@article {240, title = {The Biomedical Engineer{\textquoteright}s Pledge: Overview and Context}, journal = {Medical \& Biological Engineering \& Computing}, volume = {(Published online)}, year = {2025}, doi = {10.1007/s11517-025-03443-6}, url = {https://doi.org/10.1007/s11517-025-03443-6}, author = {Antoni Ivorra and Txetxu Aus{\'\i}n and Laura Becerra-Fajardo and del Ama, Antonio J. and Jesus Minguillon and Aracelys Garc{\'\i}a-Moreno and Jordi Aguil{\'o} and Filipe O. Barroso and Bijnens, Bart and Oscar Camara and Sara Capdevila and Castellanos-Fernandez, Roger and Rafael Davalos and Jean-Louis Divoux and Ahmed Eladly and Dario Farina and Garc{\'\i}a-Hombravella, Carla and Gonz{\'a}lez-L{\'o}pez, Raquel and C{\'e}sar Gonz{\'a}lez and Jordi Gr{\'\i}fols and Felipe Maglietti and Shahid Malik and Elad Maor and Guillermo Marshall and Mateu-Yus, Berta and Lluis M. Mir and Moreno, Juan C. and Xavier Navarro and N{\'u}ria Noguera and Andr{\'e}s Ozaita and Gemma Piella and Pons, Jos{\'e} Luis and Rita Quesada and Pilar Rivera-Gil and Boris Rubinsky and Ruiz-Garcia, Aurelio and Ruiz-Vargas, Albert and S{\'a}nchez-S{\'a}nchez, Maria and Andreas Schneider and Ting Shu and Villa-Sanz, Rosa and Bing Zhang and Gema Revuelta} } @article {241, title = {Invasive and Non-Invasive Remote Patient Monitoring Devices for Heart Failure: A Comparative Review of Technical Maturity and Clinical Readiness}, journal = {Sensors}, volume = {25}, year = {2025}, chapter = {6453}, doi = {10.3390/s25206453}, url = {https://www.mdpi.com/1424-8220/25/20/6453}, author = {Ivan Luque and Mar Gadea and Anna Comas and Laura Becerra-Fajardo and Javier Col{\'a}s and Antoni Ivorra} } @article {227, title = {First-in-human demonstration of floating EMG sensors and stimulators wirelessly powered and operated by volume conduction}, journal = {Journal of NeuroEngineering and Rehabilitation}, volume = {21}, year = {2024}, pages = {4}, chapter = {4}, doi = {10.1186/s12984-023-01295-5}, url = {https://doi.org/10.1186/s12984-023-01295-5}, author = {Laura Becerra-Fajardo and Jesus Minguillon and Krob, Marc O. and Camila Rogrigues and Miguel Gonz{\'a}lez-S{\'a}nchez and {\'A}lvaro Meg{\'\i}a-Garc{\'\i}a and Redondo Gal{\'a}n, Carolina and Guiti{\'e}rrez Henares, Francisco and Albert Comerma and del Ama, Antonio J. and {\'A}ngel Gil-Agudo and Francisco Grandas and Andreas Schneider and Filipe O. Barroso and Antoni Ivorra} } @conference {232, title = {Networks of Injectable Microdevices Powered and Digitally Linked by Volume Conduction for Neuroprosthetics: a Proof-of-Concept}, booktitle = {2023 11th International IEEE/EMBS Conference on Neural Engineering (NER)}, year = {2023}, doi = {10.1109/NER52421.2023.10123743}, url = {https://ieeexplore.ieee.org/abstract/document/10123743}, author = {Laura Becerra-Fajardo and Jesus Minguillon and Albert Comerma and Antoni Ivorra} } @article {215, title = {Powering Electronic Implants by High Frequency Volume Conduction: In Human Validation}, journal = {IEEE Transactions on Biomedical Engineering}, volume = {70}, year = {2023}, month = {08/2022}, pages = {659-670}, chapter = {659}, doi = {10.1109/TBME.2022.3200409}, url = {https://ieeexplore.ieee.org/document/9864046}, author = {Jesus Minguillon and Marc Tudela-Pi and Laura Becerra-Fajardo and Enric Perera-Bel and del Ama, Antonio J. and {\'A}ngel Gil-Agudo and {\'A}lvaro Meg{\'\i}a-Garc{\'\i}a and Aracelys Garc{\'\i}a-Moreno and Antoni Ivorra} } @article {214, title = {Floating EMG Sensors and Stimulators Wirelessly Powered and Operated by Volume Conduction for Networked Neuroprosthetics}, journal = {Journal of NeuroEngineering and Rehabilitation}, volume = {19}, year = {2022}, pages = {57}, chapter = {57}, doi = {10.1186/s12984-022-01033-3}, url = {https://doi.org/10.1186/s12984-022-01033-3}, author = {Laura Becerra-Fajardo and Krob, Marc O. and Jesus Minguillon and Camila Rogrigues and Christine Welsch and Marc Tudela-Pi and Albert Comerma and Filipe O. Barroso and Andreas Schneider and Antoni Ivorra} } @article {223, title = {Implantable Sensor for Measuring and Monitoring Intravascular Pressure, System Comprising Said Sensor and Method for Operating Thereof}, year = {2022}, edition = {A61B5/0215; A61B5/07; A61F2/90}, chapter = {WO 