title: Determination of free bilirubin and its binding capacity by HSA using a microfluidic chip-capillary electrophoresis device with a multi-segment circular-ferrofluid-driven micromixing injection.
abstract: A PMMA microfluidic chip-CE device with a multi-segment circular-ferrofluid-driven micromixing injector has been developed for the determination of free bilirubin and its binding capacity by HSA at equilibrium. The design of the device and its fabrication by a low cost CO(2) laser are discussed for intended applications. Under optimized conditions, the total binding capacity of HSA for bilirubin was determined as 16.3±1.4 mg/l00 mL human serum (n=3) and residual binding capacity for bilirubin 9.8 mg/100 mL (n=3) in normal infants. To assess risk of hyperbilirubinemia, free bilirubin and residual binding capacity by HSA provide a better indicator than total bilirubin, as neonates with impaired bilirubin binding capacity could be detected. In addition, residual binding capacity provides an advanced indicator to predict the onset of hyperbilirubinemia before the appearance of free bilirubin. HSA down to 94 nL is used in each titration and a full assay of four titrations takes up 376 nL HSA, sufficient for newborns with HSA in microliter range. The device has shown capable to provide adequate margin of protection to detect an early rising level of bilirubin and impaired binding capacity prior to the onset of jaundice condition.
authors.affiliation: Department of Chemistry, The University of Hong Kong, Hong Kong SAR, P R China.
authors.forename: Hui
authors.initials: H
authors.lastname: Sun
authors.forename: Zhou
authors.initials: Z
authors.lastname: Nie
authors.forename: Ying Sing
authors.initials: YS
authors.lastname: Fung
mesh_terms: D001663:Bilirubin / Q000032:analysis* / Q000097:blood / Q000378:metabolism; D004574:Electromagnetic Fields; D019075:Electrophoresis, Capillary / Q000295:instrumentation* / Q000379:methods; D052203:Ferrosoferric Oxide / Q000737:chemistry; D006801:Humans; D006932:Hyperbilirubinemia / Q000175:diagnosis; D052578:Ionic Liquids / Q000737:chemistry; D054020:Lasers, Gas; D008280:Magnetics; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods; D019904:Polymethyl Methacrylate / Q000737:chemistry; D011485:Protein Binding; D012709:Serum Albumin / Q000378:metabolism*
chemical_list: D052578:Ionic Liquids; D012709:Serum Albumin; D019904:Polymethyl Methacrylate; D001663:Bilirubin; D052203:Ferrosoferric Oxide