癌症是影响人类健康的重大疾病之一, 如何快速、方便地分离癌细胞已经成为制约临床医学和科学研究的重要问题。本文将磁珠技术与MEMS技术相结合, 提出了一种等边三角排列的N i微磁柱结构, 在磁场作用下使用CD326免疫磁珠捕获结肠癌细胞。本文对MEMS细胞捕获芯片进行了设计、加工和封装, 采用该芯片对与磁珠结合的结肠癌细胞进行了捕获, 0. 1m l/h流速下捕获效率达92%,证明该芯片具有对结肠癌细胞的捕获能力。

Circulating tumor cells (CTCs) from peripheral blood are emerging as a useful tool for the detection of malignancy, monitoring disease progression, and measuring response to therapy. We describe a unique microfluidic chip that was capable of efficient and selective separation of CTCs from peripheral whole blood samples. The ability of microfluidic chip to capture CTCs from PBS and whole blood samples was tested.Sixty-eight peripheral blood samples from 68 colorectal cancer patients were investigated for the presence of CTCs by microchip technology. The frequency of CTCs was analyzed statistically for correlation with relevant clinical data. We also examined samples from 20 healthy individuals as controls. The calculated capture efficiency was 85.7% and decreased significantly at flow rates above 2.0 ml/h. The number of CTCs isolated ranged from 3 to 236/ml for colorectal patients [99 ± 64 (mean ± SD) CTCs/ml]. None of the 20 healthy subjects had any identifiable CTCs. We identified CTCs in 46 (67.65%) of the 68 patients: in two of nine (22.22%) Dukes A, in 10 of 24 (41.67%) Dukes B, in 21 of 22 (95.45%) Dukes C, and in all 13 Dukes D patients. The detection rate in Dukes C and D patients was much higher than in Dukes A and B patients (97.73% vs. 36.36%) (p < 0.01). A significant correlation between detection of CTCs and clinical stage (r = 0.792, p < 0.01) was found, which was higher than carcinoembryonic antigen (r = 0.285, p > 0.01), carbohydrate antigen 19-9 (r = 0.258, p > 0.01), α-fetoprotein (r = 0.096, p > 0.01), and cancer antigen 125 (r = 0.134, p > 0.01). Microfluidic chip provides a novel method for capturing CTCs. The presence of CTCs correlated with clinical stage. It is important to evaluate CK-positive and DAPI-stained tumor cells together to determine the role of CTCs in tumor behavior and disease progression.

Blood analysis plays a major role in medical and science applications and white blood cells (WBCs) are most often the target of analysis. We proposed an integrated microfluidic chip for rapid trapping WBCs from whole blood directly. The microfluidic chip consists of two basic functional units: a winding channel to mix and arrays of two-layer trapping structures to trap WBCs. Red blood cells (RBCs) were eliminated through moving the winding channel and then WBCs were trapped using the arrays of trapping structures. The microfluidic chip was fabricated in the biologically compatible PDMS (polydimethylsiloxane) using MEMS (microelectromechanical system) fabrication technology. We determined the critical flow velocities of tartrazine water and brilliant blue water mixing and whole blood and red blood cell lysis buffer mixing in the winding channel. They are 0.25 μl/min and 0.05 μl/min, respectively. The critical flow velocity of the whole blood and red blood cell lysis buffer is lower due to larger volume of the RBCs and higher kinematic viscosity of the whole blood. Under this flow velocity, the RBCs were lysed completely by mixing and the WBCs were trapped by the trapping structures.

The nuclear magnetic resonance (NMR) probe has great influence on signal transmission and reception in NMR technology applications. In this paper, we present a design, fabrication, and test of an NMR probe comprised of a multilayer planar microcoil with a polydimethylsiloxane (PDMS) microchannel. First, geometric parameters of the probe are determined through theoretical analysis. Second,based on a glass substrate, the multilayer planar microcoil is manufactured using repeated photolithography and electroplating processes. During the fabrication process,the polyimide layer is used to package the coil, and the PDMS interlayer is used to adjust the distance from centerlines between the coil and the sample chamber. Third,the resistance and the quality factor of the coil are found to be 1.2158 X and 7.217, respectively, at a Larmor frequency of 28.1 MHz. Finally, the NMR probe is tested in an NMR experiment. The transverse relaxation time T2 for the solid PDMS is 20.6 ± 0.4 ms, which is in agreement with 21.1 ± 0.2 ms obtained by a Bruker Minispec MQ60.Results show that the design and fabrication of this NMR probe are feasible for time-domain NMR applications.

Microfluidics has been considered as a potential technology to miniaturize the conventional equipments and technologies. It offers advantages in terms of small volume, low cost, short reaction time and high-throughput. The applications in biology and medicine research and related areas are almost the most extensive and profound. With the appropriate scale that matches the scales of cells, microfluidics is well positioned to contribute significantly to cell biology. Cell culture, fusion and apoptosis were successfully performed in microfluidics. Microfluidics provides unique opportunities for rare circulating tumour cells isolation and detection from the blood of patients, which furthers the discovery of cancer stem cell biomarkers and expands the understanding of the biology of metastasis. Nucleic acid amplification in microfluidics has extended to single-molecule, high-throughput and integration treatment in one chip. DNA computer which is based on the computational model of DNA biochemical reaction will become practice from concept in the future. In addition, microfluidics offers a versatile platform for protein-protein interactions, protein crystallization and high-throughput screening. Although microfluidics is still in its infancy, its great potential has already been demonstrated and will provide novel solutions to the high-throughput applications.