2022/184801 A1}, author = {Antoni Ivorra and Laura Becerra-Fajardo and Albert Comerma and Jesus Minguillon} } @article {216, title = {Wireless networks of injectable microelectronic stimulators based on rectification of volume conducted high frequency currents}, journal = {Journal of Neural Engineering}, volume = {19}, year = {2022}, pages = {056015}, chapter = {056015}, doi = {10.1088/1741-2552/ac8dc4}, url = {https://iopscience.iop.org/article/10.1088/1741-2552/ac8dc4}, author = {Aracelys Garc{\'\i}a-Moreno and Albert Comerma and Marc Tudela-Pi and Jesus Minguillon and Laura Becerra-Fajardo and Antoni Ivorra} } @article {221, title = {Implantable Electronic Sensing System for Measuring and Monitoring Medical Parameters}, year = {2021}, edition = {A61B5/00; A61B5/145; A61B5/1455; A61B5/1486}, chapter = {WO 2021/043481 A1}, author = {Antoni Ivorra and Q. Castellv{\'\i} and Laura Becerra-Fajardo} } @conference {211, title = {Injectable Temperature Sensors Based on Passive Rectification of Volume-Conducted Currents}, booktitle = {2021 IEEE Biomedical Circuits and Systems Conference (BioCAS)}, year = {2021}, publisher = {IEEE}, organization = {IEEE}, address = {Berlin, Germany}, doi = {10.1109/BioCAS49922.2021.9645006}, author = {Laura Becerra-Fajardo and Aracelys Garc{\'\i}a-Moreno and Alvarez-De-Eulate, Nerea and Antoni Ivorra} } @article {207, title = {Volume Conduction for Powering Deeply Implanted Networks of Wireless Injectable Medical Devices: a Numerical Parametric Analysis}, journal = {IEEE Access }, volume = {9}, year = {2021}, pages = {100594-100605}, chapter = {100594-100605}, doi = {10.1109/ACCESS.2021.3096729}, url = {https://ieeexplore.ieee.org/document/9481290}, author = {Marc Tudela-Pi and Jesus Minguillon and Laura Becerra-Fajardo and Antoni Ivorra} } @conference {210, title = {In Vitro Evaluation of a Protocol and an Architecture for Bidirectional Communications in Networks of Wireless Implants Powered by Volume Conduction}, booktitle = {5th International Conference on Neurorehabilitation (ICNR2020)}, volume = {28}, year = {2020}, pages = {103-108}, publisher = {Springer Nature}, organization = {Springer Nature}, edition = {Converging Clinical and Engineering Research on Neurorehabilitation IV, Biosystems \& Biorobotics}, doi = {10.1007/978-3-030-70316-5_17}, author = {Laura Becerra-Fajardo and Jesus Minguillon and Camila Rogrigues and Filipe O. Barroso and Pons, Jos{\'e} Luis and Antoni Ivorra} } @article {193, title = {Injectable Sensors Based on Passive Rectification of Volume-Conducted Currents}, journal = {IEEE Transactions on Biomedical Circuits and Systems}, volume = {14}, year = {2020}, pages = {867-878}, chapter = {867}, doi = {10.1109/TBCAS.2020.3002326}, url = {https://ieeexplore.ieee.org/document/9117042}, author = {Shahid Malik and Q. Castellv{\'\i} and Laura Becerra-Fajardo and Marc Tudela-Pi and Aracelys Garc{\'\i}a-Moreno and Maryam Shojaei Baghini and Antoni Ivorra} } @article {196, title = {Interleaved intramuscular stimulation with minimally overlapping electrodes evokes smooth and fatigue resistant forces}, journal = {Journal of Neural Engineering}, volume = {17}, year = {2020}, pages = {046037}, chapter = {046037}, doi = {10.1088/1741-2552/aba99e}, url = {https://doi.org/10.1088/1741-2552/aba99e}, author = {Ahmed Eladly and Jaume Del Valle and Jesus Minguillon and Borja Mercadal and Laura Becerra-Fajardo and Xavier Navarro and Antoni Ivorra} } @article {189, title = {Power Transfer by Volume Conduction: In Vitro Validated Analytical Models Predict DC Powers above 1 mW in Injectable Implants}, journal = {IEEE Access}, volume = {8}, year = {2020}, pages = {37808-37820}, chapter = {37808}, doi = {10.1109/ACCESS.2020.2975597}, author = {Marc Tudela-Pi and Laura Becerra-Fajardo and Aracelys Garc{\'\i}a-Moreno and Jesus Minguillon and Antoni Ivorra} } @conference {173, title = {First Steps Towards an Implantable Electromyography (EMG) Sensor Powered and Controlled by Galvanic Coupling}, booktitle = {World Congress on Medical Physics and Biomedical Engineering 2018. IFMBE Proceedings}, volume = {68/3}, year = {2018}, month = {2019}, pages = {19-22}, publisher = {Springer}, organization = {Springer}, address = {Prague, Czech Republic}, abstract = {

