scholarly journals Antiviral Nanostructures That Reduce the Viability of Coronaviruses SARS-CoV-2 and HCoV-NL63

2021 ◽  
Author(s):  
Alka Jaggessar ◽  
Prasad KDV Yarlagadda ◽  
Kirsten Spann
Keyword(s):  
Antibacterial Properties ◽  
Infectious Period ◽  
Structured Surfaces ◽  
Nanostructured Surfaces ◽  
Viral Loads ◽  
Healthcare Settings ◽  
Risk Environments ◽  
Plastic Surface ◽  
Human Coronaviruses ◽  
Respiratory Droplets

Abstract Background: The rapid emergence and global spread of the COVID-19 causing Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) and its subsequent mutated strains, has caused unprecedented health, economic and social devastation. Respiratory viruses can be transmitted through both direct and indirect channels, including aerosol respiratory droplets and contamination of inanimate surfaces. Current methods of virus inactivation on surfaces include chemicals and biocides and while effective, continuous, and repetitive cleaning of all surfaces is not always viable. Recent work in the field of biomaterials engineering has established the antibacterial effects of hydrothermally synthesised TiO2 nanostructured surfaces against both Gram-negative and positive bacteria. This study investigates the effectiveness of TiO2 nanostructured surfaces against two human coronaviruses: SARS-CoV-2 and HCoV-NL63 for surface-based inactivation. Results: Results show that structured surfaces reduced live infectious viral loads of SARS-CoV-2 and HCoV-NL63 by 5 log and 3 log, respectively after 5 hours compared to non-structured surfaces. Interestingly, infectious virus remained present on the control plastic surface after 7 hours exposure.Conclusions: These encouraging results establish the potential use of nanostructured surfaces to reduce the transmission and spread of coronaviruses, by reducing the virus’ infectious period on a surface. The dual antiviral and antibacterial properties of these surfaces give them potential application in high-risk environments such as hospitals and healthcare settings.

TECHNOLOGIES FOR MANUFACTURING NANOSTRUCTURED SURFACES

2020 ◽  
Author(s):  
Андрей Дмитриевич Бухтеев ◽  
Виктория Буянтуевна Бальжиева ◽  
Анна Романовна Тарасова ◽  
Фидан Гасанова ◽  
Светлана Викторовна Агасиева
Keyword(s):  
Plastic Deformation ◽  
Surface Modification ◽  
Severe Plastic Deformation ◽  
Pressing Pressure ◽  
Pressure Treatment ◽  
Structured Surfaces ◽  
Nanostructured Surfaces ◽  
Angular Pressing ◽  
Multilayer Composites ◽  
Compaction Of Powders

В данной статье рассматривается применение и технологии получения наноструктурированных поверхностей. Рассмотрены такие методы как компактирование порошков (изостатическое прессование, метод Гляйтера), интенсивная пластическая деформация (угловое кручение, равноканальное угловое прессование, обработка давлением многослойных композитов) и модификация поверхности (лазерная обработка, ионная бомбардировка). This article discusses the application and technology for obtaining nano-structured surfaces. Methods such as compaction of powders (isostatic pressing, Gleiter method), severe plastic deformation (angular torsion, equal-channel angular pressing, pressure treatment of multilayer composites) and surface modification (laser treatment, ion bombardment) are considered.

scholarly journals Disinfection of SARS-CoV-2 Contaminated Surfaces of Personal Items with UVC-LED Disinfection Boxes

Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 598
Author(s):  
Maren Bormann ◽  
Mira Alt ◽  
Leonie Schipper ◽  
Lukas van de Sand ◽  
Mona Otte ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Close Contact ◽  
Credit Cards ◽  
Organic Matrix ◽  
Viral Loads ◽  
Small Aerosol ◽  
Time Periods ◽  
Respiratory Droplets ◽  
Glass Metal

