title: A microfluidic linear node array for the study of protein-ligand interactions.
abstract: We have developed a microfluidic device for the continuous separation of small molecules from a protein mixture and demonstrated its practical use in the study of protein-ligand binding, a crucial aspect in drug discovery. Our results demonstrated dose-dependent binding between bovine serum albumin (BSA) and its small-molecule site marker, Eosin Y (EY), and found that the binding reached a plateau when the BSA : EY ratio was above 1, which agreed with the eosin binding capacity of BSA reported in literature. By streamline control using a combination of two fundamental building blocks (R and L nodes) with a microdevice operated at a high flow rate (up to 1300 μL h(-1)), a solution barrier was created to "filter" off protein/protein-ligand complexes such that the small unbound molecules were isolated and quantified easily. The percentage decrease of small molecules with increasing protein concentration indicated the presence of binding events. Several fluorophores with different molecular weights were used to test the performance of the microfluidic "filter", which was tunable by 1) the total flow rate, and/or 2) the flow distribution ratio between the two device inlets; both were easily controllable by changing the syringe pump settings. Since the microdevice was operated at a relatively high flow rate, aliquots were easily recovered from the device outlets to facilitate off-chip detection. This microfluidic design is a novel and promising tool for preliminary drug screening.
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau SAR, China. cheukwli@umac.mo.
authors.forename: Cheuk-Wing
authors.initials: CW
authors.lastname: Li
authors.forename: Guodong
authors.initials: G
authors.lastname: Yu
authors.forename: Jingyun
authors.initials: J
authors.lastname: Jiang
authors.forename: Simon Ming-Yuen
authors.initials: SM
authors.lastname: Lee
authors.forename: Changqing
authors.initials: C
authors.lastname: Yi
authors.forename: Wanqing
authors.initials: W
authors.lastname: Yue
authors.forename: Mengsu
authors.initials: M
authors.lastname: Yang
mesh_terms: D000818:Animals; D002417:Cattle; D004801:Eosine Yellowish-(YS) / Q000737:chemistry*; D008024:Ligands; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation; D012710:Serum Albumin, Bovine / Q000737:chemistry*
chemical_list: D008024:Ligands; D012710:Serum Albumin, Bovine; D004801:Eosine Yellowish-(YS)