Regulating Fluid Flow Utilizing Protein Pumps
Design Physical Sciences & Mathematics 2025 Graduate ExhibitionPresentation by Shanid Shrestha
Exhibition Number 608
Abstract
Lanthanide metals (Lns) are rare earth elements (REEs) and abundant in nature. Many of them have become irreplaceable constituents of the modern technological landscape, including consumer electronics, rechargeable batteries, and medical imaging. However, it is difficult to identify and separate the individual elements from each other because of the closeness of their ionic radii. Light rare earth elements (LREEs) refer to the rare earth elements with lower atomic numbers, while heavy rare earth elements (HREEs) are those with higher atomic numbers with the distinction primarily based on their different chemical properties and applications due to their varying atomic radii and electronic configurations. Lanmodulin (LanM), is a protein that preferentially binds to light Lns and achieves changes in structure. We have shown that the binding of lanthanide ions to surface-attached LanM results in significant fluid flows whose magnitude is a sensitive function of the identity and concentration of specific lanthanide ions. The binding-induced fluid flow can be quantified using optical microscopy by tracking tracer particles and thus provides a facile, fast, and low-cost non-spectroscopic method for distinguishing light and heavy REEs. As a result, we can distinguish between certain neighboring lanthanide ions, particularly among the valuable middle and heavy REEs. The observed fluid flow is density-driven and originates from the conformational change upon specific lanthanide ion binding to the protein resulting in the expulsion of water molecules from the binding pocket.
Importance
Lanthanides are a group of metals that are essential for modern technology such as smartphones, rechargeable batteries, and medical imaging machines. However, it’s hard to differentiate these elements because they are similar in size and properties. We’ve discovered a new method to distinguish these elements apart by attaching a protein called LanModulin to a surface. This protein has the ability to bind to the light lanthanide metal ions, changing its shape in the process. During the conformational change, the protein pushes out water, causing fluid movements that we can monitor by optical microscopy. By tracking these fluid movements, we can quickly and economically identify specific rare earth elements without the aid of expensive instruments.