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is transmitted from person to person by close contact, small aerosol respiratory droplets, and potentially via contact with contaminated surfaces. Herein, we investigated the effectiveness of commercial UVC-LED disinfection boxes in inactivating SARS-CoV-2-contaminated surfaces of personal items. We contaminated glass, metal, and plastic samples representing the surfaces of personal items such as smartphones, coins, or credit cards with SARS-CoV-2 formulated in an organic matrix mimicking human respiratory secretions. For disinfection, the samples were placed at different distances from UVC emitting LEDs inside commercial UVC-LED disinfection boxes and irradiated for different time periods (up to 10 min). High viral loads of SARS-CoV-2 were effectively inactivated on all surfaces after 3 min of irradiation. Even 10 s of UVC-exposure strongly reduced viral loads. Thus, UVC-LED boxes proved to be an effective method for disinfecting SARS-CoV-2-contaminated surfaces that are typically found on personal items.

scholarly journals Bacteria Death and Osteoblast Metabolic Activity Correlated to Hydrothermally Synthesised TiO2 Surface Properties

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1201 ◽  
Author(s):  
Alka Jaggessar ◽  
Asha Mathew ◽  
Tuquabo Tesfamichael ◽  
Hongxia Wang ◽  
Cheng Yan ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Properties ◽  
Metabolic Activity ◽  
Mechanical Stability ◽  
Antibacterial Properties ◽  
Mechanical Tests ◽  
Nanostructured Surfaces ◽  
Surface Contact Angle ◽  
Cellular Metabolic Activity ◽  
Structure Height

Orthopaedic surgery comes with an inherent risk of bacterial infection, prolonged antibiotic therapy and revision surgery. Recent research has focused on nanostructured surfaces to improve the bactericidal and osseointegrational properties of implants. However, an understanding of the mechanical properties of bactericidal materials is lacking. In this work, the surface properties of hydrothermal TiO2 nanostructured surfaces are investigated for their effect on bactericidal efficiency and cellular metabolic activity of human osteoblast cells. TiO2 nanostructures, approximately 307 nm in height and 14 GPa stiffness, were the most effective structures against both gram-positive (Staphylococcus aureus) and gram-negative (Pseudomonas aeruginosa) bacteria. Statistical analysis significantly correlated structure height to the death of both bacteria strains. In addition, the surface contact angle and Young’s modulus were correlated to osteoblast metabolic activity. Hydrophilic surfaces with a contact angle between 35 and 50° produced the highest cellular metabolic activity rates after 24 hours of incubation. The mechanical tests showed that nanostructures retain their mechanical stability and integrity over a long time-period, reaffirming the surfaces’ applicability for implants. This work provides a thorough examination of the surface, mechanical and wettability properties of multifunctional hydrothermally synthesised nanostructured materials, capable of killing bacteria whilst improving osteoblast metabolic rates, leading to improved osseointegration and antibacterial properties of orthopaedic implants.

scholarly journals Model-Driven Controlled Alteration of Nanopillar Cap Architecture Reveals its Effects on Bactericidal Activity

2020 ◽  
Vol 8 (2) ◽  
pp. 186 ◽  
Author(s):  
Taiyeb Zahir ◽  
Jiri Pesek ◽  
Sabine Franke ◽  
Jasper Van Pee ◽  
Ashish Rathore ◽  
...  
Keyword(s):  
Bactericidal Activity ◽  
Cell Envelope ◽  
Antibacterial Properties ◽  
Biophysical Model ◽  
Surface Measurement ◽  
Dependent Manner ◽  
Bending Rigidity ◽  
Nanostructured Surfaces ◽  
Model Driven ◽  
Antibacterial Surfaces

Nanostructured surfaces can be engineered to kill bacteria in a contact-dependent manner. The study of bacterial interactions with a nanoscale topology is thus crucial to developing antibacterial surfaces. Here, a systematic study of the effects of nanoscale topology on bactericidal activity is presented. We describe the antibacterial properties of highly ordered and uniformly arrayed cotton swab-shaped (or mushroom-shaped) nanopillars. These nanostructured surfaces show bactericidal activity against Staphylococcus aureus and Pseudomonas aeruginosa. A biophysical model of the cell envelope in contact with the surface, developed ab initio from the infinitesimal strain theory, suggests that bacterial adhesion and subsequent lysis are highly influenced by the bending rigidity of the cell envelope and the surface topography formed by the nanopillars. We used the biophysical model to analyse the influence of the nanopillar cap geometry on the bactericidal activity and made several geometrical alterations of the nanostructured surface. Measurement of the bactericidal activities of these surfaces confirms model predictions, highlights the non-trivial role of cell envelope bending rigidity, and sheds light on the effects of nanopillar cap architecture on the interactions with the bacterial envelope. More importantly, our results show that the surface nanotopology can be rationally designed to enhance the bactericidal efficiency.

