Short-term effect of humid airflow on antimicrobial air filters using Sophora flavescens nanoparticles

Evaluation of Antimicrobial Effect of Zinc Pyrithione against Airborne Fungi and Bacteria Growth Collected onto New and Loaded HVAC Fibrous Filters

Microbial growth onto HVAC filters was observed in real conditions with possible degradation of the indoor air quality. The filtration performance of marketed antimicrobial filters containing zinc pyrithione was tested under laboratory conditions and compared to that of similar filters with the same classification, F7 (EN779:2002). The filtration performance of the two tested filters during loading with PM10 particles was quantified in an experimental setup with filter pressure drop measurement and particle counting upstream and downstream of the filters. The microbial growth on the new and loaded filters, both contaminated with a microbial airborne consortium composed of two bacteria (Gram-positive and -negative) and fungi, was quantified by colony-forming units after conditioning the filters for a few days under controlled temperature (25 °C) and humidity (50% or 90% relative humidity). The results reveal that there was no degradation of the filtration performance of the filters treated with the antimicrobial agent. The efficiency of the antimicrobial treatment, i.e., the ability to inhibit the growth of microorganisms during the incubation period, was significant with the new filters regarding the fungal growth, but the results demonstrate that the antimicrobial treatment became inefficient with the loaded filters.

Face Masks in the New COVID-19 Normal: Materials, Testing, and Perspectives

The increasing prevalence of infectious diseases in recent decades has posed a serious threat to public health. Routes of transmission differ, but the respiratory droplet or airborne route has the greatest potential to disrupt social intercourse, while being amenable to prevention by the humble face mask. Different types of masks give different levels of protection to the user. The ongoing COVID-19 pandemic has even resulted in a global shortage of face masks and the raw materials that go into them, driving individuals to self-produce masks from household items. At the same time, research has been accelerated towards improving the quality and performance of face masks, e.g., by introducing properties such as antimicrobial activity and superhydrophobicity. This review will cover mask-wearing from the public health perspective, the technical details of commercial and home-made masks, and recent advances in mask engineering, disinfection, and materials and discuss the sustainability of mask-wearing and mask production into the future.

Role and mechanism of matrine alone and combined with acitretin for HaCaT cells and psoriasis-like murine models

BACKGROUND

Acitretin and matrine have been used in the treatment of psoriasis in China. This study was designed to investigate the role and related mechanisms of matrine alone and in combination with acitretin in the treatment of psoriasis in vitro and in vivo.

METHODS

HaCaT cells were treated with matrine at different concentrations of 0 (blank control), 0.2, 0.4, 0.8, and 1.6 mg/mL for 24, 48, 72 h, respectively. 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium cell viability assay was used to assess the growth and proliferation of HaCaT cells. Cell cycle and apoptosis were detected by flow cytometry. Expression of protein was detected by Western blotting. Autophagy was observed by transmission electron microscopy. Then HaCaT cells were assigned to normal saline (NS) control group, matrine (0.4 mg/mL) group, acitretin (10 μmol/L) group, and matrine plus acitretin group, and the above methods were repeated. In animal experiments, the cumulative score (erythema, scaling, thickening) as a measure of the severity of inflammation was used to measure the skin performance of mice after treated with matrine 50 mg/kg, acitretin 4.5 mg/kg or combination of the two drugs on the psoriasis-like mouse models, respectively. Pathological findings of the lesions were observed, and the protein expressions in the lesions were detected by immunohistochemistry.

RESULTS

Cell proliferation inhibition was seen in HaCaT cells with treatment of matrine in a dose- and time-dependent manner (P < 0.01, respectively). Cell cycle G0/G1 phase arrest was observed in a dose-dependent way (P < 0.01). The expression of p21 (P < 0.05), LC3II/I (P < 0.01), and Beclin 1 (P < 0.01) increased and the expression of cyclin D1 (P < 0.05) decreased with increasing doses of matrine. Compared with the blank control, more autophagosomes were seen in HaCaT cells treated with matrine at 0.4 mg/mL by transmission electron microscopy (2.667 ± 1.202 vs. 21.33 ± 1.453, t = 9.899, P < 0.01). Cell proliferation inhibition and degree of the G0/G1 phase arrest was significantly higher in matrine plus acitretin group than those in matrine, acitretin, or the NS control group (P < 0.01, respectively). Compared with matrine or acitretin group, the expression of p21 (P < 0.05, P < 0.05) and LC3II/I (P < 0.01, P < 0.05) in matrine plus acitretin group increased significantly and the expression of cyclin D1 (P < 0.01, P < 0.05) and p62 (P < 0.05, P < 0.05) was reduced significantly. Compared with matrine or acitretin, matrine plus acitretin significantly down-regulated the phosphorylation of phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway (P < 0.05) and its downstream p-p70S6K (P < 0.05). In addition, the cumulative score of mice in the matrine plus acitretin group was significantly better than that in the matrine or acitretin group (1.480 ± 0.230 vs. 2.370 ± 0.241, P < 0.01; 1.480 ± 0.230 vs. 2.888 ± 0.341, P < 0.01). The expression of LC3 protein in the matrine plus acitretin group was also higher than that in the matrine, acitretin, or the NS control group (P < 0.05, respectively).

