dr. V. Giagka

Assistant Professor
Bioelectronics (BE), Department of Microelectronics

Expertise: Design and fabrication of active implantable devices; Analog and mixed-signal integrated circuits for biomedical applications

Themes: Electroceuticals, Flexible implants, Microsystem integration, Neuroprosthetics, - stimulation and -modulation

Biography

Vasiliki (Vasso) Giagka was born in Athens, Greece, in 1984. She received the M.Eng. degree in electronic and computer engineering from Aristotle University of Thessaloniki, Thessaloniki, Greece, in 2009. She then moved to London to join the Analogue and Biomedical Electronics Group at University College London, UK from where she received the PhD degree in 2014. In 2015 she joined the Implanted Devices Group at University College London, UK, as a research associate.

She currently, since September 2015, holds an assistant professor position at the Bioelectronics Group at Delft University of Technology, Delft, The Netherlands, and since September 2018 she is also leading the group Technologies for Bioelectronics, at Fraunhofer Institute for Reliability and Microintegration IZM, Berlin, Germany. Between her two affiliations, she is carrying out research on the design and fabrication of active neural interfaces. In particular, she is investigating new approaches for neural stimulation and wireless power transfer, as well as, implant miniaturization, microsystem integration, packaging and encapsulation to meet the challenges of bioelectronic medicines.

EE-BD Biomedical Devices (BD) profile

A profile in our MSc-EE program dedicated to biomedical devices. Biomedical devices are used for medical diagnosis, monitoring and treatment. They can be fixed, portable, wearable, implantable and injectable. They are active and thus embed electronics, computing and software

EE4555 Active implantable biomedical microsystems

Cardiac pacemakers, cochlear implants, neuroprostheses, brain–computer interfaces, deep organ pressure sensors, precise drug delivery units, bioelectronic medicine and electroceuticals

ET4127 Themes in Biomedical Electronics

BioMEMS, biosensors, bioelectronics, ultrasound, microfluidics, wavefield imaging in monitoring, diagnosis and treatment

ET4130 Bioelectricity

Bioelectric phenomena, their sources and their mathematical analysis. Applications to neurostimulation and neuroprosthetic.

TM12003 Electrostimulation of Neurophysiological systems

Education history

G3-M10 Minor Translational Neuroscience

(not running) The minor Translational Neuroscience for medical students covers the most important clinical (TRF) and research themes and gives the students a good insight in the added value of translational neuroscience research.

POSITION-II: innovation in smart medical instruments

InForMed

An Integrated Pilot Line for Micro-Fabricated Medical Devices

  1. Silicone encapsulation of thin-film SiOx, SiOxNy and SiC for modern electronic medical implants: a comparative long-term ageing study
    C. Lamont; T. Grego; K. Nanbakhsh; A. Shah Idil; V. Giagka; A. Vanhoestenberghe; S. Cogan; N. Donaldson;
    Journal of Neural Engineering,
    March 2021.
    document

  2. Development of dorsal root ganglion (DRG) multichannel stimulator prototype for use in early clinical trials
    K. Kolovou-Kouri; S. Soloukey; B.S. Harhangi; W.A. Serdijn; V. Giagka;
    In Book of Abstracts, 8th Dutch Biomedical Engineering Conf. (BME) 2021,
    Virtual, 28-29 January 2021.
    document

  3. Schlieren Visualization of Focused Ultrasound Beam Steering for Spatially Specific Stimulation of the Vagus Nerve
    Shinnosuke Kawasaki; Eric Dijkema; Marta Saccher; Vasiliki Giagka; Jean Schleipen; Ronald Dekker;
    In Proc. 2021 10th International IEEE/EMBS Conference on Neural Engineering (NER),
    Online, IEEE, May 4-6 2021.
    Keywords: ... Neural Interfaces - Neural stimulation, Neural Interfaces - Implantable systems, Neural Interfaces - Neural microsystems and Interface engineering.

