Nuestros investigadores

Isabel Ayerdi Olaizola

Publicaciones científicas más recientes (desde 2010)

Autores: Fuentes, M.D.C, (Autor de correspondencia); Pérez, N; Ayerdi, Isabel;
ISSN 0040-6090  Vol. 636  2017  págs. 438 - 445
Microfabrication technology in the biomedical field has provided microelectrode arrays for neural implants with new development opportunities. The need for more complex physiological functions and miniaturization, as well as the use of new materials for more flexible electrodes, can now be satisfied. PDMS (Polydimethylsiloxane) substrates are elastic, biocompatible and permeable to oxygen, in addition to being a highly stable material. However, the implementation of microfabrication techniques such as deposition and patterning processes on these new substrates is not straightforward. This paper will describe the development of a reliable method to metalize thin film microelectrodes on a highly flexible medical grade PDMS layer that is suitable for long-term implantation. Platinum (Pt) microelectrodes were deposited by physical vapor deposition and pattern transfer by lift-off was chosen. Standard photolithography was used to pattern a conventional positive photoresist and was optimized to improve adhesion and to avoid cracks in the resist. The electrical behavior of the metal-polymer interface was analyzed using multiplexed DC measurements. The resistance values of seven samples and a control were acquired sequentially. Special attention was paid to the connectorization from the flexible microelectrodes to a rigid substrate. Measurements were carried out in an air-protected environment as well as in a biological environment designed to mimic the environment of the human body. Long-term stability of the Pt-PDMS interface was strongly influenced by the electrode configuration and its connection. A characteristic electrical behavior was observed for a straight-electrode configuration. This configuration demonstrated significant drift of resistance values of more than 4% during the initial 56 h. By contrast, a stable behavior was observed for a loop electrode design, with only small variations of less than +/- 0.5% caused by thermal fluctuations. (C) 2017 Elsevier B.V. All rights reserved.
Autores: Mandayo, G. G., (Autor de correspondencia); Hammes, E.; et al.
ISSN 2212-0114  Vol. 14  Nº Part 3  2015  págs. 475 - 485
The objective of the work described in this paper is to develop a device to monitor air quality in indoor environments integrating three conductometric gas sensors based on thin film and nanostructured metal oxide semiconductors (SnO2, NiO and ZnO). The sensors are incorporated into a single robust, reliable and cheap detection platform, which includes air pre-conditioning and electronics. The main aim of the device is to integrate with HVAC (Heat Ventilation and Air Conditioning) in an energy-efficient way whilst maintaining a high air quality standard within the building. Due to the lack of common EU legislation, the target gases and detection limits have been set after reviewing the literature and the recommendations of different agencies in Europe and the US, focusing on indoor Volatile Organic Compounds (VOCs).
Autores: Pérez, N; Tavera, T.; Ellman, M.; et al.
ISSN 0169-4332  Vol. 258  Nº 23  2012  págs. 9370 - 9373
This work presents the fabrication of hollow-core metallic structures with a complete laser interference lithography (LIL) process. A negative photoresist is used as sacrificial layer. It is exposed to the pattern resulting from the interference of two laser beams, which produces a structure of photoresist lines with a period of 600 nm. After development of the resist, platinum is deposited on the samples by DC sputtering and the resist is removed with acetone. The resulting metallic structures consist in a continuous platinum film that replicates the photoresist relief with a hollow core. The cross section of the channels is up to 0.1 mu m(2). The fabricated samples are characterized by FESEM and FIB. This last tool helps to provide a clear picture of the shape and size of the channels. Conveniently dimensioned, this array of metallic submicrometric channels can be used in microfluidic or IC cooling applications. (c) 2012 Elsevier B.V. All rights reserved.
Autores: Manrique, Raquel; Picciaffuoco, S.; Gracia, Javier; et al.
Revista: International Journal of Pediatric Otorhinolaryngology
ISSN 0165-5876  Vol. 75  Nº Supl. 1  2011  págs. 85
Autores: Rodríguez, Ainara; Olaizola, Santiago Miguel; Ayerdi, Isabel;
There is an increasing interest in nanoscience and nanotechnology due to the new physics and chemistry that are accessible on the nanoscale and because of the large potential for new products and devices that they provide. Therefore, the ability to fabricate structures on the nanoscale with high precision and in a wide variety of materials is a crucial issue for the development of the nanoscience and nanotechnology. Lithography and the other processes associated with it are the core of the nanotechnology revolution. One of the most promising techniques for the fabrication of structures on the nanoscale is Laser Interference Lithography (LIL). LIL, also known as holographic or interferometric lithography, is a well-established concept largely explored in lithography. However, a pulsed multi- beam LIL tool for nanoscale structuring of materials that can scale beyond laboratory prototypes into cost effective industrial processes is not yet defined. In this document, a versatile and automatic high-power multiple beam interference lithography system design capable of overcoming the limitations of manual setups is presented.