Professor Valerie Pierre

Departmental Seminar
Professor Valerie Pierre
Department of Chemistry
University of Minnesota
Host: Professor Larry Que

Inorganic Receptors for Phosphate for Medical and Environmental Applications

Accumulation of phosphate in many inland and coastal waters primarily due to wastewater discharge and agricultural runoff can lead to eutrophication, causing substantial detrimental environmental impact including harmful algal blooms, fish-kills, and the formation of hypoxic dead zones. Accumulation of phosphate in blood, a condition called hyperphosphatemia, affects most patients with advanced chronic and acute kidney disease and kidney failure. Maintenance hemodialysis does not remove phosphate from blood effectively; thus, almost all patients on maintenance hemodialysis have hyperphosphatemia. The inability to manage this disorder contributes significantly to the increase in morbidity and mortality of advanced kidney disease. Both of these problems could be resolved with immobilized phosphate receptors that have high affinity for phosphate in water and that are highly selective over competing anions, notably bicarbonate and chloride. Through the development of these receptors, we determined how minor differences in the ligand lead to substantial changes in recognition of anions by the metal complex. The nature of the coordinating group, that of the metal ion, the geometry of the metal complex, its charge, and the presence of a hydrogen-bonding network all affect anion recognition, binding, and selectivity. Lastly, in order to be translatable and economically viable, any blood- or water-filtering technology must also be regenerable. This property requires receptors that are both reversible and controllable. The ability of our inorganic receptors complexes to catch phosphate and release it at will upon addition of an external trigger makes them promising candidates for the development of a new class of recyclable selective filtration technology.

Research

The Pierre’s research group exploits coordination and organic chemistry to solve medical and environmental problems. The group uses siderophores, natural products synthesized by bacteria to chelate iron, as a template to design novel chemical probes and imaging agents to rapidly diagnose bacterial infections in vitro and in vivo and to develop antibiotics with improved efficacy against antimicrobial-resistant bacteria.

As part of our environmental efforts, we are designing new complexes, supramolecular receptors and polymeric membranes to remove pollutants and toxic compounds such as phosphates, arsenate and cyanide from surface water