{"title":"Biocompatible design of bioresorbable electronics and materials.","authors":"Minki Hong, Gilmo Kim, Seunghun Han, Jahyun Koo","doi":"10.1007/s13534-026-00576-x","DOIUrl":"https://doi.org/10.1007/s13534-026-00576-x","url":null,"abstract":"<p><p>Biocompatibility is the defining determinant for the clinical translation of implantable biomedical devices. As bioelectronics evolve toward softer, electroactive, and bioresorbable systems, traditional definitions of biocompatibility-largely focused on cytotoxicity and gross inflammation-are no longer sufficient. Instead, emerging bioresorbable devices demand <i>multidimensional biocompatibility</i>, encompassing immune modulation, mechanical and electrical matching, controlled degradation, and functional stability over clinically relevant time windows. This review offers a biocompatibility-focused overview of recent advances in bioresorbable materials and electronics, known as transient devices. Emphasis is placed on how material selection, device architecture, and degradation pathways jointly govern immune responses and tissue integration. A comparative framework is introduced to relate material classes to immune outcomes and degradation behaviors, and current biocompatibility evaluation metrics and international standards (ISO 10993) are critically discussed. Finally, we propose design guidelines and future research directions to accelerate the translation of next-generation bioresorbable electronics.</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 3","pages":"643-652"},"PeriodicalIF":2.8,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13129179/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147822210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Low-power analog and mixed-signal circuit techniques for next-generation miniature implantable neural interface systems.","authors":"Linran Zhao, Yaoyao Jia","doi":"10.1007/s13534-026-00574-z","DOIUrl":"https://doi.org/10.1007/s13534-026-00574-z","url":null,"abstract":"<p><p>Miniature implantable neural interface devices are increasingly critical for both neuroscience research and clinical neuromodulation applications. However, device miniaturization imposes stringent constraints on power, area, and performance, creating challenges for implementing energy-efficient neuromodulation, high-fidelity neural recording, and wireless data telemetry. This review provides a comprehensive overview of low-power circuit designs enabling next-generation neural interfaces. We discuss energy-efficient stimulation drivers for optogenetic neuromodulation, highlighting advanced switched-capacitor-based techniques that reduce supply voltage requirements while maintaining high-current LED pulses. Low-noise neural recording frontends, including preamplifier-fronted structures, as well as ΔΣ ADC-based and NS-SAR-based direct-digitizing architectures, are reviewed with emphasis on techniques for dynamic range extension, linearity improvement, and artifact tolerance. Finally, state-of-the-art backscatter-based wireless telemetry methods are presented, covering load-shift keying (LSK), frequency-splitting, and push-pull quadrature modulation approaches that decouple power and data transfer to achieve high data rates with minimal energy consumption. This review highlights the critical role of circuit-level innovations in overcoming the power and performance limitations of miniature implants and provides insights for the design of next-generation neural interface systems.</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 3","pages":"681-692"},"PeriodicalIF":2.8,"publicationDate":"2026-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13129172/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147822187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Basharat Hussain, Abid Ullah, Israr Ali, Sheraz Haider, Hyeuk Jin Han, Gangtae Jin
{"title":"Advances in semiconductor materials and device architectures for biomedical systems: a mini review.","authors":"Basharat Hussain, Abid Ullah, Israr Ali, Sheraz Haider, Hyeuk Jin Han, Gangtae Jin","doi":"10.1007/s13534-026-00573-0","DOIUrl":"https://doi.org/10.1007/s13534-026-00573-0","url":null,"abstract":"<p><p>The latest improvements in semiconductor engineering have made it possible for the medical field to take advantage of the new capabilities of sensing, diagnosing, neural modulating, and monitoring therapeutics, among others. The merging of nanomaterials, microfabrication techniques, and flexible electronics have turned the traditional biomedical devices into smart systems that are extremely sensitive and minimally invasive. The article presents a review of the new semiconductor-based technologies in the field of biomedicine, focusing on material innovations, system-level integration, and clinical application pathways. Bio-integrated sensors, neuromodulation platforms, and semiconductor enabled point-of-care diagnostics are the areas that will be discussed during this mini review. A thorough analysis is done on the main challenges like long-term biocompatibility, signal stability in complex biological environments, and scalable manufacturing. Moreover, alternate directions, like soft implantable electronics, AI-integrated semiconductor biosystems, and high-density neural interfaces are discussed as potential future developments. This review is aimed at giving biomedical engineering researchers a clear but thorough view of the continuous reshaping of biomedical engineering by semiconductor innovations.