Characterization of Jumping-Droplet Condensation on Nanostructured Surfaces With Quartz Crystal Microbalance

2017 ◽  
Author(s):  
Junwei Su ◽  
Hamed Esmaeilzadeh ◽  
Chefu Su ◽  
Majid Charmchi ◽  
Marina Ruths ◽  
...  
Keyword(s):  
Frequency Shift ◽  
Quartz Crystal Microbalance ◽  
Microscopic Observation ◽  
Quartz Crystal ◽  
Structured Surfaces ◽  
Nanostructured Surfaces ◽  
Acoustic Technique ◽  
Flow Condensation ◽  
Droplet Condensation

The spontaneously jumping motion of condensed droplets by coalescence on superhydrophobic surfaces has been an active area of research due to its great potential for enhancing the condensation efficiency. Despite a considerable amount of microscopic observations, the interfacial wetting characterization during jumping-droplet condensation is still notably lacking. This work focuses on applying a novel acoustic sensor - quartz crystal microbalance (QCM), to characterize the interfacial wetting on nanostructured surfaces during jumping-droplet condensation. Copper oxide nanostructures were generated on the surface of QCM with a chemical etching method. Based on the geometry of the nanostructures, we modified a theoretical model to reveal the relationship between the frequency shift of the QCM and the wetting states of the surfaces. It was found that the QCM is extremely sensitive to the penetrated liquid in the structured surfaces. Then, the QCM with nanostructured surface was tested on a customed flow condensation setup. The dynamic interfacial wetting characteristics were quantified by the normalized frequency shift of the QCM. Combined with microscopic observation of the corresponding drop motion, we demonstrated that partial wetting (PW) droplets with an about 25% penetrated area underwent spontaneously jumping by coalescence. However, the PW droplets no longer jumped when the penetrated area exceeds 50% due to the stronger adhesion between liquid and the surface. It shows that the characterization of the penetrated liquid in micro/nanostructures, which is very challenging for microscopic observation, can be easily carried out by this acoustic technique.

scholarly journals Increasing the efficiency and yield of a tuberculosis contact investigation through electronic data systems matching

2015 ◽  
Vol 22 (5) ◽  
pp. 1089-1093 ◽  
Author(s):  
Jennifer M Sanderson ◽  
Douglas C Proops ◽  
Lisa Trieu ◽  
Eloisa Santos ◽  
Bruce Polsky ◽  
...  
Keyword(s):  
Health Data ◽  
Infectious Period ◽  
Data Systems ◽  
Maternity Ward ◽  
Immunization Registry ◽  
Healthcare Settings ◽  
Data Matching ◽  
Contact Investigation ◽  
Electronic Health ◽  
Electronic Data Systems

Abstract Background Electronic health data may improve the timeliness and accuracy of resource-intense contact investigations (CIs) in healthcare settings. Methods In September 2013, we initiated a CI around a healthcare worker (HCW) with infectious tuberculosis (TB) who worked in a maternity ward. Two sources of electronic health data were employed: hospital-based electronic medical records (EMRs), to identify patients exposed to the HCW, and an electronic immunization registry, to obtain contact information for exposed infants and their providers at two points during follow-up. Results Among 954 patients cared for in the maternity ward during the HCW’s infectious period, the review of EMRs identified 285 patients (30%) who interacted with the HCW and were, thus, exposed to TB. Matching infants to the immunization registry offered new provider information for 52% and 30% of the infants in the first and second matches. Providers reported evaluation results for the majority of patients (66%). Conclusion Data matching improved the efficiency and yield of this CI, thereby demonstrating the usefulness of enhancing CIs with electronic health data.

