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In multiplexed analysis, lab on a chip (LoC) devices are advantageous due to the low sample and reagent volumes required. Although optical detection is preferred for providing high sensitivity in a contactless configuration, multiplexed optical LoCs are limited by the technological complexity for integrating multiple light sources and detectors in a single device. To address this issue, we present a microfluidic-controlled optical router that enables measurement in four individual optical channels using a single light source and detector, and without movable parts. The optofluidic device is entirely fabricated in polydimethylsiloxane (PDMS) by soft-lithography, compatible with standard microfabrication technologies, enabling monolithic integration in LoCs. In the device, in-coupled light from an optical fiber is collimated by a polymeric micro-lens and guided through a set of four sequentially connected micro-chambers. When a micro-chamber is filled with water, light is transmitted to the next one. If it is empty of liquid, however, total internal reflection (TIR) occurs at the PDMS-air interface, re-directing the light to the output optical fiber. The router presents high performance, with low cross-talk (, The research leading to these results has received funding from the European Research Council under the European Community's ERC grant agreement no 209243 and the Horizon 2020 (H2020) project ND4ID (grant agreement no 675412). Dr. X. M.-B. was supported by the “Ramón y Cajal” program from the Spanish Government. We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).

A photonic lab-on-a-chip (PhLoC) was developed for rapid determination of interleukin-2 (IL-2) levels secreted by lymphocytes using measurement of optical absorbance. Optical and microfluidic components, including lenses, mirrors, and flow channels, were monolithically created using poly(dimethylsiloxane) (PDMS). Sample and reagent solutions were processed in the form of liquid columns separated by air. A flow channel structure with an air bypass was used to release air between solution columns and to exchange solutions in the measuring chamber, avoiding the intrusion of air into the measuring chamber and the denaturation of the capture antibodies. The concentration of IL-2 was measured by enzyme-linked immunosorbent assay (ELISA) in the PhLoC. The total time required for the ELISA was less than 30 min. Clear concentration dependence was confirmed for IL-2 concentrations ranging from 50 to 1000 pg/mL. Thus, the concentration of IL-2 secreted by lymphocytes following activation by concanavalin A (Con A) co...

The integration of micro-optical elements with microfluidics leads to the highly promising photonic lab-on-a-chip analytical systems (PhLoCs). In this work, we re-examine the main principles which are underneath the on-chip spectrophotometric detection, approaching the PhLoC concept to a nonexpert audience.

Elementary PDMS-based building blocks of fluidic, optical and optofluidic components for Lab on a chip (LOC) platforms has here been developed. All individual modules are compatible and can be anchored and released with the help of puzzle-type connectors This approach is a powerful toolbox to create modular optofluidic systems (MOPS), which can be modified/upgraded to user needs and in-situ reconfigurable. In addition, the PDMS can locally be functionalized, defining a modular biosensor. Measurements in absorbance and fluorescence have been pursued as demonstrator.

The integration of detection mechanisms with microfluidics may be one of the most promising routes towards widespread application of Lab-on-a-Chip (LoC) devices. Photonic detection methods like in the so-called Photonic Lab-on-a-Chip (PhLoC) have advantages such as being non-invasive, easy to sterilize and highly sensitive even with short integration times and thus allow in situ monitoring and quantification of biological and chemical processes. The readout of such detection methods usually requires special training of potential users, as in most cases they are confronted with the need of establishing fiber-optics connections to and from the PhLoC and/or rely on the use of complex laboratory equipment. Here, we present a low-cost and robust chip-to-world interface (CWI), fabricated by CO2-laser machining, facilitating the non-expert use of PhLoCs. Fiber-optics with standard SMA-connectors (non-pigtailed) and PhLoCs can be plugged into the CWI without the need for further adjustments. This standardization bestows great versatility on the interface, providing a direct link between PhLoCs and a wide range of light sources and photo-detectors. The ease-of-use of the proposed simple plug mechanism represents a step forward in terms of user-friendliness and may lead PhLoC devices to practical applications., The research leading to these results has been partly funded by the European Union's Seventh Framework Programme (FP7/2007–2013) under grant agreement no. 317916. X. Muñoz-Berbel acknowledges the Spanish Ministry of Economy and Competitiveness for the Ramon y Cajal grant. P. Giménez-Gómez is grateful to MINECO, Spain for the financial support through a research studentship of the FPI Program.

Cardiovascular diseases are the first cause of death globally. Their early diagnosis requires ultrasensitive tools enabling the detection of minor structural and functional alterations in small arteries. Such analyses have been traditionally performed with video imaging-based myographs, which helped to investigate the pathophysiology of the microvessels. Since new vascular questions have emerged, substantial modifications are necessary to improve the performance of imaging and tracking software, reducing the cost and minimizing the microvessel cleaning and manipulation. To address these limitations, we present a photonic microsystem fabricated in polydimethylsiloxane and integrating micro-optical elements and a lightguide-cantilever for sub-micrometric analysis of small arteries (between 125 and 400μm of basal diameter). This technology enables simultaneous measurement of arterial distension, stiffness, vasomotion, and heartbeat and without the need for advanced imaging system. The microsystem has a limit of detection of 2μm, five times lower than video imaging-based myographs, is two times more sensitive than them (0.5 μm/mmHg), reduces variability to half and doubles the linear range reported in these myographs. More importantly, it allows the analysis of intact arteries preserving the integrity and function of surrounding tissues. Assays can be conducted in three configurations according to the surrounding tissue: (i) isolated arteries (in vitro) where the surrounding tissue is partially removed, (ii) non-isolated arteries (in vivo) with surrounding tissue partially removed, and (iii) intact arteries in vivo preserving surrounding tissue as well as function and integrity. This technology represents a step forward in the prediction of cardiovascular risk. info:eu-repo/semantics/acceptedVersion