</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 3","pages":"663-680"},"PeriodicalIF":2.8,"publicationDate":"2026-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13129054/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147822136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Energy-efficient neural stimulation system design for implantable medical devices.","authors":"Joonghoon Kang, Kyeongho Eom, Han-Sol Lee, Hyun-Su Lee, Hyungjin Jung, Hojae Chon, Minkyung Ahn, Hyung-Min Lee","doi":"10.1007/s13534-026-00572-1","DOIUrl":"https://doi.org/10.1007/s13534-026-00572-1","url":null,"abstract":"<p><p>Implantable medical devices for neural stimulation have received great attention in biomedical applications to restore or modulate sensory and motor function. Many miniaturized implants rely on wireless power transfer, where deliverable power is limited and the on-chip supply becomes time-varying under coil misalignment and link activity. At the same time, wide electrode-tissue interface (ETI) variability complicates compliance, efficiency, and long-term charge balance, making a highly efficient and safe stimulator essential. This paper surveys neural stimulation architectures by organizing prior work into current-controlled stimulation (CCS), voltage-controlled stimulation (VCS), and switched-capacitor stimulation (SCS). For CCS and VCS, we discuss adaptive energy-delivery techniques that reduce headroom loss and monitoring/correction approaches that enforce charge safety under ETI variation. For SCS, we highlight charging-interface and residual-management strategies, as well as discharge-based stimulus families, that strongly influence end-to-end efficiency and stimulation efficacy under tight power budgets.</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 3","pages":"653-662"},"PeriodicalIF":2.8,"publicationDate":"2026-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13129026/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147822156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Biodegradable capacitive sensors for biomedical applications: sensitivity and lifetime.","authors":"Minki Hong, Seunghun Han, Gilmo Kim, Jahyun Koo","doi":"10.1007/s13534-026-00570-3","DOIUrl":"https://doi.org/10.1007/s13534-026-00570-3","url":null,"abstract":"<p><p>Biodegradable implantable and wearable biomedical sensors have attracted growing attention as a promising alternative to conventional permanent electronic devices, offering transient functionality that eliminates the need for secondary surgical removal and mitigates electronic waste accumulation. Among various sensing modalities, capacitive sensors have emerged as a particularly attractive platform for monitoring mechanically derived physiological signals owing to their structural simplicity, low power consumption, and compatibility with soft materials. Despite extensive academic progress, however, the clinical translation and commercialization of biodegradable capacitive sensors remain limited. A central challenge arises from the inherent trade-off between sensing sensitivity and operational lifetime. Structural and material modifications that enhance sensitivity often accelerate degradation, whereas strategies designed to prolong functional lifetime can compromise mechanical compliance and signal fidelity. Achieving a precise balance between these competing requirements is therefore critical for practical deployment in biomedical applications. In this review, we systematically examine biodegradable capacitive sensors with a focus on sensitivity enhancement and lifetime modulation as the two key determinants of device performance. We summarize design strategies for improving sensitivity through sensor architecture optimization and dielectric layer engineering, and we review encapsulation approaches for controlling degradation behavior and functional lifetime. By critically analyzing how these complementary strategies are selectively implemented to meet the distinct demands of wearable and implantable biomedical applications, this review provides practical design guidelines and highlights future research directions aimed at advancing biodegradable capacitive sensors toward clinical implementation and scalable manufacturing.</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 3","pages":"627-641"},"PeriodicalIF":2.8,"publicationDate":"2026-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13129153/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147822197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Advanced silicon nanomembrane based bioelectronics for flexible and stretchable implantable systems.","authors":"Junseok Lee, Yena Lee, Hanbi Woo, Minji Hong, Doohyun J Lee, Mingyu Sang","doi":"10.1007/s13534-026-00568-x","DOIUrl":"https://doi.org/10.1007/s13534-026-00568-x","url":null,"abstract":"<p><p>As the paradigm of modern medicine shifts toward prevention and management, the importance of implantable electronics for real-time physiological monitoring and therapeutic intervention has surged, yet the mechanical mismatch between conventional rigid devices and soft tissues poses significant challenges regarding inflammation and long-term performance. Consequently, this review hierarchically analyzes advanced semiconductor integration