CONCLUSIONS

Matrine has therapeutic potentials for psoriasis. Matrine and acitretin show synergistic effect via cell cycle arrest and autophagy induction by PI3K/Akt/mTOR pathway.

Radix Sophorae Flavescentis inhibits proliferation and induces apoptosis of AGS human gastric cancer cells

Traditional herbal medicines are being increasingly used worldwide to treat cancer. Radix Sophorae Flavescentis (RSF) is a Chinese herb, which has numerous pharmacological properties, including anti‑tumour effects. In this study, we investigated the mechanisms underlying RSF‑induced apoptosis in human gastric cancer cells (AGS cells). We found that RSF treatment (20‑200 µg/ml) inhibited the proliferation of AGS cells and increased the sub‑G1 phase ratio. RSF‑induced cell death was associated with the downregulation of BCl‑2 and upregulation of Bax. In addition to increasing the expression levels of apoptosis‑mediating surface antigen FAS and Fas ligand, RSF also activated caspase‑3; however, mitogen‑activated protein kinase appeared to inhibit RSF‑induced cell death. RSF also led to an increased production of reactive oxygen species. Based on these results, we propose that RSF could be a potential therapeutic agent for gastric cancer.

Experimental and Modeling Studies on the Filtration of SiO2 Nanoparticles Aerosolized from Different Solvents

The filtration performance of a fibrous filter in removing nano-SiO₂ aerosols atomized using different solvents including methanol, ethanol, 1-propanol, water, and the ethanol/water mixture has been investigated. Through discrete element method (DEM) simulation and filtration experiments, the efficiency variation caused by the combinative interaction of the particle-filter adhesion and interparticle attraction has been analyzed and verified. The adhesion force between the solvent-coated nanoparticles and the filter is considered as the key factor to influence their initial filtration efficiency and can be balanced by their interparticle interaction. The stronger the adhesion, the higher the initial filtration efficiency. Primary aggregate is formed through the particle-fiber interaction, and further agglomerate is caused by particle migration on the fibers, i.e. secondary aggregate. Hydrogen bonding interaction is considered as the main factor causing interparticle secondary agglomeration, and plenty of OH groups existing in the nano-SiO₂ aerosols yielded from alcohol promotes the particle secondary aggregation. As a result, the Brown diffusion capture of the filter is significantly abated, and the as-formed agglomerate is scraped off the filter surface by the alcohol molecules, causing the filtration efficiency decreases. This study highlights the surface affinity properties of nanoaerosols and their balance between particle-particle and particle-fiber interactions in the filtration process.

Synergic Anti-Pruritus Mechanisms of Action for the Radix Sophorae Flavescentis and Fructus Cnidii Herbal Pair

Radix Sophorae Flavescentis (RSF) and Fructus Cnidii (FC) compose a typical herbal synergic pair in traditional Chinese medicine (TCM) for pruritus symptom treatments. The mechanisms of action for the synergy are not understood. This paper aims at predicting the anti-pruritus targets and the main active ingredients for the RSF and FC herbal pair. We demonstrate that the RSF-FC herbal pair can be elucidated by mining the chemical structures of compounds derived from RSF and FC. Based on chemical structure data, the putative targets for RSF and FC were predicted. Additional putative targets that interact with the anti-pruritus targets were derived by mapping the putative targets onto a PPI network. By examining the annotations of these proteins, we conclude that (1) RSF's active compounds are mainly alkaloids and flavonoids. The representative putative targets of the alkaloids are inflammation-related proteins (MAPK14, PTGS2, PTGS2, and F2) and pruritus-related proteins (HRH1, TRPA1, HTR3A, and HTR6). The representative putative targets of the flavonoids are inflammation-related proteins (TNF, NF-κB, F2, PTGS2, and PTGS2) and pruritus-related proteins (NR3C1 and IL2). (2) FC's active compounds are mainly coumarins. Their representative putative targets are CNS-related proteins (AChE and OPRK1) and inflammation-related proteins (PDE4D, TLR9, and NF-κB). (3) Both RSF and FC display anti-inflammatory effects, though they exhibit their anti-pruritus effects in different ways. Their synergy shows that RSF regulates inflammation-related pruritus and FC regulates CNS-related pruritus.

