Biomimetic heterogeneous patterning of hepatic and endothelial cells, which start from randomly distributed cells inside the microfluidic chamber, via the chip design of enhanced field-induced dielectrophoresis (DEP) trap is demonstrated and reported in this paper. The concentric-stellate-tip electrode array design in this chip generates radial-pattern electric fields for the DEP manipulation of the live liver cells. By constructing the geometric shape and the distribution of stellate tips, the DEP electrodes enhance the desired spatial electric-field gradients to guide and snare individual cells to form the desired biomimetic pattern. With this proposed microfluidic chip design, the original randomly distributed hepatocytes inside the microfluidic chamber can be manipulated in parallel and align into the desired pearl-chain array pattern. This radial pattern mimics the lobular morphology of real liver tissue. The endothelial cells, then, are snared into the additional pearl-chain array and settle at the space in-between the previous hepatic pearl-chain array. By this cell-lab chip, we demonstrate the in vitro reconstruction of the heterogeneous lobule-mimetic radial pattern with good cell viability after cell patterning. This work reports the rapid in-parallel patterning of the dual types of live liver cells via the enhanced DEP trap inside the microfluidic chip.

Engineering functional tissues and organs in vitro is considered integral to regenerative medicine. Many recent cell patterning technique developments position cells at a pre-designated pattern to improve tissue engineering efficiency and quality and to facilitate 3-D cell-cell interaction exploration. Among these techniques, dielectrophoresis (DEP)-based cell patterning advantageously offers speed, ease of operation, low degree of cell damage, and precision. This article reviews recent advances in DEP-based patterning techniques, including electrode design, suitable buffer and hydrogel, effects of the electric current to cells, combination potential with other techniques, as well as efforts to generate 3-D tissues.

MEMS micro-T-switches actuated via electrochemical bubbles for cell sorting applications in a monolithic chip level are proposed and successfully demonstrated. The electrolysis-bubble actuator, which has the features of low operation temperature and high surface-tension force, is developed to actuate the micro-T-switch sorting structure in our device. The double T-structure design, the T-shape microchannel with the movable micro-T-switch structure located at the junction of the T-shape microchannel, with the electrolysis-bubble actuator makes an active-binary switch function available for cell sorting applications. The room temperature operation and the low voltage required for electrolysis actuation minimize the possibility of cell-damage that happens in the conventional high electric separation instruments, such as flow cytometry. The function of our micro-T-switch chip with a low required actuation voltage of 3.0 approximately 3.5 V is demonstrated by using human hepatoma cells in this paper. The pH-value measurements characterize the pH-value variation and distribution in the actuating chambers and the mainstream microchannels to trace the possible liver-cell injury due to the pH-value variation during electrolysis-actuation operation. The 84.1% cell viability in the sorted human hepatoma cells through our micro-T-switch sorter is observed via the fluorescence assay technique. Furthermore, 70.2% of total injected cells recover in culture after sorting and grow into colonies after micro-T-switch sorting operation. In this paper, we describe the design, microfabrication, and characterization of our micro-T-switch cell-sorting chip. We also report the cell-sorting demonstration and the cell viability results for the mammalian liver cells through our micro-T-switch cell-sorting chip.

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Rubilactone (1), dihydromollugin (2), and mollugin (3) are naturally occurring products found in Rubia cordifolia, which is a famous Chinese herb with anti tumor, viral inhibition and other activities. Synthetic studies were carried out in these naphthoic acid esters starting from 1,4‐dihydroxy‐2‐naphthoic acid. In this study, we finished the synthesis of rubilactone which has not been reported before and also synthesized dihydromollugin and mollugin with better yields with different approaches compared to those previously reported in the literature.