    Abstract: ... In the bioelectronic medicine field, vagus nerve stimulation (VNS) is a promising technique that is expected to treat numerous inflammatory conditions, in addition to the currently FDA approved treatment for epilepsy, depression and obesity [1]. However, current VNS techniques are still limited in the spatial resolution that they can achieve, which limits its therapeutic effect and induces side effects such as coughing, headache and throat pain. In our prior work, we presented a curved ultrasound (US) transducer array with a diameter of 2 mm and with 112 miniature US transducer elements, small enough to be wrapped around the vagus nerve for precise ultrasound nerve stimulation [2]. Due to the curved alignment of the US transducers with 48 of the elements simultaneously excited, the emitted US was naturally focused at the center of the curvature. Building on this work, we employ a beam steering technique to move the focal spot to arbitrary locations within the focal plane of the transducer array. The beam steering was controlled through an in-house built US driver system and was visualized using a pulsed laser schlieren system. The propagation of the US pulse in water was imaged and recorded. This method was found to be a rapid and effective means of visualizing the US propagation.

  4. Towards a wireless system that can monitor the encapsulation of mm-sized active implants in vivo for bioelectronic medicine
    Kambiz Nanbakhsh;Vasiliki Giagka;
    In Proc. 2021 10th International IEEE/EMBS Conference on Neural Engineering (NER),
    Online, IEEE, May 4-6 2021.
    Keywords: ... Neural Interfaces - Implantable systems, Neural Interfaces - Neural microsystems and Interface engineering.

    Abstract: ... Active neural interfaces for bioelectronic medicine are envisioned to be mm-sized. Such miniaturization is at the moment hampered by the available wireless power techniques as well as the large volume the conventional hermetic packaging adds to the implant. Alternatively, conformal coatings are being explored for the protection of the implant electronics. Such approach has the potential to allow for the use of RF (radio-frequency) energy for powering, and miniaturization to the extreme of having a single IC (integrated circuit) as the whole implant (single chip implants). The longevity of conformal encapsulation can be assessed using accelerated soak tests in a dedicated apparatus in vitro, but these are usually not sufficient, as they fail to reveal additional failure modes that manifest themselves in vivo. Therefore, to investigate the performance of conformal coatings in vivo a compact, mm-sized wireless monitoring system is required. The development of such a system exhibits several challenges, mostly concerned with how, to receive enough energy in such a small implant to power the monitoring sensor and transmit information regarding the integrity of the coating. In this paper proposes a system architecture for such a mm-sized wireless system, suitable for medium-to-long term monitoring of implants, by designing the whole system as a single monolithic IC. It is shown, by experiments, simulation or analytically that the identified challenges are possible to overcome.

  5. Investigation of the long-term adhesion and barrier properties of a PDMS-Parylene stack with PECVD ceramic interlayers for the conformal encapsulation of neural implants
    Nasim Bakhshaee; Ronald Dekker; Ole Holk; Ursa Tiringer; Peyman Taheri; Domonkos Horvath; Tibor Nanasi; István Ulbert; Wouter Serdijn; Vasiliki Giagka;
    In IEEE European Microelectronics and Packaging Conference (EMPC),
    Online, September 2021.
    document

  6. UV and IR laser-patterning for high-density thin-film neural interfaces,” in Proc.
    Andrada Velea; Joshua Wilson; Anna Pak; Manuel Seckel; Sven Schmidt; Stefan Kosmider; Nasim Bakhshaee; Wouter Serdijn; Vasiliki Giagka;
    In IEEE European Microelectronics and Packaging Conference (EMPC) 2021,
    Online, September 2021.
    document

  7. Schlieren Visualization of Focused Ultrasound Beam Steering for Spatially Specific Stimulation of the Vagus Nerve In Proc. 2021 10th , Online, IEEE, May 4-6 2021.
    Shinnosuke Kawasaki; Eric Dijkema; Marta Saccher; Vasiliki Giagka; Jean Schleipen; Ronald Dekker;
    In 10th International IEEE/EMBS Conference on Neural Engineering (NER),
    Online, May 4-6 2021. 2021.

  8. Dorsal Root Ganglion (DRG) Versatile Stimulator Prototype Developed for Use in Locomotion Recovery Early Clinical Trials
    Konstantina Kolovou-Kouri; Sadaf Soloukey; Frank Huygen; Sanjay Biswadjiet Harhangi; Wouter Serdijn; Vasiliki Giagka;
    In 10th International IEEE/EMBS Conference on Neural Engineering (NER),
    Online, IEEE, May 4-6 2021 2021.

