Atmospheric plasma sources as potential tools for surface and hand disinfection

Good hand hygiene has proven to be essential in reducing the uncontrolled spread of human pathogens. Cold atmospheric plasma (CAP) may provide an alternative to disinfecting hands with ethanol-based handrubs when handwashing facilities are unavailable. CAP can be safely applied to the skin if the energy is well controlled. In this study, radio frequency (RF) and direct current (DC) plasma sources were built with a pin-to-mesh electrodes configuration inside a fused silica tube with a 5 mm inner diameter. Microbiological assays based on EN 13697:2015+A1:2019 using Escherichia coli DSM 682 or Staphylococcus epidermidis DSM 20044 were used to examine the antimicrobial effect of various plasma conditions. Metal and silicone disks that model skin were used as inoculation matrices. The prototype air RF CAP achieved significant disinfection in the MHz range on stainless steel and silicone substrates. This is equivalent to half the performance of direct current CAP, which is only effective on conductive substrates. Using only electricity and air CAP could, with further optimization to increase its efficacy, replace or complement current hand disinfection methods, and mitigate the economic burden of public health crises in the future

Désinfection par plasma froid pour l'hygiène des mains

Face à l'épidémie de Covid-19, l'importance de l'hygiène des mains est sans cesse rappelée, le premier des gestes barrières étant en effet de se laver les mains très régulièrement. Bien que l'application de lotions à base d'alcool se soit révélé efficace, le lavage des mains suivi d'un séchage par jets d'air reste la méthode préférée. Les plasmas atmosphériques froids, dit aussi non thermiques, utilisant l'air ambiant comme gaz plasmagène peuvent constituer une alternative à la désinfection des mains lorsqu'il n'y a pas de sanitaires à proximité

Désinfection par plasma froid à l'air ambiant pour l'hygiène des mains

Face à l’épidémie de Covid-19, l’importance de l’hygiène des mains est sans cesse rappelée, le premier des gestes barrières étant en effet de se laver les mains très régulièrement. Bien que l'application de lotions à base d'alcool se soit révélée efficace, le lavage des mains suivi d'un séchage par jets d’air reste la méthode préférée. Les plasmas atmosphériques froids, dit aussi non-thermiques, utilisant l’air ambiant comme gas plasmagène peuvent constituer une alternative à la désinfection des mains lorsqu’il n’y a pas d’installations sanitaires à proximités. La puissance électrique est contrôlée de manière à éviter tout effet délétère sur la peau. Dans cette étude, nous avons testé divers générateurs produisant divers types de plasmas. Des essais microbiologiques basés sur la norme EN 13697:2015+A1:2019 ont été réalisés avec des microorganismes non-pathogènes, sur des surfaces en métal ou en silicone pour modéliser la peau. En utilisant des techniques d'induction électromagnétique dans la gamme des MHz, nous avons produit un jet stable de plasma froid d'air atteignant un niveau significatif de désinfection sur des substrats conducteurs et non conducteurs. La performance sur les surfaces en silicone est presque aussi élevée qu’avec des plasmas à courant continu qui eux, par contre, ne sont efficaces que sur les substrats conducteurs. Consommant uniquement de l'électricité, le plasma froid d’air ambiant pourrait remplacer ou compléter les méthodes actuelles de désinfection des mains et atténuer le fardeau économique des crises de santé publique à l'avenir

Immunogenicity and safety of one dose of diphtheria, tetanus, acellular pertussis and poliomyelitis vaccine (Repevax®) followed by two doses of diphtheria, tetanus and poliomyelitis vaccine (Revaxis®) in adults aged ≥40 years not receiving a diphtheria- and tetanus-containing vaccination in the last 20 years