In the past it has been proposed to use implanted electromyography (EMG) sensors for myoelectric control. In contrast to surface systems, these implanted sensors provide signals with low cross-talk. To achieve this, miniature implantable devices that acquire and transmit real-time EMG signals are necessary. We have recently in vivo demonstrated electronic implants for electrical stimulation which can be safely powered and independently addressed by means of galvanic coupling. Since these implants lack bulky components as coils and batteries, we anticipate it will be possible to accomplish very thin implants to be massively deployed in tissues. We have also shown that these devices can have bidirectional communication. The aim of this work is to demonstrate a circuit architecture for embedding EMG sensing capabilities in our galvanically powered implants. The circuit was simulated using intramuscular EMG signals obtained from an analytical infinite volume conductor model that used a similar implant configuration. The simulations showed that the proposed analog front-end is compatible with the galvanic powering scheme and does not affect the implant{\textquoteright}s ability to perform electrical stimulation. The system has a bandwidth of 958 Hz, an amplification gain of 45 dB, and an output-referred noise of 160 {\textmu}Vrms. The proposed embedded EMG sensing capabilities will boost the use of these galvanically powered implants for diagnosis, and closed-loop control.

}, doi = {10.1007/978-981-10-9023-3_4}, author = {Laura Becerra-Fajardo and Antoni Ivorra} } @conference {172, title = {Powering Implants by Galvanic Coupling: A Validated Analytical Model Predicts Powers Above 1 mW in Injectable Implants}, booktitle = {World Congress on Medical Physics and Biomedical Engineering 2018. IFMBE Proceedings}, volume = {68/3}, year = {2018}, month = {2019}, pages = {23-26}, publisher = {Springer}, organization = {Springer}, address = {Prague, Czech Republic}, abstract = {

While galvanic coupling for intrabody communications has been proposed lately by different research groups, its use for powering active implantable medical devices remains almost non-existent. Here it is presented a simple analytical model able to estimate the attainable power by galvanic coupling based on the delivery of high frequency (\>1 MHz) electric fields applied as short bursts. The results obtained with the analytical model, which is in vitro validated in the present study, indicate that time-averaged powers above 1 mW can be readily obtained in very thin (diameter \< 1 mm) and short (length \< 20 mm) elongated implants when fields which comply with safety standards (SAR \< 10 W/kg) are present in the tissues where the implants are located. Remarkably, the model indicates that, for a given SAR, the attainable power is independent of the tissue conductivity and of the duration and repetition frequency of the bursts. This study reveals that galvanic coupling is a safe option to power very thin active implants, avoiding bulky components such as coils and batteries.

}, doi = {10.1007/978-981-10-9023-3_5}, author = {Marc Tudela-Pi and Laura Becerra-Fajardo and Antoni Ivorra} } @conference {175, title = {Two-Port Networks to Model Galvanic Coupling for Intrabody Communications and Power Transfer to Implants}, booktitle = {2018 IEEE Biomedical Circuits and Systems Conference (BioCAS)}, year = {2018}, month = {10/2018}, pages = {407-410}, isbn = {978-1-5386-3603-9}, doi = {10.1109/BIOCAS.2018.8584691}, author = {Laura Becerra-Fajardo and Marc Tudela-Pi and Antoni Ivorra} } @article {152, title = {Demonstration of 2 mm thick microcontrolled injectable stimulators based on rectification of high frequency current bursts}, journal = {IEEE Transactions on Neural Systems and Rehabilitation Engineering}, volume = {25}, year = {2017}, pages = {1343 - 1352}, chapter = {1343}, doi = {10.1109/TNSRE.2016.2623483}, author = {Laura Becerra-Fajardo and Marieluise Schmidbauer and Antoni Ivorra} } @conference {156, title = {Injectable Stimulators Based on Rectification of High Frequency Current Bursts: Power Efficiency of 2~mm Thick Prototypes}, booktitle = {Converging Clinical and Engineering Research on Neurorehabilitation II: Proceedings of the 3rd International Conference on NeuroRehabilitation (ICNR2016), October 18-21, 2016, Segovia, Spain}, year = {2017}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, address = {Cham}, abstract = {

