Additive abuse in fishery, such as tricaine methanesulfonate (MS222), ciprofloxacin (CPFX), and malachite green (MG), threatens public human health and interferes with the ecological equilibrium of water resources. However, the majority of the present detection methods suffer from high costs, complex operations, and poor portability. Therefore, real-time and rapid detection of the above additive by mobile devices is becoming increasingly important. Here we report the fabrication and performance of an entirely electrochemical system with USB-stick size for simultaneous detection of MS222, CPFX, and MG, as well as pH and permittivity. The limits of detections are 0.17, 0.67, and 0.28 µg/mL, while the resolution ratios are 10 %, 10 %, and 5 % for MS222, MG, and CPFX, respectively. For both pH and permittivity, they have linear regressions measured by brightness and capacitance of the sample respectively, at the range of 1.5-9 (pH) and 10-20 (permittivity). The interference experiments, using target analytes (40 μg/mL) and 15 interfering analytes (80 μg/mL), demonstrated the anti-interference performance of the sensor patches. The field studies on carps, catfishes, and chubs indicated that the developed integrated portable system could be used for real sample analysis with high performance.

A perfluoropolyether (PFPE)-based microfluidic device with cross-junction microchannels was fabricated with the purpose of producing uniform droplets. The microchannels were developed using CO2 laser engraving. PFPE was chosen as the main material because of its excellent solvent resistance. Polyethylene glycol diacrylate (PEGDA) was mixed with PFPE to improve the hydrophilic properties of the inner surface of the microchannels. The microchannels of the polydimethylsiloxane microfluidic device had a blackened and rough surface after laser engraving. By contrast, the inner surface of the microchannels of the PFPE-PEGDA microfluidic device exhibited a smooth surface. The lower power and faster speed of the laser engraving resulted in the development of microchannels with smaller dimensions, less than 30 μm in depth. The PFPE and PFPE-PEGDA microfluidic devices were used to produce uniform water and oil droplets, respectively. We believe that such a PFPE-based microfluidic device with CO2-laser-engraved microchannels can be used as a microfluidic platform for applications in various fields, such as biological and chemical analysis, extraction, and synthesis.

UNASSIGNED: Polyetheretherketone (PEEK) is a highly sought-after thermoplastic due to its exceptional mechanical properties and biocompatibility. However, bonding PEEK to indirect composite resin (ICR) or denture-based resin (DBR) can be challenging. Laser engraving technology has shown potential to improve bonding for other materials; thus, this study aims to evaluate its effectiveness for PEEK.
UNASSIGNED: The experiment involved preparing ingot-shaped PEEK samples, which were then categorized into four groups based on the treatment method employed: without treatment, air abrasion, sulfuric acid etching, and laser engraving (LS). Subsequently, the samples were bonded to ICR or DBR, and their shear bond strength (SBS) was tested with or without thermocycling using a universal testing machine. Furthermore, the failure mode was observed, with statistical analyses conducted to compare the results.
UNASSIGNED: The grid-like microslit structure of LS group displayed the highest SBS for bonding PEEK to ICR or DBR (P < 0.05). During the bonding of PEEK to ICR, resin residue and penetration into the microslits were frequently observed in the LS group, indicating cohesive failure. However, when PEEK was bonded to DBR, mixture failure was frequently observed without thermocycling. After thermocycling, only the LS group showed cohesive failure, while the majority of specimens exhibited mixture failure.
UNASSIGNED: Laser engraving significantly improves the SBS between PEEK and both ICR and DBR. Furthermore, it was observed that resin had penetrated the microslits, indicating that laser engraving has great potential as a surface treatment method.

