基于SOI基底的高通量细胞电融合芯片

提出了一种以MEMS技术为基础, 可在低电压驱动条件下工作的创新型细胞电融合芯片. 该芯片的设计原理在于通过缩短微电极间的间距, 在低电压条件下获得足够强度的排队和融合电场强度. 原型芯片以SOI硅片为加工材料, 通过刻蚀方式在顶层低阻硅形成微电极和微通道; 在微电极上沉淀2 μm厚的铝膜以降低电阻率, 提高导电性; 通过PECVD方法形成150 nm厚SiO2保障铝膜的抗腐蚀性及芯片生物相容性; 芯片最终采用DIP法进行封装. 在该芯片上进行了低电压(传统电融合设备工作电压的1/20)驱动条件下的基于介电电泳的细胞排队实验及后期的细胞电融合实验, 结果表明, 细胞多以两两结合的方式排列, 与传统的细胞融合电仪器相比较, 降低了多细胞排队概率, 进而减少了传统电融合设备多细胞融合的概率, 为细胞高效率融合奠定了基础. 在加载的低电压短脉冲信号后, 微通道中形成了高压短脉冲电场, 在脉冲作用下, 烟草原生质体细胞在微通道中发生了融合, 融合时间(2 min)远低于传统电融合方法(10~30 min), 融合率远远高于传统的PEG方法(融合率小于1%)和传统电融合方法(利用BTX ECM 2001细胞电融合系统得到, 融合率小于5%).

SOI-based Cell Electrofusion Chip

A MEMS-based novel cell electrofusion chip design was presented for exploring cell electrofusion in a low-voltage condition. Its essence is on the using of microfabrication to shorten the distance between an electrode pair, hence decreasing the required voltage during the alignment and fusion. The chip prototype was fabricated on a SOI substrate, which was subsequently covered by the aluminium film(~2 μm thickness) to enhance the conductivity and SiO2(150 nm thickness) film to improve the biocompatibility, and packaged via DIP method. On-chip dielectrophoresis-based cell alignment and cell fusion experiments were explored where much smaller voltage(only 1/20 of traditional electrofusion device) was required. Most cells were aligned as cell-cell twins under dielectrophoretic force, which is of significant advantage than multi-cell alignment in traditional method. Tobacco mesophyll protoplasts electrofusion experiments have been explored on the microchip. After load a series of shiort-duration(50 μs) and low-voltage(~40 V) electric pulse, many aligned cells could be fused within several minutes under the high-strength electric field(1—10 kV/cm). It is much faster than traditional method(10—30 min). Compared with PEG(less than 1%) and traditional electrofusion(less than 5%) methods, higher fusion efficiency(about 31%) was also obtained.