Search Results (183)

A novel long-lasting luminescent composite material based on the (Ca,Sr)-Al-O system was synthesized using a solution combustion method. (Ca,Sr)₃Al₂O₆ is the primary phase, with SrAl₂O₄ as a controllable secondary phase. Compared to conventional single-phase SrAl₂O₄ phosphors, the introduction of a calcium-rich hexaaluminate matrix creates additional defects and a specific trap distribution at the composite interface, significantly improving carrier storage and release efficiency. Eu²⁺ + Nd³⁺ synergistic doping enables precise control of the trap depth and number. Under 365 nm excitation, Eu²⁺ emission is located at ~515 nm, with Nd³⁺ acting as an effective trap center. Under optimal firing conditions at 700 °C (Eu²⁺ = 0.02, Nd³⁺ = 0.003), the afterglow lifetime exceeds 30 s. Furthermore, The (Ca,Sr)₃Al₂O₆ host stabilizes the lattice and optimizes defect states, while synergizing with the SrAl₂O₄ secondary phase to improve the afterglow performance. This composite phosphor exhibits excellent dual-mode anti-counterfeiting properties: long-lasting green emission under 365 nm excitation and transient blue-violet emission under 254 nm excitation. Based on this, a screen-printing ink was prepared using the phosphor and ethanol + PVB, enabling high-resolution QR code printing. Pattern recognition and code verification can be performed both in the UV on and off states, demonstrating its great potential in high-security anti-counterfeiting applications. Compared to traditional single-phase SrAl₂O₄ systems, this study for the first time constructed a composite trap engineering of the (Ca,Sr)₃Al₂O₆ primary phase and the SrAl₂O₄ secondary phase, achieving the integration of dual-mode anti-counterfeiting functionality with a high-resolution QR code fluorescent ink. Full article

A rapid screening method to identify suitable candidate inks for printed electronics applications is necessary. Herein, we investigate the in-plane thermoelectric properties of PEDOT:PSS for energy harvesting applications on human skin using silver nanoparticle inkjet-printed test structures. The in-plane electrical and thermal conductivity are measured. The Seebeck coefficient, ZT figure of merit, and power factor are consequently determined. PEDOT:PSS films resulted in low-efficiency thermoelectric properties at 293 K to 313 K and demonstrated a correlation between film thickness and in-plane thermoelectric properties. This study demonstrates that the test structures enable generalisable characterisation of thin-film inkjet-printable materials for thermoelectric purposes. Full article

Myocardial infarction (MI) remains one of the most common cardiovascular diseases and a leading cause of morbidity and mortality worldwide. In recent years, natural polymeric patches have attracted increasing attention as a promising therapeutic platform for myocardial tissue repair. This study explored the fabrication and evaluation of screen-printed electrodes (SPEs) on chitosan film as a novel platform for cardiac patch applications. Chitosan is a biodegradable and biocompatible natural polymer that provides an ideal substrate for SPEs, providing mechanical stability and promoting cell adhesion. Silver ink was employed to enhance electrochemical performance, and the electrodes exhibited strong adhesion and structural integrity under wet conditions. Mechanical testing and swelling ratio analysis were conducted to assess the patch’s physical robustness and aqueous stability. Silver ink was employed to enhance electrochemical performance, which was evaluated using cyclic voltammetry. In vitro, electrical stimulation through the chitosan–SPE patch significantly increased the expression of cardiac-specific genes (GATA-4, β-MHC, troponin I) in bone marrow mesenchymal stem cells (BMSCs), indicating early cardiogenic differentiation potential. In vivo, the implantation of the chitosan–SPE patch in a rat MI model demonstrated good tissue integration, preserved myocardial structure, and enhanced ventricular wall thickness, indicating that the patch has the potential to serve as a functional cardiac scaffold. These findings support the feasibility of screen-printed electrodes fabricated on chitosan film substrates as a cost-effective and scalable platform for cardiac repair, offering a foundation for future applications in cardiac tissue engineering. Full article

