DEPARTMENT OF CHEMISTRY

Regenerable MOF-based Protective Cloth Against Biological and Chemical Threats

The most recent global health crisis caused by the SARS-CoV-2 outbreak and the alarming use of chemical warfare agents highlight the necessity to produce efficient protective clothing and masks against biohazardous and chemical threats. However, the development of such a multi-functional protective textile that can supply adequate protection for the public is in a nascent stage.

A research team led by Prof. Farha at Northwestern University has designed and synthesized multifunctional and regenerable N-chlorine based biocide and detoxifying textiles using a Zr-based metal–organic framework (MOF) coating as a regenerable chlorine carrier. This coating, a MOF called UiO-66-NH₂, possesses abundant amine groups in the organic linker to allow for reversible chlorine bonding and release.

A chlorine bleaching converted the amine groups located on the MOF linker to active N-chlorine structures. The fibrous composite exhibited rapid biocide activity against both Gram-negative bacteria (E. coli) and Gram-positive bacteria (S. aureus) with up to a 99.99999% reduction within 5 min for each strain as well as a 99.999% reduction of SARS-CoV-2 within 15 min. Moreover, the active chlorine loaded MOF/fiber composite selectively and rapidly degraded sulfur mustard and its chemical simulant 2-chloroethyl ethyl sulfide (CEES) with half-lives less than 3 minutes under ambient conditions.

“We’ve developed the first regenerable MOF based protective cloth against both biological and chemical threats,” said Omar K. Farha, who led the research. “It is quite different than other protective textile materials, which serve to delay the penetration, rather than achieve the detoxification, of the selected threats. Our study demonstrated a strategy to design protective wear that can detoxify the SARS-CoV-2 virus and protect against the malicious use of chemical blistering agents’’

The authors found that active chlorine in the composite is very stable after storage for 40 days under ambient conditions, and the biocide efficiency was fully maintained. Encouragingly, the slowly released chlorine could be easily regenerated by a simple chlorine bleaching. The good reusability of the MOF based protective cloth is critical in addressing the growing waste caused by disposable healthcare textiles. Toward the question of the large-scale viability of this composite, Farha said “The production of the MOF-based protective cloth is industrially scalable as it only needs the most common processing equipment accessible in textile industry.”

Farha is the Dow Chemical Company Research Professor in the Department of Chemistry and a member of Northwestern’s International Institute for Nanotechnology. Kaikai Ma, a postdoctoral fellow in Farha’s group, is the co-first on this study. Several other coauthors have also contributed to this study. The research was supported by an NSF Rapid Award (2029270) for the antibacterial study and the Army Research Office (W911NF2020136) for the preparation of MOF/fiber composites.

The research was featured in phys.org.

For more on the story read Northwestern Now.