Novel polymer composite coated with ethylcellulose nanoparticle from waste paper as an alternative material to extracorporeal oxygenation membrane

Extracorporeal membrane oxygenator (ECMO) is a valuable technology to support people with acute respiratory distress syndrome (ARDS) and is recommended for COVID-19 patients. This study aims to fabricate polymer-based composite membranes coated with ethylcellulose nanoparticles from waste paper and identify the performance of the composite as ECMO candidates. Composite membranes were made from four types of polymers, namely, nylon, PTFE (polytetrafluoroethylene), Pebax® MH-1657, and SBS (poly-(styrene-b-butadiene-b-styrene)). PDMS (polydimethylsiloxane) 1 wt.% and ethylcellulose nanoparticles (3% and 10 wt.%) were used as membrane coatings to increase their hydrophobic properties. The success of cellulose isolation and ethylcellulose synthesis from waste paper was confirmed by the FTIR and XRD analysis. The size of the synthesized ethylcellulose nanoparticles was 32.68 nm. The coating effect on composite membranes was studied by measuring the contact angle, membrane porosity, protein quantification tests, and single gas permeation of O2 and CO2. Based on the protein quantification test, the protein could not pass through the Pebax/PDMS and SBS/PDMS composites coated with 10 wt.% ethylcellulose;this indicated less risk of plasma leakage. The gas permeation test on nylon/PDMS, PTFE/PDMS, and SBS/PDMS composites coated with 10% ethylcellulose resulted high CO2/O2 selectivity, respectively, 2.17, 3.48, and 3.22 as good indication for extracorporeal oxygenation membrane.

Preparation of PLA-based SMS nonwoven composites and its applications in protective apparel

The global COVID-19 pandemic has triggered a huge demand for the protective nonwovens. However, the main raw material of nonwovens comes from petroleum, and the massive consumption of petroleum-based polymers brings great pressure to ecosystem. Therefore, it is significant to develop biodegradable protective barrier products. In this work, a polylactic-based composite (a tri-layer nonwovens composed of spunbond, meltblown and spunbond, SMS) was prepared and applied for protective apparel. The surface morphology and chemical changes of the fibers were characterized and analyzed by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and energy dispersive spectroscopy (EDS). The liquid contact angle and permeability, breathability and moisture permeability, frictional charge and mechanical strength of the samples were evaluated and compared. The samples degradability was also recorded. The results demonstrate that the optimum formula for anti-fouling treatment on SMS is F-30. The treated fabric possesses superior liquid repellency and anti-permeability, with contact angles of water and alcohol at 128° and 115° respectively, while the alcohol repellent grade reaches level 7. The treated sample has less strength loss but exhibits favorable breathability, moisture permeability and anti-static properties, which can meet the requirements of protective apparels. After fluorine resin coating, the composite still provide excellent degradation performance, and the weight loss rate reaches more than 80% after 10 days water degradation. These results provide new insights for the application of PLA-based SMS in biodegradable protective apparel. © 2023 The Textile Institute.

Structure, Morphology, and Surface Chemistry of Surgical Masks and Their Evolution up to 10 Washing Cycles

The Covid-19 crisis has led to a massive surge in the use of surgical masks worldwide, causing risks of shortages and high pollution. Various decontamination techniques are currently being studied to reduce these risks by allowing the reuse of masks. In this study, surgical masks were washed up to 10 times, each cycle under the same conditions. The consequences of the washing cycles on the structure, fiber morphology, and surface chemistry have been studied through several characterization techniques: scanning electron microscopy, wetting angle measurements, infrared spectroscopy, X-ray diffraction, and X-ray photoelectrons spectroscopy. The washing process did not induce large changes in the hydrophobicity of the surface, the contact angle remaining constant throughout the cycles. The composition observed in the IR spectrum also remained unchanged for washed masks up to 10 cycles. Some slight variations were observed during X-ray analysis: the crystallinity of the fibers as well as the size of the crystals increases with the number of wash cycles. The XPS analysis shows that after 10 cycles, the surface of the masks underwent a slight oxidation. In the SEM images, changes were observed in the arrangement of the fibers, which are more visible the more times the mask has been washed: they align themselves in bundles, form areas with holes in the mask layer, and are crushed in some areas. © 2023 American Chemical Society

