Publications

2026

• Aerosol-Jet Printed and Photonically Cured Sensors Embedded in 3D Printed Smart Orthoses: A Preliminary Study

  Mauro Serpelloni

  Enhancing 3D printed objects with embedded electronics is an increasing need and opportunity in the field of Internet of Things (IoT), Biomedical applications and Industry 4.0. 3D printed prostheses are emerging rapidly, embedding sensors in them can enable monitoring during recovery phases or long term to assess their integrity without modifying structure or patient?s experience. In this work, a first example of strain gauge embedded inside a 3D printed structure realized with AJP and photonic curing is presented. Commercially available printer and material such as PLA are considered in this preliminary study. To produce the proof-of-concept samples, the 3D printing process was initiated and paused at a certain layer, which was post produced by the printer itself using ironing technique, then the sensor was printed by Aerosol Jet Printing technique using a silver nanoparticulate ink, which was then cured via photonic sintering; finally, the 3D printing process was resumed to complete the structure. A set of not embedded sensors were used to validate the sensors? fabrication process and sensing capabilities. Post processed surface and sensors were characterized morphologically using a profilometer, resulting in a surface with average roughness of 0.72 ?m (89% less than non-ironed surface) and a homogenous track width of 200 ?m. Flexural 3-Point bending tests were conducted to measure electrical response. Sensitivity in 3-Point bending tests was found to be 0.87 ± 0.12 (?/?)/? with R2 of 0.98 minimum. Proof-of-concept embedded strain sensors were subjected also to flexural testing and validated the feasibility of the process.

• Wireless Instrumented Ankle Foot Orthosis (AFO) for Gait Cycle Monitoring: A preliminary Study

  Mauro Serpelloni

  Ankle Foot Orthoses are used for rehabilitation after ankle injuries or pathologies, but their effectiveness and recovery time can be affected by improper patient use. To address this issue, an instrumented Ankle Foot Orthosis can assist doctors in monitoring the patient?s gait cycle, enabling the development of a personalized rehabilitation plan. In this paper, an Ankle Foot Orthosis capable of monitoring the gait cycle and the deformation of the orthosis is proposed and preliminary analyzed. The system consists of two force sensors to detect ground contact, a strain gauge bridge to measure orthosis deformation, and an inertial module to analyze the gait cycle. An Arduino Nano is used to acquire these signals after electronic conditioning. The microcontroller transmits data to a lowpower Bluetooth module, which communicates with a LabVIEW program where the data is displayed in real time and stored in a text file. After characterizing the entire system, a PCB board is developed and mounted onto the orthosis using a support printed with a 3D printer.

• Recovery of Patient-Reported Outcome Measures vs Gait Parameters Obtained by Instrumented Insoles After Tibial and Malleolar Fractures: Prospective Longitudinal Observational Study

  Bergita Ganse

  "Background: New technologies from the field of mobile health (mHealth) are increasingly used to improve patient monitoring during rehabilitation. While in recent years, mobile phones, health apps, personal digital assistants, and smartwatches opened up new diagnostic and monitoring opportunities for patients, the development of innovative sensor devices, such as instrumented insoles, has now reached a sufficient level of usability with promising opportunities for clinical practice. According to research on the best method for monitoring recovery after musculoskeletal injury or surgery, the Patient-Reported Outcome Measurement Information System (PROMIS) and wearables such as instrumented insoles are among the most promising newer options. However, it is unknown how a patient?s health perception and improvements in instrumented insole-derived gait parameters correlate after surgery for tibial or malleolar fractures. Objective: This study aimed to compare the longitudinal trajectories in separate PROMIS (sub)scores with gait and further patient-specific parameters, as well as associations between PROMIS scores and gait parameters. It was also aimed to determine the influence of anthropometric parameters and comorbidities. Methods: A total of 85 patients (39 women and 46 men; average age 50.8, SD 17.1 years) requiring surgery after tibial or malleolar fractures were included in this prospective longitudinal observational study. In the hospital and during follow-up visits, the patients completed the PROMIS Global Health and Pain Interference questionnaires. During the same visits, individually fitted instrumented insoles with 16 pressure sensors, an accelerometer, and a gyroscope each were used to assess the maximal force, pressure distribution, and angular velocity during walking with data being recorded at 100 Hz. Statistical analyses were conducted using linear mixed effect models, pairwise Spearman correlation coefficients, and generalized additive models. Results: The gait parameters assessed via the instrumented insoles quickly improved during the first 3 months after surgery, followed by a slowing of further improvement. After surgery, the PROMIS scores increased or decreased to extrema that were reached after 6 weeks to 3 months, followed by a return to preinjury values. Between 3 and 6 months, no significant improvements in PROMIS scores were observed. Between 6 months and 1 year, the Physical Health and Mental Health scores still improved significantly (P=.003 in both cases). Men had better Physical Health and lower Pain Interference scores than women (P=.01 and P=.03, respectively). Hypertension had a negative effect on the Physical Health score (P=.03). The associations between the PROMIS score and gait parameters were strongest at approximately 3 months after surgery, predominantly between the Pain Interference score and gait parameters. Conclusions: The patients? perception improved later than the objective gait parameters obtained by instrumented insoles did. When the gait pattern improved, pain perception correlated with the gait parameters. Trial Registration: German Clinical Trials Registry DRKS00025108; https://drks.de/search/en/trial/DRKS00025108"

