Prospects of TiO2-based photocatalytic degradation of microplastic leachates related disposable facemask, a major COVID-19 waste

COVID-19 is one of the serious catastrophes that have a substantial influence on human health and the environment. Diverse preventive actions were implemented globally to limit its spread and transmission. Personnel protective equipment (PPE) was an important part of these control approaches. But unfortunately, these types of PPE mainly comprise plastics, which sparked challenges in the management of plastic waste. Disposable face masks (DFM) are one of the efficient strategies used across the world to ward off disease transmission. DFMs can contribute to micro and nano plastic pollution as the plastic present in the mask may degrade when exposed to certain environmental conditions. Microplastics (MPs) can enter the food chain and devastate human health. Recognizing the possible environmental risks associated with the inappropriate disposal of masks, it is crucial to avert it from becoming the next plastic crisis. To address this environmental threat, titanium dioxide (TiO2)-based photocatalytic degradation (PCD) of MPs is one of the promising approaches. TiO2-based photocatalysts exhibit excellent plastic degradation potential due to their outstanding photocatalytic ability, cost efficiency, chemical, and thermal stability. In this review, we have discussed the reports on COVID-19 waste generation, the limitation of current waste management techniques, and the environmental impact of MPs leachates from DFMs. Mainly, the prominence of TiO2 in the PCD and the applications of TiO2-based photocatalysts in MPs degradation are the prime highlights of this review. Additionally, various synthesis methods to enhance the photocatalytic performance of TiO2 and the mechanism of PCD are also discussed. Furthermore, current challenges and the future research perspective on the improvement of this approach have been proposed.

Nano-copper ions assembled cellulose-based composite with antibacterial activity for biodegradable personal protective mask.

The current SARS-CoV-2 pandemic has resulted in the widespread use of personal protective equipment, particularly face masks. However, the use of commercial disposable face masks puts great pressure on the environment. In this study, nano-copper ions assembled cotton fabric used in face masks to impart antibacterial activity has been discussed. To produce the nanocomposite, the cotton fabric was modified by sodium chloroacetate after its mercerization, and assembled with bactericidal nano-copper ions (about 10.61 mg·g-1) through electrostatic adsorption. It demonstrated excellent antibacterial activity against Staphylococcus aureus and Escherichia coli because the gaps between fibers in the cotton fabric allow the nano-copper ions to be fully released. Moreover, the antibacterial efficiency was maintained even after 50 washing cycles. Furthermore, the face mask constructed with this novel nanocomposite upper layer exhibited a high particle filtration efficiency (96.08% ± 0.91%) without compromising the air permeability (28.9 min·L-1). This green, economical, facile, and scalable process of depositing nano-copper ions onto modified cotton fibric has great potential to reduce disease transmission, resource consumption, and environmental impact of waste, while also expanding the range of protective fabrics.

High-Performance Flexible Humidity Sensor Based on MoOX Nanoparticle Films for Monitoring Human Respiration and Non-Contact Sensing

Flexible humidity sensors with high sensitivity, fast response time, and outstanding reliability have the potential to revolutionize electronic skin, healthcare, and non-contact sensing. In this study, we employed a straightforward nanocluster deposition technique to fabricate a resistive humidity sensor on a flexible substrate, using molybdenum oxide nanoparticles (MoOx NPs). We systematically evaluated the humidity-sensing behaviors of the MoOx NP film-based sensor and found that it exhibited exceptional sensing capabilities. Specifically, the sensor demonstrated high sensitivity (18.2 near zero humidity), a fast response/recovery time (1.7/2.2 s), and a wide relative humidity (RH) detection range (0-95%). The MoOx NP film, with its closely spaced granular nanostructure and high NP packing density, exhibited insensitivity to mechanical deformation, small hysteresis, good repeatability, and excellent stability. We also observed that the device exhibited distinct sensing kinetics in the range of high and low RH. Specifically, for RH > 43%, the response time showed a linear prolongation with increased RH. This behavior was attributed to two factors: the higher physical adsorption energy of H2O molecules and a multilayer physical adsorption process. In terms of applications, our sensor can be easily attached to a mask and has the potential to monitor human respiration owing to its high sensing performance. Additionally, the sensor was capable of dynamically tracking RH changes surrounding human skin, enabling a non-contact sensing capability. More significantly, we tested an integrated sensor array for its ability to detect moisture distribution in the external environment, demonstrating the potential of our sensor for contactless human-machine interaction. We believe that this innovation is particularly valuable during the COVID-19 epidemic, where cross-infection may be averted by the extensive use of contactless sensing. Overall, our findings demonstrate the tremendous potential of MoOx NP-based humidity sensors for a variety of applications, including healthcare, electronic skin, and non-contact sensing.

