Bradley Nelson


Last Name

Nelson

First Name

Bradley

ORCID

0000-0001-9070-6987

Organisational unit

03627 - Nelson, Bradley J. (emeritus) / Nelson, Bradley J. (emeritus)

Search Results

Publications 1 - 10 of 170
  • Quantifying Collective Cell Migration and Cell-Generated Mechanical Forces in a 3D Microtissue Model of Wound Healing
    Item type: Other Conference Item
    Sakar, Mahmut Selman; Eyckmans, Jeroen; Shenoy, Vivek; et al. (2014)
    Tissue Engineering. Part A
  • Magnetically Guided Laser Surgery for the Treatment of Twin‐to‐Twin Transfusion Syndrome
    Item type: Journal Article
    Lussi, Jonas; Gervasoni, Simone; Mattille, Michelle; et al. (2022)
    Advanced Intelligent Systems
    Twin-to-twin transfusion syndrome (TTTS) is a severe disorder that often leads to the death of monochorionic twin fetuses, if left untreated. Current prenatal interventions to treat the condition involve the use of rigid fetoscopes for targeted laser coagulation of the vascular anastomoses. These tools are limited in their area of operation, making treatment challenging, especially in cases with anterior placentation. Herein, a robotic platform to perform this task using remote magnetic navigation is proposed. In contrast to rigid tools, the presented custom magnetic fetoscope is highly flexible, dexterous, and has considerable advantages, including safety and precision. A visual servoing algorithm that allows the surgeon to navigate in the uterus with submillimeter precision is introduced. The system has been validated on ex vivo human placentas in a setting that mimics the real intraoperative conditions.
  • Telesurgery and the importance of context
    Item type: Review Article
    Heemeyer, Florian; Boehler, Quentin; Kim, Min-Soo; et al. (2025)
    Science Robotics
    Telesurgery has the potential to overcome geographical barriers in surgical care, encouraging its deployment in areas with sparse surgical expertise. Despite successful in-human experiments and substantial technological progress, the adoption of telesurgery remains slow. In this Review, we analyze the reasons for this slow adoption. First, we identify various contexts for telesurgery and highlight the vastly different requirements for their realization. We then discuss why procedures with high urgency and skill sparsity are particularly suitable for telesurgery. Last, we summarize key research areas essential for further progress. The goal of this Review is to provide the reader with a comprehensive analysis of the current state of telesurgery research and to provide guidance for faster adoption of this exciting technology.
  • Biodegradable Small-Scale Swimmers for Biomedical Applications
    Item type: Review Article
    Llacer-Wintle, Joaquin; Rivas-Dapena, Anton; Chen, Xiang-Zhong; et al. (2021)
    Advanced Materials
    Most forms of biomatter are ephemeral, which means they transform or deteriorate after a certain time. From this perspective, implantable healthcare devices designed for temporary treatments should exhibit the ability to degrade and either blend in with healthy tissues, or be cleared from the body with minimal disruption after accomplishing their designated tasks. This topic is currently being investigated in the field of biomedical micro- and nanoswimmers. These tiny devices have the ability to move through fluids by converting physical or chemical energy into motion. Several architectures of these devices have been designed to mimic the motion strategies of nature's motile microorganisms and cells. Due to their motion abilities, these devices have been proposed as minimally invasive tools for precision healthcare applications. Hence, a natural progression in this field is to produce motile structures that can adopt, or even surpass, similar transient features as biological systems. The fate of small-scale swimmers after accomplishing their therapeutic mission is critical for the successful translation of small-scale swimmers' technologies into clinical applications. In this review, recent research efforts are summarized on the topic of biodegradable micro- and nanoswimmers for biomedical applications, with a focus on targeted therapeutic delivery.
  • Robotics and AI in the Global South
    Item type: Other Journal Item
    Matsiko, Amos; Nelson, Bradley (2023)
    Science Robotics
    An increasing presence of robotics and artificial intelligence in the Global South calls for responsible implementation.
  • Human Gait-labeling Uncertainty and a Hybrid Model for Gait Segmentation
    Item type: Working Paper
    Wu, Jiaen; Maurenbrecher, Henrik; Schaer, Alessandro; et al. (2021)
    TechRxiv
    Motion capture systems are widely accepted as ground-truth for gait analysis and are used for the validation of other gait analysis systems.To date, their reliability and limitations in manual labeling of gait events have not been studied. Objectives: Evaluate human manual labeling uncertainty and introduce a new hybrid gait analysis model for long-term monitoring. Methods: Evaluate and estimate inter-labeler inconsistencies by computing the limits-of-agreement; develop a model based on dynamic time warping and convolutional neural network to identify a valid stride and eliminate non-stride data in walking inertial data collected by a wearable device; Gait events are detected within a valid stride region afterwards; This method makes the subsequent data computation more efficient and robust. Results: The limits of inter-labeler agreement for key gait events of heel off, toe off, heel strike, and flat foot are 72 ms, 16 ms, 22 ms, and 80 ms, respectively; The hybrid model's classification accuracy for a stride and a non-stride are 95.16% and 84.48%, respectively; The mean absolute error for detected heel off, toe off, heel strike, and flat foot are 24 ms, 5 ms, 9 ms, and 13 ms, respectively. Conclusions: The results show the inherent label uncertainty and the limits of human gait labeling of motion capture data; The proposed hybrid-model's performance is comparable to that of human labelers and it is a valid model to reliably detect strides in human gait data. Significance: This work establishes the foundation for fully automated human gait analysis systems with performances comparable to human-labelers.
