Healthy aims: developing new medical implants and diagnostic equipment

Healthy Aims is a €23-million, four-year project, funded under the EU’s Information Society Technology Sixth Framework program to develop intelligent medical implants and diagnostic systems (www.healthyaims.org). The project has 25 partners from 10 countries, including commercial, clinical, and research groups. This consortium represents a combination of disciplines to design and fabricate new medical devices and components as well as to test them in laboratories and subsequent clinical trials. The project focuses on medical implants for nerve stimulation and diagnostic equipment based on straingauge technology

SINPHOS - SINgle PHOton spectrometer for biomedical application

In the last decades several experiments have clearly demonstrated that, once illuminated, all biological systems emit for some time a very weak flux of photons, called Delayed Luminescence (DL). Some recent results have shown the possibility of using the DL as a diagnostic tool in the field of optical biopsy or of multi-dimensional diagnostics. Following such indications we decided to start developing SINPHOS, a monolithic micro-device, capable of measuring simultaneously the time distribution and the spectrum of photons coming from a weak source. Two important innovative aspects will characterize this spectrometer: the optical part, realized by means of the Deep Lithography with Particles (DLP), and SPAD (Single Photon Avalanche Diode) detectors under development along with ST-Microelectronics

Fabricación de un Micro Sensor de Presión Implantable Aplicado a Medir Desviaciones Dentro de la Cochlea

The Cochlear Implant is broadly worn by people with deep hearing damage. This device makes up an electrode array to electrically stimulate the auditory nerves. When the electrode is implanted into the inner ear by surgery, the scala tympani is ill-treated due to the strong pressure applied on the internal ear structures. To minimize this intra-cochlear trauma, it is proposed to fabricate a micro pressure-sensor and built it in the electrode array, in such a way that the pressure applied by the electrode is measured. This work selected the MEMS SU-8 Fabry-Perot interferometer-based pressure sensor. This paper describes the sensor fabrication process carried out, and explains how to integrate this sensor with the electrode array.El implante coclear es ampliamente utilizado por personas con año auditivo profundo. Este dispositivo se compone de un conjunto de electrodos que estimulan eléctricamente los nervios auditivos. Cuando el electrodo es insertado quirúrgicamente en el oído interno, la escala timpani es maltratada debido a las considerables presiones aplicadas a las estructuras internas del oído. Esto ocasiona trauma, lo cual es indeseado. y es principalmente causado por el contacto del electrodo con las paredes de la cóclea. Para minimizar este trauma, se propone fabricar un MEMS sensor de presión para que sea integrado al conjunto de electrodos; permitiendo medir la presión aplicada al oído. Este trabajo ha seleccionado el SU8 MEMS sensor de presión basado en el efecto de interferencia óptica. Este artículo describe el proceso de fabricación del sensor y como se puede integrar al array de electrodos

Prototyping micro-optical components with integrated out-of-plane coupling structures using deep lithography with protons: art. no. 618504

We present Deep Lithography with Protons (DLP) as a rapid prototyping technology to fabricate waveguide-based micro-optical components with monolithically integrated 45 degrees micro-mirrors acting as out-of-plane couplers, splitting the optical signal in 3 separated paths. For the first time, two different proton beam sizes are used during one irradiation and a 20 mu m collimating aperture is chosen to accurately define the out-of-plane coupling structures. We fully optimized the DLP process for this 20 mu m proton beam and we measured the surface roughness (R-q=27.5nm) and the flatness (R-t=3.17 mu m) of the realized components. Finally, we experimentally measured the optical transmission efficiency of the micro-optical splitter component. The results are in excellent agreement with non-sequential ray-tracing simulations performed for the design. Above that, we present a pluggable out-of-plane coupler incorporating a single micro-mirror for the 90 degrees coupling of light to or from polymer multimode waveguides integrated on a printed circuit board (PCB). This millimeter-sized mass-reproducible component can then be readily inserted into laser ablated cavities. Non-sequential ray-tracing simulations are performed to predict the optical performance of the component, showing coupling efficiencies up to 78%. These results are then experimentally verified using piezo-motorized positioning equipment with submicron accuracy in a multimode fiber-to-fiber coupling scheme, showing coupling efficiencies up to 56%. The fabricated coupling components are suitable for low-cost mass production since our micro-optical prototyping technology is compatible with standard replication techniques, such as hot embossing and injection molding, has been shown before

Investigation of a new electrode array technology for a central auditory prosthesis.

