Review Articles MORE

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  Advances in microneedle electrodes for electromyography acquisition in sports rehabilitation

  Abstract Full Text PDF Electromyography (EMG) is widely used in sports rehabilitation to evaluate muscle activation, coordination, fatigue, and functional recovery, yet reliable recording remains limited by the electrode-skin interface during repeated motion and prolonged wear. Microneedle electrodes offer a distinct interface strategy by penetrating the stratum corneum and forming lower-impedance, more stable electrical contact than conventional wet or dry electrodes. This review discusses microneedle electrodes for EMG acquisition in sports rehabilitation from a design-to-application perspective. We first clarify the interface requirements of EMG recording in rehabilitation settings and the technical rationale for using microneedle interfaces. We then summarize material and structural design strategies in silicon-, polymer-, and metal-based systems, focusing on how they balance penetration capability, mechanical compliance, stretchability, conductivity, and recording stability. Fabrication routes are further examined in terms of material-structure-process coupling, followed by applications in static assessment, dynamic motion monitoring, and clinical rehabilitation evaluation. This review integrates interface requirements, design, manufacturing, and validation to provide a structured overview of microneedle EMG electrodes' capabilities and limitations for sports rehabilitation.

  Electromyography (EMG) is widely used in sports rehabilitation to evaluate muscle activation, coordination, fatigue, and functional recovery, yet reliable recording remains limited by the electrode-skin interface during repeated motion and prolonged wear. Microneedle electrodes offer a distinct interface strategy by penetrating the stratum corneum and forming lower-impedance, more stable electrical contact than conventional wet or dry electrodes. This review discusses microneedle electrodes for EMG acquisition in sports rehabilitation from a design-to-application perspective. We first clarify the interface requirements of EMG recording in rehabilitation settings and the technical rationale for using microneedle interfaces. We then summarize material and structural design strategies in silicon-, polymer-, and metal-based systems, focusing on how they balance penetration capability, mechanical compliance, stretchability, conductivity, and recording stability. Fabrication routes are further examined in terms of material-structure-process coupling, followed by applications in static assessment, dynamic motion monitoring, and clinical rehabilitation evaluation. This review integrates interface requirements, design, manufacturing, and validation to provide a structured overview of microneedle EMG electrodes' capabilities and limitations for sports rehabilitation.
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  Organic electrochemical transistor-based theranostics: materials, mechanisms, and system integration

  Abstract Full Text PDF Organic electrochemical transistors (OECTs), leveraged by their unique volumetric doping mechanism and ultra-high transconductance performance, have emerged as a pivotal device platform for constructing high-performance bioelectronic interfaces. OECT-based theranostics aim to develop intelligent closed-loop systems that integrate sensing, decision-making, and execution, thereby overcoming the latency and discretization limitations of traditional medical models when managing dynamic physiological fluctuations. This article systematically reviews the performance evolution of OECT materials from p-type to n-type, discusses critical strategies for enhancing device stability and transconductance density, such as side-chain engineering and ladder-type molecular design, while emphasizing the essential role of complementary logic circuits in minimizing the static power consumption of implantable electronics. Furthermore, breakthroughs in OECT-based neuromorphic computing are addressed; by simulating synaptic plasticity (STP/LTP) and engineering organic electrochemical neurons (OECNs), a highly efficient sensing-computing closed-loop architecture has been realized. The current application landscape of OECTs in electrophysiological monitoring, neurochemical sensing, and multimodal synergistic sensing is detailed, alongside a summary of high-density array fabrication and system integration strategies, including 3D printing, inkjet printing, and 3D hydrogel integration. Finally, future outlooks are provided, focusing on challenges such as the environmental stability of n-type materials, multimodal signal crosstalk, and long-term clinical reliability.