Nanomedicine for drug resistant pathogens and COVID-19 using mushroom nanocomposite inspired with bacteriocin - A review.

Multidrug resistant (MDR) pathogens have become a major global health challenge and have severely threatened the health of society. Current conditions have become worse as a result of the COVID-19 pandemic, and infection rates in the future will rise. It is necessary to design, respond effectively, and take action to address these challenges by investigating new avenues. In this regard, the fabrication of metal NPs utilized by various methods, including green synthesis using mushroom, is highly versatile, cost-effective, eco-compatible, and superior. In contrast, biofabrication of metal NPs can be employed as a powerful weapon against MDR pathogens and have immense biomedical applications. In addition, the advancement in nanotechnology has made possible to modify the nanomaterials and enhance their activities. Metal NPs with biomolecules composite prevent the microbial adhesion and kills the microbial pathogens through biofilm formation. Bacteriocin is an excellent antimicrobial peptide that works well as an augmentation substance to boost the antimicrobial effects. As a result, we concentrate on the creation of new, eco-compatible mycosynthesized metal NPs with bacteriocin nanocomposite via electrostatic, covalent, or non-covalent bindings. The synergistic benefits of metal NPs with bacteriocin to combat MDR pathogens and COVID-19, as well as other biomedical applications, are discussed in this review. Moreover, the importance of the adverse outcome pathway (AOP) in risk analysis of manufactured metal nanocomposite nanomaterial and their future possibilities were also discussed.

Engineered Highly Porous Polyvinyl Alcohol Hydrogels with Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and Graphene Nanosheets for Musculoskeletal Tissue Engineering: Morphology, Water Sorption, Thermal, Mechanical, Electrical Properties, and Biocompatibility.

Electroactive composite materials are very promising for musculoskeletal tissue engineering because they can be applied in combination with electrostimulation. In this context, novel graphene-based poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/polyvinyl alcohol (PHBV/PVA) semi-interpenetrated networks (semi-IPN) hydrogels were engineered with low amounts of graphene (G) nanosheets dispersed within the polymer matrix to endow them with electroactive properties. The nanohybrid hydrogels, obtained by applying a hybrid solvent casting-freeze-drying method, show an interconnected porous structure and a high water-absorption capacity (swelling degree > 1200%). The thermal characterization indicates that the structure presents microphase separation, with PHBV microdomains located between the PVA network. The PHBV chains located in the microdomains are able to crystallize; even more after the addition of G nanosheets, which act as a nucleating agent. Thermogravimetric analysis indicates that the degradation profile of the semi-IPN is located between those of the neat components, with an improved thermal stability at high temperatures (>450 °C) after the addition of G nanosheets. The mechanical (complex modulus) and electrical properties (surface conductivity) significantly increase in the nanohybrid hydrogels with 0.2% of G nanosheets. Nevertheless, when the amount of G nanoparticles increases fourfold (0.8%), the mechanical properties diminish and the electrical conductivity does not increase proportionally, suggesting the presence of G aggregates. The biological assessment (C2C12 murine myoblasts) indicates a good biocompatibility and proliferative behavior. These results reveal a new conductive and biocompatible semi-IPN with remarkable values of electrical conductivity and ability to induce myoblast proliferation, indicating its great potential for musculoskeletal tissue engineering.

Green ecofriendly electrochemical sensing platform for the sensitive determination of doxycycline.

