Abstract
An optical fiber sensing system, for monitoring oxygen aiming in vivo nuclear magnetic resonance (NMR) applications is presented. Oxygen detection is based on the dynamic quenching of the fluorescence of a ruthenium complex trapped in the porous structure of a sol-gel silica film. Oxygen concentration is determined by phase-modulation fluorometry. Preliminary results concerning the characterization of doped sol-gel thin films deposited by dip coating in glass slides and in optical fiber probes are presented. Four different probe configurations are tested and compared. Best results are obtained with a fiber taper configuration which shows reproducibility and best excitation efficiency. This structure is fully characterized and some considerations regarding optimal fiber optical sensing probes for 02 detection are addressed.

Abstract
In this work, two all-fiber interferometric configurations based on suspended core fibers (SCF) are investigated. A Fabry-Perot cavity (FPC) made of SCF spliced in-between segments of single-mode and hollow-core fiber is proposed. The interferometric signals are generated by the refractive-index mismatches between the two fibers in the splice region and at the end of the suspended-core fiber. An alternative sensing head configuration formed by the insertion of a length of SCF as a birefringence element in a Sagnac loop interferometer is also demonstrated. In this structure, the interferometric signals are generated by interfering two counter propagating beams with different polarization states which propagate through a length of SCF as a birefringence element. The sensitivity to pressure and temperature was determined for both configurations. The results show that the pressure sensitivities are -4.68 x 10(-5) nm/psi and 0.032 nm/psi for FPC and Sagnac loop interferometers, respectively. The temperature sensitivity of both structures has been obtained and the results have been discussed.

Abstract
A new family of gene delivery vectors is synthesized consisting of a medium-size generation PAMAM dendrimer (generation 5, with amine termini) core randomly linked at the periphery to hydrophobic chains that vary in length (12 to 16 carbon alkyl chains) and number (from 4.2 to 9.7 in average). The idea subjacent to the present work is to join the advantages of the cationic nature of the dendrimer with the capacity of lipids to interact with biological membranes. Unlike other amphiphilic systems designed for the same purpose, where the hydrophobic and hydrophilic moieties coexist in opposite sides, the present vectors have a hydrophilic interior and a hydrophobic corona. The vectors are characterized in respect to their ability to neutralize, bind and compact plasmid DNA (pDNA). The complexes formed between the vectors and pDNA are analyzed concerning their size, zeta-potential, resistance to serum nucleases, capacity of being internalized by cells and transfection efficiency. These new vectors show a remarkable capacity for mediating the internalization of pDNA with minimum cytotoxicity, being this effect positively correlated with the -CH(2)-content present in the hydrophobic corona. Gene expression in MSCs, a cell type with relevancy in the regenerative medicine clinical context, is also enhanced using the new vectors but, in this case, the higher efficiency is shown by the vectors containing the smallest hydrophobic chains.

Abstract
In this study an optical fibre sensor system was conceived for simultaneous detection of the strain and the acoustic emission due to damage. It consists of a fibre Bragg grating and a Fabry-Perot interferometer. For the interrogation of the Fabry-Perot cavity, an innovative low cost process based on the generation of two quadrature phase-shifted signals using two fibre Bragg gratings was implemented, allowing the recovery of the change in the cavity length. An automated processing system, based on Kohonen's self-organizing maps is also presented, for future classification of the acoustic emission waves detected by the optic fibre sensor.

Abstract
A scheme for the simultaneous determination of oxygen and temperature using quantum dots and a ruthenium complex is demonstrated. The luminescent complex [Ru(II)-tris(4,7-diphenyl-1,10-phenanthroline)](2+) is immobilized in a non-hydrolytic sol-gel matrix and used as the oxygen sensor. The temperature information is provided by the luminescent emission of core-shell CdSe-ZnS semiconductor nanocrystals immobilized in the same material. Measurements of oxygen and temperature could be performed with associated errors of +/- 2% of oxygen concentration and +/- 1 degrees C, respectively In addition, it is shown that while the dye luminescence intensity is quenched both by oxygen and temperature, the nanocrystals luminescent emission responds only to temperature. Results presented demonstrate that the combined luminescence response allows the simultaneous assessment of both parameters using a single optical fiber system. In particular, it was shown that a 10% error in the measured oxygen concentration, induced by a change in the sample temperature, could be compensated using the nanocrystals temperature information and a correction function.

Abstract
Fiber optic sensors have a set of properties that make them very attractive in biomechanics. However, they remain unknown to many who work in the field. Some possible causes are scarce information, few research groups using them in a routine basis, and even fewer companies offering turnkey and affordable solutions. Nevertheless, as optical fibers revolutionize the way of carrying data in telecommunications, a similar trend is detectable in the world of sensing. The present review aims to describe the most relevant contributions of fiber sensing in biomechanics since their introduction, from 1960s to the present, focusing on intensity-based configurations. An effort has been made to identify key researchers, research and development (R&D) groups and main applications. © The Author(s) 2012.