Fabrication of noble metal–based antimicrobial nanosystems

Recently, the outbreak of diverse infectious diseases mainly caused by microbes led to increase in the human mortality rate. Microbes being small cell structures are more powerful to fight with human cells for their proliferation as well as subsequent growth. At times, it pioneers the world with its contagiousness (for example, swine flu, SARS-CoV-2, dengue virus, etc.) causing greater impact to public health. Numerous efforts are in progress to design and develop efficient antimicrobial systems. Antimicrobial systems include self-disinfecting surfaces, wall coatings, paints, sanitizers, etc., to improve their microbial resistance to surfaces as well as killing of pathogens. Noble metal–based antimicrobial systems are pioneers of the field right from history. Under the broad category of noble metal nanostructures, silver (Ag), gold (Au), platinum (Pt), palladium (Pd), and copper (Cu) prove its excellence as high-ranked antimicrobial markers. Yet, there exist some challenges to uplift its efficacy, henceforth fabrication process with its associated theory for building competent antimicrobial nanosystems with noble metals should be paid attention. The crucial factor is the fabrication step within which their properties would be tuned greatly. By proper design of fabrication process, noble metals could possibly function rapidly to destroy the microbial colonization by breaking the respiratory chains of pathogens of concern. Development of hydrophobic surfaces for noble metal nanomaterial–based antimicrobial systems is increasing in recent era, since it can act as shield against bio film formation by the microbial adherence to surfaces. This chapter entitles the diverse fabrication procedures with their mechanisms, pairing process of noble metals, surface modifications, tuning parameters at synthetic stages for engineering the noble metal–based antimicrobial nanosystems to enrich the higher biocidal resistance. © 2023 Elsevier Inc. All rights reserved.

Organic Electrochemical Transistors (OECTs): Advancements and Exciting Prospects for Future Biosensing Applications

Over the past few decades, the field of organic electronics has depicted proliferated growth, due to the advantageous characteristics of organic semiconductors, such as tunability through synthetic chemistry, simplicity in processing, cost-effectiveness, and low-voltage operation, to cite a few. Organic electrochemical transistors (OECTs) have recently emerged as a highly promising technology in the area of biosensing and flexible electronics. OECT-based biosensors are capable of sensing brain activities, tissues, monitoring cells, hormones, DNAs, and glucose. Sensitivity, selectivity, and detection limit are the key parameters adopted for measuring the performance of OECT-based biosensors. This article highlights the advancements and exciting prospects of OECTs for future biosensing applications, such as cell-based biosensing, chemical sensing, DNA/ribonucleic acid (RNA) sensing, glucose sensing, immune sensing, ion sensing, and pH sensing. OECT-based biosensors outperform other conventional biosensors because of their excellent biocompatibility, high transconductance, and mixed electronic-ionic conductivity. At present, OECTs are fabricated and characterized in millimeter and micrometer dimensions, and miniaturizing their dimensions to nanoscale is the key challenge for utilizing them in the field of nanobioelectronics, nanomedicine, and nanobiosensing.

Fabrication, Testing, and 3D Comprehensive Analysis of Swept-Tip Tiltrotor Blades

This paper covers the design, fabrication, testing, and modeling of a family of Froude-scale tiltrotor blades. They are designed with the objective of gaining a fundamental understanding of the impact of a swept tip on tiltrotor whirl flutter. The goal of this paper is to describe the development of the blades needed for this purpose. The rotor is three bladed with a diameter of 4.75 ft. The blades have a VR-7 profile, chord of 3.15 inches, and linear twist of −37◦ per span. The swept-tip blades have a sweep of 20◦ starting at 80%R. The blade properties are loosely based on the XV-15 design. A CATIA and Cubit-based high-fidelity three-dimensional (3D) finite element model is developed. It accurately represents the fabricated blade and is analyzed with X3D. Experiments in a vacuum chamber were carried out to demonstrate the structural integrity of the blades. Measured frequencies and strains were validated with X3D predictions proving the fidelity of the 3D model. Thus, even though the wind tunnel facilities were closed due to COVID-19, hover and forward flight calculations for the blade stress could be performed using the high-fidelity 3D structural model. The results prove the blades have sufficient structural integrity and stress margins to allow for wind tunnel testing. © 2023 Vertical Flight Society.

