Investigating Chemical Systems That Mimic Natural Processes

NYU Abu Dhabi Chemistry Professor Panče Naumov looks beyond bioluminescence as an observed phenomenon to the reaction at the molecular level.

Fireflies and other luminous organisms may be a rather unassuming subject for solid-state chemists, but the nifty in-built enzymatic process these insects use to emit a luminescent glow for elementary communication functions is of great interest to the fields of science and medicine. This natural process of energy conversion, from chemical energy to light, has use in biological imaging of live tissues, particularly in the role of detecting pathogens. However, as practical applications were being developed to leverage this chemical reaction in the field of medicine, the underlying processes and mechanisms of bioluminescence itself were not well understood.

To improve scientific knowledge on this process, NYU Abu Dhabi Chemistry Professor Panče Naumov (who was at Osaka University at the time) decided to look beyond bioluminescence as an observed phenomenon to the reaction at the molecular level.

Bioluminescence occurs when an enzyme, lucerifase, binds together with a molecule called luciferin, resulting in several steps of chemical reactions that convert luciferin into oxyluciferin, an extremely unstable molecule responsible for emitting light. In 2009, Naumov, along with fellow researchers, used the method of X-ray diffraction to determine the crystal and molecular structure of oxyluciferin, providing essential knowledge for the reconstruction of the mechanism of bioluminescence for practical application.

In his solid-state and structural chemistry lab at NYUAD, Naumov is now expanding upon this research to investigate other chemical systems that mimic natural processes. The lab, which houses a team of four postdoctoral researchers, is principally concerned with investigating the conversion of energy from its different forms, particularly among chemical, mechanical, light, and thermal energy. "When converting from one type of energy to another, there is a physical process involved," Naumov explained. "We want to investigate the mechanism of these physical processes at the molecular level, and understand how we can recreate these by using certain materials, and how we can make these processes more efficient. Our unique approach is to combine solid-state supramolecular chemistry with photochemistry and photophysics to reach a new interest in science."

Prior to joining NYUAD, Naumov had already made noteworthy progress in inducing polychromatic light emission using synthetic molecules and light stimuli, but this time around he is developing an entirely different approach by using natural systems and processes. In this new research, the light emission appears as a consequence of a chemical reaction, so research involves altering the chemical reaction or reactants themselves to produce a different color of emission. This is just one project in the team's study of energy conversion, but like this study, the lab's other research areas are also inspired by processes observed in nature.

Our unique approach is to combine solid-state supramolecular chemistry with photochemistry and photophysics to reach a new interest in science.

Panče Naumov, NYUAD Chemistry Professor

"We can learn a lot from nature," Naumov explained. "We can try to mimic natural systems, like photosynthesis, through which nature can create carbohydrates using sunlight, carbon dioxide, water, and minerals. By learning about this and utilizing similar processes in a laboratory setting,
we can employ them for a controlled conversion of energy — like an artificial photosynthesis." The seeds for new research ideas may range from long-standing scientific observations that remain previously uninvestigated, or by starting first with practical goals and looking to natural processes to identify the materials best suited for the purpose.

One of these priority research areas is the synthesis of pharmaceutical drugs through inducing a natural light to chemical energy conversion. "Solar light can be used directly to shorten the reaction sequence for producing pharmaceuticals, reducing high energy costs and achieving the same goal in fewer steps, with higher efficiency and without using solvents," Naumov said. "Solvents not only create a waste byproduct, but they require energy to be removed once the desired medicine has
been produced." The research team will determine information about molecule structures and the way they react, then pre-orient molecules within the solid state. These reactant chemical structures will then be exposed to direct sunlight with the aim to stimulate a photoreaction that will fuse molecules into a new chemical structure, for example, one similar to commonly used pharmaceuticals. Advancements in this kind of technology would be significant for places like the UAE, which have abundant amounts of natural sunlight.

Another example of this natural energy conversion is the use of specific materials as actuators that can cause movement on a very small scale. Components of microfluidic devices, which are used as "lab-on-a-chip" for biochemical assays, for instance, can be controlled through tiny actuating elements. This technology of actuating materials may also assist in the construction of artificial muscles that would move and be controlled by thermal or electrical stimuli. Research in energy conversion may also lead to the development of smart material structures, which change their properties according to energy impact, such as glass that adapts its levels of transparency based on the direction and incidence of incoming light.

Naumov, who hails from Macedonia, was drawn to this field of research because of the undiscovered potential for practical application of a number of unconventional natural phenomena, as opposed to other areas of research in energy conversion, like solar energy, that are reaching their efficacy limits. His experience in solid-state and structural chemistry and molecular structure has been essential in understanding these processes and reactions.

"Basically, the understanding of the structure of the molecules and how they change translates into understanding of the properties of materials and how the properties change. From there we can understand how the processes occur and with what efficiency. This means that in order to improve any dynamic process we need to first understand the underlying chemical structure."