  DOI: https://drks.de/search/en/trial/DRKS00025108

• A multimodal biomechanics dataset with synchronized kinematics and internal tissue motions during reaching

  Duarte Folgado

  Tissue motions within body segments, such as the relative movements of muscles, fascia, and bone, remain largely unexplored despite their relevance to movement dysfunction, force transmission, and motor skill. Here, we present a time-synchronized multimodal dataset that bridges this gap by capturing both internal tissue dynamics and conventional biomechanical measurements during arm reaching. Thirty-six participants across three expertise levels (world-class athletes, regional athletes, and untrained individuals) performed slow, rhythmic reaching movements while we recorded data using B-mode ultrasound imaging, motion capture, electromyography, and accelerometry. The dataset includes processed signals, derived parameters (segmented reach events, tissue boundary motion, arm kinematics, tremor events, and muscle activation levels), and metadata. Notably, using the DUSTrack point-tracking workflow, we provide trajectories for 11 points across approximately 300,000 ultrasound frames from the upper arm. This resource enables at least three primary applications: (1) supervised training and benchmarking of deep learning models for point tracking in ultrasound videos, (2) development of ultrasound-based metrics for characterizing soft tissue mechanics, and (3) biomechanical investigation of how tissue-level dynamics support motor performance. All data, processing code, and tutorials are provided in accessible formats with documentation.

  DOI: doi.org/10.1038/s41597-026-07019-3

• Aerosol-Jet Printed and Photonically Cured Sensors Embedded in 3D-Printed Smart Orthoses: A Preliminary Study

  Mauro Serpelloni

  Enhancing 3D printed objects with embedded electronics is an increasing need and opportunity in the field of Internet of Things (IoT), Biomedical applications and Industry 4.0. 3D printed prostheses are emerging rapidly, embedding sensors in them can enable monitoring during recovery phases or long term to assess their integrity without modifying structure or patient's experience. In this work, a first example of strain gauge embedded inside a 3D printed structure realized with AJP and photonic curing is presented. Commercially available printer and material such as PLA are considered in this preliminary study. To produce the proof-of-concept samples, the 3D printed was initiated and paused at a certain layer, which was post produced by the printer itself using ironing technique, then the sensor was printed by Aerosol Jet Printing technique using a silver nanoparticulate ink, which was then cured via photonic sintering; finally, the 3D printing process was resumed to complete the structure. A set of not embedded sensors were used to validate the sensors' fabrication process and sensing capabilities. Post processed surface and sensors were characterized morphologically using a profilometer, resulting in a surface with average roughness of 0.72 µm (89% less than non-ironed surface) and a homogenous track width of 200um. Flexural 3-Point bending tests were conducted to measure electrical response. Sensitivity in 3-Point bending tests was found to be 0.87 +- 0.13 (?/?)/epsilon with R2 of [0.98] minimum. Proof-of-concept embedded strain sensors were subjected also to flexural testing and validated the feasibility of the process.