scholarly journals Antigen Testing for COVID-19 Asymptomatic Screening: Why it Should be Preferred Over PCR Insights From Navy Region Japan’s Experience With a Comprehensive Antigen Testing Strategy

2021 ◽  
Author(s):  
Ross A Mullinax
Keyword(s):  
Public Health ◽  
Infectious Virus ◽  
Infectious Period ◽  
Test Results ◽  
Testing Strategy ◽  
Viral Loads ◽  
Viral Culture ◽  
Polymerase Chain ◽  
Antigen Testing

ABSTRACT Polymerase chain reaction (PCR) is commonly used in asymptomatic screening testing, but is suboptimal for this purpose as it will identify many old persistent positives that are no longer infectious. This can result in placement of individuals that are not infectious to others into isolation. This results in substantial adverse impact to military manning and operations, without any benefit to public health. Antigen testing does not have this same drawback. Antigen testing, while less sensitive than PCR, will identify the vast majority of infectious positives, especially those with higher viral loads that are more likely to transmit to others. Importantly, use of antigen testing will also greatly increase the certainty of benefit from isolation, reducing the risk of isolating those individuals who are beyond their infectious period and pose no threat to public health. The literature on this topic is reviewed, with particular focus on studies that perform viral culture in addition to PCR and antigen testing. This allows for determination of sensitivity for infectious virus. Also, Navy Region Japan’s experience with a comprehensive antigen testing strategy is described. The challenges presented by persistent positive PCR test results are examined, as well as the real-world benefits from implementing widespread use of antigen testing.

scholarly journals RT-LAMP has high accuracy for detecting SARS-CoV-2 in saliva and naso/oropharyngeal swabs from asymptomatic and symptomatic individuals

2021 ◽  
Author(s):  
Stephen P Kidd ◽  
Dan Burns ◽  
Bryony Armson ◽  
Andrew D Beggs ◽  
Emma L. A Howson ◽  
...  
Keyword(s):  
Preparation Method ◽  
Rna Extraction ◽  
Improved Method ◽  
Diagnostic Specificity ◽  
Sample Preparation Method ◽  
Viral Loads ◽  
Healthcare Settings ◽  
Frequent Interval ◽  
Oropharyngeal Swab ◽  
Asymptomatic Individuals

Previous studies have described RT-LAMP methodology for the rapid detection of SARS-CoV-2 in nasopharyngeal/oropharyngeal swab and saliva samples. Here we describe the validation of an improved simple sample preparation method for Direct SARS-CoV-2 RT-LAMP, removing the need for RNA extraction, using 559 swabs and 86,760 saliva samples from asymptomatic and symptomatic individuals across multiple healthcare settings. Using this improved method we report a diagnostic sensitivity (DSe) of 70.35% (95% CI 63.48-76.60%) on swabs and 84.62% (79.50-88.88%) on saliva, with diagnostic specificity (DSp) 100% (98.98-100.00%) on swabs and 100% (99.72-100.00%) on saliva when compared to RT-qPCR. Analysing samples with RT-qPCR ORF1ab CT values of <25 and <33 (high and medium-high viral loads, respectively), we found DSe of 100% (96.34-100%) and 77.78% (70.99-83.62%) for swabs, and 99.01% (94.61-99.97%) and 87.32% (80.71-92.31%) for saliva. We also describe RNA RT-LAMP (on extracted RNA) performed on 12,619 swabs and 12,521 saliva samples to provide updated performance data with DSe and DSp of 95.98% (92.74-98.06%) and 99.99% (99.95-100%) for swabs, and 80.65% (73.54-86.54%) and 99.99% (99.95-100%) for saliva, respectively. We also report on daily samples collected from one individual from symptom onset where both Direct and RNA RT-LAMP detected SARS-CoV-2 in saliva collected on all six days where symptoms were recorded, with RNA RT-LAMP detecting SARS-CoV-2 for an additional further day. The findings from these studies demonstrate that RT-LAMP testing of swabs and saliva is potentially applicable to a variety of use-cases, including frequent, interval-based testing of saliva from asymptomatic individuals via Direct RT-LAMP that may be missed using symptomatic testing alone.

