Sestier C, Sabolovic D
INSERM Unit 313, Hopital Pitié Salpétrière, Paris, France.
Electrophoresis. 1998 Oct;19(14):2485-90. doi: 10.1002/elps.1150191422.
Measuring the electrophoretic mobility of superparamagnetic particles (0.5-4.5 microns mean size) was undertaken to probe the coupling of lectins and antibodies to their surface. Coupling was either noncovalent (antigen-antibody and biotin-streptavidin linkage) or covalent (tosyl-activated beads). The direct observation of the electrophoresis of single particles illuminated in dark field and processed by image analysis allowed the determination of their apparent electrophoretic mobility. Mobilities ranged from -0.5 micron s-1/CmV-1 to +1 micron s-1/CmV-1 when measured at 20 degrees C in 0.15 M NaCl and 30 mg/mL sorbitol, pH 7.4. The relative standard deviation was less than 0.1%. Surface immobilization of charged proteins onto the superparamagnetic beads shifted their electrophoretic mobility up to 200%; this was also quantitatively correlated with some specific properties (enzymatic activity, antigen-binding activity, lectin-binding activity). Although particle electrophoresis has mainly been reported for the study of surface adsorption phenomenon, it may be a versatile tool for controlling covalent modifications of particles designed for therapeutical targeting or chromatographic use and may also apply to a quantitative analysis of ligand-binding interactions.
为了探究凝集素和抗体与超顺磁性颗粒（平均尺寸为0.5 - 4.5微米）表面的偶联情况，对其电泳迁移率进行了测量。偶联方式包括非共价（抗原 - 抗体和生物素 - 链霉亲和素连接）或共价（甲苯磺酰活化珠）。通过对暗场照明下单颗粒电泳进行直接观察并经图像分析处理，可以测定它们的表观电泳迁移率。在20℃、0.15 M NaCl和30 mg/mL山梨醇（pH 7.4）条件下测量时，迁移率范围为 -0.5微米·秒⁻¹/（厘米·伏⁻¹）至 +1微米·秒⁻¹/（厘米·伏⁻¹）。相对标准偏差小于0.1%。带电荷蛋白质在超顺磁性珠上的表面固定使它们的电泳迁移率变化高达200%；这也与一些特定性质（酶活性、抗原结合活性、凝集素结合活性）存在定量相关性。尽管颗粒电泳主要用于研究表面吸附现象，但它可能是一种通用工具，可用于控制设计用于治疗靶向或色谱用途的颗粒的共价修饰，也可应用于配体结合相互作用的定量分析。