The detection of pharmaceutical compounds in extremely low concentrations remains a challenge despite recent advancements in electrochemical sensing. In this study, a green hydrothermally synthesized nickel hydroxide-graphene hybrid material was used for the point-of-care determination of the antibiotic doxycycline (DOXY), which is a promising treatment for COVID-19 and other infections. The electrochemical sensor, based on a screen-printed electrode modified with the hybrid material, was able to detect DOXY in the range of 5.1 × 10-8 to 1.0 × 10-4 M, with a low detection limit of 9.6 × 10-9 M. This approach paves the way for eco-friendly and sustainable methods of nanomaterial synthesis for electrochemical analyses, particularly in point-of-care drug monitoring, and has the potential to improve access to testing platforms.

Biosensors for virus detection

Diseases caused by pathogenic viruses, such as Ebola, Zika, HIV, and SARS-CoV-2, have challenged the world in recent years leading to an urgent need for novel virus diagnostic technologies in medical, sanitation, and food applications. Unlike current technologies, biosensors present an enormous potential to address the demand for sensitive, robust, and cost-effective virus detection tools employing various recognition units such as antibodies, enzymes, peptides, nucleic acids, peptide nucleic acids, and molecularly imprinted polymers to specifically target viral protein, genetic material, or whole virus. These elements are often combined with quantum dots, nanocomposites, metallic nanoparticles, and graphene to enhance the sensing performance. In this chapter, while reviewing the current trends in virus diagnostics, we discuss the working principles of various virus biosensors by focusing on affinity materials, transducer properties, fabrication methods, and nanostructures involved to provide a deep understanding of virus targeting sensor platforms. © 2023 Elsevier Inc. All rights reserved.

Sustainable development of pine biocarbon derived thermally stable and electrically conducting polymer nanocomposite films

Biocarbon (BC) has recently emerged as the biomass-derived filler for sustainable development of polymer nanocomposites. The concerned nanocomposites find their potential applications as heat resistant, electrically conducting coatings and in energy storage. Under the current pandemic scenario, the similar polymer-based coatings derived from carbonaceous fillers are also under trial for sustainable control over the propagation of the coronavirus. Industrialization and anthropogenic activities are continuously increasing the wastes on earth and simultaneously demand of energy in each sector of life. To resolve both of these, the present investigation deals with sustainable development of a series of polycarbonate (PC) based organic paint (OP) in the presence of pine cone- derived nano BC (0.95%) supplemented with talc (0.18 g), mica (0.50 g), silica (0.80 g), clay (1.50 g) and selected dyes. The OP was subsequently cast into thermally stable and electrically conductive films (ECF). A representative ECF derived from brilliant yellow dye (1 wt%) was characterized through Fourier transform infrared spectra, scanning electron microscopy, X-ray diffraction spectra, simultaneous thermogravimetric-differential thermal analysis-differential thermal gravimetric analysis and four probe DC conductivity measurements. The study reveals the nano structured nature of pine cone-derived BC and respective ECF. DC conductivity (σDC ×73.5 10-2 S/cm) of ECF was found independent on concentration of dye at 100V, 25±1°C. © 2022 Scrivener Publishing LLC.

Solid-state ion-selective electrodes for the first potentiometric determination of the anti-COVID 19 drug Remdesivir in human plasma; A comparative study.