strategies for flexible and stretchable implantable systems, utilizing Silicon Nanomembrane (SiNM) technology as a core building block to achieve mechanical compliance while maintaining CMOS compatibility. We systematically examine flexible substrate processing and patterning techniques, including laser-induced graphene (LIG) and printing methods, and place special emphasis on conformal encapsulation strategies using inorganic/organic multilayer thin films to ensure miniaturization and reliability in harsh biological environments. Furthermore, the review covers system-level integration issues, including hierarchical wireless communication strategies tailored to implantation depth and hybrid energy harvesting technologies for battery-free operation, ultimately proposing that the organic integration of these elements is essential for realizing next-generation \"Fully Autonomous Bio-integrated Systems\".</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 3","pages":"607-626"},"PeriodicalIF":2.8,"publicationDate":"2026-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13129031/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147822191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jong Won Lee, Ji Won Lee, Ho Jun Shin, Jinhong Park, Sung-Hyuk Sunwoo, Dong Chan Kim, Hyun-Do Jung, Soo-Hong Lee, Gi Doo Cha
{"title":"Advances in functional composite hydrogels for the treatment of degenerative arthritis.","authors":"Jong Won Lee, Ji Won Lee, Ho Jun Shin, Jinhong Park, Sung-Hyuk Sunwoo, Dong Chan Kim, Hyun-Do Jung, Soo-Hong Lee, Gi Doo Cha","doi":"10.1007/s13534-026-00566-z","DOIUrl":"10.1007/s13534-026-00566-z","url":null,"abstract":"<p><p>Osteoarthritis (OA) is a degenerative joint disease that presents an increasing public health burden as global populations age. Current pharmacologic treatments, such as nonsteroidal anti-inflammatory drugs (NSAIDs) and glucocorticoids, primarily alleviate symptoms but fail to prevent structural degeneration. To address this therapeutic gap, biomaterial-based tissue scaffolds have been developed to provide mechanical support while delivering therapeutic signals. Conventional scaffolds composed of bioceramics or polymers provide mechanical strength and stability but suffer from poor biocompatibility, limited processability, and inadequate integration with native cartilage. Hydrogels have emerged as promising alternatives owing to their extracellular matrix (ECM)-mimicking properties, biocompatibility, and injectability. However, pristine hydrogels often suffer from insufficient mechanical strength and rapid degradation, limiting their long-term effectiveness. Composite hydrogels, including cell-laden or nanocomposite systems, have been explored to address these limitations. Although these strategies could enhance regeneration, mechanical integrity, or drug delivery, each approach alone remains insufficient for comprehensive OA treatment. Recent advances in cell-nanocomposite hydrogels, which integrate therapeutic cells and nanoparticles within a hydrogel matrix, offer synergistic improvements across regeneration, controlled drug delivery, and mechanical support. These systems can also enhance cell viability and differentiation through growth factor-mediated signaling, thereby supporting superior cartilage regeneration. This review traces the evolution of functional composite hydrogels for OA treatment, detailing their design strategies and therapeutic potential. It also outlines the current challenges and future directions for translating cell-nanocomposite hydrogels into clinical practice.</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 2","pages":"353-368"},"PeriodicalIF":2.8,"publicationDate":"2026-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13013759/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147522098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sean Gosnell, Turaj Ashuri, Saleh Gharaie, Amir Ali Amiri Moghadam
{"title":"Soft parallel robots for medical ultrasound imaging: a comprehensive review and future directions.","authors":"Sean Gosnell, Turaj Ashuri, Saleh Gharaie, Amir Ali Amiri Moghadam","doi":"10.1007/s13534-026-00559-y","DOIUrl":"10.1007/s13534-026-00559-y","url":null,"abstract":"<p><p>Ultrasound imaging is a vital diagnostic tool, yet its effectiveness is often constrained by operator variability, occupational strain, and limited access to skilled sonographers. This paper reviews soft robotic ultrasound systems across major databases and recent literature. We examine teleoperated, collaborative, and autonomous platforms, analyzing mechanical architectures ranging from rigid to soft and continuum designs with respect to positional accuracy, physical human-robot interaction safety, and integration with advanced sensing and artificial intelligence. Regulatory precedents are also reviewed to highlight pathways toward clinical adoption. Rigid robotic platforms currently dominate, offering high precision but requiring complex controls to address safety concerns. In contrast, soft and continuum robotic systems provide inherent compliance, enabling safer patient interactions and greater adaptability. Advances in distributed sensing, physics-informed modeling, and artificial intelligence-driven control have further enhanced their potential, though challenges in real-time control, computational efficiency, and regulatory validation remain. Overall, robotic ultrasound represents a compelling frontier in medical imaging: while rigid systems ensure accuracy, soft and continuum parallel designs promise safer, more adaptive, and scalable solutions. This review underscores the potential of robotic ultrasound to improve diagnostic consistency, reduce clinician burden, and expand healthcare access through intelligent and adaptive robotic technologies.</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 2","pages":"387-410"},"PeriodicalIF":2.8,"publicationDate":"2026-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13013787/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147522250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yemin Kim, Junhyuck Lee, Jaejun Kil, Dongrim Kim, Taegil Jeong, Byunghun Lee
