Microseparator based-on 4-phase travelling wave dielectrophoresis for lab-on-a-chip applications

506-515Separation of micron-sized particles is a challenge by highly miniaturized channel systems. In order to offer the ability of smaller volumes and high throughput in Lab-on-a-chip devices more miniaturized components are needed. Due to very low Reynolds number of buffer fluid, microseparators based on travelling wave dielectrophoresis effect have a good efficiency in such applications. In the present paper, a microchannel technique based on surface micromachining is modified to a microseparator. The proposed device is a miniaturized 4-phase travelling wave microseparator with the height of 5 µm, which can be used for separation of biological particles such as cells and some types of viruses. According to numerical simulations, the device can separate and sort different species, as well as different sized cells of the same species. Due to fabrication process, the electrodes made of highly doped poly-silicon are covered by a thin silicon-nitride layer. Additional advantage of the silicon-nitride layer over electrode arrays is the prevention of high electric field gradient. The effect of this thin insulating layer on functionality of the microseparator has been investigated. The simulation results show that a good separation occurs in the frequency range of 1MHz, when electrical conductivity of buffer fluid is near 1μs/m. The fabrication process is presented and influences of other parameters such as permittivity of fluid and fluid conductivity on the operation of the separator are discussed

Multisensor-integrated organs-on-chips platform for automated and continual in situ monitoring of organoid behaviors

Organ-on-a-chip systems areminiaturizedmicrofluidic 3D human tissue and organ models designed to recapitulate the important biological and physiological parameters of their in vivo counterparts. They have recently emerged as a viable platform for personalized medicine and drug screening. These in vitro models, featuring biomimetic compositions, architectures, and functions, are expected to replace the conventional planar, static cell cultures and bridge the gap between the currently used preclinical animal models and the human body. Multiple organoid models may be further connected together through the microfluidics in a similar manner in which they are arranged in vivo, providing the capability to analyze multiorgan interactions. Although a wide variety of human organ-on-a-chip models have been created, there are limited efforts on the integration of multisensor systems. However, in situ continual measuring is critical in precise assessment of the microenvironment parameters and the dynamic responses of the organs to pharmaceutical compounds over extended periods of time. In addition, automated and noninvasive capability is strongly desired for long-term monitoring. Here, we report a fully integrated modular physical, biochemical, and optical sensing platform through a fluidics-routing breadboard, which operates organ-on-a-chip units in a continual, dynamic, and automated manner.We believe that this platform technology has paved a potential avenue to promote the performance of current organ-on-a-chip models in drug screening by integrating a multitude of real-time sensors to achieve automated in situ monitoring of biophysical and biochemical parameters