An automated method for in vitro anticancer drug efficacy monitoring based on cell viability measurement using a portable photodiode array chip

Microfluidic endothelium-on-a-chip development, from in vivo to in vitro experimental models

In the last years, animal testing in medical research has been a controversial topic because of various reasons, such as ethical considerations and species differences. Therefore, more attention has been given to develop new technologies that can replace animal experiments and create in vitro models. Organ-on-a-chip (OOC) technology is a new and advanced technology based on microfluidic devices that can mimic the structure and function of entire organs and tissues as in vitro models. OOC models are miniature tissues and organs that assign characteristics for three-dimensional (3D) cell culture representation that resemble the original organs, together with their specific microenvironment microfluidic systems and specific biophysical processes, in order to mimic the normal physiological conditions and functionalities of the organs. Existing OOC models, such as liver, pancreas, heart, skin, brain, kidney, vessels, have been developed and designed for a specific function study. This review focuses on the main knowledge concerning OOC research and especially vascular endothelium-on-a-chip (EOC) model, developed in order to offer specific tools for studying vascular functions in physiological and pathological conditions. The field of OOC devices is still at the beginning, but in the future, this technology may have important roles in developing novel therapeutic approaches, offering new therapeutic molecules and providing the first step towards personalized medicine.

Time-lapse contact microscopy of cell cultures based on non-coherent illumination

Video microscopy offers outstanding capabilities to investigate the dynamics of biological and pathological mechanisms in optimal culture conditions. Contact imaging is one of the simplest imaging architectures to digitally record images of cells due to the absence of any objective between the sample and the image sensor. However, in the framework of in-line holography, other optical components, e.g., an optical filter or a pinhole, are placed underneath the light source in order to illuminate the cells with a coherent or quasi-coherent incident light. In this study, we demonstrate that contact imaging with an incident light of both limited temporal and spatial coherences can be achieved with sufficiently high quality for most applications in cell biology, including monitoring of cell sedimentation, rolling, adhesion, spreading, proliferation, motility, death and detachment. Patterns of cells were recorded at various distances between 0 and 1000 μm from the pixel array of the image sensors. Cells in suspension, just deposited or at mitosis focalise light into photonic nanojets which can be visualised by contact imaging. Light refraction by cells significantly varies during the adhesion process, the cell cycle and among the cell population in connection with every modification in the tridimensional morphology of a cell.

Salicylate-induced translocation of prestin having mutation in the GTSRH sequence to the plasma membrane

Prestin is a key molecule for mammalian hearing. The present study investigated changes in characteristics of prestin by culturing prestin-transfected cells with salicylate, an antagonist of prestin. As a result, the plasma membrane localization of prestin bearing a mutation in the GTSRH sequence, which normally accumulates in the cytoplasm, was recovered. Moreover, the nonlinear capacitance of the majority of the mutants, which is a signature of prestin activity, was also recovered. Thus, the present study discovered a new effect of salicylate on prestin, namely, the promotion of the plasma membrane expression of prestin mutants in an active state.

Interdigitated microelectrode array-coupled bipolar semiconductor photodiode array (IMEA-PDA) microchip for on-chip electrochemiluminescence detection

This paper reports the design, fabrication and testing of a microchip wherein interdigitated microelectrode arrays (IMEA) were integrated with bipolar semiconductor photodiode array (PDA) chip to fabricate a highly compact embodiment for on-chip handling of solutions and electrochemiluminescence (ECL) detection. A 12 x 12 micro array of photodiodes, each coupled with an interdigitated microelectrode array (IMEA), an array of current amplifiers, and a photodiode element-addressing circuit were integrated into a single 2 x 2 cm² IC chip. Each photodiode had dimensions of 300 x 300 μm² and the photodiode-to-photodiode distance was 100 μm. The chip was successfully applied to the on-chip quantification of electro-chemiluminescing probe-labeled single stranded oligonucleotides. The minimum detectable limit at signal/noise ≥ 3 was found to be 5 x 10⁻¹⁴ moles of oligonucleotides with a sample volume as low as 5 microl (i.e., 10 fmole/μl). The attractive features of the developed IMEA-PDA microchip are that a plurality of samples can be analyzed simultaneously using a chip and that for a given sample the data can be averaged from values obtained from multiple, individually addressed pixels. These in turn bring in speed and statistical confidence in analysis. The IMEA-PDA microchip system has the potential to be used as a versatile and highly compact chemical analysis tool for chemical sensing and metrology applications.

Integrated particle detection chip for environmental monitoring

This paper reports an integrated particle detection chip for low-cost and point-of-interest environmental monitoring; it consists of a micro virtual impactor and a micro corona discharger. With this system, airborne particles are introduced into the micro virtual impactor of the chip where they are classified according to their aerodynamic diameters. The particles are then charged and their number-concentration is detected in the micro corona discharger from the electrical current carried by the charged particles. The characteristics of each component were first analyzed, and the components were then integrated into a single chip. The micro virtual impactor was designed to have a cut-off diameter of 600 nm or 1.0 microm. Its classification characteristics were examined by classifying polydisperse particles-dioctyl sebacate particles ranging in diameter from 100 to 600 nm and carbon particles ranging in diameter from 0.6 to 10 microm. From the classification results, the cut-off diameter of the micro virtual impactor was measured to be either 550 nm or 1.1 microm. The micro corona discharger was fabricated based on a sharp silicon tip and a planar electrode and charged particles at 1.3 kV. Using the integrated particle detection chip comprising the micro virtual impactor and the micro corona discharger, the sensitivity for monodisperse particles-500 nm dioctyl sebacate in diameter-was measured to be 8 x 10(-7) pA/(particle cm(-3)).