Ongoing clinical studies on patients recently implanted with the auditory midbrain implant (AMI) into the inferior colliculus (IC) for hearing restoration have shown that these patients do not achieve performance levels comparable to cochlear implant patients. The AMI consists of a single-shank array (20 electrodes) for stimulation along the tonotopic axis of the IC. Recent findings suggest that one major limitation in AMI performance is the inability to sufficiently activate neurons across the three-dimensional (3-D) IC. Unfortunately, there are no currently available 3-D array technologies that can be used for clinical applications. More recently, there has been a new initiative by the European Commission to fund and develop 3-D chronic electrode arrays for science and clinical applications through the NeuroProbes project that can overcome the bulkiness and limited 3-D configurations of currently available array technologies. As part of the NeuroProbes initiative, we investigated whether their new array technology could be potentially used for future AMI patients. Since the NeuroProbes technology had not yet been tested for electrical stimulation in an in vivo animal preparation, we performed experiments in ketamine-anesthetized guinea pigs in which we inserted and stimulated a NeuroProbes array within the IC and recorded the corresponding neural activation within the auditory cortex. We used 2-D arrays for this initial feasibility study since they were already available and were sufficient to access the IC and also demonstrate effective activation of the central auditory system. Based on these encouraging results and the ability to develop customized 3-D arrays with the NeuroProbes technology, we can further investigate different stimulation patterns across the ICC to improve AMI performance

Basic aspects of deep lithography with particles for the fabrication of micro-optical and micromechanical structures

The strength of today's deep lithographic micro-machining technologies is their ability to fabricate monolithic building-blocks including optical and mechanical functionalities that can be precisely integrated in more complex photonic systems. In this contribution we present the physical aspects of Deep Lithography with ion Particles (DLP). We investigate the impact of the ion mass, energy and fluence on the developed surface profile to find the optimized irradiation conditions for different types of high aspect ratio micro-optical structures. To this aim, we develop a software program that combines the atomic interaction effects with the macroscopic beam specifications. We illustrate the correctness of our simulations with experimental data that we obtained in a collaboration established between the accelerator facilities at TUM, LNS and VUB. Finally, we review our findings and discuss the strengths and weaknesses of DLP with respect to Deep Lithography with X-rays (LIGA)

Prototyping micro-optical components with integrated out-of-plane coupling structures using deep lithography with protons: art. no. 618504

We present Deep Lithography with Protons (DLP) as a rapid prototyping technology to fabricate waveguide-based micro-optical components with monolithically integrated 45 degrees micro-mirrors acting as out-of-plane couplers, splitting the optical signal in 3 separated paths. For the first time, two different proton beam sizes are used during one irradiation and a 20 mu m collimating aperture is chosen to accurately define the out-of-plane coupling structures. We fully optimized the DLP process for this 20 mu m proton beam and we measured the surface roughness (R-q=27.5nm) and the flatness (R-t=3.17 mu m) of the realized components. Finally, we experimentally measured the optical transmission efficiency of the micro-optical splitter component. The results are in excellent agreement with non-sequential ray-tracing simulations performed for the design. Above that, we present a pluggable out-of-plane coupler incorporating a single micro-mirror for the 90 degrees coupling of light to or from polymer multimode waveguides integrated on a printed circuit board (PCB). This millimeter-sized mass-reproducible component can then be readily inserted into laser ablated cavities. Non-sequential ray-tracing simulations are performed to predict the optical performance of the component, showing coupling efficiencies up to 78%. These results are then experimentally verified using piezo-motorized positioning equipment with submicron accuracy in a multimode fiber-to-fiber coupling scheme, showing coupling efficiencies up to 56%. The fabricated coupling components are suitable for low-cost mass production since our micro-optical prototyping technology is compatible with standard replication techniques, such as hot embossing and injection molding, has been shown before.We present Deep Lithography with Protons (DLP) as a rapid prototyping technology to fabricate waveguide-based micro-optical components with monolithically integrated 45 degrees micro-mirrors acting as out-of-plane couplers, splitting the optical signal in 3 separated paths. For the first time, two different proton beam sizes are used during one irradiation and a 20 mu m collimating aperture is chosen to accurately define the out-of-plane coupling structures. We fully optimized the DLP process for this 20 mu m proton beam and we measured the surface roughness (R-q=27.5nm) and the flatness (R-t=3.17 mu m) of the realized components. Finally, we experimentally measured the optical transmission efficiency of the micro-optical splitter component. The results are in excellent agreement with non-sequential ray-tracing simulations performed for the design. Above that, we present a pluggable out-of-plane coupler incorporating a single micro-mirror for the 90 degrees coupling of light to or from polymer multimode waveguides integrated on a printed circuit board (PCB). This millimeter-sized mass-reproducible component can then be readily inserted into laser ablated cavities. Non-sequential ray-tracing simulations are performed to predict the optical performance of the component, showing coupling efficiencies up to 78%. These results are then experimentally verified using piezo-motorized positioning equipment with submicron accuracy in a multimode fiber-to-fiber coupling scheme, showing coupling efficiencies up to 56%. The fabricated coupling components are suitable for low-cost mass production since our micro-optical prototyping technology is compatible with standard replication techniques, such as hot embossing and injection molding, has been shown before.P

Comb-like, silicon-based NeuroProbes array with four 10-mm-long probe shafts separated by 400 µm.

<p>Each shank is comprised of eight IrOx electrode sites. The array is interconnected to a highly flexible polyimide ribbon cable interfacing with a zero insertion force (ZIF) connector on a printed circuit board (PCB) that was connected to the stimulator. For probe insertion, the probe comb is fixed adhesively to the insertion plate and attached to a micromanipulator. The 100-µm-thick probe shanks proved to be stiff enough for insertion into deep brain structures.</p