In the Internet of Things (IoT) era, the demand for cost-effective, flexible, wearable antennas and circuits has been growing. Accordingly, screen-printing techniques are becoming more popular due to their lower costs and high-volume manufacturing. This paper presents and investigates a full-screen-printed 1 × 4 Quasi-Yagi-Uda antenna array on a high-transparency flexible Zeonor thin-film substrate for emerging 26 GHz band (24.25–27.55 GHz) 5G applications. As part of this study, screen-printing implementation rules are developed by properly managing ink layer thickness on a transparent flexible Zeonor thin-film dielectric to achieve a decent antenna array performance. In addition, a screen-printing repeatability study has been carried out through a performance comparison of 24 antenna array samples manufactured by our research partner from CEA-Liten Grenoble. Despite the challenging antenna array screen printing at higher frequencies, the measured results show a good antenna performance as anticipated from the traditional subtractive printed circuit board (PCB) manufacturing process using standard substrates. It shows a wide-band matched input impedance from 22–28 GHz (i.e., 23% of relative band-width) and a maximum realized gain of 12.8 dB at 27 GHz. Full article

Textile-based wearable devices are rapidly gaining traction in the Internet of Things paradigm and offer distinct advantages for data collection and analysis across a wide variety of applications. Seamlessly integrating electronics in textiles remains a technical challenge, especially when the textiles’ essential properties, such as comfort, breathability, and flexibility, are meant to be preserved. This article investigates screen printing as a textile post-processing technique for electronic integration, and highlights its versatility, cost-effectiveness, and adaptability in terms of design and customization. The study examines two silver-based inks screen-printed on an Oxford polyester textile substrate with a focus on substrate preparation and treatment. Before printing, the textile samples were cleaned with nitrogen gas and then subjected to low-pressure oxygen plasma treatment. For comparative analysis, two samples printed on polyethylene terephthalate (PET) serve as a reference. The findings highlight the importance of plasma treatment in optimizing the printability of textiles and demonstrate that it notably improves the electrical properties of conductive inks. Despite some remaining challenges, the study indicates that screen-printed electronics show promising potential for advancing the development of e-textiles and sensor-integrated wearables. Full article

An electrochemical aptasensor was developed for the rapid and sensitive detection of ciprofloxacin (CPX) in milk samples. The device was fabricated on a polyethylene terephthalate (PET) substrate using a screen-printing technique with carbon-based conductive ink. Gold nanoparticles (AuNPs) were incorporated to enhance aptamer immobilization and facilitate electron transfer at the electrode surface. The sensor’s analytical performance was optimized by adjusting key parameters, including AuNP volume, DNA aptamer concentration, and incubation times for both the aptamer and the blocking agent (6-mercapto-1-hexanol, MCH). Differential pulse voltammetry (DPV) measurements demonstrated a linear response ranging from 10 to 50 nmol L⁻¹ and a low detection limit of 3.0 nmol L⁻¹. When applied to real milk samples, the method achieved high recovery rates (101.4–106.7%) with a relative standard deviation below 3.1%, confirming its robustness. This disposable and cost-effective aptasensor represents a promising tool for food safety monitoring, with potential for adaptation to detect other pharmaceutical residues in dairy products. Full article

This paper presents a comparative analysis of performance for several antenna prototypes using a screen-printing process. This analysis was performed using various bow-tie antenna configurations, including single-band and multi-band antennas with linear or circular polarization over multiple operating frequency ranges. For antenna implementations, three different conductive inks and two resolutions of screen masks were tested. The performance of the fabricated prototypes has then been compared to the copper laser-etched antennas. This study revealed that with the proper selection of ink thinness, screen-printed bow-tie antennas achieve similar performances to copper laser-etched bow-tie antennas up to 6 GHz, even for linearly polarized and circularly polarized antennas. However, the printing resolution should be improved by reducing the ink thickness for bow-tie antennas at higher operating frequencies. The measurement results show a successful agreement after improving the printing resolution of the fabricated 5.8 GHz and 15 GHz bi-band bow-tie antennas. Full article