Establishing sensitive and targeted analytical methodologies for drug identification in biological fluids as well as screening of treatments that can counteract the most severe COVID-19 infection-related side effects are of utmost importance. Here, first attempts have been made for determination of the anti-COVID drug Remdesivir (RDS) in human plasma using four potentiometric sensors. Calixarene-8 (CX8) was used as an ionophore applied to the first electrode (Sensor I). The second had a layer of dispersed graphene nanocomposite coating (Sensor II). (Sensor III) was fabricated using nanoparticles of polyaniline (PANI) as ion-to-electron transducer. A reverse-phase polymerization using polyvinylpyrrolidone (PVP) was employed to create a graphene-polyaniline (G/PANI) nanocomposite electrode (Sensor IV). Surface morphology was confirmed by Scanning Electron Microscope (SEM). UV absorption spectra and Fourier Transform Ion Spectrophotometry (FTIR) also supported their structural characterization. The impact of graphene and polyaniline integration on the functionality and durability of the manufactured sensors was examined using the water layer test and signal drift. In the ranges of concentration of 10-7 to 10-2 mol/L and 10-7 to 10-3, sensors II & IV exhibited linear responses; respectively while sensors I & III displayed linearity within 10-6 to 10-2 mol/L. The target drug was easily detectable using LOD down to 100 nmol/L. The developed sensors satisfactorily offered sensitive, stable, selective and accurate estimate of Remdesivir (RDS) in its pharmaceutical formulation as well as spiked human plasma with recoveries ranging from 91.02 to 95.76 % with average standard deviations less than 1.85. The suggested procedure was approved in accordance with ICH recommendations.

An electrochemical PNA-based sensor for the detection of the SARS-CoV-2 RdRP by using surface-initiated-reversible-addition-fragmentation-chain-transfer polymerization technique.

Coronavirus disease 2019 is one of the global health problems. Herein, a highly sensitive electrochemical biosensor has been designed to detect the RNA-dependent RNA polymerase (RdRP) of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) (SARS-CoV-2 RdRP). Herein, the surface-initiated reversible-addition-fragmentation-chain-transfer polymerization was used to amplify the electrochemical signal. To do that, the thiol-terminated peptide nucleic acid (PNA) probes were first immobilized on the surface of a screen-printed electrode modified with reduced graphene oxide-gold nanocomposite and then the fixed concentration of the SARS-CoV-2 RdRP was added to the electrode surface to interact with PNA probes. Subsequently, the Zr 4+ ions were added to interact with the phosphate groups of the SARS-CoV-2 RdRP. It allowed us to polymerase the ferrocenylmethyl methacrylate (FcMMA) and 4-cyano-4-(phenylcarbonothioylthio)-pentanoic acid on the SARS-CoV-2 RdRP chain. Since the poly-FcMMA has an electrochemical signal, the response of the PNA-based sensor to SARS-CoV-2 RdRP was increased in the range of 5-500 aM. The limit of detection was calculated to be 0.8 aM which is lower than the previous sensor for SARS-CoV-2 RdRP detection. The proposed PNA-based sensor showed high selectivity to the SARS-CoV-2 RdRP in the presence of the gene fragments of influenza A and Middle East respiratory syndrome coronavirus.

Cellulosic fiber nanocomposite application review with zinc oxide antimicrobial agent nanoparticle: an opt for COVID-19 purpose.

Cellulosic fiber (CF) in nanoform is emergingly finding its way for COVID-19 solution for instance via nanocomposite/nanoparticle from various abundant biopolymeric waste materials, which may not be widely commercialized when the pandemic strikes recently. The possibility is wide open but needs proper collection of knowledge and research data. Thus, this article firstly reviews CF produced from various lignocellulosic or biomass feedstocks' pretreatment methods in various nanoforms or nanocomposites, also serving together with metal oxide (MeO) antimicrobial agents having certain analytical reporting. CF-MeO hybrid product can be a great option for COVID-19 antimicrobial resistant environment to be proposed considering the long-established CF and MeO laboratory investigations. Secondly, a preliminary pH investigation of 7 to 12 on zinc oxide synthesis discussing on Fouriertransform infrared spectroscopy (FTIR) functional groups and scanning electron microscope (SEM) images are also presented, justifying the knowledge requirement for future stable nanocomposite formulation. In addition to that, recent precursors suitable for zinc oxide nanoparticle synthesis with emergingly prediction to serve as COVID-19 purposes via different products, aligning with CFs or nanocellulose for industrial applications are also reviewed.

Ultrasensitive electrochemical biosensors based on zinc sulfide/graphene hybrid for rapid detection of SARS-CoV-2.