Hybrid metal matrix composites (HMMCs) are a special type of material, possessing combined properties that belong to alloys and metals according to market demands. Therefore, they are used in different areas of industry and the properties of this type of material are useful in engineering applications, e.g., in aircraft engines and electrotechnical parts. The structure of the material requires a number of scientific studies to develop an appropriate processing technology. The paper presents the susceptibility of material from the HMMCs group with the EN AC-44300 (AISi12(Fe)) aluminum alloy matrix with a two-component reinforcement made of alumina particles (AP) and aluminosilicate fibers (AF) to thermal treatment with a laser beam. During this process, laser engraving of the researched material with variable beam power Pav and variable speed of the laser head vl were carried out. A metallographic analysis of the material was carried out. After laser engraving, surface structural changes of the material were determined. The properties of the surface geometric structure of processed material were also examined. Presented studies concern laser engraving on the surface of composite from the HMMC group, which was made by vacuum infiltration. Thanks to this method, it is possible both to produce shaped and precise composite castings with saturated reinforcement and to consequently minimize machining losses. Metal-ceramic composites from the HMMC group are hard-to-machine materials which create problems during machining. The aim of these studies was to develop a laser engraving technology with Al matrix composite with the addition of Al2O3 particles and aluminosilicate fibers, which constitute the reinforcement. The focus was on the selection of engraving parameters (beam power and speed of movement of the laser head). Clear examples of engraving, suitable for macro-assessment, were obtained with minimal change in the initial surface structure of the composite.

The significant potential of flexible sensors in various fields such as human health, soft robotics, human-machine interaction, and electronic skin has garnered considerable attention. Capacitive pressure sensor is popular given their mechanical flexibility, high sensitivity, and signal stability. Enhancing the performance of capacitive sensors can be achieved through the utilization of gradient structures and high dielectric constant media. This study introduced a novel dielectric layer, employing the BaTiO3-PDMS material with a gradient micro-cones architecture (GMCA). The capacitive sensor was constructed by incorporating a dielectric layer GMCA, which was fabricated using laser engraved acrylic (PMMA) molds and flexible copper-foil/polyimide-tape electrodes. To examine its functionality, the prepared sensor was subjected to a pressure range of 0-50 KPa. Consequently, this sensor exhibited a remarkable sensitivity of up to 1.69 KPa-1 within the pressure range of 0-50 KPa, while maintaining high pressure-resolution across the entire pressure spectrum. Additionally, the pressure sensor demonstrated a rapid response time of 50 ms, low hysteresis of 0.81%, recovery time of 160 ms, and excellent cycling stability over 1000 cycles. The findings indicated that the GMCA pressure sensor, which utilized a gradient structure and BaTiO3-PDMS material, exhibited notable sensitivity and a broad linear pressure range. These results underscore the adaptability and viability of this technology, thereby facilitating enhanced flexibility in pressure sensors and fostering advancements in laser manufacturing and flexible devices for a wider array of potential applications.

In recent years, laser engraving has received widespread attention as a convenient, efficient, and programmable method which has enabled high-quality porous graphene to be obtained from various precursors. Laser engraving is often used to fabricate the dielectric layer with a microstructure for capacitive pressure sensors; however, the usual choice of electrodes remains poorly flexible metal electrodes, which greatly limit the overall flexibility of the sensors. In this work, we propose a flexible capacitive pressure sensor made entirely of thermoplastic polyurethane (TPU) and laser-induced graphene (LIG) derived from wood. The capacitive pressure sensor consisted of a flexible LIG/TPU electrode (LTE), an LIG/TPU electrode with a microhole array, and a dielectric layer of TPU with microcone array molded from a laser-engraved hole array on wood, which provided high sensitivity (0.11 kPa-1), an ultrawide pressure detection range (20 Pa to 1.4 MPa), a fast response (~300 ms), and good stability (>4000 cycles, at 0-35 kPa). We believe that our research makes a significant contribution to the literature, because the easy availability of the materials derived from wood and the overall consistent flexibility meet the requirements of flexible electronic devices.