Precise Epitope Organization with Self‐adjuvant Framework Nucleic Acid for Efficient COVID‐19 Peptide Vaccine Construction

Peptide vaccines have advantages in easy fabrication and high safety, but their effectiveness is hampered by the poor immunogenicity of the epitopes themselves. Herein, we constructed a series of framework nucleic acids (FNAs) with regulated rigidity and size to precisely organize epitopes in order to reveal the influence of epitope spacing and carrier rigidity on the efficiency of peptide vaccines. We found that assembling epitopes on rigid tetrahedral FNAs (tFNAs) with the appropriate size could efficiently enhance their immunogenicity. Further, by integrating epitopes from SARS‐CoV‐2 on preferred tFNAs, we constructed a COVID‐19 peptide vaccine which could induce high titers of IgG against the receptor binding domain (RBD) of SARS‐CoV‐2 spike protein and increase the ratio of memory B and T cells in mice. Considering the good biocompatibility of tFNAs, our research provides a new idea for developing efficient peptide vaccines against viruses and possibly other diseases.

Vito Project: Hull / Mooring Design & Platform Installation

In 2009, the Vito field was discovered in more than 4,000 ft of water approximately 150 miles offshore from New Orleans, Louisiana. The project produces from reservoirs nearly 30,000 feet below sea level. This paper provides an overview of the Hull & Mooring system, executing a minimum technical scope to produce a simplistic design. This paper is part of a Vito Project series at OTC 2023, and the other papers are listed in the references. The original Vito project execution strategy was to replicate the Shell mega-project of Appomattox. As the industry and market began to change in 2015, the project faced significant financial hurdles, and the project team decided to refresh the design concept to reduce cost and simplify. The team regrouped to propose a smaller semi-submersible Floating Production System (FPS) with a simplistic mooring design. The Topsides was designed to be lifted as a single module, with a payload of less than 10,000 st to enable competitive tendering process. The redesigned FPS concept was moored with 12 taut, chain – polyester – chain mooring line system utilizing an in-line mooring tensioner, removing the traditional mechanically complicated and space demanding "on-vessel" winch systems. Vito employed a passive hull system, with all ballasting occurring over the top without hull penetrations. There were no pump rooms within the hull as equipment is accessed from top of column, removing the need for regular hull access to maintain equipment. The hull compartmentation also followed a simple approach, containing only 12 ballast tanks to reduce fabrication cost. The hull design also included simplified ring stiffening for columns which eliminated the traditional orthogonally stiffened systems. Additionally, the structure utilized an upper column frame structure to support the topsides deck and served as a bracing for supporting columns at the top for squeeze-pry loads and bracing for supporting columns during dry tow. The simplification of the stiffening system and topsides deck support design reduced interfaces between hull and topsides and also opened up options for fabrication of topsides and hull. Key challenges included developing installation methods without traditional FPS mooring chain jacks and increasing installation options by not requiring a large installation derrick barge and enabling use of common anchor handler vessels. The project experienced fabrication delays due to COVID-19, which required creative solutions transporting the FPS from Singapore to the Gulf of Mexico. The design team © 2023, Offshore Technology Conference.

Tailoring Arduino for Interactive Digital Fabrication: Mechanism, Algorithms, Cases

This study presents the introduction of Arduino to undergraduate architecture students through a series of project-based exercises in two different universities. The main motivation of study is based on supporting students' motivation, engagement, and creativity under remote education conditions in the context of digital fabrication. This research consolidates the digital fabrication pedagogy efficiency in the time of post COVID-19 using both distant and hybrid learning modes. Students have exerted a dedication effort and enjoyed digital craft especially while using Arduino despite the virtual teaching classes. Kinetic applications have received students' total endorsement and hands-on involvement supported with theoretical lectures focusing on fabrication techniques, materials and tools along with parametric algorithmic design. Assignments are both structured and semi-structured to promote their skills and grant them a free-flexible pedagogical approach. © 2023 IEEE.