  9. Bidirectional Bioelectronic Interfaces: System Design and Circuit Implications
    Y. Liu; A. Urso; R. Martins da Ponte; T. Costa; V. Valente; V. Giagka; W.A. Serdijn; T.G. Constandinou; T. Denison;
    IEEE Solid-State Circuits Magazine,
    Volume 12, Issue 2, pp. 30-46, 23 June 2020. DOI: 10.1109/MSSC.2020.2987506
    document

  10. A Chip Integrity Monitor for Evaluating Moisture/Ion Ingress in mm-Sized Single-Chip Implants
    Omer Can Akgun; Kambiz Nanbakhsh; Vasiliki Giagka; Wouter Serdijn;
    IEEE Transactions on Biomedical Circuits and Systems,
    7 July 2020. DOI: 10.1109/TBCAS.2020.3007484
    Keywords: ... —Chip integrity, flexible implants, encapsulation, interlayer dielectric (ILD), silicon dioxide, resistance, time-mode, monitoring, reliability.

    document

  11. Monolithic Integration of a Smart Temperature Sensor on a Modular Silicon-based Organ-on-a-Chip Device
    Ronaldo Martins da Ponte; Nikolas Gaio; Henk van Zeijl; Sten Vollebregt; Paul Dijkstra; Ronald Dekker; Wouter A. Serdijn; Vasiliki Giagka;
    Sensors and Actuators A: Physical,
    Nov. 21 2020. ISSN 0924-4247.
    Keywords: ... Organs-on-a-chip; Smart temperature sensor; Time-mode domain signal processing; MEMS; CMOS Monolithic Integration; MEMS-Electronics co-fabrication.

    Abstract: ... One of the many applications of organ-on-a-chip (OOC) technology is the study of biological processes in human induced pluripotent stem cells (iPSCs) during pharmacological drug screening. It is of paramount importance to construct OOCs equipped with highly compact in situ sensors that can accurately monitor, in real time, the extracellular fluid environment and anticipate any vital physiological changes of the culture. In this paper, we report the co-fabrication of a CMOS smart sensor on the same substrate as our silicon-based OOC for real-time in situ temperature measurement of the cell culture. The proposed CMOS circuit is developed to provide the first monolithically integrated in situ smart temperature-sensing system on a micromachined silicon-based OOC device. Measurement results on wafer reveal a resolution of less than ±0.2 °C and a nonlinearity error of less than 0.05% across a temperature range from 30 °C to 40 °C. The sensor's time response is more than 10 times faster than the time constant of the convection-cooling mechanism found for a medium containing 0.4 ml of PBS solution. All in all, this work is the first step towards realising OOCs with seamless integrated CMOS-based sensors capable to measure, in real time, multiple physical quantities found in cell culture experiments. It is expected that the use of commercial foundry CMOS processes may enable OOCs with very large scale of multi-sensing integration and actuation in a closed-loop system manner.

    document

  12. PDMS-Parylene Adhesion Improvement via Ceramic Interlayers to Strengthen the Encapsulation of Active Neural Implants
    Nasim Bakhshaee; Ronald Dekker; Wouter Serdijn; Vasiliki Giagka;
    Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC),
    July 2020. DOI: 10.1109/EMBC44109.2020.9175646
    document

  13. Wafer-scale Graphene-based Soft Implant with Optogenetic Compatibility
    A.I. Velea; S. Vollebregt; G.K. Wardhana; V. Giagka;
    In Proc. IEEE Microelectromech. Syst. (MEMS) 2020,
    Vancouver, Canada, IEEE, Jan. 2020.
    document

  14. Circuit Design Considerations for Power-Efficient and Safe Implantable Electrical Neurostimulators
    Rui Guan; Pedro G. Zufiria; Vasiliki Giagka; Wouter A. Serdijn;
    In proc. IEEE Latin American Symposium on Circuits and Systems (LASCAS 2020),
    San Jose, Costa Rica, IEEE, IEEE, February 25-28 2020.
    document

  15. Long-term encapsulation of platinum metallization using a HfO2 ALD - PDMS bilayer for non-hermetic active implants
    K. Nanbakhsh; R. Ritasalo; W.A. Serdijn; V. Giagka;
    In Proc. IEEE Electron. Comp. Tech. Conf. (ECTC) 2020,
    Orlando, FL, USA, IEEE, May 2020.
    document

