title: Channel surface patterning of alternating biomimetic protein combinations for enhanced microfluidic tumor cell isolation.
abstract: Here, we report a new method for multicomponent protein patterning in a microchannel and also a technique for improving immunoaffinity-based circulating tumor cell (CTC) capture by patterning regions of alternating adhesive proteins using the new method. The first of two proteins, antiepithelial cell adhesion molecule (anti-EpCAM), provides the specificity for CTC capture. The second, E-selectin, increases CTC capture under shear. Patterning regions with and without E-selectin allows captured leukocytes, which also bind E-selectin and are unwanted impurities in CTC isolation, to roll a short distance and detach from the capture surface. This reduces leukocyte capture by up to 82%. The patterning is combined with a leukocyte elution step in which a calcium chelating buffer effectively deactivates E-selectin so that leukocytes may be rinsed away 60% more efficiently than with a buffer containing calcium. The alternating patterning of this biomimetic protein combination, used in conjunction with the elution step, reduces capture of leukocytes while maintaining a high tumor cell capture efficiency that is up to 1.9 times higher than the tumor cell capture efficiency of a surface with only anti-EpCAM. The new patterning technique described here does not require mask alignment and can be used to spatially control the immobilization of any two proteins or protein mixtures inside a sealed microfluidic channel.
authors.affiliation: Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois 60607, USA.
authors.forename: Cari
authors.initials: C
authors.lastname: Launiere
authors.forename: Marissa
authors.initials: M
authors.lastname: Gaskill
authors.forename: Gregory
authors.initials: G
authors.lastname: Czaplewski
authors.forename: Ja Hye
authors.initials: JH
authors.lastname: Myung
authors.forename: Seungpyo
authors.initials: S
authors.lastname: Hong
authors.forename: David T
authors.initials: DT
authors.lastname: Eddington
mesh_terms: D015815:Cell Adhesion Molecules / Q000378:metabolism; D045744:Cell Line, Tumor; D002469:Cell Separation / Q000295:instrumentation*; D019040:E-Selectin / Q000378:metabolism; D006801:Humans; D055767:Immobilized Proteins / Q000378:metabolism*; D007962:Leukocytes / Q000166:cytology; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D009360:Neoplastic Cells, Circulating / Q000378:metabolism*; D011485:Protein Binding; D013499:Surface Properties
chemical_list: D015815:Cell Adhesion Molecules; D019040:E-Selectin; D055767:Immobilized Proteins