Influence of water content on the inactivation of P. digitatum spores using an air–water plasma jet

In order to investigate whether an air–water plasma jet is beneficial to improve the efficiency of inactivation, a series of experiments were done using a ring-needle plasma jet. The water content in the working gas（air） was accurately measured based on the Karl Fischer method. The effects of water on the production of OH（A;Σ;–X;Π;） and O（3p;P–3s;S） were also studied by optical emission spectroscopy. The results show that the water content is in the range of 2.53–9.58 mg l;, depending on the gas/water mixture ratio. The production of OH（A;Σ;–X;Π;） rises with the increase of water content, whereas the O（3p;P–3s;S） shows a declining tendency with higher water content. The sterilization experiments indicate that this air–water plasma jet inactivates the P. digitatum spores very effectively and its efficiency rises with the increase of the water content. It is possible that OH（A;Σ;–X;Π;） is a more effective species in inactivation than O（3p;P–3s;S） and the water content benefit the spore germination inhibition through rising the OH（A;Σ;–X;Π;） production. The maximum of the inactivation efficacy is up to 93% when the applied voltage is -6.75 kV and the water content is 9.58 mg l;.

Reactive oxygen species in plasma against E.coli cells survival rate

In this paper, we report on the contrastive analysis of inactivation efficiency of E. coli cells in solution with different disinfection methods. Compared with the hydrogen peroxide solution and the ozone gas, the atmospheric-pressure He plasma can completely kill the E. coli cells in the shortest time. The inactivation efficiency of E. coli cells in solution can be well described by using the chemical reaction rate model. X-ray photoelectron spectroscopy(XPS) analysis shows that the C–O or C=O content of the inactivated E. coli cell surface by plasma is predominantly increased, indicating the quantity of oxygen-containing species in plasma is more than those of two other methods, and then the C–C or C–H bonds can be broken, leading to the etching of organic compounds. Analysis also indicates that plasma-generated species can play a crucial role in the inactivation process by their direct reactions or the decompositions of reactive species, such as ozone into OH radicals in water, then reacting with E. coli cells.

Corrigendum to“Reactive oxygen species in plasma against E.coli cells survival rate”

Recently, we found some errors in Fig. 3 of the article Chin. Phys. B 24 085201 (2015). Upon a thorough examination of the raw data materials, we confirm that the image error did not impact any of the findings and conclusions of the paper. Based on this, we have made corrections to the original article.

Ultra-fast bacterial inactivation of Cu_(2)O@halloysite nanotubes hybrids with charge adsorption and physical piercing ability for medical protective fabrics

Metals have been used for wound treatment and toxicity testing since ancient times.With the development of nanotechnology,metal oxides have been proven to have excellent sterilization and disinfection functions.However,the rapid bacterial inactivation efficiency and trapping physicochemical killing ability remain simultaneously undemonstrated in antibacterial nanohybrids.Here,we demonstrate a method for in-situ reduction of small-sized Cu_(2)O particles on one-dimensional inorganic halloysite nanotubes(HNTs).The resultant Cu_(2)O@HNTs hybrids not only give Cu_(2)O excellent dispersibility,but also exert the synergistic effect of the charge adsorption of metal oxides and the physical piercing effect of the small-sized nanotubes.Furthermore,the release of Cu^(2+)from hybrids damages cell membranes and denatures proteins and DNA.Through this sterilization mechanism,Cu_(2)O@HNTs allow for the inactivation rate of Escherichia coli to reach 94.5%within 2 min and complete inactivation within 10 min.This excellent sterilization mode makes Cu_(2)O@HNTs exhibit excellent broad-spectrum antibacterial activity and inactivation efficiency,while shows weak cytotoxicity.These hybrids were further applied in the processing of functional antibacterial fibers and fabrics.Thus,we believe that this excellent antibacterial hybrid is practically attractive in this critical time of the COVID-19 pandemic.