Towards microalbuminuria determination on a disposable diagnostic microchip with integrated fluorescence detection based on thin-film organic light emitting diodes.
As a first step towards a fully disposable stand-alone diagnostic microchip for determination of urinary human serum albumin (HSA), we report the use of a thin-film organic light emitting diode (OLED) as an excitation source for microscale fluorescence detection. The OLED has a peak emission wavelength of 540 nm, is simple to fabricate on flexible or rigid substrates, and operates at drive voltages below 10 V. In a fluorescence assay, HSA is reacted with Albumin Blue 580, generating a strong emission at 620 nm when excited with the OLED. Filter-less discrimination between excitation light and generated fluorescence is achieved through an orthogonal detection geometry. When the assay is performed in 800 microm deep and 800 microm wide microchannels on a poly(dimethylsiloxane)(PDMS) microchip at flow rates of 20 microL min(-1), HSA concentrations down to 10 mg L(-1) can be detected with a linear range from 10 to 100 mg L(-1). This sensitivity is sufficient for the determination of microalbuminuria (MAU), an increased urinary albumin excretion indicative of renal disease (clinical cut-off levels: 15-40 mg L(-1)).
Hofmann
Oliver
O
Molecular Vision Ltd., 90 Fetter Lane, London, EC4A 1JP, United Kingdom.
Wang
Xuhua
X
Demello
John C
JC
Bradley
Donal D C
DD
Demello
Andrew J
AJ
D000419:Albuminuria / Q000175:diagnosis*; D005453:Fluorescence; D006801:Humans; D056656:Lab-On-A-Chip Devices; D008027:Light; D008832:Microchemistry / Q000295:instrumentation / Q000379:methods; D046208:Microchip Analytical Procedures / Q000379:methods*; D012680:Sensitivity and Specificity; D012709:