Investigation and Optimization of Effects of 3D Printer Process Parameters on Performance Parameters.

Professionals in industries are making progress in creating predictive techniques for evaluating critical characteristics and reactions of engineered materials. The objective of this investigation is to determine the optimal settings for a 3D printer made of acrylonitrile butadiene styrene (ABS) in terms of its conflicting responses (flexural strength (FS), tensile strength (TS), average surface roughness (Ra), print time (T), and energy consumption (E)). Layer thickness (LT), printing speed (PS), and infill density (ID) are all quantifiable characteristics that were chosen. For the experimental methods of the prediction models, twenty samples were created using a full central composite design (CCD). The models were verified by proving that the experimental results were consistent with the predictions using validation trial tests, and the significance of the performance parameters was confirmed using analysis of variance (ANOVA). The most crucial element in obtaining the desired Ra and T was LT, whereas ID was the most crucial in attaining the desired mechanical characteristics. Numerical multi-objective optimization was used to achieve the following parameters: LT = 0.27 mm, ID = 84 percent, and PS = 51.1 mm/s; FS = 58.01 MPa; TS = 35.8 MPa; lowest Ra = 8.01 m; lowest T = 58 min; and E = 0.21 kwh. Manufacturers and practitioners may profit from using the produced numerically optimized model to forecast the necessary surface quality for different aspects before undertaking trials.

The SmithVent Experience and a Framework for Collaborative Distributed Design and Fabrication

This paper addresses the collaborative journey of the SmithVent team, a 30-person distributed group of volunteers, who designed, fabricated, and tested a simplified and cost-efficient ventilator over a three-month period, and won the CoVent-19 Challenge in July 2020. The paper first presents the SmithVent experience through a co-constructed narrative that describes the team's approaches to collaborative distributed design and fabrication. The paper next reviews frameworks from five theoretical lenses and then details the process of extracting, synthesizing, and organizing relevant factors to create a new and emergent framework reflective of the SmithVent experience. Lastly, the paper discusses educational implications of the SmithVent experience and proposed framework, emphasizing that the team's strategies provide a model for educational and industry settings for future collaborative and distributed design and fabrication.

Dependence of SARS-CoV-2 (COVID-19) inactivation ability on the crystallinity level of transparent Cu2O thin films

The inactivation ability of SARS-CoV-2 (COVID-19) was examined using two types of transparent Cu2O thin films with different crystallinities on a Na-free glass substrate. The low-crystallinity Cu2O thin film, which was fabricated by irradiating 254 nm ultraviolet (UV)-light with an intensity of 6.72 mW cm(-2) onto a spin-coated precursor film involving Cu2+ complexes at room temperature, exhibited an outstanding COVID-19 inactivation ability to reduce 99.999% of the virus after 1 h of incubation. The X-ray diffraction results of the UV-irradiated thin film indicated a cubic Cu2O lattice with a small crystallite size of 2 +/- 1 nm. Conversely, the high-crystallinity Cu2O thin film with a crystallite size of 16 +/- 3 nm, obtained by heating a spin-coated precursor film containing another Cu2+ complex, showed a negligibly low inactivation activity at the same level as the Na-free glass substrate. The eluted concentrations of Cu ions from both Cu2O thin films were analyzed after immersion in Dulbecco's modified Eagle's medium (DMEM) for 0.25-2 h. The eluted Cu-ion concentration of 1.16 ppm was observed for the UV-irradiated thin film by DMEM immersion after 1 h, but that of 0.04 ppm was observed for the heat-treated thin film. This indicated that an important factor of virus inactivation on Cu2O thin films is highly related to the elution of Cu ions that occurred from the surface in the medium.

