Antimicrobial Air Filters Using Natural Euscaphis japonica Nanoparticles

Abstract

Controlling bioaerosols has become more important with increasing participation in indoor activities. Treatments using natural-product nanomaterials are a promising technique because of their relatively low toxicity compared to inorganic nanomaterials such as silver nanoparticles or carbon nanotubes. In this study, antimicrobial filters were fabricated from natural Euscaphis japonica nanoparticles, which were produced by nebulizing E. japonica extract. The coated filters were assessed in terms of pressure drop, antimicrobial activity, filtration efficiency, major chemical components, and cytotoxicity. Pressure drop and antimicrobial activity increased as a function of nanoparticle deposition time (590, 855, and 1150 µg/cm2filter at 3-, 6-, and 9-min depositions, respectively). In filter tests, the antimicrobial efficacy was greater against Staphylococcus epidermidis than Micrococcus luteus; ~61, ~73, and ~82% of M. luteus cells were inactivated on filters that had been coated for 3, 6, and 9 min, respectively, while the corresponding values were ~78, ~88, and ~94% with S. epidermidis. Although statistically significant differences in filtration performance were not observed between samples as a function of deposition time, the average filtration efficacy was slightly higher for S. epidermidis aerosols (~97%) than for M. luteus aerosols (~95%). High-performance liquid chromatography (HPLC) and electrospray ionization-tandem mass spectrometry (ESI/MS) analyses confirmed that the major chemical compounds in the E. japonica extract were 1(ß)-O-galloyl pedunculagin, quercetin-3-O-glucuronide, and kaempferol-3-O-glucoside. In vitro cytotoxicity and disk diffusion tests showed that E. japonica nanoparticles were less toxic and exhibited stronger antimicrobial activity toward some bacterial strains than a reference soluble nickel compound, which is classified as a human carcinogen. This study provides valuable information for the development of a bioaerosol control system that is environmental friendly and suitable for use in indoor environments.

Effects of human activities on concentrations of culturable bioaerosols in indoor air environments

“…Several studies that have measured concentrations of bioaerosols in indoor and outdoor environments have shown that bioaerosols can significantly affect human health conditions (Ren, Jankun & Leaderer, 1999;Zhu et al, 2003). Therefore, it is necessary to monitor and control bioaerosols in the air for occupational safety and public health purposes (Hwang et al, 2015;Lee et al, 2012;Mainelis et al, 2002;Nazaroff, 2014).…”

Development of an automated wet-cyclone system for rapid, continuous and enriched bioaerosol sampling and its application to real-time detection

“…Staphylococcus epidermidis (ATCC 12228) and Micrococcus luteus (ATCC 9341) were used as the test airborne microorganisms. These Gram-positive bacteria are commonly found in indoor environments and on human skin [31,32], and are used widely in bioaerosol research [21,[33][34][35]. In particular, S. epidermidis is an important opportunistic pathogen and is the most common source of infections on indwelling medical devices [36].…”

Recent advances in antimicrobial air filter

“…In addition to its high antimicrobial activity, natural products are considered as less toxic than inorganic antimicrobial agent. Hwang et al [41] investigated the preparation antimicrobial filter by employing nebulization or aerosol process for coating a filter with Euscaphis japonica nanoparticles. They found that pressure drop and antimicrobial activities of the filter were function of deposition time.…”