  • Reverse-engineering lift control in fruit flies
    Item type: Conference Paper
    Graetzel, Chauncey F.; Nelson, Bradley; Fry, Steven N. (2008)
    2008 2nd IEEE RAS & EMBS International Conference on Biomedical Robotics and Biomechatronics
    Fruit flies represent an important model system to study sensorimotor pathways. In this paper, we describe a quantitative reverse-engineering approach to study lift control in fruit flies. Flies were tethered to a MEMS micro force sensor and their forces measured while stimulated with moving patterns. Their wing motions were simultaneously measured with a custom designed high speed vision system. We characterized the fliespsila response to vertically-oscillating patterns in a Bode diagram and fit a transfer function to the frequency response data. The frequency response characteristics are compared to those of other artificial and natural lift controllers. This work shows how engineering can provide both strong technical tools and an analytical framework to explain biological sensorimotor pathways, a task that is highly relevant to the design of artificial devices at similar dynamic scales.
  • Metal-Organic Frameworks in Motion
    Item type: Review Article
    Terzopoulou, Anastasia; Nicholas, James; Chen, Xiang-Zhong; et al. (2020)
    Chemical Reviews
    During the last two decades, engineering motion with small-scale matter has received much attention in several areas of research, ranging from supramolecular chemistry and colloidal science to robotics and automation. The numerous discoveries and innovative concepts realized in motile micro- and nanostructures have converged in the field of small-scale swimmers. These man-made micro- and nanomachines can move in fluids by transforming different forms of energy to mechanical motion. Recently, metal–organic frameworks (MOFs), which are crystalline coordination polymers with high porosity, have been proposed as key building blocks in several small-scale swimmer designs. These materials possess the required features for motile micro- and nanodevices, such as high cargo-loading capacity, biodegradability, biocompatibility, and stimuli-responsiveness. In this review, we take a journey through the major breakthroughs and milestones realized in the area of MOF-based small-scale swimmers. First, a brief introduction to the field of small-scale swimmers is provided. Next, we review different strategies that have been reported for imparting motion to MOFs. Finally, we emphasize the incorporation of molecular machines into the MOF’s architecture as the means to create highly integrated small-scale swimmers. The strategies and developments explored in this review pave the way toward the use of motile MOFs for a variety of applications in the fields of biomedicine, environmental remediation, and on-the-fly chemistry.
  • Single-Step Synthesis of Sub-10 nm Magnetic Nanoparticles with High Saturation Magnetization and Broad pH Stability
    Item type: Journal Article
    Pustovalov, Vitaly; Landers, Fabian C.; Hertle, Lukas; et al. (2024)
    Advanced Engineering Materials
    Iron oxide nanoparticles hold great potential for future biomedical applications but, to date, usually suffer from reduced magnetic properties compared to their bulk counterparts. The replacement of Fe(III) ions with Zn(II) ions can enhance their magnetic properties while keeping their biocompatibility characteristics. Yet, common synthesis methods for these highly magnetic particles require using environmentally harmful solvents, multiple steps, and postfunctionalization, all while being affected by poor scalability and high polydispersity. To address these challenges, in this study, a single-step coprecipitation-based method is developed to fabricate gelatin-coated, zinc-substituted, sub-10 nm-sized iron oxide nanoparticles exhibiting high saturation magnetization. This single-step synthesis benefits from simplicity and robustness, capable of yielding large amounts of highly magnetic nanoparticles without the utilization of environmentally harmful or highly toxic reagents. Furthermore, in situ gelatin coating during the synthesis ensures particle stability in aqueous solutions over a wide range of pH and enhances cell compatibility. Systematic investigations show a direct correlation between the particles’ magnetization and the concentrations of Zn(II) and NaOH, where particles with a zinc-to-iron ratio of Zn:Fe = 0.18:2.82 reach a maximum saturation magnetization of 91.2 emu g⁻¹. Thus, these particles are promising candidates for biomedical applications.
  • Gradiometer-based magnetic localization for medical tools
    Item type: Journal Article
    Fischer, Cedric; Quirin, Thomas; Chautems, Christophe; et al. (2023)
    IEEE Transactions on Magnetics
    Remote magnetic navigation offers various possibilities for medical interventions. Magnetic catheters can be wirelessly steered with high precision and accuracy through complex structures, as they are generally more dexterous and flexible than their manually steered counterparts. Position feedback is essential for many tasks. However, most commercially available systems do not integrate well with the magnetic navigation systems. As a result, fluoroscopy is still widely used in many interventions despite the known associated health risks. In this study, we propose a localization method that uses multiple Hall sensors to measure the magnetic fields produced by the magnetic navigation system and estimate the full sensor pose without the need for a separate dedicated mapping system. This makes the magnetic navigation system a 2-in-1 system that can be used for simultaneous navigation and localization of a medical tool. We perform an optimization of the sensors’ array design in simulation and investigate the influence of the magnetic fields and gradients on the localization accuracy to provide information on the minimal requirements for a magnetic navigation system for this task.
Publications 1 - 10 of 170