A novel isothermal digital amplification system and its application for absolute quantification of respiratory infectious virus

Herein, we establish a novel isothermal digital amplification system termed digital nicking and extension chain reaction system-based amplification (dNESBA) by utilizing the isothermal NESBA technique and the newly developed miniaturized fluorescence monitoring system (mFMS). dNESBA enables parallel isothermal NESBA reactions in more than 10,000 localized droplet microreactors and read the fluorescence signals rapidly in 150 s by mFMS. This system could identify the genomic RNA (gRNA) extracted from target respiratory syncytial virus A (RSV A) as low as 10 copies with remarkable specificity. The practical applicability of dNESBA was also successfully verified by reliably detecting the gRNA in the artificial sputum samples with excellent reproducibility and accuracy. Due to the intrinsic advantages of isothermal amplifying technique including the elimination of the requirement of thermocycling device and the enhanced portability of the miniaturized read-out equipment, the dNESBA technique equipped with mFMS could serve as a promising platform system to achieve point-of-care (POC) digital molecular diagnostics, enabling absolute and ultra-sensitive quantification of various infectious pathogens even in an early stage.Copyright © 2023

A Microfluidic Biosensor for Rapid Detection of Covid-19

We have designed, fabricated, and tested a MEMS-based impedance biosensor for accurate and rapid detection of severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) using of clinical samples. The device consists of focusing region that concentrate low quantities of the virus present in the samples to a detectable threshold, trap region hat maximize the captured virus, and detection region to detect the virus with high selectivity and sensitivity, using an array of interdigitated electrodes (IDE) coated with a specific antibody. Changes in the impedance value due to the binding of the SARS-COV-2 antigen to the antibody will indicate positive or negative result. The device was able to detect inactivated SARS-COV-2 antigen present in phosphate buffer saline (PBS) with a concentration as low as 50 TCID50/ml in 30 minutes. In addition, the biosensor was able to detect SARS-COV-2 in clinical samples (swabs) with a sensitivity of 84 TCID50/ml, also in 30 minutes. © 2023 IEEE.

Hybrid Opto‐Thermocycler for RT‐qPCR Detects SARS‐CoV‐2

Although real‐time quantitative reverse transcription polymerase chain reaction (RT‐qPCR) is the gold standard for detecting the virus severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) and other pathogens, the coronavirus disease 2019 (COVID‐19) pandemic has highlighted the scarcity of instruments, devices, and reagents for polymerase chain reaction (PCR) testing in constrained settings. At least for under‐resourced countries, it has become critical to deploy instruments that can be rapidly constructed and satisfy this demand. Instead of separating the optical system from the thermal module (typical of qPCR thermocyclers), we report a portable Hybrid Opto‐Thermocycler—dubbed HybOT Cycler—that takes advantage of the high‐temperature tolerances (>100 °C) of electronic and optical components to combine thermal control, illumination, and fluorescence detection into a highly integrated hybrid module. This simple configuration allowed us to reduce the overall number of components, thus simplifying its assembly and reducing the instrument size. The HybOT Cycler is wirelessly controlled from an application installed in a tablet. PCR assays are carried out in a bubble‐free microfluidic device that can be easily replicated from an acrylic mold. Using the HybOT Cycler, down to 100 copies/µL of genetic material of the virus SARS‐CoV‐2 with 95% sensitivity and 100% specificity is detected. The HybOT Cycler can assist in diagnosing SARS‐CoV‐2 and other pathogens in resource‐poor settings. [ FROM AUTHOR] Copyright of Advanced Materials Technologies is the property of John Wiley & Sons, Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Flexible Printed Circuitry on Fabric for Wearable Electronics Applications

Health awareness has increased worldwide since the COVID 2019 pandemic, creating a strong demand for wearable electronics. Wearable sensors for monitoring a patient's health are prevalent to reduce medical costs and decrease in-person clinic visits. Integrating electronics into clothes is challenging because most fabrics are porous and incompatible with the existing manufacturing methods, such as screen printing. The indirect printing method was employed to fabricate electrical circuitry on a textile substrate by printing it on a heat transfer polymer (HTP) and attaching it to the target cloths by stitching or glueing. Such a fabrication process has the potential to lead the way in developing new intelligent clothes. However, the durability of the printed circuitry in this manufacturing process on a cloth is still unknown and requires investigation. Therefore, this paper's objective is to study the durability of printed circuitries on fabric by applying constant cyclic loading. The test vehicle is a printed conductive silver interdigitating circuitry on fabric. Another test vehicle on a polyethylene terephthalate (PET) substrate was fabricated for a benchmark. A constant cyclic loading at 1Hz at a 50% duty cycle was applied to the test vehicles 100,000 times. The printed circuitry was monitored by logging the voltage in an electrical voltage divider configuration while the sensor was pressed and released. The result indicates that the fabric test vehicle can still function after the 100,000 cycles of the cyclic loading test and is comparable to that on the PET substrate. The recorded voltage-to-force values of the printed sensor on the fabric drifted upward and downward up to 3% over the loading cycles. The optical microscope observation on the cyclic loading samples showed signs of shear stresses on the printed silver and electrically conductive films, which could cause the tips of the silver interdigitating fingers to shatter. The study indicates that the properly manufactured circuits on fabric can be reliable and utilized for wearable applications. © 2022 IEEE.