  Organic electrochemical transistors (OECTs), leveraged by their unique volumetric doping mechanism and ultra-high transconductance performance, have emerged as a pivotal device platform for constructing high-performance bioelectronic interfaces. OECT-based theranostics aim to develop intelligent closed-loop systems that integrate sensing, decision-making, and execution, thereby overcoming the latency and discretization limitations of traditional medical models when managing dynamic physiological fluctuations. This article systematically reviews the performance evolution of OECT materials from p-type to n-type, discusses critical strategies for enhancing device stability and transconductance density, such as side-chain engineering and ladder-type molecular design, while emphasizing the essential role of complementary logic circuits in minimizing the static power consumption of implantable electronics. Furthermore, breakthroughs in OECT-based neuromorphic computing are addressed; by simulating synaptic plasticity (STP/LTP) and engineering organic electrochemical neurons (OECNs), a highly efficient sensing-computing closed-loop architecture has been realized. The current application landscape of OECTs in electrophysiological monitoring, neurochemical sensing, and multimodal synergistic sensing is detailed, alongside a summary of high-density array fabrication and system integration strategies, including 3D printing, inkjet printing, and 3D hydrogel integration. Finally, future outlooks are provided, focusing on challenges such as the environmental stability of n-type materials, multimodal signal crosstalk, and long-term clinical reliability.
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  Challenges, development and future of silica abrasives in chemical mechanical polishing derived from past six decades

  Abstract Full Text PDF Chemical mechanical polishing (CMP) serves as an indispensable process for achieving global planarization in semiconductor manufacturing, especially as integrated circuit (IC) technology advances to sub-7 nm nodes, where atomic-level surface flatness becomes crucial. Silica abrasives, which account for over 90% of the abrasive market in advanced CMP processes, operate not through simple mechanical grinding but through a key "chemical-mechanical synergistic" mechanism: chemically softening the wafer surface, then mechanically removing the softened layer to expose a new surface, which is further softened and removed, repeating this cycle to produce a smooth wafer. Despite their prevalence, conventional silica abrasives still face challenges, including relatively low material removal rate (MRR), a tendency to agglomerate, leading to poor dispersion and surface defects, and limitations in achieving ultimate surface uniformity. Significant progress has been made to address these issues. Development has progressed from simple spherical particles to complex structural designs (such as mesoporous, hollow, and raspberry-shaped structures) to enhance slurry transport and mechanical action. Surface chemical modifications (e.g., using amino or polymer groups) can improve dispersion stability and reduce scratching. Furthermore, composites with other materials (e.g., ceria, polymers) and precise control of particle size distribution are key to enhancing performance. These innovative approaches have yielded significant performance gains. State-of-the-art slurries have demonstrated the ability to achieve surface roughness below 0.1 nm RMS. The development of silica abrasives is increasingly focused on sustainability and smart manufacturing. A prominent direction is the design of biodegradable abrasives that disintegrate after use, thereby simplifying post-chemical mechanical polishing (CMP) cleanup and minimizing environmental impact—an approach fully aligned with green manufacturing principles. This review systematically summarizes the progress of silica abrasives for CMP over the past 60 years. This summary provides theoretical insights and forward-looking strategies to overcome the current limitations of abrasive technology. We believe this review will be helpful in advancing the field of CMP abrasives towards next-generation semiconductor manufacturing.

