Hin Sebastian, Paust Nils, Rombach Markus, Lüddecke Jan, Specht Mara, Zengerle Roland, Mitsakakis Konstantinos
Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
IMTEK-Laboratory for MEMS Applications, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
Micromachines (Basel). 2022 Nov 29;13(12):2112. doi: 10.3390/mi13122112.
Centrifugal microfluidics enables fully automated molecular diagnostics at the point-of-need. However, the integration of solid-phase nucleic acid extraction remains a challenge. Under this scope, we developed the magnetophoresis under continuous rotation for magnetic bead-based nucleic acid extraction. Four stationary permanent magnets are arranged above a cartridge, creating a magnetic field that enables the beads to be transported between the chambers of the extraction module under continuous rotation. The centrifugal force is maintained to avoid uncontrolled spreading of liquids. We concluded that below a frequency of 5 Hz, magnetic beads move radially inwards. In support of magnetophoresis, bead inertia and passive geometrical design features allow to control the azimuthal bead movement between chambers. We then demonstrated ferrimagnetic bead transfer in liquids with broad range of surface tension and density values. Furthermore, we extracted nucleic acids from lysed mosquitoes reaching comparable results of eluate purity (LabDisk: A260/A280 = 1.6 ± 0.04; Reference: 1.8 ± 0.17), and RT-PCR of extracted RNA (LabDisk: Ct = 17.9 ± 1.6; Reference: Ct = 19.3 ± 1.7). Conclusively, magnetophoresis at continuous rotation enables easy cartridge integration and nucleic acid extraction at the point-of-need with high yield and purity.
离心微流控技术可实现即时全自动化分子诊断。然而,固相核酸提取的整合仍是一项挑战。在此背景下,我们开发了连续旋转磁泳技术用于基于磁珠的核酸提取。四个固定的永久磁铁排列在一个试剂盒上方,产生一个磁场,使磁珠在连续旋转的情况下在提取模块的各腔室之间传输。离心力得以维持,以避免液体不受控制地扩散。我们得出结论,在频率低于5Hz时,磁珠沿径向向内移动。为支持磁泳技术,磁珠惯性和被动几何设计特征有助于控制磁珠在各腔室之间的方位运动。然后,我们展示了在具有广泛表面张力和密度值的液体中铁磁珠的转移。此外,我们从裂解的蚊子中提取了核酸,洗脱液纯度达到了可比结果(LabDisk:A260/A280 = 1.6 ± 0.04;参考值:1.8 ± 0.17),并且对提取的RNA进行了RT-PCR(LabDisk:Ct = 17.9 ± 1.6;参考值:Ct = 19.3 ± 1.7)。总之,连续旋转磁泳技术可实现试剂盒的轻松整合以及即时核酸提取,且产量高、纯度高。