Co-immobilization of Enzymes and Aptamers to Create Self-Regenerating Ultrafiltration Membranes for Toxin Removal

Abstract

Aptamer-functionalized membranes are a promising platform for toxin removal and small-molecule sequestration. However, this function can be compromised when the aptamer binding sites become saturated, and regeneration of the membrane requires heat and multiple washes to restore the aptamer binding capabilities. Additionally, bound molecules can be eluted into water sources, resulting in recontamination. Herein, we address this challenge by creating autonomously self-regenerating membranes through the tandem use of aptamers and enzymes to trap and degrade small-molecule contaminants. To demonstrate this approach, we developed an enzyme–aptamer-functionalized membrane that sequesters and degrades the small-molecule contaminant bisphenol A (BPA) from water. We show that BPA is not only depleted but also degraded, as the membrane is able to be reused for multiple cycles without the need for heat or washing to restore function. Given the large number of reported DNA aptamers for small molecule analytes, we envision that this research will provide a broadly applicable platform for the removal of waterborne contaminants.