  16. PDMS to Parylene Adhesion Improvement for Encapsulating an Implantable Device
    Nasim Bakhshaee; R. Dekker; W.A. Serdijn; V. Giagka;
    In Proc. 42nd Int. Conf. of the IEEE Engineering in Medicine and Biology (EMBC) 2020,
    Montreal, Canada, July 2020.
    document

  17. Engineering long-lasting and spatially selective active neural interfaces for bioelectronic medicine (invited presentation)
    Vasiliki Giagka;
    In 17th International Conference on Nanosciences & Nanotechnologies (NN20) 2020,
    Thessaloniki, Greece, July 2020.
    document

  18. Soft, flexible and transparent graphene-based active spinal cord implants for optogenetic studies
    A. Velea; S. Vollebregt; V. Giagka;
    In proc. 13th International Symposium on Flexible Organic Electronics (ISFOE20) 2020,
    Thessaloniki, Greece, July 2020.
    document

  19. Towards CMOS Bulk Sensing for In Situ Evaluation of ALD Coatings for Millimeter Sized Implants
    K. Nanbakhsh; R. Ritasalo; W.A. Serdijn; V. Giagka;
    In Proc. 42nd Int. Conf. of the IEEE Engineering in Medicine and Biology (EMBC) 2020,
    Montreal, Canada, July 2020.
    document

  20. If the Medicine of the future is Bioelectronic, how does the pill of the future look like? – and what does it take to make it? (invited presentation)
    Vasiliki Giagka;
    In NanoVision 2020 “Sense of materials” Virtual Symposium,
    12-13 Nov. 2020.
    document

  21. Comments on “Compact, Energy-Efficient High-Frequency Switched Capacitor Neural Stimulator With Active Charge Balancing"
    Alessandro Urso; Vasiliki Giagka; Wouter A. Serdijn;
    IEEE Transactions on Biomedical Circuits and Systems,
    2019. DOI: 10.1109/TBCAS.2019.2898555
    document

  22. An Ultra High-Frequency 8-Channel Neurostimulator Circuit with 68% Peak Power Efficiency
    Alessandro Urso; Vasiliki Giagka; Marijn Van Dongen; Wouter A. Serdijn;
    IEEE Transactions on Biomedical Circuits and Systems,
    2019. DOI: 10.1109/TBCAS.2019.2920294
    document

  23. Towards a Semi-Flexible Parylene-Based Platform Technology for Active Implantable Medical Devices
    Nasim Bakhshaee; Marta Kluba; Ronald Dekker; Wouter Serdijn; Vasiliki Giagka;
    Book of Abstracts, 2019 International Winterschool on Bioelectronics Conference (BioEl 2019),
    Marchch 2019. International Winterschool on Bioelectronics Conference (BioEl 2019), Kirchberg, Tirol, Austria, 16-23 March 2019..

  24. Towards a Semi-flexible Parylene-based Platform Technology for Active Implantable Medical Devices
    Nasim Bakhshaee; Marta Kluba; Ronald Dekker; Wouter Serdijn; Vasiliki Giagka;
    Book of Abstracts, SAFE 2019,
    July 2019. SAFE 2019, Delft, the Netherlands, July 4-5 2019..

  25. Towards a semi-flexible parylene-based platform technology for active implantable medical devices
    Nasim Bakhshaee; Marta Kluba; Ronald Dekker; Wouter Serdijn; Vasiliki Giagka;
    Book of abstracts, 7th Dutch Biomedical Engineering Conf. (BME) 2019,
    Issue 1-1, pp. 1, January 2019.
    document

  26. EMBEDDING SMALL ELECTRONIC COMPONENTS INTO TINY FLEXIBLE IMPLANTS
    Anna Pak; Wouter A. Serdijn; Vasiliki Giagka;
    In Book of Abstracts, 7th Dutch Biomedical Engineering Conf. (BME) 2019,
    Jan. 24-25 2019.
    document

  27. TOWARDS AN ACTIVE GRAPHENE-PDMS IMPLANT
    Gandhika K Wardhana; Wouter A. Serdijn; Sten Vollebregt; Vasiliki Giagka;
    In Book of Abstracts, 7th Dutch Biomedical Engineering Conf. (BME) 2019,
    Jan. 24-25 2019.
    document