International audienceINTRODUCTION:The immunogenicity and safety of one dose of Tdap-IPV (tetanus, diphtheria, acellular pertussis and inactivated poliomyelitis vaccine) and two doses of Td-IPV (tetanus, diphtheria and inactivated poliomyelitis vaccine) were assessed in adults who had not received a diphtheria- and tetanus-containing vaccine in the last 20 years.METHODS:This open-label, multicentre study was conducted in adults aged ≥ 40 years with no diphtheria- and tetanus-containing vaccine in the last 20 years. Participants received one dose of Tdap-IPV followed by two doses of Td-IPV (0, 1, 6 month schedule). Primary immunogenicity objectives: to demonstrate acceptable seroprotection rates (percentage of participants with antibody titre above threshold) post-dose 3 for diphtheria (≥ 0.1IU/mL by seroneutralization assay [SNA]); tetanus (≥ 0.1IU/mL by enzyme-linked immunosorbent assay [ELISA]); and poliomyelitis (≥ 8 1/dil by SNA); and to evaluate the percentage of participants with an antibody concentration ≥ 5EU/mL (by ELISA) for pertussis antigens post-dose 1. Seroprotection rates were acceptable if the lower limit of the 95% confidence interval (CI) was >95%. Percentage of participants with basic clinical immunity against diphtheria (≥ 0.01IU/mL) was also assessed. Safety (adverse events [AEs] and serious AEs) was assessed after each dose.RESULTS:Overall, 336 participants were included (mean age: 60.2 years). Post-dose 3 seroprotection rates were: diphtheria, 94.6% (CI 91.5-96.8); tetanus and poliomyelitis, 100% (CI: 98.8-100). Percentage of participants with an antibody titre ≥ 5EU/mL against pertussis antigens was ≥ 95.8% for all five pertussis components. Basic clinical immunity against diphtheria was achieved in 100% (CI: 98.8-100) of participants. AEs were reported more frequently following vaccination with Tdap-IPV (post-dose 1: 65.3%) than with Td-IPV (post-dose 2: 48.3%; post-dose 3: 50.3%).CONCLUSIONS:This study highlights the benefits of using Tdap-IPV followed by two doses of Td-IPV in an adult population to achieve maximal protection against diphtheria, tetanus, poliomyelitis and pertussis simultaneously

Fast prototyping for atmospheric plasma sources integration into air hand dryers

Motivated by the current COVID-19 pandemic and the need to find alternative methods to contain and battle it, the purpose of this innovative project is to conceive a disinfection module equipped with a cold atmospheric plasma source. Such a plasma source was developed for a potential integration into pulsed air hand dryers. This type of plasma is known for its ability to generate reactive oxygen and nitrogen species that initiate bio-molecular reactions involved in bacterial and viral deactivation mechanisms. This study shows how additive manufacturing helped accelerate the prototyping of a nozzle allowing the preservation of the plasma flow from circulation cells and external interferences in the discharge’s surrounding

Fermentative liberation of ellagic acid from walnut press cake ellagitannins

Oil is extracted from walnut leaves behind large quantities of defatted press cake that is still rich in valuable nutrients. Aspergillus oryzae and Rhizopus oligosporus, two molds traditionally used in Asia, have the necessary enzymes to use the nutrients in the walnut press cake. Walnuts and the press cake contain ellagitannins, known as precursors for ellagic acid and urolithins. In this study, experiments to optimize the solid-state fermentation of walnut press cake were performed in order to liberate ellagic acid from ellagitannins. Extracts of fermented products were then analyzed with an HPLC-DAD to measure the liberation of ellagic acid from ellagitannins. Good growth of R. oligosporus and A. oryzae mycelia on the walnut press cake was observed. A single mold culture was subjected to a hydration of 0.8 mL/g, an addition of 37.5 mmol/kg acetic acid (AA) and 1% NaCl, and an incubation temperature of 25 °C; these were observed to be good conditions for solid-state fermentation for walnut press cake. The highest ellagic acid concentration was obtained at 48 h. At 72 h, degradation dominated the liberation of ellagic acid