With the goal of substituting a hard metallic material for the soft Ultra High Molecular Weight Polyethylene (UHMWPE) presently used to make the bases of skis for alpine skiing, we used two non-thermodynamic equilibrium surface treatments with ultra-short (7-8 ps) laser pulses to modify the surface of square plates (50 × 50 mm2) made of austenitic stainless steel AISI 301H. By irradiating with linearly polarized pulses, we obtained Laser Induced Periodic Surface Structures (LIPSS). By laser machining, we produced a laser engraving on the surface. Both treatments produce a surface pattern parallel to one side of the sample. For both treatments, we measured with a dedicated snow tribometer the friction coefficient µ on compacted snow at different temperatures (-10 °C; -5 °C; -3 °C) for a gliding speed range between 1 and 6.1 ms-1. We compared the obtained µ values with those of untreated AISI 301H plates and of stone grinded, waxed UHMWPE plates. At the highest temperature (-3 °C), near the snow melting point, untreated AISI 301H shows the largest µ value (0.09), much higher than that of UHMWPE (0.04). Laser treatments on AISI 301H gave lower µ values approaching UHMWPE. We studied how the surface pattern disposition, with respect to the gliding direction of the sample on snow, affects the µ trend. For LIPSS with pattern, orientation perpendicular to the gliding direction on snow µ (0.05) is comparable with that of UHMWPE. We performed field tests on snow at high temperature (from -0.5 to 0 °C) using full-size skis equipped with bases made of the same materials used for the laboratory tests. We observed a moderate difference in performance between the untreated and the LIPSS treated bases; both performed worse than UHMWPE. Waxing improved the performance of all bases, especially LIPSS treated.

In this work, we developed a facile method to fabricate laser induced versatile graphene-metal nanoparticles (LIG-MNPs) electrodes with redox molecules sensing capabilities. Unlike conventional post-electrodes deposition, versatile graphene-based composites were engraved by a facile synthesis process. As a general protocol, we successfully prepared modular electrodes including LIG-PtNPs and LIG-AuNPs and applied them to electrochemical sensing. This facile laser engraving process enables rapid preparation and modification of electrodes, as well as simple replacement of metal particles modification towards varied sensing targets. The LIG-MNPs showed high sensitivity towards H2O2 and H2S due to their excellent electron transmission efficiency and electrocatalytic activity. By simply changing the types of coated precursors, the LIG-MNPs electrodes have successfully achieved real-time monitoring of H2O2 released from tumor cells and H2S contained in wastewater. This work contributed a universal and versatile protocol for quantitatively detecting a wide range of hazardous redox molecules.

Wearable fabric sensors have attracted enormous attention due to their huge potential in human health and activity monitoring, human-machine interaction and the Internet of Things (IoT). Among natural fabrics, bast fabric has the advantage of high strength, good resilience and excellent permeability. Laser engraving, as a high throughput, patternable and mask-free method, was demonstrated to fabricate fabric sensors. In this work, we developed a simplified, cost-effective and environmentally friendly method for engraving ramie fabric (a kind of bast fabric) directly by laser under an ambient atmosphere to prepare strain and humidity sensors. We used carboxymethylcellulose (CMC) to pretreat ramie fabric before laser engraving and gained laser-carbonized ramie fabrics (LCRF) with high conductivity (65 Ω sq-1) and good permeability. The strain and humidity sensors had high sensitivity and good flexibility, which can be used for human health and activity monitoring.

Textile-based electronics hold great promise because they can endow wearable devices with soft and comfortable characteristics. However, the inherent porosity and fluffiness of fabrics result in high surface roughness, which presents great challenges in the manufacture of high-performance fabric electrodes. In this work, we propose a thermal transfer printing method to address the above challenges, in which electrodes or circuits of silver flake/thermoplastic polyurethane (TPU) composites are prefabricated on a release film by coating and laser engraving and then laminated by hot-pressing to a variety of fabrics and textiles. This universal and scalable production technique enables fabric electrodes to be made without compromising the original wearability, washability, and stretchability of textiles. The prepared fabric electrodes exhibit high conductivity (5.48 × 104 S/cm), high adhesion (≥1750 N/m), good abrasion/washing resistance, high patterning resolution (∼40 μm), and good electromechanical performance up to 50% strain. To demonstrate the potential applications, we developed textile-based radio frequency identification (RFID) tags for remote identification and a large-sized heater for wearable thermotherapy. More importantly, the solvent-free thermal transfer printing technology developed in this paper enables people to DIY interesting flexible electronics on clothes with daily tools, which can promote the commercial application of smart textile-based electronics.