  28. POLYMER-ENCAPSULATED SINGLE-CHIP IMPLANTS FOR BIOELECTRONIC MEDICINE
    Kambiz Nanbakhsh; Wouter Serdijn; Vasiliki Giagka;
    In Book of Abstracts, 7th Dutch Biomedical Engineering Conf. (BME) 2019,
    Jan. 24-25 2019.
    document

  29. TOWARDS A SEMI-FLEXIBLE PARYLENE-BASED PLATFORM TECHNOLOGY FOR ACTIVE IMPLANTABLE MEDICAL DEVICES
    Nasim Bakhshaee; Marta Kluba; Ronald Dekker; Wouter Serdijn; Vasiliki Giagka;
    In Book of Abstracts, 7th Dutch Biomedical Engineering Conf. (BME) 2019,
    Jan. 24-25 2019.
    document

  30. THE INFLUENCE OF SOFT ENCAPSULATION MATERIALS ON THE WIRELESS POWER TRANSFER LINKS EFFICIENCY
    Anastasios Malissovas; Wouter A. Serdijn; Vasiliki Giagka;
    In Book of Abstracts, 7th Dutch Biomedical Engineering Conf. (BME) 2019,
    Jan. 24-25 2019.
    document

  31. DESIGN AND CUSTOM FABRICATION OF A SMART TEMPERATURE SENSOR FOR AN ORGAN-ON-A-CHIP PLATFORM
    Martins da Ponte, Ronaldo; Vasiliki Giagka; Wouter A. Serdijn;
    In Book of Abstracts, 7th Dutch Biomedical Engineering Conf. (BME) 2019,
    Jan. 24-25 2019.
    document

  32. DESIGN OF A MULTI-FUNCTIONAL SMART OPTRODE FOR ELECTROPHYSIOLOGY AND OPTOGENETICS
    Martins da Ponte, Ronaldo; Chengyu Huang; Vasiliki Giagka; Wouter A. Serdijn;
    In Book of Abstracts, 7th Dutch Biomedical Engineering Conf. (BME) 2019,
    Jan. 24-25 2019.
    document

  33. Pressure measurement of geometrically curved ultrasound transducer array for spatially specific stimulation of the vagus nerve
    S. Kawasaki; V. Giagka; M. de Haas; M. Louwerse; V. Henneken; C. van Heesch; R. Dekker;
    In Proc. IEEE Conf. on Neural Eng. (NER) 2019,
    San Francisco, CA, USA, March 2019.
    Abstract: ... Vagus nerve stimulators currently on the market can treat epilepsy and depression. Recent clinical trials show the potential for vagus nerve stimulation (VNS) to treat epilepsy, autoimmune disease, and traumatic brain injury. As we explore the benefits of VNS, it is expected that more possibilities for a new treatment will emerge in the future. However, existing VNS relies on electrical stimulation, whose limited selectivity (due to its poor spatial resolution) does not allow for any control over which therapeutic effect to induce. We hypothesize that by localizing the stimulation to fascicular level within the vagus nerve with focused ultrasound (US), it is possible to induce selective therapeutic effects with less side effects. A geometrically curve US transducer array that is small enough to wrap around the vagus nerve was fabricated. An experiment was conducted in water, with 48 US elements curved in a 1 mm radius and excited at 15 MHz to test the focusing capabilities of the device. The results show that the geometrical curvature focused the US to an area with a width and height of 110 μm and 550 μm. This will be equivalent to only 2.1% of the cross section of the vagus nerve, showing the potential of focused US to stimulate individual neuronal fibers within the vagus nerve selectively.

    document

  34. Embedding Small Electronic Components into Tiny Flexible Implants
    Anna Pak; Wouter A. Serdijn; Vasiliki Giagka;
    In Book of Abstracts, 2019 International Winterschool on Bioelectronics Conference (BioEl 2019),
    Kirchberg, Tirol, Austria, 16-23 March 2019.
    document

  35. Towards a Semi-Flexible Parylene-Based Platform Technology for Active Implantable Medical Devices
    Nasim Bakhshaee; Marta Kluba; Ronald Dekker; Wouter Serdijn; Vasiliki Giagka;
    In Book of Abstracts, 2019 International Winterschool on Bioelectronics Conference (BioEl 2019),
    Kirchberg, Tirol, Austria, 16-23 March 2019.
    document