Development of reusable cloth mask with nanoparticle filtration efficiency greater than 95%

ABSRACT: After the rapid spread of SARS-Cov-2 virus, the use of masks was suggested by the world health organization (WHO) to reduce the virus transmission, whose primary mode of transmission was suggested to be through respiratory droplets. The recommended face coverings were single use surgical and respirator masks made of non-woven materials. With the increased demand for masks worldwide, the environmental impacts of mask disposal and the pollution caused by microplastic fibers of the non-woven materials were presented. This challenge necessitates the need for the development of a novel reusable mask reducing the environmental effects, while providing the necessary personal protective properties. Based on the ASTM F2299 standard test method, the performance, i.e., particle-size dependent filtration efficiency and pressure drop were studied for 20 samples with multilayer knit fabrics of natural and synthetic fibers (inner layer of pure cotton, cotton-nylon and cotton-polyester, middle layer of Lycra, and outer layer of superhydrophobic polyester). The results show that all the samples had an efficiency of >94% and 87–99% for large (250 (Formula presented.) –1 (Formula presented.) m) and small (100–250 nm) particles, respectively. The best performing structure has a material composition of 41% superhydrophobic polyester, 26% natural cotton, 24% nylon and 9% Lycra. The filtration efficiency, pressure drop, and quality factor for this sample are 97.8% (for 100 nm particles), 4.04 mmH2O/cm2 and 4.77 kPa−1, respectively. It was also demonstrated that the developed mask maintains its performance after 50 wash/dry cycles, verifying its reusability. It should be noted that charge neutralizer was not used in the experimental setup of this study which might have led to enhanced results for the filtration efficiency of small (100–250 nm) particles due to the dominance of electrostatic attraction. However, several samples were tested by the third-party company who uses a certified testing equipment based on ASTM F2299, and similar results were obtained. Copyright © 2022 American Association for Aerosol Research.

Relationship between color facemasks and their electron donor acceptor character

Protective facemasks made of non-woven fabric are widely used during the Covid-19 pandemic. In the literature, it is reported that the surface properties of the facemasks are among the factors that could influence their filtration efficiency. Moreover, these properties could even have an effect on the step that precedes the filtration, which consists in the adhesion of the microorganism on the surface of these facemasks. In this study, we evaluate electron donor and acceptor character of the surface of five colored masks made of non-woven fabric using the contact angle method. The contact angle measurements showed that the five masks used in this work are classified as hydrophobic while the electron donor/acceptor character varies according to the color of the five facemasks. These results are discussed in terms of their potential impact on adhesion of microorganisms on the surface of the mask. © 2023

An investigation into the aging of disposable face masks in landfill leachate

Due to the excessive use of disposable face masks during the COVID-19 pandemic, their accumulation has posed a great threat to the environment. In this study, we explored the fate of masks after being disposed in landfill. We simulated the possible process that masks would experience, including the exposure to sunlight before being covered and the contact with landfill leachate. After exposure to UV radiation, all three mask layers exhibited abrasions and fractures on the surface and became unstable with the increased UV radiation duration showed aging process. The alterations in chemical groups of masks as well as the lower mechanical strength of masks after UV weathering were detected to prove the happened aging process. Then it was found that the aging of masks in landfill leachate was further accelerated compared to these processes occurring in deionized water. Furthermore, the carbonyl index and isotacticity of the mask samples after aging for 30 days in leachate were higher than those of pristine materials, especially for those endured longer UV radiation. Similarly, the weight and tensile strength of the aged masks were also found lower than the original samples. Masks were likely to release more microparticles and high concentration of metal elements into leachate than deionized water after UV radiation and aging. After being exposed to UV radiation for 48 h, the concentration of released particles in leachate was 39.45 muL/L after 1 day and then grew to 309.45 muL/L after 30 days of aging. Seven elements (Al, Cr, Cu, Zn, Cd, Sb and Pb) were detected in leachate and the concentration of this metal elements increased with the longer aging time. The findings of this study can advance our understanding of the fate of disposable masks in the landfill and develop the strategy to address this challenge in waste management. Copyright © 2023 Elsevier B.V.

Electrospun PVB/AVE NMs as mask filter layer for win-win effects of filtration and antibacterial activity.