• Wireless Instrumented Ankle Foot Orthosis (AFO) for Gait Cycle Monitoring

  Mauro Serpelloni

  Ankle?foot orthoses (AFOs) are widely used in the rehabilitation of patients with neurological or musculoskeletal disorders. However, treatment outcomes may be influenced by incorrect use of the device or by inappropriate orthosis selection. Since many types of AFOs are available, differing in materials, stiffness, and geometry, an objective evaluation tool can support clinical decision-making. This work presents the design, development, and characterization of an instrumented AFO able to quantify relevant gait parameters in an objective way. The proposed device integrates three measurement modalities in a compact wearable structure. Two longitudinal strain gauges estimate ankle plantar- and dorsiflexion angles. Two force-sensitive elements detect foot?ground contact and allow identification of stance and swing phases of the gait cycle. A single inertial measurement unit (IMU) is used to measure lateral shank inclination. The strain-gauge-based angle estimation was validated against a gold-standard motion capture system, achieving a root mean square error of approximately 1.5 degrees and showing higher accuracy than the IMU for plantar/dorsiflexion measurement, while maintaining a simple electronic architecture. The force sensors were validated using a force platform and demonstrated reliable detection of loading and unloading events. Monitoring lateral inclination through the single IMU provides additional information related to balance and potential fall risk. Data are transmitted via Bluetooth Low Energy (BLE) to a custom Python-based application for real-time visualization and recording. Overall, the results validate the electronic instrumentation and demonstrate reliable system performance, indicating that the proposed instrumented AFO represents a promising platform for objective gait assessment and future clinical applications.

• A Dynamic Wireless SIMO System for High Bandwidth Real-Time Stable Link Endoscope Procedures

  Miguel Roque

  Real-time wireless capsule endoscopy (WCE) requires a stable, high-throughput in-body-to-out-body link. However, the procedure itself is inherently dynamic, and peristaltic movement drives continuous capsule translations and rotations that can cause strong channel variability and intermittent fades. While many WCE telemetry studies focus on transmitter design and static path-loss characterization, the receiver-side architecture is often treated as a fixed component, despite its critical role in preventing outages during the exam. In this paper, we propose a dynamic single-input multiple-output (SIMO) system that adaptively switches among external receiver antennas based on the capsule?s three-dimensional orientation, as estimated by onboard inertial measurement units (IMUs), with the objective of maximizing the instantaneous expected link margin. The proposed approach is experimentally validated using a tissue-mimicking phantom with emulated capsule rotations and is bench-marked against a conventional single-antenna receiver baseline. The proposed SIMO system improves connection quality and increases instantaneous throughput from 1.19 Mbps to 1.64 Mbps (median values), corresponding to a ~37% upgrade, while also improving channel power stability. These results underscore the importance of dynamic receiver diversity for achieving robust high-bandwidth WCE and support its adoption in future clinical-grade products.

  DOI: https://doi.org/10.1109/JERM.2026.3702252

• Dual-Band Patch Antenna for on-Body to in-Body Applications

  Miguel Roque

  On-body radio links for implantable biomedical devices require compact, low-cost antennas that can operate reliably when placed directly on the skin, while still complying with electromagnetic exposure regulations and supporting efficient power and data transfer. This work presents a low-cost, PCB-fabricated dual-band on-body patch antenna operating in the 433 MHz and 2.45 GHz ISM bands, enabling a hybrid interface with sub-GHz for power delivery and 2.45 GHz operation for data telemetry. The antenna (40 x 50.4 mm2) is implemented on 0.6 mm FR-4 with coaxial feeding and a shorting pin to lengthen the 2.45 GHz current path. A silicone superstrate is also added to improve tissue matching. The design was optimized in Ansys HFSS using a detailed human body model and validated with an on-body prototype. Practical measurements show S11 better than -18 dB at 433 MHz and -26 dB at 2.45 GHz, with 6.46% and 6.04% bandwidths, respectively. Simulated peak spatial-average SAR (1 g/10 g) complies with limits at 1 W input power in both bands. The proposed antenna provides a validated, robust and manufacturable dual-band on-body interface for implantable devices.

  DOI: 10.1109/IMBioC69142.2026.11541154

• Master Thesis - Development and Characterization of Instrumented Crutches for Enhanced Gait Analysis

  Mauro Serpelloni

• Long-Term Evaluation of Bone Healing Monitoring Using an Instrumented Plate with Measurement Sensors (Smart Implant) over 10 Years

  Tobias Barth

  A total of 66 smart implants were included. As a measure of bony stability, the relative elastic compliance of the osteosynthesis was determined from the gradient between the applied external load and the measured implant load over the entire healing process. The healing process of non-unions of the femur with a smart implant was tracked by telemetric measurements over a timespan of up to 10 years. The measurements of the longest healing process show a very slow but constant decrease in force transmission over the implant, radiological fi ndings over 10 years show corresponding consolidation until bony healing. The use of a telemetrically instrumented bone plate, a so-called smart implant, to monitor the healing process is a successful procedure to support the clinician in his decision to take further surgical measures or to wait until healing occurs.