A Systematic Study of Pool Boiling Heat Transfer on Multiscale Structured Surfaces

2014 ◽  
Author(s):  
Russell P. Rioux ◽  
Eric C. Nolan ◽  
Calvin H. Li
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Multiple Scales ◽  
Pool Boiling ◽  
Theoretical Models ◽  
Sintering Process ◽  
Structured Surfaces ◽  
Pool Boiling Heat Transfer ◽  
Nanostructured Surfaces ◽  
Modified Surfaces

A study has been conducted to examine the effects of macroscale, microscale, and nanoscale surface modifications in water pool boiling heat transfer and to determine the effects of combining the multiple scales. Nanostructured surfaces were created by acid etching, while microscale and macroscale surfaces were manufactured through a sintering process. Six structures were studied as individual and/or collectively integrated surfaces: polished plain, flat nanostructured, flat porous, modulated porous, nanostructured flat porous, and nanostructured modulated porous. Boiling performance was measured in terms of critical heat flux (CHF) and heat transfer coefficient (HTC). Both HTC and CHF have been greatly improved on all modified surfaces compared to the polished baseline. The CHF and HTC of the hybrid multiscale modulated porous surface have achieved the most significant improvements of 350% and 200% over the polished plain surface, respectively. Nanoscale, microscale, and macroscale integrated surfaces have been proven to have the most significant improvements on HTC and CHF. Experimental results were compared to the predictions of a variety of theoretical models with an attempt to evaluate both microscale and nanoscale models. It was concluded that models for both microscale and nanoscale structured surfaces needed to be further developed to be able to have good quantitative predictions of CHFs on structured surfaces.

scholarly journals Surgical Mask Partition Reduces the Risk of Noncontact Transmission in a Golden Syrian Hamster Model for Coronavirus Disease 2019 (COVID-19)

2020 ◽  
Vol 71 (16) ◽  
pp. 2139-2149 ◽  
Author(s):  
Jasper Fuk-Woo Chan ◽  
Shuofeng Yuan ◽  
Anna Jinxia Zhang ◽  
Vincent Kwok-Man Poon ◽  
Chris Chung-Sing Chan ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Syrian Hamster ◽  
Antigen Expression ◽  
Hamster Model ◽  
Golden Syrian Hamster ◽  
Healthcare Settings ◽  
Clinical Scoring ◽  
Respiratory Droplets ◽  
Viral Nucleocapsid

Abstract Background Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is believed to be mostly transmitted by medium- to large-sized respiratory droplets, although airborne transmission may be possible in healthcare settings involving aerosol-generating procedures. Exposure to respiratory droplets can theoretically be reduced by surgical mask usage. However, there is a lack of experimental evidence supporting surgical mask usage for prevention of COVID-19. Methods We used a well-established golden Syrian hamster SARS-CoV-2 model. We placed SARS-CoV-2-challenged index hamsters and naive hamsters into closed system units each comprising 2 different cages separated by a polyvinyl chloride air porous partition with unidirectional airflow within the isolator. The effect of a surgical mask partition placed between the cages was investigated. Besides clinical scoring, hamster specimens were tested for viral load, histopathology, and viral nucleocapsid antigen expression. Results Noncontact transmission was found in 66.7% (10/15) of exposed naive hamsters. Surgical mask partition for challenged index or naive hamsters significantly reduced transmission to 25% (6/24, P = .018). Surgical mask partition for challenged index hamsters significantly reduced transmission to only 16.7% (2/12, P = .019) of exposed naive hamsters. Unlike the severe manifestations of challenged hamsters, infected naive hamsters had lower clinical scores, milder histopathological changes, and lower viral nucleocapsid antigen expression in respiratory tract tissues. Conclusions SARS-CoV-2 could be transmitted by respiratory droplets or airborne droplet nuclei which could be reduced by surgical mask partition in the hamster model. This is the first in vivo experimental evidence to support the possible benefit of surgical mask in prevention of COVID-19 transmission, especially when masks were worn by infected individuals.

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