Early detection of circulating tumor cells (CTCs) in a patient's blood is essential to accurate prognosis and effective cancer treatment monitoring. The methods used to detect and separate CTCs should have a high recovery rate and ensure cells viability for post-processing operations, such as cell culture and genetic analysis. In this paper, a novel dielectrophoresis (DEP)-based microfluidic system is presented for separating MDA-MB-231 cancer cells from various subtypes of WBCs with the practical cell viability approach. Three configurations for the sidewall electrodes are investigated to evaluate the separation performance. The simulation results based on the finite-element method show that semi-circular electrodes have the best performance with a recovery rate of nearly 95% under the same operational and geometric conditions. In this configuration, the maximum applied electric field (1.11 × 105 V/m) to separate MDA-MB-231 is lower than the threshold value for cell electroporation. Also, the Joule heating study in this configuration shows that the cells are not damaged in the fluid temperature gradient (equal to 1 K). We hope that such a complete and step-by-step design is suitable to achieve DEP-based applicable cell separation biochips.
In this paper, a tunable low power slow light photonic crystal device with a silicon-on-insulator platform is proposed based on the combination of an asymmetric defects coupled-cavity waveguide and the electromagnetically induced transparency (EIT) phenomenon. Modulating the refractive index of special regions in the suggested structure by the EIT phenomenon leads to a relatively wideband slow light device with adjustable group index in the same structure. Using this feature, a small and compact delay line is introduced that has many applications in optical telecommunications, especially in buffers. The numerical calculations show that the group index of 80-98 over the slow light bandwidth from 3.2 to 2.6 nm is achievable for the central wavelength of 1546-1555 nm, respectively. The device malfunction, due to fabrication errors, is modeled, and the tunable characteristics of the proposed structure are verified.
In this paper, a dynamically-tunable band-stop filter based on periodically patterned graphene nanostrip and nanodisk in THz wavelength is proposed and numerically investigated at room temperature. The properties of proposed structure are calculated by using the finite-difference time-domain method. The patterned graphenes are excited by the incident light which leads to absorb two different ranges of spectral wavelength. The simulated results show that a wide free spectral range can be achieved by using multilayer graphene. More importantly, it is found that the transmission dips can be dynamically controlled by adjusting the gate voltage. Moreover, the transmission dips change with graphene mobility which corresponds to graphene intrinsic loss. Finally, the proposed metamaterial structure may be used for many applications such as tunable sensors, active plasmonic switches, and slow light devices.
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