Microfluidic Organ-on-A-chip: A Guide to Biomaterial Choice and Fabrication.

Organ-on-A-chip (OoAC) devices are miniaturized, functional, in vitro constructs that aim to recapitulate the in vivo physiology of an organ using different cell types and extracellular matrix, while maintaining the chemical and mechanical properties of the surrounding microenvironments. From an end-point perspective, the success of a microfluidic OoAC relies mainly on the type of biomaterial and the fabrication strategy employed. Certain biomaterials, such as PDMS (polydimethylsiloxane), are preferred over others due to their ease of fabrication and proven success in modelling complex organ systems. However, the inherent nature of human microtissues to respond differently to surrounding stimulations has led to the combination of biomaterials ranging from simple PDMS chips to 3D-printed polymers coated with natural and synthetic materials, including hydrogels. In addition, recent advances in 3D printing and bioprinting techniques have led to the powerful combination of utilizing these materials to develop microfluidic OoAC devices. In this narrative review, we evaluate the different materials used to fabricate microfluidic OoAC devices while outlining their pros and cons in different organ systems. A note on combining the advances made in additive manufacturing (AM) techniques for the microfabrication of these complex systems is also discussed.

Dependence of SARS-CoV-2 (COVID-19) inactivation ability on the crystallinity level of transparent Cu2O thin films

The inactivation ability of SARS-CoV-2 (COVID-19) was examined using two types of transparent Cu2O thin films with different crystallinities on a Na-free glass substrate. The low-crystallinity Cu2O thin film, which was fabricated by irradiating 254 nm ultraviolet (UV)-light with an intensity of 6.72 mW cm(-2) onto a spin-coated precursor film involving Cu2+ complexes at room temperature, exhibited an outstanding COVID-19 inactivation ability to reduce 99.999% of the virus after 1 h of incubation. The X-ray diffraction results of the UV-irradiated thin film indicated a cubic Cu2O lattice with a small crystallite size of 2 +/- 1 nm. Conversely, the high-crystallinity Cu2O thin film with a crystallite size of 16 +/- 3 nm, obtained by heating a spin-coated precursor film containing another Cu2+ complex, showed a negligibly low inactivation activity at the same level as the Na-free glass substrate. The eluted concentrations of Cu ions from both Cu2O thin films were analyzed after immersion in Dulbecco's modified Eagle's medium (DMEM) for 0.25-2 h. The eluted Cu-ion concentration of 1.16 ppm was observed for the UV-irradiated thin film by DMEM immersion after 1 h, but that of 0.04 ppm was observed for the heat-treated thin film. This indicated that an important factor of virus inactivation on Cu2O thin films is highly related to the elution of Cu ions that occurred from the surface in the medium.

A Comprehensive Overview of Additive Manufacturing Processes Through a Time-Based Classification Model

The ongoing crisis caused by the COVID-19 pandemic produced major reshuffles on the world map, bringing imbalance, uncertainty, and accumulated stress. Due to supply chain disruptions, the need for innovation has emerged both as a priority and a necessity and three-dimensional printing (3DP) proved to be a primary, smart, effective, and innovative additive manufacturing (AM) method. AM refers to the direct fabrication of complex geometries, using a computer-aided design (CAD) model or a three-dimensional scanner output. This article presents a literature review of AM technologies, chronologically sorted, and proposes a multilevel classification model. The suggested research approach appears a triangular methodology that encompasses the current ISO/ASTM 52900:2021 report. The first objective of this article is to form two double-level classification models of AM processes, depending on the technology and material factors. The second objective is to clarify in which of the proposed categories each AM process is included;and the third one is to investigate if the proposed taxonomy is related to the time spot, in which AM processes were invented. The contribution of this article lies in determining the factors that are crucial for the growth of AM ecosystem. The novelty of the proposed classification lies in the definition of an optimal option for each industrial application based on the different AM processes, the variety of materials, and the evolution of technology over the years. In this way, investing in AM is more systematic and less risky.