Background/Objectives: Effective drug delivery systems require precise formulation and understanding of excipient impact on active pharmaceutical ingredient (API) stability and efficacy, as uncontrolled interactions can compromise outcomes. This study developed and validated a semi-solid extrusion (SSE) 3D printing method for polyvinyl alcohol (PVA)-based hydrogel disks with metronidazole (MET). These disks served as a standardized platform to assess excipient influence on MET’s antimicrobial activity, focusing on plasticizers (polyethylene glycol 400, glycerol, propylene glycol, and diethylene glycol monoethyl ether)—excipients that modify hydrogel properties for their application in printing dressing matrices—with the platform’s capabilities demonstrated using in vitro antimicrobial susceptibility testing against Bacteroides fragilis. Methods: Hydrogel inks based on PVA with added plasticizers and MET were prepared. These inks were used to 3D-print standardized disks. The MET content in the disks was precisely determined. The antimicrobial activity of all formulation variants was evaluated using the disk diffusion method against B. fragilis. Results: The incorporated plasticizers did not negatively affect the antimicrobial efficacy of MET against B. fragilis. All printed hydrogel matrices exhibited clear antimicrobial activity. The 3D-printed disks showed high repeatability and precision regarding MET content. Conclusions: SSE 3D printing is viable for manufacturing precise, reproducible MET-loaded PVA hydrogel disks. It provides a standardized platform to evaluate diverse excipient impacts, like plasticizers, on API antimicrobial performance. The tested plasticizers were compatible with MET. This platform aids rational formulation design and screening for optimal excipients in designed formulations and for various pharmaceutical applications. Full article

Printed electronics employ established printing methods to create low-cost, mechanically flexible devices including batteries, supercapacitors, sensors, antennas and RFID tags on plastic, paper and textile substrates. This review focuses on the specific contribution of screen printing to that landscape, examining how ink viscosity, mesh selection and squeegee dynamics govern film uniformity, pattern resolution and ultimately device performance. Recent progress in advanced ink systems is surveyed, highlighting carbon allotropes (graphene, carbon nano-onions, carbon nanotubes, graphite), silver and copper nanostructures, MXene and functional oxides that collectively enhance mechanical robustness, electrical conductivity and radio-frequency behavior. Parallel improvements in substrate engineering such as polyimide, PET, TPU, cellulose and elastomers demonstrate the technique’s capacity to accommodate complex geometries for wearable, medical and industrial applications while supporting environmentally responsible material choices such as water-borne binders and bio-based solvents. By mapping two decades of developments across energy-storage layers and functional electronics, the article identifies the key process elements, recurring challenges and emerging sustainable practices that will guide future optimization of screen-printing materials and protocols for high-performance, customizable and eco-friendly flexible devices. Full article

This study aimed to evaluate the degree of contamination of water matrices (deionised water, spring water, tap water) in a 14-week experiment using film samples from commercial bags printed with water- and solvent-based inks. The effect of different lighting conditions on leaching and ecotoxicity was also investigated. Samples were exposed for 24 h to natural sunlight and to no light in a darkroom. A significant increase in contaminants in the aqueous matrices was observed in regard to the 12-week leaching potential of the components from the films in regard to all the lighting variants and aqueous matrices analysed: an increase in dissolved organic carbon (DOC), total organic carbon (TOC), and total suspended solids (TSS). Based on the procedures carried out, the relationship between the lighting conditions and the amount of the constituents released into the aqueous matrices was not confirmed. The concentration of total organic carbon in all the samples peaked between weeks 6 and 9 of the study, followed by a gradual reduction in leaching. This phenomenon could be linked to the gradual depletion of the substances present in the samples or to the achievement of a concentration equilibrium between the aqueous matrix and the sample and/or to the formation of deposits on the surface of the films, which hindered the migration of the substances into the solutions. Ecotoxicity tests performed between 7 and 14 weeks showed most samples’ toxic and highly toxic effects on the growth of Lemna minor fronds and Sinapis alba/Lepidium sativum roots. In contrast, no toxic effects were observed in regard to most of the samples during screening mortality tests on Daphnia magna and Artemia salina. This study highlights the need for further research into the effects of plastic pollution on the aquatic environment. Full article

