. Depending on the size and composition of the nanocrystals, their absorption and emission properties can be altered. Over the last few years, PNCs have become popular for use in various sensing applications, such as solar cells and LEDs, due to their capacity for detecting UV (and even lower) wavelengths which are not detectable by silicon detectors. In the new imaging sensor, the PNC layer absorbs UV photons and re-emits light in the visible (green) spectrum which is detected by the tiered silicon photodiodes. With this data, UV signatures can be identified and mapped.
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Healthcare and Other Fields
Healthcare isn’t the only area that is relevant in today’s society. There are various other industries and disciplines that are important and worth exploring.
Biomedical markers such as amino acids, proteins, and enzymes are present in greater concentrations in cancerous tissues than in healthy tissues. When these markers are exposed to ultraviolet light, they emit visible light in a process known as autofluorescence. According to Nie, the major obstacle in making scientific progress had been the difficulty of imaging in the UV spectrum. To address this issue, they have now developed a technology that enables them to image UV radiation with great sensitivity, and to discern minor spectral variations.
The distinct UV fluorescence of cancer and healthy cells, due to their different concentrations of markers, enabled the team to evaluate their imaging device’s ability to distinguish between them. Tests revealed that the device had a 99% accuracy rate in doing so.
Gruev, Nie, and the research group they are working with imagine that this sensor can be employed in surgical operations. One of the primary concerns is ascertaining how much tissue needs to be taken away to guarantee that all the margins are clean and, in these circumstances, such a sensor could assist in the decision-making process when a surgeon is eliminating a malignant tumor.
Nie explains that this novel imaging technology allows us to recognize cancerous and healthy cells, and can be utilized for various other purposes than just health. Besides butterflies, there are other living beings that have the ability to perceive UV light, and with this sensor, biologists can gain more insight on their hunting and mating behaviors. This equipment also has potential to be taken underwater, as despite the fact that the majority of UV radiation is absorbed by water, there is still sufficient to affect the environment and the animals that perceive and make use of the UV light.