The COVID-19 pandemic has caused serious social and public health problems. In the field of personal protection, the facial masks can prevent infectious respiratory diseases, safeguard human health, and promote public safety. Herein, we focused on preparing a core filter layer for masks using electrospun polyvinyl butyral/apocynum venetum extract nanofibrous membranes (PVB/AVE NMs), with durable interception efficiency and antibacterial properties. In the spinning solution, AVE acted as a salt to improve electrical conductivity, and achieve long-lasting interception efficiency with adjustable pore size. It also played the role of an antibacterial agent in PVB/AVE NMs to achieve win-win effects. The hydrophobicity of PVB-AVE-6% was 120.9° whereas its filterability reached 98.3% when the pressure drop resistance was 142 Pa. PVB-AVE-6% exhibited intriguing properties with great antibacterial rates of 99.38% and 98.96% against S. aureus and E. coli, respectively. After a prolonged usability test of 8 h, the filtration efficiency of the PVB/AVE masks remained stable at over 97.7%. Furthermore, the antibacterial rates of the PVB/AVE masks on S. aureus and E. coli were 96.87% and 96.20% respectively, after using for 2 d. These results indicate that PVB/AVE NMs improve the protective performance of ordinary disposable masks, which has certain application in air filtration.

Physics of droplet impact on flexible materials: A review

Droplet impact on a flexible substrate is a prevalent phenomenon in nature and various advanced technologies such as soft bio-printing, tissue engineering, smart biomaterials and flexible electronics. Recent rapid advancement in new functional surfaces, ultra-high-speed imaging, nanotechnology, deep learning, advanced computational strength and the relation between fluid dynamics and interfacial science have intensified the physical understanding of droplet impact on soft materials. Once a droplets impacts on a solid surface, it deposits, spreads, rebounds or splashes. Given the importance of the droplet impact onto soft substrates in biotechnology, medicine and advanced flexible electronics, a deep physical understanding of such complex phenomenon is vital. This review initially presents the liquid-solid interaction physics and relevant interfacial science. Next, this review discusses the physics of droplet impact on soft materials with different physical and interfacial characteristics. Moreover, this review presents advancements in droplet impact on elastic materials relevant to new technologies such as soft electronics, elastic smart biomaterials, tissue engineering and the fight against COVID-19 pandemic. Finally, this review lays out future research directions related to current problems in such complex physical phenomenon.

Effect of Hydrogel Contact Angle on Wall Thickness of Artificial Blood Vessel.

Vascular replacement is one of the most effective tools to solve cardiovascular diseases, but due to the limitations of autologous transplantation, size mismatch, etc., the blood vessels for replacement are often in short supply. The emergence of artificial blood vessels with 3D bioprinting has been expected to solve this problem. Blood vessel prosthesis plays an important role in the field of cardiovascular medical materials. However, a small-diameter blood vessel prosthesis (diameter < 6 mm) is still unable to achieve wide clinical application. In this paper, a response surface analysis was firstly utilized to obtain the relationship between the contact angle and the gelatin/sodium alginate mixed hydrogel solution at different temperatures and mass percentages. Then, the self-developed 3D bioprinter was used to obtain the optimal printing spacing under different conditions through row spacing, printing, and verifying the relationship between the contact angle and the printing thickness. Finally, the relationship between the blood vessel wall thickness and the contact angle was obtained by biofabrication with 3D bioprinting, which can also confirm the controllability of the vascular membrane thickness molding. It lays a foundation for the following study of the small caliber blood vessel printing molding experiment.

PCL- And Gelatin-based Electrospun Biological Scaffolds For In Vitro Lung Tissue Engineering

