MicroLIQUID (Spain)

In this study, cell responses on micropatterned films that were changing in groove–ridge widths and pattern depth were investigated to compare the degree of size effects from X–Y and Z planes. Poly(caprolactone) films with five different groove–ridge sizes and three pattern depths were prepared by hot embossing technique. In general, the morphologies of osteoblast cell were not changed noticeably by the size changes in groove–ridges with the same depth size. However, cell morphologies were changed significantly when pattern depths were increased from 1.35 to 4.95 µm. Also, the cell morphology change between different groove–ridges was significant when the pattern depth was small (1.35 µm), and these effects were diminished or masked when the pattern depth was increased to 4.95 µm. Linear regression analysis further clarifies that unit size changes in depth may affect cell length and orientation rates 2.4 and 4 times, respectively, in comparison to rates obtained from X–Y planes.

In this work, an Android application for measurement of nitrite concentration and pH determination in combination with a low-cost paper-based microfluidic device is presented. The application uses seven sensing areas, containing the corresponding immobilized reagents, to produce selective color changes when a sample solution is placed in the sampling area. Under controlled conditions of light, using the flash of the smartphone as a light source, the image captured with the built-in camera is processed using a customized algorithm for multidetection of the colored sensing areas. The developed image-processing allows reducing the influence of the light source and the positioning of the microfluidic device in the picture. Then, the H (hue) and S (saturation) coordinates of the HSV color space are extracted and related to pH and nitrite concentration, respectively. A complete characterization of the sensing elements has been carried out as well as a full description of the image analysis for detection. The results show good use of a mobile phone as an analytical instrument. For the pH, the resolution obtained is 0.04 units of pH, 0.09 of accuracy, and a mean squared error of 0.167. With regard to nitrite, 0.51% at 4.0 mg L(-1) of resolution and 0.52 mg L(-1) as the limit of detection was achieved.

In this paper, the implementation and characterization of a hand-held and simple biosensor for in-situ endotoxin determination are described. The integrated biosensor developed here is based on the electrochemical detection of endotoxin using polymyxin B as bioreceptor immobilized onto gold electrodes via a self-assembled monolayer. The cyclic voltammetry, electrochemical impedance spectroscopy, and atomic force microscopy were used to characterize the biosensor performance and properties throughout the functionalization process. In addition, a comparative analysis of the behavior and features of two alternative electrochemical techniques for endotoxin detection was carried out. The biosensing device fabricated by thin-film technologies provided a simple and robust method to detect low concentrations of endotoxin.

Here we present the development of a tunable microfluidic device for single cell studies that combines a number of technologies for applications in cell therapy and cancer research. The fabricated device consists of a main trapping module and two clip-on units. In this work optimum fabrication, cell trapping and seeding parameters are described. This versatile microfabricated platform will enable the investigation of fundamental biological processes such as cell migration or intercellular communications without the necessity of any surface functionalization and in a more in-vivo like manner.

The development of new point of care coagulation assay devices is necessary due to the increasing number of patients requiring long-term anticoagulation in addition to the desire for appropriate, targeted anticoagulant therapy and a more rapid response to optimization of treatment. The majority of point of care devices currently available for hemostasis testing rely on clot-based endpoints which are variable, unreliable and limited to measuring only certain portions of the coagulation pathway. Here we present a novel fluorescence-based anti-Factor Xa (FXa) microfluidic assay device for monitoring the effect of anticoagulant therapy at the point of care. The device is a disposable, laminated polymer microfluidic strip fabricated from a combination of hydrophobic and hydrophilic cyclic polyolefins to allow reagent deposition in addition to effective capillary fill. Zeonor was the polymer of choice resulting in low background fluorescence (208.5 AU), suitable contact angles (17.5°± 0.9°) and capillary fill times (20.3 ± 2.1 s). The device was capable of measuring unfractionated heparin and tinzaparin from 0-0.8 U ml(-1) and enoxaparin from 0-0.6 U ml(-1) with average CVs < 10%. A linear correlation was observed between the device and the fluorescent assay in the plate for plasma samples spiked with UFH, with an R(2) value of 0.99, while correlations with tinzaparin and enoxaparin resulted in sigmoidal responses (R(2) = 0.99). Plasma samples containing UFH resulted in a linear correlation between the device and a standard chromogenic assay with an R(2) value of 0.98, with both LMWHs resulting in sigmoidal relationships (R(2) = 0.99).