  DOI: https://doi.org/10.3390/s25185779

• Recent Advances in Wireless Power and Data Transfer for Implantable Biomedical Devices: A Scoping Review

  Duarte Folgado

  Wireless implantable biomedical devices (IBMDs) enable continuous physiological monitoring and therapeutic interventions through miniaturized radio-frequency (RF) front-ends. Their development is constrained by the heterogeneous electromagnetic properties of human tissues and stringent clinical safety requirements. This scoping review, conducted following the PRISMA-ScR framework, maps recent methods and performance metrics for wireless power and data transfer in IBMDs. A search of the Scopus database identified 75 peer-reviewed Q1?Q2 journal articles published between 2020 and 2024. Most systems are implanted below the skin surface, with data-focused architectures predominating over power-only and hybrid solutions. Radiative coupling in the GHz range dominates data transmission, supporting data rates up to 250 Mbps, whereas inductive coupling in the kHz?MHz bands is most effective for power transfer, with reported efficiencies up to 93%. Despite these technological advances, only a minority of the studies complied with SAR safety thresholds at 1 W transmit power, particularly under the stricter SAR 1 g criterion. This review synthesizes recent engineering approaches, anatomical trade-offs, and safety considerations, and outlines design directions for clinically viable, multifunctional wireless IBMDs.

  DOI: https://doi.org/10.1016/j.biosx.2026.100777

• DUSTrack: Semi-automated point tracking in ultrasound videos

  Duarte Folgado

  Ultrasound technology enables safe, non-invasive imaging of dynamic tissue behavior, making it a valuable tool in medicine, biomechanics, and sports science. However, accurately tracking tissue motion in B-mode ultrasound remains challenging due to speckle noise, low edge contrast, and out-of-plane movement. These challenges complicate the task of tracking anatomical landmarks over time, which is essential for quantifying tissue dynamics in many clinical and research applications. This manuscript introduces DUSTrack (Deep learning and optical flow-based toolkit for UltraSound Tracking), a semi-automated framework for tracking arbitrary points in B-mode ultrasound videos. We combine deep learning with optical flow to deliver high-quality and robust tracking across diverse anatomical structures and motion patterns. The toolkit includes a graphical user interface that streamlines the generation of high-quality training data and supports iterative model refinement. It also implements a novel optical-flow-based filtering technique that reduces high-frequency frame-to-frame noise while preserving rapid tissue motion. Semi-automated tracking with DUSTrack demonstrates superior accuracy compared to contemporary zero-shot point trackers and performs on par with specialized methods. This establishes its potential as a general tool for clinical and biomechanical research?one that can generate accurate training data for developing foundation models in ultrasound point tracking. We demonstrate DUSTrack?s versatility through three use cases: cardiac wall motion tracking in echocardiograms, muscle deformation analysis during reaching tasks, and fascicle tracking during ankle plantarflexion. As an open-source solution, DUSTrack offers a powerful, flexible framework for point tracking to quantify tissue motion from ultrasound videos. DUSTrack is available at https://github.com/praneethnamburi/DUSTrack.

• SmILE: Smart Implants for Life Enrichment

  Duarte Folgado

  "Objective: Non-Communicable Diseases (NCDs), such as osteoarthritis, osteoporosis, joint and ligament degeneration, and frailty fractures, along with their associated complications, pose a significant threat to older adults, often leading to irreversible declines in health, functionality, and autonomy. The EU-funded Smart Implants for Life Enrichment (SmILE) project aims to develop a complete system and methodology for early risk detection and continuous health monitoring in older adults by leveraging the potential of bone implants as sensors.

  Methods: SmILE is combining smart implants, wearable sensors, and an AI-powered digital platform to enable early risk detection and ongoing health monitoring. A novel chip platform will be embedded into existing orthopedic implants to gather real-time data, complemented by data from wearable sensors. This multimodal dataset will be analyzed using machine learning to generate personalized risk profiles, track post-surgical recovery, and provide predictive insights. The system will be co-designed with end-users and stakeholders to ensure usability, patient agency, and adherence to data governance and privacy regulations. The design process will consider physical, mental, socio-economic, and environmental contexts of patients and care contexts.

  Expected Results: SmILE aims to deliver a validated digital platform that enables personalized, patient-controlled management of musculoskeletal NCDs, promotes healthy aging, and helps reduce healthcare costs. The main expected results are: (1) An integrated platform to collect, manage, analyze, and securely share multimodal health data from older patients using AI and machine learning; (2) A pan-European, patient-centered data governance model that empowers individuals to control their health data in alignment with regulatory frameworks; and (3) A citizen- and patient-driven solution tailored to the needs of aging populations. The methodologies will be validated through six use cases involving innovative orthopedic and assistive technologies, ranging from intelligent walking aids to instrumented implants, addressing key challenges in musculoskeletal health and functional recovery."