Transparent nanometric organic luminescent films as UV-active components in photonic structures

A new kind of visible-blind organic thin-film material, consisting of a polymeric matrix with a high concentration of embedded 3-hydroxyflavone (3HF) dye molecules, that absorbs UV light and emits green light is presented. The thin films can be grown on sensitive substrates, including flexible polymers and paper. Their suitability as photonic active components photonic devices is demonstrated. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

UV laser-induced high resolution cleaving of Si wafers for micro-nano devices and polymeric waveguide characterization

In this work we propose a method for cleaving silicon-based photonic chips by using a laser based micromachining system, consisting of a ND:YVO4laser emitting at 355 nm in nanosecond pulse regime and a micropositioning system. The laser makes grooved marks placed at the desired locations and directions where cleaves have to be initiated, and after several processing steps, a crack appears and propagate along the crystallographic planes of the silicon wafer. This allows cleavage of the chips automatically and with high positioning accuracy, and provides polished vertical facets with better quality than the obtained with other cleaving process, which eases the optical characterization of photonic devices. This method has been found to be particularly useful when cleaving small-sized chips, where manual cleaving is hard to perform; and also for polymeric waveguides, whose facets get damaged or even destroyed with polishing or manual cleaving processing. Influence of length of the grooved line and speed of processing is studied for a variety of silicon chips. An application for cleaving and characterizing sol–gel waveguides is presented. The total amount of light coupled is higher than when using any other procedure

Bio-Photonic Sensing Cells over transparent substrates for anti-gestrinone antibodies biosensing

[EN] In a previous work we introduced the term Bio-Photonic Sensing Cells (BICELLs), referred to periodic networks of nano-pillar suitable for biosensing when are vertically interrogated. In this article, we demonstrate the biosensing capabilities of a type of micrometric size BICELLs made of SU-8 nano-pillars fabricated over transparent substrates. We verify the biochips functionality comparing the theoretical simulations with the experimental results when are optically interrogated in transmission. We also demonstrate a sensitivity enhancement by reducing the pitch among nano-pillars from 800 to 700. nm. Thus, the Limit of Detection achievable in these types of BICELLs is in the order of 64. pg/mL for 700. nm in pitch among nano-pillars in comparison with 292. pg/mL for 800. nm in pitch when are interrogated by Fourier Transform Visible and Infrared Spectrometry. The experiments exhibited a good reproducibility with a relative standard deviation of 0.29% measured within 8 days for a specific concentration. Finally, BICELLs functionality was tested in real conditions with unpurified rabbit serum for detecting anti-gestrinone antibodies, demonstrating the high performance of this type of BICELLs to detect specific antibodies having immobilized the suitable bioreceptors onto the sensing surface. © 2011 Elsevier B.V.This work is done within the support of the Spanish Ministry of Science and Innovation under project BIOPSIA (REF: TEC2008-06574). The authors thanks the Comunidad de Madrid and Universidad Politecncia de Madrid (Project BIO-VERSATIL, Ref CCG10-UPM/SEM-5096), Generalitat Valenciana (project ACOMP/2010/009 and PROMETEO 2010/008) and Dr Eva Brun for providing the rabbit serum containing polyclonal antibodies for gestrinone studies. F.J.O. is grateful to the Generalitat Valenciana for the postdoctoral grant included in the VALi + d 2010 Programme for Postdoctoral Researchers.Sanza, F.; Holgado, M.; Ortega Higueruelo, FJ.; Casquel Del Campo, R.; López-Romero, D.; Bañuls Polo, MJ.; Laguna, MF.... (2011). Bio-Photonic Sensing Cells over transparent substrates for anti-gestrinone antibodies biosensing. Biosensors and Bioelectronics. 26:4842-4847. https://doi.org/10.1016/j.bios.2011.06.010S484248472

Cost-effective SU-8 micro-structures by DUV excimer laser lithography for label-free biosensing

Cost-effective SU-8 micro-structures on a silicon substrate were developed using 248 nm excimer laser KrF projection, studying the influence of the different variables on the final pattern geometry, finding out that the most critical are exposure dose and post-bake condition. Also a novel and cost effective type of photomask based on commercial polyimide Kapton produced by 355 nm DPSS laser microprocessing was developed, studying the influence of the cutting conditions on the photomask. Finally, as a likely application the biosensing capability with a standard BSA/antiBSA immunoassay over a 10 × 10 micro-plates square lattice of around 10 ¿m in diameter, 15 ¿m of spacing and 400 nm in height was demonstrated, finding a limit of detection (LOD) of 33.4 ng/ml which is in the order of magnitude of bioapplications such as detection of cortisol hormone or insulin-like growth factor. Low cost fabrication and vertical interrogation characterization techniques lead to a promising future in the biosensing technology field. © 2010 Elsevier B.V. All rights reserved.Funding for the study was provided by the Spanish Ministry of Science and Innovation under BIOPSIA project no. TEC2008-06574-C03.Sanza, FJ.; Laguna, MF.; Casquel Del Campo, R.; Holgado, M.; Angulo Barrios, C.; Ortega Higueruelo, FJ.; López-Romero, D.... (2011). Cost-effective SU-8 micro-structures by DUV excimer laser lithography for label-free biosensing. Applied Surface Science. 257(12):5403-5407. https://doi.org/10.1016/j.apsusc.2010.10.010S540354072571