Realizing rapid and reliable degradation and detection of highly toxic organophosphorus (OP) nerve agent (NA) threats has become increasingly crucial for health protection of warfighters, civilians, and etc. Several enzymes with phosphotriesterase-like activity (PTEs) have been conventionally used to successfully hydrolyze OP NAs and then towards their detection in the current literature. The major drawback of using PTE biocatalysts is their low operational/storage stability at elevated temperatures and their fragility in uncontrolled chemical environments. Toward addressing these limitations and realizing field-deployable substitutes, metal organic frameworks (MOFs) have emerged as rugged and robust biomimetic alternatives. The tunable ultra or nanoporosity and linker defect-engineering of MOFs enables the high-affinity capture of small molecules such as organophosphates. This unique capability allows MOFs to act as molecular level catalytic reactors to hydrolyze these bound organophosphates under the appropriate aqueous environments. The products from this organophosphate hydrolysis can then be used to detect and discriminate between lethal OP NA such as sarin, venomous agent X (VX), etc. The major disadvantage of using conventional MOF catalysts is that almost all MOF structures bear low space-time yields and are synthesized under extreme conditions with high temperature and high pressure, which ultimately limits their scalability. Hence, this work focused on the utilization of a green zirconium-MOF (MIP-202) catalyst. In this work, MIP-202 was synthesized on a gram scale, and various MOF activation procedures were evaluated to enhance the catalytic activity of MIP-202 toward near-neutral pH hydrolysis of OP NAs. The MIP-202 catalyst was then utilized in a portable MIP-202/F-ISE (MIP-202/fluoride ion-selective electrode) electrochemical sensor chip fabrication and sensor responses were determined using electroanalytical tools. Finally, the MIP-202-based catalytic NA recognition layer was employed on a Bluetooth enabled wearable textile-based electrochemical sensor platform. The wearable sensor yielded a fast and reliable response towards aerosol-phase G-type NA surrogate detection and the outstanding thermal/storage stability of the MIP-202/F-ISE sensor, thus enabling its application to remote/on-site field detection of G-type NAs in real-life scenarios.

Green metal organic frameworks towards efficient nerve agent hydrolysis and thermally robust biomimetic sensing applications

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.