The coronavirus disease 2019 (COVID-19) is a highly contagious and fatal disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In general, the diagnostic tests for COVID-19 are based on the detection of nucleic acid, antibodies, and protein. Among different analytes, the gold standard of the COVID-19 test is the viral nucleic acid detection performed by the quantitative reverse transcription polymerase chain reaction (qRT-PCR) method. However, the gold standard test is time-consuming and requires expensive instrumentation, as well as trained personnel. Herein, we report an ultrasensitive electrochemical biosensor based on zinc sulfide/graphene (ZnS/graphene) nanocomposite for rapid and direct nucleic acid detection of SARS-CoV-2. We demonstrated a simple one-step route for manufacturing ZnS/graphene by employing an ultrafast (90 s) microwave-based non-equilibrium heating approach. The biosensor assay involves the hybridization of target DNA or RNA samples with probes that are immersed into a redox active electrolyte, which are detectable by electrochemical measurements. In this study, we have performed the tests for synthetic DNA samples and, SARS-CoV-2 standard samples. Experimental results revealed that the proposed biosensor could detect low concentrations of all different SARS-CoV-2 samples, using such as S, ORF 1a, and ORF 1b gene sequences as targets. This microwave-synthesized ZnS/graphene-based biosensor could be reliably used as an on-site, real-time, and rapid diagnostic test for COVID-19. Supplementary Information: The online version contains supplementary material available at 10.1007/s42114-023-00630-7.

Dry powder formulation of azithromycin for COVID-19 therapeutics.

Azithromycin is an antibiotic proposed as a treatment for the coronavirus disease 2019 (COVID-19) due to its immunomodulatory activity. The aim of this study is to develop dry powder formulations of azithromycin-loaded poly(lactic-co-glycolic acid) (PLGA) nanocomposite microparticles for pulmonary delivery to improve the low bioavailability of azithromycin. Double emulsion method was used to produce nanoparticles, which were then spray dried to form nanocomposite microparticles. Encapsulation efficiency and drug loading were analysed, and formulations were characterised by particle size, zeta potential, morphology, crystallinity and in-vitro aerosol dispersion performance. The addition of chitosan changed the neutrally-charged azithromycin only formulation to positively-charged nanoparticles. However, the addition of chitosan also increased the particle size of the formulations. It was observed in the NGI® data that there was an improvement in dispersibility of the chitosan-related formulations. It was demonstrated in this study that all dry powder formulations were able to deliver azithromycin to the deep lung regions, which suggested the potential of using azithromycin via pulmonary drug delivery as an effective method to treat COVID-19.

Docking of COVID-19 Main Protease and TD-DFT/DMOl3 Simulated method, Synthesis, and Characterization with hybrid nanocomposite thin films and its applications

Using the precipitation polymerization method copolymer poly methyl methacrylate co acrylonitrile was synthesized. Hybrid nanocomposite thin films [P(MMA-co-AN)/ZnO]HNC were prepared using the dip casting method by adding ZnO nanoparticles by the ratios 0.25, 0.20, 0.15, and 0.10 according to the weight of P(MMA-co-AN). Fourier Transform Infrared Spectroscopy (FTIR), UV-Vis optical properties, and laser photoluminescence PL characterization techniques were used to study [P(MMA-co-AN)/ZnO]HNC films. In addition, density functional theory (DFT), optimization via TD-DFTD/Mol3, and Cambridge Serial Total Energy Bundle (TD-FDT/CASTEP) were used to perform the geometrical study. FTIR spectra from [P(MMA-co-AN)/ZnO]HNC indicates the interaction between the copolymer and ZnO nanoparticles. In the wavelength range of 190 – 800 nm, the optical properties of [P(MMA-co-AN)/ZnO]HNC were considered. The direct energy band gap was found to be changed from 4.1 eV for P (MMA – co – AN) to 3.19 eV for 0.25 ZnO, while the concentration of 0.20 ZnO was the highest in the Urbach energy with 0.17 eV. The refractive index nλ=700 ranges from 1.48 to 1.81 for the concentration of 0.15 ZnO. Three emission peaks at 393 nm, 527 nm, and 775 nm were figured in the laser photoluminescence spectra of [P(MMA-co-AN)/ZnO]HNC films. In order to attain the restrained action of studied ligands (hybrid nanocomposite) novel coronavirus (COVID 19) main protest (6LU7) molecular docking studies were performed. The predicted energy gab by TD-DFT/DMOl3 was found to be agreed with the experimental data in a good manner.