  36. An Ultra High-Frequency 8-Channel Neurostimulator Circuit with 68% Peak Power Efficiency
    Alessandro Urso; Vasiliki Giagka; Marijn Van Dongen; Wouter A. Serdijn;
    In Book of Abstracts, 2019 International Symposium on Integrated Circuits and Systems (ISICAS 2019),
    Venice, Italy, IEEE, 29-30 August 2019. DOI: 10.1109/TBCAS.2019.2920294
    document

  37. Monolithic Integration of an In-situ Smart Sensor in a Silicon-based Organ-on-a-chip Platform for Monitoring the Temperature of Stem Cell Culture
    R. Ponte; V. Giagka; W. Serdijn;
    In Book of Abstracts, SAFE 2019,
    Delft, the Netherlands, July 4-5 2019.
    document

  38. Towards a semi-flexible parylene-based platform technology for active implantable medical devices
    Nasim Bakhshaee; M. Kluba; R. Dekker; W. Serdijn; V. Giagka;
    In Book of Abstracts, SAFE 2019,
    Delft, the Netherlands, July 4-5 2019.
    document

  39. Polymer-Encapsulated Single-Chip Implants for Bioelectronic Medicine
    K. Nanbakhsh; W. Serdijn; V. Giagka;
    In Book of Abstracts, SAFE 2019,
    Delft, the Netherlands, July 4-5 2019.
    document

  40. Flexible, graphene-based active implant for spinal cord stimulation in rodents
    A.I. Velea; S. Vollebregt; V. Giagka;
    In Book of Abstracts, SAFE 2019,
    Delft, the Netherlands, July 4-5 2019.
    document

  41. Design and MEMS microfabrication of a multifunctional smart optrode for combined optogenetics and electrophysiology studies
    R. Ponte; C. Huang; V. Giagka; W. Serdijn;
    In Book of Abstracts, SAFE 2019,
    Delft, the Netherlands, July 4-5 2019.
    document

  42. Effect of Signals on the Encapsulation Performance of Parylene Coated Platinum Tracks for Active Medical Implants
    Kambiz Nanbakhsh; Marta Kluba; B. Pahl; F. Bourgeois; Ronald Dekker; Wouter Serdijn; V. Giagka;
    In Proc. 41st Int. Conf. of the IEEE Engineering in Medicine and Biology (EMBC) 2019,
    Berlin, Germany, IEEE, July 23-27 2019.
    document

  43. Embedding small and thin electronics into flexible implants
    A. Pak; W.A. Serdijn; V. Giagka;
    In Book of Abstracts, SAFE 2019,
    Delft, the Netherlands, July 4-5 2019.
    document

  44. A Chip Integrity Monitor for Evaluating Long-term Encapsulation Performance Within Active Flexible Implants
    Omer Can Akgun; Kambiz Nanbakhsh; Vasiliki Giagka; Wouter A. Serdijn;
    In Proc. IEEE Biomedical Circuits and Systems Conference (BioCAS 2019),
    IEEE, October 17-19 2019.
    document

  45. Towards a Microfabricated Flexible Graphene-Based Active Implant for Tissue Monitoring During Optogenetic Spinal Cord Stimulation
    A.I. Velea; S. Vollebregt; V. Giagka;
    In Book of Abstracts, IEEE Nanotech. Mater. Dev. Conf. (NMDC) 2019,
    Stockholm, Sweden, IEEE, Oct. 2019.
    Abstract: ... Our aim is to develop a smart neural interface with transparent electrodes to allow for electrical monitoring of the site of interest during optogenetic stimulation of the spinal cord. In this work, we present the microfabrication process for the wafer-level development of such a compact, active, transparent and flexible implant. The transparent, passive array of electrodes and tracks have been developed using graphene, on top of which chips have been bonded using flip-chip bonding techniques. To provide high flexibility, soft encapsulation, using polydimethylsiloxane (PDMS) has been used. Preliminary measurements after the bonding process have shown resistance values in the range of kΩ for the combined tracks and ball-bonds.

