Department of Chemical Engineering and Biotechnology, University of Cambridge, New Museums Site, Pembroke St, Cambridge CB2 3RA, UK.
Biomaterials. 2009 Nov;30(33):6548-55. doi: 10.1016/j.biomaterials.2009.08.023. Epub 2009 Aug 27.
A previously developed cell labelling methodology has been evaluated to assess its potential to precisely control the degree of magnetic labelling. The two-step method provides a quick way of labelling cells by first biotinylating the cell membrane proteins and then binding streptavidin paramagnetic particles onto the biotinylated proteins. Characterisation studies on biotinylated HeLa cells have revealed that the biotin concentration on the cell surface can be varied by changing the biotinylating reagent concentration. At the optimal concentration (750 microm), a substantial surface biotin density (approximately 10(8) biotin per cell) could be achieved within 30 min. The degree of magnetic labelling could be altered by adjusting the concentration of paramagnetic particles added to the cells and the binding of the particles onto the cell surface was not considerably affected by the biotin density on the cell surface. The magnetic moment of the labelled cells was measured and correlated well with the degree of magnetic labelling. Cell viability studies indicated that the magnetic labelling was not cytotoxic. Magnetically labelled cells were then successfully targeted and manipulated by magnetic fields to form three dimensional multicellular structures.
先前开发的细胞标记方法已被评估，以评估其精确控制磁标记程度的潜力。两步法通过首先生物素化细胞膜蛋白，然后将链霉亲和素顺磁颗粒结合到生物素化蛋白上来快速标记细胞。对生物素化 HeLa 细胞的特征研究表明，通过改变生物素化试剂的浓度可以改变细胞表面的生物素浓度。在最佳浓度（750 µm）下，在 30 分钟内可实现大量的表面生物素密度（每个细胞约 10(8)个生物素）。通过调整添加到细胞中的顺磁颗粒的浓度可以改变磁标记的程度，并且颗粒与细胞表面的结合不受细胞表面生物素密度的显著影响。标记细胞的磁矩已被测量，并与磁标记程度很好地相关。细胞活力研究表明，磁标记没有细胞毒性。然后成功地通过磁场靶向和操纵磁性标记的细胞，形成三维多细胞结构。