Purpose/Objectives: Acute and chronic respiratory diseases constitute a substantial socioeconomic burden on a global scale, as made abundantly clear in the last two years with the rampant coronavirus disease 2019 (COVID-19) pandemic. Alas, the development of new therapies for pathological respiratory conditions has been hindered by the inadequacy of current preclinical models, which often fail to provide reliable predictions on drug safety and efficacy in humans. In particular, considerable anatomical and physiological differences between the respiratory systems of commonly used animal models and humans are one of the main issues leading to high drug attrition and clinical failure rates. Accordingly, the generation of physiologically relevant preclinical lung models for early drug development and pharmaceutical research is urgently needed. In this work, poly(ϵ-caprolactone) (PCL) and gelatin were used as raw materials to produce electrospun scaffolds for in vitro lung tissue engineering, in order to generate human biomimetic platforms for preclinical drug safety and efficacy testing. Methodology: PCL and gelatin were mixed at varying volume ratios: 1:0 (PP), 6:1 (PPG61), 4:1 (PPG41), and 2:1 (PPG21), so as to determine the optimal gelatin concentration for cell adhesion and growth. Poly(vinylpyrrolidone) (PVP) was added to every polymer mixture to facilitate the electrospinning process, and electrospun fibrous matrices were fabricated using a needleless electrospinning technique. Scaffold morphology, chemical composition, and wettability were characterized with scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and water contact angle analysis, respectively. Biocompatibility testing was performed using human bronchial (16HBE) and alveolar (A549) epithelial cell lines, consisting of cell metabolic activity, proliferation, and adhesion evaluation over two weeks of in vitro culture. Results: All polymer blends resulted in the formation of electrospun scaffolds with a nanofibrous structure. The addition of gelatin in PPG61 scaffolds improved fiber morphology compared to PP formulations, but increasing proportions of this polymer in PPG41 and PPG21 mats caused a larger number of defects, such as beading and branching. FTIR analysis confirmed the presence of PCL and PVP in PP scaffolds, as well as the addition of gelatin in all PPG blends. Moreover, as expected, all scaffolds were hydrophilic, with water contact angles below 90°, being suitable for protein adsorption and cell adhesion. Regarding 16HBE and A549 cell viability, surprisingly, no major differences were found between the different formulations over the two-week culture period, showing that all polymer blends were equally capable of promoting cell adhesion and growth. While PP scaffolds significantly outperformed PPG electrospun mats in early timepoints, no such differences were identified at the end of the experimental period. Conclusion/Significance: These results suggested that PCL, PVP, and/or gelatin blend electrospun scaffolds are conducive to lung epithelial cell adhesion and proliferation. Nevertheless, further studies investigating epithelial cell differentiation and function should be conducted to fully assess the suitability of these biomaterials as platforms for in vitro lung tissue engineering.

Antimicrobial Activity of a Titanium Dioxide Additivated Thermoset

The transmission of pathogens via surfaces poses a major health problem, particularly in hospital environments. Antimicrobial surfaces can interrupt the path of spread, while photocatalytically active titanium dioxide (TiO2) nanoparticles have emerged as an additive for creating antimicrobial materials. Irradiation of such particles with ultraviolet (UV) light leads to the formation of reactive oxygen species that can inactivate bacteria. The aim of this research was to incorporate TiO2 nanoparticles into a cellulose-reinforced melamine-formaldehyde resin (MF) to obtain a photocatalytic antimicrobial thermoset, to be used, for example, for device enclosures or tableware. To this end, composites of MF with 5, 10, 15, and 20 wt% TiO2 were produced by ultrasonication and hot pressing. The incorporation of TiO2 resulted in a small decrease in tensile strength and little to no decrease in Shore D hardness, but a statistically significant decrease in the water contact angle. After 48 h of UV irradiation, a statistically significant decrease in tensile strength for samples with 0 and 10 wt% TiO2 was measured but with no statistically significant differences in Shore D hardness, although a statistically significant increase in surface hydrophilicity was measured. Accelerated methylene blue (MB) degradation was measured during a further 2.5 h of UV irradiation and MB concentrations of 12% or less could be achieved. Samples containing 0, 10, and 20 wt% TiO2 were investigated for long-term UV stability and antimicrobial activity. Fourier-transform infrared spectroscopy revealed no changes in the chemical structure of the polymer, due to the incorporation of TiO2, but changes were detected after 500 h of irradiation, indicating material degradation. Specimens pre-irradiated with UV for 48 h showed a total reduction in Escherichia coli when exposed to UV irradiation.

Growth of a fluid-infused patch from droplet drainage into a thin porous layer

Growth of a fluid-infused patch on a thin porous layer, e.g. on a piece of paper or cloth, is related to the transmission of virus particles through exhaled droplets and aerosols. We present a theoretical model to describe how a wet patch develops gradually through imbibition, once a sessile droplet attaches at a permeable surface and drains gradually into a thin porous layer. Two limiting cases are considered based on different assumptions on the motion of the contact line during the coupled process of drop drainage and patch growth: (i) the apparent contact angle remains unchanged, so the radius of a sessile droplet decreases with time;and (ii) the location of the contact line remains pinned, so the contact angle decreases as time progresses. The model leads to evolution pathways for both the droplet and the fluid film within the porous layer, without introducing arbitrary fitting parameters. Potential implications of the model and its solutions are also discussed briefly in the context of the outspread of COVID-19, employing physical parameters for exhaled droplets, paper and cloth.