    document

  46. Towards a Microfabricated Flexible Graphene-Based Active Implant for Tissue Monitoring During Optogenetic Spinal Cord Stimulation
    A.I. Velea; S. Vollebregt; T. Hosman; A. Pak; V. Giagka;
    In Proceedings IEEE Nanotechnology Materials and Devices Conference (NMDC) 2019,
    Stockholm, Sweden, Oct. 2019.
    Abstract: ... This work aims to develop a smart neural interface with transparent electrodes to allow for electrical monitoring of the site of interest during optogenetic stimulation of the spinal cord. In this paper, a microfabrication process for the wafer-level development of such a compact, active, transparent and flexible implant is presented. Graphene has been employed to form the transparent array of electrodes and tracks, on top of which chips have been bonded using flip-chip bonding techniques. To provide high flexibility, soft encapsulation, using polydimethylsiloxane (PDMS) has been used. Making use of the "Flex-to-Rigid" (F2R) technique, cm-size graphene-on-PDMS structures have been suspended and characterized using Raman spectroscopy to qualitatively evaluate the graphene layer, together with 2-point measurements to ensure the conductivity of the structure. In parallel, flip-chip bonding processes of chips on graphene structures were employed and the 2-point electrical measurement results have shown resistance values in the range of kΩ for the combined tracks and ball-bonds.

    document

  47. Realizing flexible bioelectronic medicines for accessing the peripheral nerves – technology considerations
    Vasiliki Giagka; Wouter Serdijn;
    Bioelectronic Medicine,
    Volume 4, Issue 8, June 26 2018. DOI: 10.1186/s42234-018-0010-y
    document

  48. An Energy-Efficient, Inexpensive, Spinal Cord Stimulator with Adaptive Voltage Compliance for Freely Moving Rats
    Olafsdottir, Gudrun Erla; Serdijn, Wouter A.; Giagka, Vasiliki;
    In Proc. 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society,
    Honolulu, HI, USA, IEEE, July 17-21 2018.
    document

  49. An Ultrasonically Powered and Controlled Ultra-High-Frequency Biphasic Electrical Neurostimulator
    Lucia Tacchetti; Wouter A. Serdijn; Vasiliki Giagka;
    In proc. IEEE Biomedical Circuits and Systems Conference (BioCAS 2018),
    IEEE, Oct. 17-19 2018.
    document

  50. Design and Custom Fabrication of a Smart Temperature Sensor for an Organ-on-a-chip Platform
    Martins da Ponte, Ronaldo; Vasiliki Giagka; Wouter A. Serdijn;
    In proc. IEEE Biomedical Circuits and Systems Conference (BioCAS 2018),
    IEEE, Oct. 17-19 2018.
    document

  51. MEMS-Electronics Integration: A Smart Temperature Sensor for an Organ-on-a-chip Platform
    Martins da Ponte, Ronaldo; Vasiliki Giagka; Wouter A. Serdijn;
    In Proc. ProRISC,
    Enschede, the Netherlands, June 7-8 2018.
    document

  52. Circuit and systems for polymeric implants: designing towards increased device lifetimes
    K. Nanbakhsh; V. Giagka; W.A. Serdijn;
    In Proc. ProRISC,
    Enschede, the Netherlands, June 7-8 2018.
    document

  53. Towards a Family of Customisable Flexible Neural Implants
    Vasiliki Giagka; Wouter Serdijn;
    In Book of Abstracts, 6th Dutch Bio-Medical Engineering Conference, 26 and 27 January 2017, Egmond aan Zee, The Netherlands,
    2017.
    document

  54. A wireless sensor for monitoring encapsulation performance in non-hermetic implants
    K. Nanbakhsh; V. Giagka; W. A. Serdijn;
    In Proc. Design of Medical Devices Conf. (DMD) 2017 Microfabrication for Medical Devices,
    Eindhoven, 14 – 15 Nov. 2017.
    document

  55. Towards a Flexible Implant with Distributed Electronics, Wireless Communication and Energy Transfer
    Martins da Ponte, Ronaldo; Vasiliki Giagka; Wouter Serdijn;
    In Book of Abstracts, 6th Dutch Bio-Medical Engineering Conference, 26 and 27 January 2017, Egmond aan Zee, The Netherlands,
    2017.
    document

  56. MEMS-electronics integration: a smart temperature sensor for an organ-on-a-chip platform
    Martins da Ponte, Ronaldo; V. Giagka; W.A. Serdijn;
    In Proc. Design of Medical Devices Conf. (DMD) 2017 Microfabrication for Medical Devices,
    Eindhoven, 14 – 15 Nov 2017.
    document

