Department of Chemical Engineering, University of Virginia, 102 Engineers' Way, Charlottesville, VA 22904-4741, USA.
J Chromatogr A. 2012 Nov 16;1264:48-56. doi: 10.1016/j.chroma.2012.09.064. Epub 2012 Sep 26.
We compare the rates of adsorption of two monoclonal antibodies (mAbs) with different adsorption properties on the cation exchangers UNOsphere™ S and Nuvia™ S. The former contains large open pores while the latter is based on a backbone matrix similar to UNOsphere™ S but also contains grafted charged polymers. Both single component and two-component adsorption are considered. Adsorption capacity and rates are much higher for Nuvia™ S indicating that protein interactions with the charged grafted polymers facilitate both binding and diffusional transport. Intraparticle concentration profiles obtained by confocal microscopy show sharp fronts for UNOsphere™ S but diffuse profiles for Nuvia™ S. Transport is thus controlled by pore diffusion for UNOsphere™ S but is described by a single file diffusion (SFD) mechanism for Nuvia™ S. As a result, single and two-component adsorption occur at similar rates for UNOsphere™ S independent of the direction for transport. For Nuvia™ S, however, transport is very fast for single or two-component co-adsorption but very slow when counter diffusion of the two mAbs takes place within the particles. The transport models developed in this work allow a prediction of separation performance for overloaded conditions typical of process scale applications.
我们比较了两种具有不同吸附性能的单克隆抗体（mAbs）在阳离子交换剂 UNOsphere™ S 和 Nuvia™ S 上的吸附速率。前者含有大的开放孔，而后者基于与 UNOsphere™ S 相似的骨架基质，但也含有接枝的带电聚合物。同时考虑了单组分和双组分吸附。Nuvia™ S 的吸附容量和速率要高得多，这表明蛋白质与带电接枝聚合物的相互作用既促进了结合又促进了扩散传输。通过共聚焦显微镜获得的颗粒内浓度分布显示 UNOsphere™ S 的前沿很尖锐，而 Nuvia™ S 的分布很弥散。因此，对于 UNOsphere™ S，扩散控制了传输，而对于 Nuvia™ S，则由单分子扩散（SFD）机制来描述。结果，对于 UNOsphere™ S，无论是单组分还是双组分吸附，其吸附速率都相似，而与传输方向无关。然而，对于 Nuvia™ S，当两种 mAbs 在颗粒内发生反向扩散时，单组分或双组分共吸附的传输速度非常快，而反向扩散的传输速度非常慢。本工作中开发的传输模型可用于预测过程规模应用中典型的过载条件下的分离性能。