Unconstrained Hand Dorsal Veins Image Database and Recognition System

Hand veins can be used effectively in biometric recognition since they are internal organs that, in contrast to fingerprints, are robust under external environment effects such as dirt and paper cuts. Moreover, they form a complex rich shape that is unique, even in identical twins, and allows a high degree of freedom. However, most currently employed hand-based biometric systems rely on hand-touch devices to capture images with the desired quality. Since the start of the COVID-19 pandemic, most hand-based biometric systems have become undesirable due to their possible impact on the spread of the pandemic. Consequently, new contactless hand-based biometric recognition systems and databases are desired to keep up with the rising hygiene awareness. One contribution of this research is the creation of a database for hand dorsal veins images obtained contact-free with a variation in capturing distance and rotation angle. This database consists of 1548 images collected from 86 participants whose ages ranged from 19 to 84 years. For the other research contribution, a novel geometrical feature extraction method has been developed based on the Curvelet Transform. This method is useful for extracting robust rotation invariance features from vein images. The database attributes and the veins recognition results are analyzed to demonstrate their efficacy.

Coppers film fabrication on glass substrate by complex reduction method for rapid inactivation of SARS-CoV-2 (COVID-19)

A Cu film with the ability to rapidly inactivate the COVID-19 virus was easily fabricated at approximately 23°C on a Na-free glass substrate. The well-adhered Cu films with thickness of approximately 16 μm and surface area of 8.71 10-3 m2 g-1 were obtained by immersion of the glass substrate into an aqueous solution with dissolved Cu (II) complex of ammonia and ascorbic acid. The interface bonded between the film and glass substrate was very strong, such that the film did not peel off even when it was exposed to an ultrasonic wave of 100 mW (42 kHz) in water. The anti-COVID-19 activity in Dulbecco's modified Eagle's medium (DMEM) is effective within 2 h and is faster than that of commercial copper plates. The changes in the relative abundance of Cu2O and CuO crystallines on the Cu film due to DMEM treatment and those in surface morphology were examined by X-ray diffraction peak analysis and field emission-scanning electron microscopy, respectively. The flame atomic absorption analyses of the recovered solutions after DMEM treatment indicated that the Cu ions from the Cu film with DMEM treatment for 1 hour at a concentration of 0.64 ± 0.03 ppm were eluted 2.3 times faster than those from the Cu plate. The rapid elution of Cu ions from Cu2O crystallines on the film in the early stage is the primary factor in the inactivation of the COVID-19 virus, as elucidated from the time dependence of eluted Cu ions by DMEM treatment. Results from thermogravimetric and differential thermal analysis (TG-DTA) of the powder scratched from the Cu film suggested that a trace amount of organic residues remaining in the Cu film was important in the rapid activity. © 2022 World Scientific Publishing Company.

Developing Novel Biointerfaces: Using Chlorhexidine Surface Attachment as a Method for Creating Anti‐Fungal Surfaces

There is an increasing focus in healthcare environments on combatting antimicrobial resistant infections. While bacterial infections are well reported, infections caused by fungi receive less attention, yet have a broad impact on society and can be deadly. Fungi are eukaryotes with considerable shared biology with humans, therefore limited technologies exist to combat fungal infections and hospital infrastructure is rarely designed for reducing microbial load. In this study, a novel antimicrobial surface (AMS) that is modified with the broad‐spectrum biocide chlorhexidine is reported. The surfaces are shown to kill the opportunistic fungal pathogens Candida albicans and Cryptococcus neoformans very rapidly (<15 min) and are significantly more effective than current technologies available on the commercial market, such as silver and copper.