  57. Towards a wearable near infrared spectroscopic probe for monitoring concentrations of multiple chromophores in biological tissue in vivo
    Danial Chitnis; Dimitrios Airantzis; David Highton; Rhys Williams; Phong Phan; Vasiliki Giagka; Samuel Powell; Robert J Cooper; Ilias Tachtsidis; Martin Smith; Clare E Elwell; Jeremy C Hebden; Nicholas Everdell;
    Review of Scientific Instruments,
    Volume 87, Issue 6, pp. 065112, June 1 2016. Publisher: AIP Publishing.
    document

  58. Flexible active electrode arrays with ASICs that fit inside the rat's spinal canal
    Vasiliki Giagka; Andreas Demosthenous; Nick Donaldson;
    Biomedical Microdevices,
    Volume 17, Issue 6, pp. 106 - 118, December 2015. DOI 10.1007/s10544-015-0011-5.
    document

  59. An Implantable Versatile Electrode-Driving ASIC for Chronic Epidural Stimulation in Rats
    Vasiliki Giagka; Clemens Eder; Nick Donaldson; Andreas Demosthenous;
    IEEE Transactions on Biomedical Circuits and Systems,
    Volume 9, Issue 3, pp. 387 - 400, June 2015. DOI 10.1109/TBCAS.2014.2330859.
    document

  60. Flexible Active Electrode Arrays For Epidural Spinal Cord Stimulation
    Vasiliki Giagka;
    PhD thesis, University College London, Analogue and Biomedical Electronics Group, Department of Electronic and Electrical Engineering, January, 28 2015.
    document

  61. Evaluation and optimization of the mechanical strength of bonds between metal foil and aluminium pads on thin ASICs using gold ball studs as micro-rivets
    Vasiliki Giagka; Anne Vanhoestenberghe; Nick Donaldson; Andreas Demosthenous;
    In Proc. Electronics System-Integration Technology Conference,
    Helsinki, Finland, IEEE, pp. 1 - 5, September 2014.
    document

  62. Controlled silicon IC thinning on individual die level for active implant integration using a purely mechanical process
    Vasiliki Giagka; Nooshin Saeidi; Andreas Demosthenous; Nick Donaldson;
    In Proc. 64th Electronic Components and Technology Conference,
    Orlando, Florida, USA, IEEE, pp. 2213 - 2219, May 2014.
    document

  63. A dedicated electrode driving ASIC for epidural spinal cord stimulation in rats
    Vasiliki Giagka; Clemens Eder; Virgilio Valente; Anne Vanhoestenberghe; Nick Donaldson; Andreas Demosthenous;
    In Proc. 20th International Conference on Electronics, Circuits and Systems,
    Abu Dhabi, UAE, IEEE, pp. 469 - 472, December 2013.
    document

  64. In vivo evaluation and failure analysis of an implantable electrode array for epidural spinal cord stimulation in paralysed rats
    Vasiliki Giagka; Anne Vanhoestenberghe; Nick Donaldson; Andreas Demosthenous;
    In imaps-uk Annual Conference MicroTech 2013 Showcasing Microassembly,
    Cambridge, UK, pp. 1, March 2013.

  65. An Implantable Stimulator System For Neuro-Rehabilitation In Paralyzed Rats
    Vasiliki Giagka; Nick Donaldson; Andreas Demosthenous;
    In Young Researchers Futures Meeting - Neural Engineering,
    Warwick, UK, pp. 1, September 2012.

  66. Towards a low-power active epidural spinal cord array controlled through a two wire interface
    Vasiliki Giagka; Andreas Demosthenous; Nick Donaldson;
    In Proc. 8th Conf. Ph.D. Research in Microelectronics and Electronics,
    Aachen, Germany, VDE, pp. 247 - 250, June 2012.
    document

  67. Flexible platinum electrode arrays for epidural spinal cord stimulation in paralyzed rats: An in vivo and in vitro evaluation
    Vasiliki Giagka; Anne Vanhoestenberghe; Nikolaus Wenger; Pavel Musienko; Nick Donaldson; Andreas Demosthenous;
    In Proc. 3rd Annual Conf. International Functional Electrical Stimulation Society UK and Ireland Chapter,
    Birmingham, UK, pp. 52 - 53, April 2012.
    document

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