  Chemical mechanical polishing (CMP) serves as an indispensable process for achieving global planarization in semiconductor manufacturing, especially as integrated circuit (IC) technology advances to sub-7 nm nodes, where atomic-level surface flatness becomes crucial. Silica abrasives, which account for over 90% of the abrasive market in advanced CMP processes, operate not through simple mechanical grinding but through a key "chemical-mechanical synergistic" mechanism: chemically softening the wafer surface, then mechanically removing the softened layer to expose a new surface, which is further softened and removed, repeating this cycle to produce a smooth wafer. Despite their prevalence, conventional silica abrasives still face challenges, including relatively low material removal rate (MRR), a tendency to agglomerate, leading to poor dispersion and surface defects, and limitations in achieving ultimate surface uniformity. Significant progress has been made to address these issues. Development has progressed from simple spherical particles to complex structural designs (such as mesoporous, hollow, and raspberry-shaped structures) to enhance slurry transport and mechanical action. Surface chemical modifications (e.g., using amino or polymer groups) can improve dispersion stability and reduce scratching. Furthermore, composites with other materials (e.g., ceria, polymers) and precise control of particle size distribution are key to enhancing performance. These innovative approaches have yielded significant performance gains. State-of-the-art slurries have demonstrated the ability to achieve surface roughness below 0.1 nm RMS. The development of silica abrasives is increasingly focused on sustainability and smart manufacturing. A prominent direction is the design of biodegradable abrasives that disintegrate after use, thereby simplifying post-chemical mechanical polishing (CMP) cleanup and minimizing environmental impact—an approach fully aligned with green manufacturing principles. This review systematically summarizes the progress of silica abrasives for CMP over the past 60 years. This summary provides theoretical insights and forward-looking strategies to overcome the current limitations of abrasive technology. We believe this review will be helpful in advancing the field of CMP abrasives towards next-generation semiconductor manufacturing.
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  Electrohydrodynamic inkjet printing of perovskite quantum dots for color-conversion micro-LED displays

  Abstract Full Text PDF Electrohydrodynamic (EHD) inkjet printing has emerged as a powerful micro-/nanofabrication technique for high-resolution perovskite quantum dot (PeQD) color-conversion layers, offering precise control over pixel morphology, dimensions, and composition. This review systematically examines the mechanisms of cone-jet and electrostatic-attraction modes in EHD printing, highlighting recent advances in PeQD ink design, solvent and ligand engineering, and printing parameter optimization. Perovskite precursor and colloidal inks are discussed in detail, emphasizing strategies to enhance droplet ejection stability, suppress coffee-ring effects, and achieve uniform, high-luminescence pixels. Ligand exchange, dual-ligand passivation, and core−shell or polymer encapsulation are shown to effectively mitigate ion migration, surface defects, and environmental degradation, thereby improving photoluminescence efficiency and stability. Multi-channel and multi-nozzle EHD printing systems enable dynamic halide composition control and parallel RGB pixel deposition, facilitating ultrahigh-resolution patterning down to submicron feature sizes. Finally, the review highlights future directions, including synergistic PeQD material synthesis, advanced ink formulation, scalable high-throughput printing, and integration of PeQD color-conversion pixels into full-color micro-LED displays with minimal crosstalk and robust operational stability. These developments collectively demonstrate the immense potential of EHD inkjet printing for next-generation high-performance display technologies.

  Electrohydrodynamic (EHD) inkjet printing has emerged as a powerful micro-/nanofabrication technique for high-resolution perovskite quantum dot (PeQD) color-conversion layers, offering precise control over pixel morphology, dimensions, and composition. This review systematically examines the mechanisms of cone-jet and electrostatic-attraction modes in EHD printing, highlighting recent advances in PeQD ink design, solvent and ligand engineering, and printing parameter optimization. Perovskite precursor and colloidal inks are discussed in detail, emphasizing strategies to enhance droplet ejection stability, suppress coffee-ring effects, and achieve uniform, high-luminescence pixels. Ligand exchange, dual-ligand passivation, and core−shell or polymer encapsulation are shown to effectively mitigate ion migration, surface defects, and environmental degradation, thereby improving photoluminescence efficiency and stability. Multi-channel and multi-nozzle EHD printing systems enable dynamic halide composition control and parallel RGB pixel deposition, facilitating ultrahigh-resolution patterning down to submicron feature sizes. Finally, the review highlights future directions, including synergistic PeQD material synthesis, advanced ink formulation, scalable high-throughput printing, and integration of PeQD color-conversion pixels into full-color micro-LED displays with minimal crosstalk and robust operational stability. These developments collectively demonstrate the immense potential of EHD inkjet printing for next-generation high-performance display technologies.