Nickel-Ion Activating Discarded COVID-19 Medical Surgical Masks for Forming Carbon-Nickel Composite Nanowires and Using as a High-Performance Lithium Battery Anode

With the prevalence of COVID-19, wearing medical surgical masks has become a requisite measure to protect against the invasion of the virus. Therefore, a huge amount of discarded medical surgical masks will be produced, which will become a potential hazard to pollute the environment and endanger the health of organisms without our awareness. Herein, a green and cost-effective way for the reasonable disposal of waste masks becomes necessary. In this work, we realized the transformation from waste medical surgical masks into high-quality carbon-nickel composite nanowires, which not only benefit the protection of the environment and ecosystem but also contribute to the realization of economic value. The obtained composite carbon-based materials demonstrate 70 S m-1 conductivity, 5.2 nm average pore diameters, 234 m2 g-1 surface areas, and proper graphitization degree. As an anode material for lithium-ion batteries, the prepared carbon composite materials demonstrate a specific capacity of 420 mA h g-1 after 800 cycles at a current density of 0.2 A g-1. It also displays good rate performance and decent cycling stability. Therefore, this study provides an approach to converting the discarded medical surgical masks into high-quality carbon nanowire anode materials to turn waste into treasure.

Additive manufacturing for biomedical applications: a review on classification, energy consumption, and its appreciable role since COVID-19 pandemic

The exponential rise of healthcare problems like human aging and road traffic accidents have developed an intrinsic challenge to biomedical sectors concerning the arrangement of patient-specific biomedical products. The additively manufactured implants and scaffolds have captured global attention over the last two decades concerning their printing quality and ease of manufacturing. However, the inherent challenges associated with additive manufacturing (AM) technologies, namely process selection, level of complexity, printing speed, resolution, biomaterial choice, and consumed energy, still pose several limitations on their use. Recently, the whole world has faced severe supply chain disruptions of personal protective equipment and basic medical facilities due to a respiratory disease known as the coronavirus (COVID-19). In this regard, local and global AM manufacturers have printed biomedical products to level the supply-demand equation. The potential of AM technologies for biomedical applications before, during, and post-COVID-19 pandemic alongwith its relation to the industry 4.0 (I4.0) concept is discussed herein. Moreover, additive manufacturing technologies are studied in this work concerning their working principle, classification, materials, processing variables, output responses, merits, challenges, and biomedical applications. Different factors affecting the sustainable performance in AM for biomedical applications are discussed with more focus on the comparative examination of consumed energy to determine which process is more sustainable. The recent advancements in the field like 4D printing and 5D printing are useful for the successful implementation of I4.0 to combat any future pandemic scenario. The potential of hybrid printing, multi-materials printing, and printing with smart materials, has been identified as hot research areas to produce scaffolds and implants in regenerative medicine, tissue engineering, and orthopedic implants.

Low-Cost Remote Laboratory for Robotics Undergraduate Learning during Covid Context

The article proposes to develop, and implement a low-cost, open-source robotics' remote laboratory, to improve online, and hybrid STE learning experience facing COVID-19 context. Electronic modules were developed using digital fabrication, and a Raspberry Pi 4 as a core. Enabling students to connect by a remote access via a VNC port, and control robot elements to complement theoretical content controlling sensors, and actuators using Python scripts. The project was implemented in two iterations, fitting data security, and network accessibility requirements. Those features, in comparison to other state-of-the-art proposals developed outside of South America, highlight our proposal as a low-cost, and open-source alternative suitable to replicate in different resource-constraints context, and to other advanced STE courses. © 2022 IEEE.

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.