Adopting Intrinsic Hydrophilic Thermoplastic Starch Composites to Fabricate Antifogging Sustainable Films with High Antibiosis and Transparency

Fogging on transparent surfaces such as goggles causes a series of hazards to users. To fabricate antifogging and low-haze transparent renewable polymer materials, intrinsic hydrophilicity with high water adsorption capability of thermoplastic starch (TPS) had been adopted. Strikingly, when benzoic acid (BA) was blended with thermoplastic starch (TPS-BA), the haze of TPS-BA was only 7.8% when it suffered the cold and warm method of antifogging measurement with 87% transmittance. Simultaneously, TPS-BA achieved an 18 mm inhibition zone for Staphylococcus aureus. To reveal the antifogging mechanism of TPS-BA films, the surficial and interior structure features were evaluated by three-dimensional optical scanner, scanning electron microscopy (SEM), contact angle testing, small-angle X-ray scattering (SAXS), X-ray diffraction (XRD), temperature-dependent Fourier transform infrared (FTIR), dynamic mechanical analysis (DMA), and so on. The incorporation of BA resulted in the roughness (Rq), water contact angle (WCA), and crystallinity of the TPS-BA film decreasing from 6.5 to 0.68 μm, 65.1 to 39.9°, and 13.6 to 6.3%, respectively. The amorphous matrix and smooth surface reduced the scattered light, allowing the TPS-BA film to achieve low haze performance and high transmittance. Importantly, the diversified and weakened hydrogen bonds formed among starch, BA, and glycerol could inhibit the formation of starch crystalline regions and allowed hydroxyl groups to quickly bond with water. Thus, when TPS-BA is placed in a high-humidity surrounding, an "expressway"is constructed for water molecules diffusing into the TPS-BA matrix. This novel low-haze, antifogging, sustainable, and facilely fabricated TPS with antibacterial properties is a promising candidate in disposable medical goggles to fight against COVID-19. © 2021 American Chemical Society. All rights reserved.

Enhanced Micro-Electric Discharge Machining-Induced Surface Modification on Biomedical Ti-6Al-4V Alloy

In the midst of a huge demand for high-precision miniaturized medical implants made up of potential biomaterials, the biomedical Ti-6Al-4V alloy meets the uncompromising standards for longevity, biocompatibility, and sterilizability required to interact with living cells in medical settings. This research tailored the existing capabilities of a traditional micro-electric discharge machining (μ-EDM) setup by adding 0, 2, 4, 6, 8, and 10 g/l bioactive zinc powder particle concentrations (PPCs) to the dielectric. A copper and brass micro-tool electrode (C-μ-TE and B-μ-TE) was employed in association with each PPC. Experiments were executed using the one-variable-at-a-time (OVAT) approach. Machining time and dimensional deviation were chosen as the response variables of Zn powder mixed-micro-EDM (Zn-PM-μ-EDM). According to the analytical findings, the combination of C-μ-TE and 6 g/l Zn PPC achieved 23.52%, 3.29%, and 17.96% lesser machining time, dimensional deviation, and recast layer thickness, respectively, compared to the B-μ-TE. The detailed study of this surface endorsed a significant modification in terms of improved recast layer thickness (26.44 μm), topography (Ra = 743.65 nm), and wettability (contact angle < 90 deg), suggesting its dental application. In addition, the observation of ZnO and TiO in X-ray diffraction and appealing in vitro cytocompatibility encourage the subsequent biological and therapeutic studies to validate the anticipated antiviral activity of the modified Ti-6Al-4V alloy surface against coronavirus (COVID-19). © 2021 International Union of Crystallography. All rights reserved.

Future antiviral polymers by plasma processing.

Coronavirus disease 2019 (COVID-19) is largely threatening global public health, social stability, and economy. Efforts of the scientific community are turning to this global crisis and should present future preventative measures. With recent trends in polymer science that use plasma to activate and enhance the functionalities of polymer surfaces by surface etching, surface grafting, coating and activation combined with recent advances in understanding polymer-virus interactions at the nanoscale, it is promising to employ advanced plasma processing for smart antiviral applications. This trend article highlights the innovative and emerging directions and approaches in plasma-based surface engineering to create antiviral polymers. After introducing the unique features of plasma processing of polymers, novel plasma strategies that can be applied to engineer polymers with antiviral properties are presented and critically evaluated. The challenges and future perspectives of exploiting the unique plasma-specific effects to engineer smart polymers with virus-capture, virus-detection, virus-repelling, and/or virus-inactivation functionalities for biomedical applications are analysed and discussed.