Scientists from Trinity College in Dublin have created a suite of biological sensors by chemically re-engineering pigments to act like tiny Venus flytraps. The sensors can detect and grab specific molecules, such as pollutants, and will soon have a host of environmental, medical and security applications.
The sensors rely on porphyrins, a class of intensely colored pigments that normally play an important role in metabolism. The most prominent examples are heme (the red blood cell pigment required to transport oxygen) and chlorophyll (the green plant pigment responsible for harvesting light and driving photosynthesis). In nature, the active versions of these molecules contain a variety of metals in their core, which gives rise to a set of unique properties.
The researchers at Trinity, under the supervision of Professor Mathias O. Senge, Chair of Organic Chemistry, chose a disruptive approach of exploring the metal-free version of porphyrins. Their work has created an entirely new range of molecular receptors.
By forcing porphyrin molecules to turn inside out, the researchers were able to exploit the formerly inaccessible core of the system. Then, by introducing functional groups near the active centre they were able to catch small molecules—such as pharmaceutical or agricultural pollutants—and then hold them in the receptor-like cavity.
Karolis Norvaiša, an Irish Research Council-funded PhD Researcher at Trinity, and first author of the study, said, “These sensors are like Venus flytraps. If you bend the molecules out of shape, they resemble the opening leaves of a Venus flytrap and, if you look inside, there are short stiff hairs that act as triggers. When anything interacts with these hairs, the two lobes of the leaves snap shut."
"The peripheral groups of the porphyrin then selectively hold suitable target molecules in place within its core, creating a functional and selective binding pocket, in exactly the same way as the finger-like projections of Venus flytraps keep unfortunate target insects inside."
The discovery was recently published in the print version of the leading international journal Angewandte Chemie International Edition.