title: Analysis of mass transport models for protein adsorption to cation exchanger by visualization with confocal laser scanning microscopy.
abstract: The mass transfer of bovine serum albumin (BSA) to a cation exchanger, SP Sepharose FF, has been studied by finite batch adsorption experiments. The uptake curve was simulated with three mass transport models (i.e., effective pore diffusion model, surface diffusion model and Maxwell-Stefan model) incorporating the particle size distribution of the adsorbent particles. All the three models can simulate the uptake curves reasonably well. However, how well these models could simulate the real concentration profile within the adsorbent particle cannot be verified by the fitness of the models to the uptake curve. Thus, confocal laser scanning microscopy (CLSM) was used to visualize protein uptake to the porous adsorbent particles during the batch experiments. Using a fluorescent dye-labeled bovine serum albumin (BSA) for the dynamic adsorption experiments, the radial concentration profiles of the labeled BSA molecules into individual adsorbent particles at different times were obtained from the CLSM images. The protein distribution profiles within various particle diameters at different time were compared with the radial protein distributions predicted from the models. It reveals that surface diffusion model describes the intraparticle protein concentration profiles better than the other two models.
authors.affiliation: Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China.
authors.forename: Xiao-Peng
authors.initials: XP
authors.lastname: Zhou
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Qing-Hong
authors.initials: QH
authors.lastname: Shi
authors.forename: Yan
authors.initials: Y
authors.lastname: Sun
mesh_terms: D000327:Adsorption; D007474:Ion Exchange; D018613:Microscopy, Confocal / Q000379:methods*; D008956:Models, Chemical; D011506:Proteins / Q000302:isolation & purification*; D012685:Sepharose / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000302:isolation & purification
chemical_list: D011506:Proteins; C097574:sepharose fast flow SP; D012710:Serum Albumin, Bovine; D012685:Sepharose