This image has been acclaimed not just for its scientific value, but also for its aesthetic beauty, earning the Wellcome Image Award in 2012. The final picture is a composite of two images taken with an upright fluorescent dissecting microscope.

Through this technique, scientists watched the embryo’s vascular system come to life in real-time. A fluorescent dye was injected into the lower part of the system and pumped throughout by the tiny heart. So, under the microscope, the growing embryo’s entire circulatory network was vividly illuminated.

For birds like chickens, the egg serves as a self-contained environment. Here, the embryo draws nutrients from the yolk while safely cocooned. And the vascular system is the vital mechanism that delivers these nutrients. It also facilitates gas exchange, as the embryo requires oxygen to grow, much like a human fetus relies on the placenta.

The injection of fluorescent dextran into the embryo’s bloodstream highlights how the heart acts as a central pump, circulating nutrients and oxygen throughout the body. But what Pasque’s image most powerfully illustrates is the embryo’s dependency on its vascular system. Without it, its growth would stall before it ever hatches.

At this stage, the embryo is no larger than a small coin. The bright reversed question mark in the middle is the chick, and the lacy circle surrounding it is the yolk.

The Role of Fluorescent Imaging in Science

Fluorescent imaging has been transformative in biological sciences, offering a non-invasive way to observe cellular and developmental processes. By tagging different parts of a biological system with fluorescent markers, scientists can trace the flow of molecules, cells, or even blood throughout an organism.

Pasque’s work exemplifies how imaging techniques have progressed, allowing researchers to capture developmental stages with exceptional clarity. While traditional microscopy techniques might obscure certain details, fluorescence makes visible the invisible, highlighting structures that would otherwise be impossible to observe in such detail.

Why Chicken Embryos?

Chickens (Gallus gallus) are a widely used model organism in developmental biology because their eggs are relatively easy to manipulate and observe. They also share key developmental processes with other vertebrates, including humans. So, studying these embryos offers critical insights into how circulatory systems form and function. And this knowledge has implications for understanding congenital defects and improving treatments for cardiovascular diseases in humans.

The use of chicken embryos in research stretches back over a century, but with modern imaging techniques, scientists can now capture developmental processes in ways previously unimaginable. By closely examining the early development of blood vessels, researchers are able to piece together how similar processes unfold in other species, including mammals.

Beyond its scientific relevance, Pasque’s image also demonstrates the intersection of science and art. The bright fluorescent hues tracing the vascular system create a visually stunning image.

Science imaging can play an important role in making complex processes accessible to a wider audience.