To overcome the miniaturization bottleneck imposed by existing power generation/transfer technologies for implantable stimulators, we have proposed a heterodox electrical stimulation method based on local rectification of high frequency (>=1\ MHz) current bursts delivered through superficial electrodes. We have reported 2\ mm thick addressable injectable stimulators, made of off-the-shelf components, that operate according to this principle. Since a significant amount of high frequency power is wasted by Joule heating, the method exhibits poor energy efficiency. In here we have performed a numerical case study in which the presence of the above implant prototypes is simulated in an anatomically realistic leg model. The results from this study indicate that, despite low power transfer efficiency (~0.05\ \%), the power consumed by the external high frequency current generator is low enough (\<4\ W) to grant the use of small portable batteries.

}, isbn = {978-3-319-46669-9}, doi = {10.1007/978-3-319-46669-9_110}, url = {http://dx.doi.org/10.1007/978-3-319-46669-9_110}, author = {Laura Becerra-Fajardo and Garcia-Arnau, Roser and Antoni Ivorra}, editor = {Ib{\'a}{\~n}ez, Jaime and Gonz{\'a}lez-Vargas, Jos{\'e} and Azor{\'\i}n, Jos{\'e} Mar{\'\i}a and Akay, Metin and Pons, Jos{\'e} Luis} } @conference {140, title = {Bidirectional communications in wireless microstimulators based on electronic rectification of epidermically applied currents}, booktitle = {Neural Engineering (NER), 2015 7th International IEEE/EMBS Conference on}, year = {2015}, month = {April}, doi = {10.1109/NER.2015.7146680}, author = {Laura Becerra-Fajardo and Antoni Ivorra} } @conference {132, title = {Charge Counter for Performing Active Charge-Balance in Miniaturized Electrical Stimulators}, booktitle = {6th European Conference of the International Federation for Medical and Biological Engineering SE - 64}, series = {IFMBE Proceedings}, volume = {45}, year = {2015}, month = {2015///}, pages = {256 - 259}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, keywords = {active charge-balance, dc-blocking capacitor, FES, miniaturization, rectifier}, isbn = {978-3-319-11127-8}, url = {http://dx.doi.org/10.1007/978-3-319-11128-5_64}, author = {Laura Becerra-Fajardo and Antoni Ivorra}, editor = {Lackovi{\'c}, Igor and Vasic, Darko} } @article {138, title = {In Vivo Demonstration of Addressable Microstimulators Powered by Rectification of Epidermically Applied Currents for Miniaturized Neuroprostheses}, journal = {Plos One}, volume = {10}, year = {2015}, month = {07/2015}, chapter = {e0131666}, doi = {10.1371/journal.pone.0131666}, url = {http://dx.doi.org/10.1371\%2Fjournal.pone.0131666}, author = {Laura Becerra-Fajardo and Antoni Ivorra} } @article {144, title = {In vivo demonstration of injectable microstimulators based on charge-balanced rectification of epidermically applied currents}, journal = {Journal of Neural Engineering}, volume = {12}, year = {2015}, chapter = {066010}, doi = {10.1088/1741-2560/12/6/066010}, author = {Antoni Ivorra and Laura Becerra-Fajardo and Q. Castellv{\'\i}} } @conference {190, title = {Flexible Thread-like Electrical Stimulation Implants Based on Rectification of Epidermically Applied Currents which Perform Charge Balance}, booktitle = {2nd International Conference on NeuroRehabilitation (ICNR2014), Aalborg, 24-26 June, 2014}, year = {2014}, pages = {447-455}, publisher = {Springer}, organization = {Springer}, address = {Aalborg, Denmark}, isbn = {978-3-319-08072-7}, doi = {10.1007/978-3-319-08072-7_67}, author = {Antoni Ivorra and Laura Becerra-Fajardo} } @conference {131, title = {Towards addressable wireless microstimulators based on electronic rectification of epidermically applied currents}, booktitle = {Annual International Conference of the IEEE Engineering in Medicine and Biology Society}, year = {2014}, month = {2014///}, pages = {3973 - 3976}, publisher = {IEEE}, organization = {IEEE}, address = {Chicago}, abstract = {

