Development of carbon nanotube-metal organic framework (MOF) hybrid antiviral microfiltration membrane

Abstract

We present the development of novel antiviral membranes by immobilizing metal organic framework (MOF) and carbon nanotubes (CNTs) on polymeric microfiltration membranes. The CNTs and the copper-based MOF (HKUST-1) were tested individually and in a hybrid form (MOF-CNT) against MS2 bacteriophage which was used as a surrogate virus. The membranes were synthesized at three different loading (5, 8 and 12% by weight) on a PVDF filtration membrane. The membranes were characterized using scanning electron microscopy, energy dispersive x-ray spectroscopy, thermogravimetric analysis, water contact angle, gas permeation tests and x-ray diffraction. Amongst the CNT immobilized (CNIM), MOF immobilized (MIM) and MOF-CNT (MCNIM) immobilized membranes, the permeate flux was highest for the CNIM (170% higher than MIM at 5% loading) followed by MCNIM (149% higher than MIM at 5% loading). This was because the small MOF particles blocked the membrane pores. No rejection of bacteriophages was observed with the plain PVDF membrane, but with the immobilization of MOF and CNTs, the antiviral activities increased with nano particles loading. The MCNIM with 12% loading exhibited a 99.6% phage deactivation. Kinetics of phage deactivation was studied for MOF, CNTs and MOF-CNT. The median lethal dose to kill 50% of the virus population (LD50) for MOF-CNT was as much as 70% lower than the CNTs and 30% lower than the pure MOF. Similarly, the time taken to deactivate 80% of the viral population (T80) for MOF-CNT was 50% less than the pure CNTs and 24% less than the pure MOF. Overall, the MOF-CNT immobilized membranes appear to be best option for antiviral activity.