{"title":"Temporal interference stimulation devices: a comprehensive review of hardware design and implementation.","authors":"Yemin Kim, Junhyuck Lee, Jaejun Kil, Dongrim Kim, Taegil Jeong, Byunghun Lee","doi":"10.1007/s13534-026-00564-1","DOIUrl":"https://doi.org/10.1007/s13534-026-00564-1","url":null,"abstract":"<p><p>Deep brain stimulation has demonstrated efficacy in treating various neurological disorders. However, its invasiveness and the associated surgical risks have motivated noninvasive approaches that can selectively modulate deep targets. Conventional transcranial electrical stimulation techniques, however, have limited capability to reach deep brain regions with high spatial focality. Temporal interference stimulation (TIS) has emerged as a promising solution to overcome these challenges, using two slightly different high-frequency carriers to generate a low-frequency envelope with improved spatial focality in tissue. Currently, TIS is being extensively validated in rodent models and has been expanded to studies using cadaveric human heads and clinical trials for various neurological disorders. However, the precision and safety of TIS strongly depends on the underlying hardware implementation. Therefore, a systematic understanding of circuit and system design is required for practical device development. This paper covers comprehensive hardware design considerations and implementation strategies for TIS devices. Major TIS waveform schemes are categorized and their impact on system complexity, channel synchronization, and stimulation performance is analyzed. For the output stage architecture, various circuit topologies are discussed regarding their voltage compliance and current driving capability. In addition, essential safety features, including charge balancing techniques and impedance monitoring methods tailored to TIS operation are reviewed. Finally, experimental validation approaches using tissue phantoms are summarized to provide guidelines for developing robust and reliable TIS systems.</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 3","pages":"595-605"},"PeriodicalIF":2.8,"publicationDate":"2026-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13129173/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147822201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Minseong Hong, YeongSeok Ye, Joungwon Kim, Jae-Ick Kim, Jong-Cheol Rah, Youngbin Tchoe
{"title":"Integrating living biomaterials into neuroelectronic systems.","authors":"Minseong Hong, YeongSeok Ye, Joungwon Kim, Jae-Ick Kim, Jong-Cheol Rah, Youngbin Tchoe","doi":"10.1007/s13534-026-00557-0","DOIUrl":"10.1007/s13534-026-00557-0","url":null,"abstract":"<p><p>Neural interface technologies stand at the threshold of a revolution, offering new possibilities for seamless, high-bandwidth interconnection between the human brain and computers. Recent progress has been driven by advances in microscale manufacturing, yielding sophisticated neural probes with diverse form factors capable of recording from macroscopic networks down to single units. These platforms span rigid-to-soft architectures and combine inorganic and organic materials, improving compatibility with the brain's mechanical and chemical properties. Despite these advances, the field still relies primarily on nonbiological electrodes, which face inherent limitations in adapting to the dynamic and complex nature of living neural tissue. Living biomaterials-integrated neuroelectronics, on the other hand, could open new possibilities by enabling technologies that adapt to the host environment, actively establish bidirectional interfaces, conform to living tissue, and support repair by leveraging the inherent regenerative and plastic capacities of living systems. This review provides an overview of recent progress, challenges, and emerging directions in the integration of living biomaterials with neuroelectronic systems. We frame biohybrid neural interfaces as the convergence of in vitro microelectrode arrays and in vivo brain interfaces and organize the review around three themes: (i) cell sources for device integration, (ii) advances in in vitro MEA platforms, and (iii) cell-integrated, living electrodes for in vivo neural interfacing. Considered jointly, the themes point to an integrated path to seamless, adaptive biohybrid neural interfaces.</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 2","pages":"307-328"},"PeriodicalIF":2.8,"publicationDate":"2026-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13013916/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147522111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}