Human exposure to air pollution and especially to nanoparticles is increasing due to the combustion of carbon-based energy vectors. Fibrous filters are among the various types of equipment potentially able to remove particles from the air. Nanofibers are highly effective in this area; however, their utilization is still a challenge due to the lack of studies taking into account both nanoparticle collection efficiency and antibacterial effect. The aim of this work is to produce and evaluate novel silver/polyacrylonitrile (Ag/PAN) electrospun fibers deposited on a nonwoven substrate to be used as air filters to remove nanoparticles from the air and also showing antibacterial activity. In order to determine the optimum manufacturing conditions, the effects of several electrospinning process parameters were analyzed such as solution concentration, collector to needle distance, flow rate, voltage, and duration. Ag/PAN nanofibers were characterized by Xray diffraction (XRD), Transmission Electron Microscopy (TEM), Fourier Transform Infra-Red spectroscopy (FTIR), Energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and Scanning Electron Microscopy (SEM). In addition, filtration performances were determined by measuring the pressure drop and collection efficiency of sodium chloride (NaCl) aerosol particles (9 to 300 nm diameters) using Scanning Mobility Particle Sizers (SMPS). Filters with high filtration efficiency (≈100%) and high-quality factor (≈0.05 Pa -1 ) were obtained even adding different concentrations of Ag nanoparticles (AgNPs) to PAN nanofibers. The resultant Ag/PAN nanofibers showed excellent antibacterial activity against 10 4 CFU/ml E.coli bacteria.The crystallinity of the silver nanoparticles was analyzed using X-ray diffraction analysis and shown in Figure S1. The peak observed at 17° for the 0AgF samples corresponds to (110) plan of PAN. Crystalline peak corresponds to silver nanoparticles were absent in all samples (1AgF, 10AgF, and 50AgF) which is due to the small size (<5nm) of silver nanoparticles.

Today, there are approximately 8 million cases of Chagas disease in the southern cone of South America alone, and about 100 million people are living with the risk of becoming infected. The present pharmacotherapy is sometimes ineffective and has serious side effects. Here, we report a series of 4,5-dihydroisoxazoles incorporating hydroxamate moieties, which act as effective inhibitors of the carbonic anhydrase (CA) from Trypanosoma cruzi (TcCA). One compound (5g) was evaluated in detail and shows promising features as an antitrypanosomal agent. Excellent values for the inhibition of growth for all three developmental forms of the parasite were observed at low concentrations of 5g (IC50 values from 7.0 to <1 μM). The compound has a selectivity index (SI) of 6.7 and no cytotoxicity to macrophage cells. Preliminary in vivo data showed that 5g reduces bloodstream parasites and that all treated mice survived; it was also more effective than the standard drug benznidazole.

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Often, solid matter is separated from particle-laden flow streams using electrospun filters due to their high specific surface area, good ability to capture aerial particulate matter, and low material costs. Moreover, electrospinning allows incorporating nanoparticles to improve the filter’s air filtration efficiency and bacterial removal. Therefore, a new, improved polyacrylonitrile (PAN) nanofibers membrane that could be used to remove air pollutants and also with antibacterial activity was developed. We engineered three different filters that are characterized by the different particles embedded in the PAN nanofibers: titanium dioxide (TiO2), zinc oxide (ZnO), and silver (Ag). Then, their filtration performance was assessed by quantifying the filtration of sodium chloride (NaCl) aerosol particles of 9 to 300 nm in diameter using a scanning mobility particle sizer. The TiO2_F filter displayed the smallest fiber diameter and the highest filtration efficiency (≈100%). Conversely, the Ag_F filter showed the highest quality factor (≈0.06 Pa−1) because of the lower air pressure drop. The resulting Ag_F nanofibers displayed a very good antibacterial activity using an Escherichia coli suspension (108 CFU/mL). Moreover, the quality factor of these membranes was higher than that of the commercially available nanofiber membrane for air filtration.

Highlights CA/CPB nanofibers have a filtration efficiency of 99.9 % for aerosol (7−300 nm). The Ergun’s porosity of the nanofibers is 98 % and the permeability about 10 −11 m 2 . CA/CPB nanofibers are biodegradable and sustainable novel air filters. The nanofibers are able to retention environmental PM 2.5 , BC and also virus.

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