Preparation and characterization of antibacterial gels of galactomannan/ZnO nanocomposite in carbopol-based matrix using mesquite seeds as the biopolymer source

Nanocomposite gels are novel materials mainly used in the medical field for the control drug release and distribution. In this study, the effect of the concentration of galactomannan/zinc oxide nanocomposite in a polymeric Carbopol matrix to obtain a functional nanocomposite gel was studied. The swelling, thermogravimetric, rheological, and antibacterial properties against Escherichia coli and Staphylococcus aureus were evaluated. The results indicate that there is a direct effect between the amount of the employed nanocomposite and the properties studied in the gels. In this regard, we present a formulation that demonstrates that the prepared nanocomposite gel has ideal properties to be used in the medical field as an antibacterial agent.

Metal oxide nanocomposite-based electrochemical biosensing studies

The growing world population is facing challenges like energy crisis, environmental sustainability, global public health problems, etc. Among these, the resolution of public health issue is of prime importance for the people to live happily and enjoy each moment of their life. However, various diseases such as diabetes mellitus, HIV, cancer, Alzheimer's disease, stroke, and other neurological diseases have no permanent cure yet. New life-threatening diseases and viruses like COVID-19, Zika, Ebola, SARS, MERS and H1N1 etc. are affecting humans, which lead to loss of life. through Early diagnosis, proper medical treatment and accessible health monitoring systems can be both life saving and cost saving for the patients. Particularly, biosensing protocols in connection to early diagnosis as well as health monitoring have placed a significant importance in biomedical sector. In the current context where population and bio-testing capacity have a remarkable gap, the effect of prompt and specific detection of target molecules is also important from the point of view of biosensor field. Hence, the development of biomedical sensors having the features such as easy to handle, cost effective, short time span for analysis, multianalyte sensing, sophisticated digital display, etc. are the need of hour. For example, glucometer is a well-known example of biosensor device;glucometer measures the sugar content present in blood sample. Similarly, various sensors such as glucowatch, tooth enamel biosensor, colorimetric sweat biosensor, etc. have wide application in biosensing for the analysis of different biomolecules. © 2022 Elsevier Inc. All rights reserved.

Highly efficient Ag doped δ-MnO2 decorated graphene: Comparison and application in electrochemical detection of H2O2.

Cytotoxic H2O2 is an inevitable part of our life, even during this contemporary pandemic COVID-19. Personal protective equipment of the front line fighter against coronavirus could be sterilized easily by H2O2 for reuse. In this study, Ag doped δ-MnO2 nanorods supported graphene nanocomposite (denoted as Ag@δ-MnO2/G) was synthesized as a nonenzymatic electrochemical sensor for the sensitive detection of H2O2. The ternary nanocomposite has overcome the poor electrical conductivity of δ-MnO2 and also the severe aggregation of Ag NPs. Furthermore, δ-MnO2/G provided a rougher surface and large numbers of functional groups for doping more numbers of Ag atoms, which effectively modulate the electronic properties of the nanocomposite. As a result, electroactive surface area and electrical conductivity of Ag@δ-MnO2/G increased remarkably as well as excellent catalytic activity observed towards H2O2 reduction. The modified glassy carbon electrode exhibited fast amperometric response time (<2 s) in H2O2 determination. The limit of detection was calculated as 68 nM in the broad linear range (0.005-90.64 mM) with high sensitivity of 104.43 µA mM-1 cm-2. No significant interference, long-term stability, excellent reproducibility, satisfactory repeatability, practical applicability towards food samples and wastewater proved the efficiency of the proposed sensor.