Environmental application of nanotechnology: air, soil, and water

Global deterioration of water, soil, and atmosphere by the release of toxic chemicals from the ongoing anthropogenic activities is becoming a serious problem throughout the world. This poses numerous issues relevant to ecosystem and human health that intensify the application challenges of conventional treatment technologies. Therefore, this review sheds the light on the recent progresses in nanotechnology and its vital role to encompass the imperative demand to monitor and treat the emerging hazardous wastes with lower cost, less energy, as well as higher efficiency. Essentially, the key aspects of this account are to briefly outline the advantages of nanotechnology over conventional treatment technologies and to relevantly highlight the treatment applications of some nanomaterials (e.g., carbon-based nanoparticles, antibacterial nanoparticles, and metal oxide nanoparticles) in the following environments: (1) air (treatment of greenhouse gases, volatile organic compounds, and bioaerosols via adsorption, photocatalytic degradation, thermal decomposition, and air filtration processes), (2) soil (application of nanomaterials as amendment agents for phytoremediation processes and utilization of stabilizers to enhance their performance), and (3) water (removal of organic pollutants, heavy metals, pathogens through adsorption, membrane processes, photocatalysis, and disinfection processes).

Antimicrobial Air Filters Using Natural Euscaphis japonica Nanoparticles

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/cm2(filter) 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.

Development and evaluation of antimicrobial activated carbon fiber filters using Sophora flavescens nanoparticles

Activated carbon fiber (ACF) filters have a wide range of applications, including air purification, dehumidification, and water purification, due to their large specific surface area, high adsorption capacity and rate, and specific surface reactivity. However, when airborne microorganisms such as bacteria and fungi adhere to the carbon substrate, ACF filters can become a source of microbial contamination, and their filter efficacy declines. Antimicrobial treatments are a promising means of preventing ACF bio-contamination. In this study, we demonstrate the use of Sophora flavescens in antimicrobial nanoparticles coated onto ACF filters. The particles were prepared using an aerosol process consisting of nebulization-thermal drying and particle deposition. The extract from S. flavescens is an effective, natural antimicrobial agent that exhibits antibacterial activity against various pathogens. The efficiency of Staphylococcus epidermidis inactivation increased with the concentration of S. flavescens nanoparticles in the ACF filter coating. The gas adsorption efficiency of the coated antimicrobial ACF filters was also evaluated using toluene. The toluene-removal capacity of the ACF filters remained unchanged while the antimicrobial activity was over 90% for some nanoparticle concentrations. Our results provide a scientific basis for controlling both bioaerosol and gaseous pollutants using antimicrobial ACF filters coated with S. flavescens nanoparticles.

Effects of ethanol extract of Radix Sophorae Flavescentis on activity of colon cancer HT29 cells

This paper mainly studied the inhibitory effect of total ethanol extract of Radix Sophorae Flavescentis on proliferation of colon cancer HT29 cells. By reflux extraction method and with ethanol as extraction solvent, different extracts were obtained at different ethanol concentrations, different solid-liquid ratios, and at different times. And their inhibitory activities against HT29 cells were compared using MTT assay. The experimental results showed that the extraction processes under three conditions can all draw relatively high inhibition rates. The optimum ethanol extraction process conditions were as follows: a solid-liquid ratio of 1:9, 80 min of heat reflux extraction with 95% ethanol.

Antimicrobial durability of air filters coated with airborne Sophora flavescens nanoparticles

Airborne biological particles containing viruses, bacteria, and/or fungi can be toxic and cause infections and allergy symptoms. Recently, natural materials such as tea tree oil and Sophora flavescens have shown promising antimicrobial activity when applied as air filter media. Although many of these studies demonstrated excellent antimicrobial efficacy, only a few of them considered external environmental effects such as the surrounding humidity, temperature, and natural degradation of chemicals, all of which can affect the antimicrobial performance of these natural materials. In this study, we investigated the antimicrobial durability of air filters containing airborne nanoparticles from S. flavescens for 5 months. Antimicrobial tests and quantitative chemical analyses were performed every 30 days. Morphological changes in the nanoparticles were also evaluated by scanning electron microscopy. The major antimicrobial compounds remained stable and active for ~90 days at room temperature. After about 90 days, the quantities of major antimicrobial compounds decreased noticeably with a consequent decrease in antimicrobial activity. These results are promising for the implementation of new technologies using natural antimicrobial products and provide useful information regarding the average life expectancy of antimicrobial filters using nanoparticles of S. flavescens.