Electrical stimulation has been explored to restore the capabilities of the nervous system in paralysis patients. This area of research and of clinical practice, known as Functional Electrical Stimulation, would greatly benefit from further miniaturization of implantable stimulators. To that end, we recently proposed and demonstrated an innovative electrical stimulation method in which implanted microstimulators operate as rectifiers of bursts of innocuous high frequency current supplied by skin electrodes, thus generating low frequency currents capable of stimulating excitable tissues. A diode could suffice in some applications but, in order to broaden the method{\textquoteright}s clinical applicability, we envision rectifiers with advanced capabilities such as current control and addressability. We plan flexible thread-like implants (diameters \< 300 urn) containing ASICs. As an intermediate stage, we are developing macroscopic implants (diameters \~{} 2 mm) made of off-the-shelf components. Here we present a circuit which responds to commands modulated within the high frequency bursts and which is able to deliver charge-balanced currents. We show that a number of these circuits can perform independent stimulation of segments of an anesthetized earthworm following commands from a computer.

}, keywords = {Batteries, Capacitors, Electrical Stimulation, Electrodes, Implants, Microcontrollers, Rectifiers}, author = {Laura Becerra-Fajardo and Antoni Ivorra} } @conference {Ivorra2013, title = {Wireless Microstimulators Based on Electronic Rectification of Epidermically Applied Currents: Safety and Portability Analysis}, booktitle = {18th IFESS Annual Conference}, year = {2013}, pages = {213{\textendash}216}, address = {Donostia-San Sebasti{\'a}n, Spain}, abstract = {

Miniaturization of implantable medical electronic devices is currently compromised by the available means for electrically powering them. Most common energy supply techniques for implants {\textendash} batteries and inductive couplers {\textendash} comprise bulky parts which, in most cases, are significantly larger than the circuitry they feed. For overcoming such miniaturization bottleneck in the case of implants for electrical stimulation, we recently proposed and demonstrated a method in which the implants operate as rectifiers of bursts of high frequency (HF) current supplied by remote electrodes. In this way, low frequency currents capable of performing stimulation of excitable tissues are generated locally around the implants whereas the auxiliary high frequency currents only cause innocuous heating. This approach has the potential to reduce the diameter of the implants to one-tenth the diameter of current microstimulators and, more importantly, to allow that most of the implants{\textquoteright} volume consists of flexible materials. Implants based on the proposed method may look like short pieces of flexible thread. With currently available microelectronic techniques, diameters down to 200 $μ$m are easily conceivable. The numerical study presented here, in which a hypothetical but plausible clinical scenario for paralysis is analyzed, shows that the auxiliary high frequency (1 MHz) currents will be indeed safe according to safety standards and that portable systems based on portable batteries will be feasible.

}, author = {Antoni Ivorra and Laura Becerra-Fajardo} } @conference {Becerra-Fajardo2012, title = {{Proof of Concept of a Stimulator Based on AC Current Rectification for Neuroprosthetics}}, booktitle = {XXX Congreso Anual de la Sociedad Espa{\~n}ola de Ingenir{\'\i}a Biom{\'e}dica}, year = {2012}, address = {San Sebasti{\'a}n, Spain}, abstract = {

For several years, researchers have developed techniques to replace and enhance the capabilities of our neural system by means of implantable electrical stimulation technologies. Even though important work has been done in this field, further progress must be accomplished in terms of miniaturization in order to ensure comfort, simpler surgical implantation procedures, and the capability of using multiple wireless smart stimulators for achieving more muscle recruitment. In the past, with the objective of accomplishing an unprecedented level of miniaturization, we have proposed the development of implantable stimulators that would act as rectifiers of AC current supplied by external electrodes. Here it is described the development and evaluation of an addressable stimulator based on discrete component technology as a proof-of-concept of the proposed method. This macroscopic version of the stimulator is capable of generating magnitude controlled bipolar pulses according to commands modulated in the AC current. Multiple evaluations were done to test the device, including DC current testing, in-vitro and in-vivo testing, concluding that the developed system is an effective proof-of-concept of the method proposed, being able to perform controlled electrical stimulation. Electrical current testing showed that anodal and cathodal currents were generated, and in-vivo testing showed the effective electrical stimulation of an anesthetized earthworm. It is concluded that the idea of developing smart rectifiers as implantable stimulators is feasible. This represents a first step towards the design of an implantable device with a miniaturization level without precedents.

}, author = {Laura Becerra-Fajardo and Antoni Ivorra} }