Emerging 3D printing based on polymers and nanomaterial additives: Enhancement of properties and potential applications

Three-dimensional printing (3D printing) has gained tremendous attention from various fields including scientific researchers and commercial industries. Polymers are the most widely used materials since they demonstrate ease of processing and ability to gain the desired properties by adding additives. Nonetheless, there are many challenges including limited printable material, slow printing speed, low resolution, functionality, and suitable property for using in specific applications. The use of nanomaterials with unique properties to improve the polymer properties has been developed leading to increased number of polymer nanocomposites with versatility. The addition of nanomaterials into polymers can significantly alter and enhance mechanical properties, thermal and electrical conductivity, including cell adhesion and proliferation in biomedical application. 3D printing technology coupled with the high-performance polymer nanocomposites can create 3D polymer structures with the precise and complex geometries, and also exhibit multi-functional properties provided by the different properties from polymers and nanomaterials. 3D printing polymer nanocomposites can be applied as the alternative materials for tissue engineering, biomedical devices, sensors, electronics and recently in personal protection during COVID-19 pandemic. The trends of utilization of polymers, well-known materials for 3D printing, coupled with nanotechnology is still continuous growing since variety of applications is rapidly expanded for advanced application, especially in biomedical field.

Polymer-Thread-Based Fully Textile Capacitive Sensor Embroidered on a Protective Face Mask for Humidity Detection

The COVID-19 pandemic has created a situation where wearing personal protective masks is a must for every human being and introduced them as a part of everyday life. This work demonstrates a new functionality embedded in single-use face masks through an embroidered humidity sensor. The design of the face mask humidity sensor is comprised of interdigitated electrodes made of polyamide-based conductive threads and common polyester threads which act as a dielectric sensing layer embroidered between them. Therefore, the embroidered sensor acts as a capacitor, the performance of which was studied in increasing humidity conditions in the frequency range from 1 Hz to 100 kHz. The moisture adsorbed by sensitive hygroscopic polyester threads altered their dielectric and permittivity properties which were detected by the change in capacitance values of the face mask sensors at different relative humidity (RH) levels. The calculated limit of detection (LOD) values for the two proposed sensors at different frequencies (1, 10, and 100 kHz) were found in the range from 11.46% RH-27.41% RH and 29.79% RH-38.65% RH. The tested sensors showed good repeatability and stability under different humidity conditions over a period of 80 min. By employing direct embroidery of silver-coated polyamide conductive threads and moisture-sensitive polyester threads onto the face mask, the present work exploits the application of polymer-based textile materials in developing novel stretchable sensing devices toward e-textile applications.

Ultrasensitive Strain Sensor Utilizing a AgF-AgNW Hybrid Nanocomposite for Breath Monitoring and Pulmonary Function Analysis.

Breath monitoring and pulmonary function analysis have been the prime focus of wearable smart sensors owing to the COVID-19 outbreak. Currently used lung function meters in hospitals are prone to spread the virus and can result in the transmission of the disease. Herein, we have reported the first-ever wearable patch-type strain sensor for enabling real-time lung function measurements (such as forced volume capacity (FVC) and forced expiratory volume (FEV) along with breath monitoring), which can avoid the spread of the virus. The noninvasive and highly sensitive strain sensor utilizes the synergistic effect of two-dimensional (2D) silver flakes (AgFs) and one-dimensional (1D) silver nanowires (AgNWs), where AgFs create multiple electron transmission paths and AgNWs generate percolation networks in the nanocomposite. The nanocomposite-based strain sensor possesses a high optimized conductivity of 7721 Sm-1 (and a maximum conductivity of 83,836 Sm-1), excellent stretchability (>1000%), and ultrasensitivity (GFs of 35 and 87 when stretched 0-20 and 20-50%, respectively), thus enabling reliable detection of small strains produced by the body during breathing and other motions. The sensor patching site was optimized to accurately discriminate between normal breathing, quick breathing, and deep breathing and analyze numerous pulmonary functions, including the respiratory rate, peak flow, FVC, and FEV. Finally, the observed measurements for different pulmonary functions were compared with a commercial peak flow meter and a spirometer, and a high correlation was observed, which highlights the practical feasibility of continuous respiratory monitoring and pulmonary function analysis.