A Highly Sensitive and Selective Optical Sensor for the On-Line Detection of Cesium in Water.

In this study, we have undertaken the development of two fluorescent sensors based on calixarene compounds for the purpose of detecting cesium in water. By introducing the sulfonate functional groups, we have considerably improved the water solubility of sensors, enabling complete dissolution of products in aqueous media and direct analysis of polluted water samples. Through rigorous experiments, we have demonstrated that the complexation of Cs+ ions with sensors 1 and 2 in water leads to a remarkable enhancement of fluorescence. This fluorescence enhancement serves as a reliable indication of cesium presence and allows for sensitive detection. To further advance the practical application of our sensors, we have successfully integrated calixarene sensors 1 and 2 into a microfluidic sensor chip. This integration has enabled real-time, on-line measurements and has resulted in the development of a portable detection device capable of detecting cesium ions in water samples at parts per billion (ppb) levels. This device holds great promise for environmental monitoring and assessment, providing a convenient and efficient solution for cesium detection. Our work represents a significant advancement in the field of cesium detection, displaying the efficacy of calixarene-based fluorescent sensors and their integration into microfluidic systems. The enhanced water solubility, fluorescence response, and portability of our detection device offers tremendous potential for applications in environmental monitoring, water quality assessment, and emergency response scenarios where rapid and accurate cesium detection is crucial.

A versatile microfluidic tool for the 3D culture of HepaRG cells seeded at various stages of differentiation.

The development of livers-on-a-chip aims to provide pharmaceutical companies with reliable systems to perform drug screening and toxicological studies. To that end, microfluidic systems are engineered to mimic the functions and architecture of this organ. In this context we have designed a device that reproduces series of liver microarchitectures, each permitting the 3D culture of hepatocytes by confining them to a chamber that is separated from the medium conveying channel by very thin slits. We modified the structure to ensure its compatibility with the culture of hepatocytes from different sources. Our device was adapted to the migratory and adhesion properties of the human HepaRG cell line at various stages of differentiation. Using this device, it was possible to keep the cells alive for more than 14 days, during which they achieved a 3D organisation and acquired or maintained their differentiation into hepatocytes. Albumin secretion as well as functional bile canaliculi were confirmed on the liver-on-a-chip. Finally, an acetaminophen toxicological assay was performed. With its multiple micro-chambers for hepatocyte culture, this microfluidic device architecture offers a promising opportunity to provide new tools for drug screening applications.

Characterization of red blood cell microcirculatory parameters using a bioimpedance microfluidic device.

This paper describes the use of a microfluidic device comprising channels with dimensions mimicking those of the smallest capillaries found in the human microcirculation. The device structure, associated with a pair of microelectrodes, provides a tool to electrically measure the transit time of red blood cells through fine capillaries and thus generate an electrical signature for red blood cells in the context of human erythroid genetic disorders, such as sickle cell disease or hereditary spherocytosis, in which red cell elasticity is altered. Red blood cells from healthy individuals, heated or not, and red blood cells from patients with sickle cell disease or hereditary spherocytosis where characterized at a single cell level using our device. Transit time and blockade amplitude recordings were correlated with microscopic observations, and analyzed. The link between the electrical signature and the mechanical properties of the red blood cells is discussed in the paper, with greater transit time and modified blockade amplitude for heated and pathological red blood cells as compared to those from healthy individuals. Our single cell-based methodology offers a new and complementary approach to characterize red cell mechanical properties in human disorders under flow conditions mimicking the microcirculation.