Sequestration
of small molecules from aqueous solutions poses a
significant and important
challenge in environmental science and human health. Current methods
focus on broadly sequestering all small molecules but are unable to
address specific small molecules of interest. Additionally, these
procedures require large amounts of resources, such as electricity
and pressure. We propose to address this challenge through the use
of DNA aptamer-functionalized ultrafiltration membranes. To demonstrate
this approach, we developed an aptamer-functionalized membrane that
sequesters and removes the small-molecule contaminant bisphenol A
(BPA) from water. We show that BPA is depleted and that the membranes
can be regenerated for multiple uses, which can allow for recovery
of the small molecule when desired. Aptamers can be selected for a
wide variety of target small molecules, making this approach highly
generalizable beyond our initial demonstration. Together, this research
offers a promising solution to improving the efficacy of small molecule
removal and recovery from aqueous matrices.
Small-molecule toxins pose a significant threat to human health and the environment, and their removal is made challenging by their low molecular weight. Aptamers show promise as affinity reagents for binding these toxins, and recently, aptamers have been utilized for both sensing and remediation applications. We found that functionalization of ultrafiltration membranes with aptamers provides a convenient scaffold for toxin sequestration, but our initial efforts in this area were limited by low functionalization efficiencies and the ability to only capture a single target molecule. Herein, we describe detailed optimization of our aptamer-functionalized ultrafiltration membrane system and subsequent use for simultaneous removal of multiple small-molecule toxins. We examine multiple critical components involved in fabricating and functionalizing the membranes, including PEG polymer molecular weight for membrane fabrication, grafting conditions for pMAA attachment, and coupling reagents for aptamer functionalization. This screening enabled us to identify a set of unique conditions in which we were able to achieve high flux, near quantitative yield for DNA attachment, and effective overall depletion of both toxins and bacterial cells. Furthermore, we demonstrate the attachment of multiple aptamers and subsequent parallel removal of atrazine, bisphenol A, and microcystin-LR in a complex lake water matrix. Our rigorous evaluation resulted in depletion of multiple small-molecule toxins, contaminants, and microorganisms, demonstrating the potential of aptamer-functionalized membranes as point-of-use decontamination systems.
Aptamer-functionalized membranes offer a promising platform for toxin removal, but regeneration of binding capacity requires heat and washing. Moreover, bound molecules can be eluted, resulting in recontamination. Here we report the tandem use of aptamers and enzymes to trap and degrade small-molecule contaminants, resulting in an autonomously self-regenerating purification system.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.