This research explores the development of highly durable flexible electronic textiles (e-textiles) for wearable electronics, focusing on improving their washability and performance. A conductive graphene-based ink was screen-printed onto a polyester textile. Water-based polyurethane (PU) coatings with variable crosslinker ratios and thickener were applied to solve washability issues. The results show that the PU coatings significantly enhanced the electrical stability and durability of the printed pathways after multiple washing cycles. The conductivity remained intact after 120 washing cycles, indicating that the final properties of the e-textile, which contained 6 wt% thickener and 3 wt% crosslinker, provided effective water protection. The results highlight the promise of these coated e-textiles for wearable electronics applications, especially in the occupational and healthcare sectors, where long-term flexibility and washability are critical. Full article

The circular economy, in which recycling plays a significant role, is increasingly becoming a primary requirement for packaging. Our research focused on the recycling of intelligent cardboard packaging. The focus of the study was to manufacture and recycle cardboard embedded with a printed RFID antenna and a thermochromic indicator and to evaluate their recyclability. The Confederation of European Paper Industries (CEPI) method was employed to assess the recyclability of cardboard printed using digital printing techniques with integrated intelligent elements. The coarse reject and concentration following coarse screening were determined, and laboratory hand sheets were made for the adhesiveness test and visual evaluation. The fine screening procedure was performed. The acquired samples were evaluated for basic, mechanical, and optical properties. The analysis indicated that the recyclability of all examined materials was exceptionally good, confirming their suitability for normal recycling processes. Furthermore, the recycling efficiency exceeds 99% for all samples. Despite the variances in the samples, including metallic functional and thermochromic ink, they did not significantly impact the final outcome. Moreover, little variations in recyclability were seen between intelligent elements printed directly on cardboard and those printed on self-adhesive labels applied to the cardboard. The research has confirmed that the printed RFID antenna and thermochromic indicator have a negligible impact on the recyclability process and final score. Full article

This study investigates the interaction between thermochromic liquid crystal (TLC) inks and bacterial nanocellulose (BNC), emphasizing their compatibility for smart packaging applications. While the chiral nematic structure of TLC pigments dictates their dynamic colour changing behaviour, this research focuses on how TLC inks interact with BNC, a biodegradable and eco-friendly substrate. This study examines material compatibility, colorimetric properties, and the influence of substrate characteristics on the thermally induced colour transitions of TLC inks. Screen printing was employed to deposit TLC inks onto BNC-based films and black uncoated paper, followed by spectrometric analysis to evaluate the temperature-dependent colour response. The results indicate that BNC serves as a promising platform for TLC ink integration, enhancing its potential for intelligent packaging and indicator systems. These findings contribute to the advancement of sustainable, responsive materials for next-generation smart packaging solutions. Full article

In recent years, the improvement in living standards and the corresponding increase in quality-of-life expectations have significantly increased the demand for advanced electronic products. This trend has generated great interest in human health monitoring and extensive research efforts. Flexible sensors in particular are being given preference because of their high extensibility, excellent biocompatibility properties, low weight, and low cost. In the present work, we took this idea further and designed flexible sensors using different substrates such as thermoplastic polyurethane (TPU), polyimide (PI), and polyethylene terephthalate (PET), fabricating them with silver paste ink using screen-printing technology. A uniform and homogeneous conductive layer was formed, which was identified through Scanning Electron Microscopy (SEM) analysis. Additionally, the width of the printed silver paste ink was approximately 100 µm. This study contributes to the design and fabrication of a new generation of flexible sensors for health monitoring. The results demonstrate that these sensors are technically possible as part of long-term wearable health-monitoring solutions for wearable health care technologies. Full article

The development of screen-printed electrochemical sensors represents a rapidly expanding research field with great potential for applications in the rapid and sensitive determination of drugs in complex matrices. This work presents a review of the state-of-the-art examples of this technology, focusing on its application in real matrices such as water, pharmaceutical formulations, and biological fluids. We discuss the main materials used in developing conductive inks, highlighting their properties and influence on sensor performance. The characterization of materials and sensors is crucial to ensure the reproducibility and reliability of results. Additionally, we address the challenges associated with the application of these sensors in complex matrices, such as interferences from other components and the need for sample pretreatment. Finally, we present future perspectives for developing screen-printed electrochemical sensors, with an emphasis on new technologies and materials that can improve the sensitivity, selectivity, and stability of these devices. Full article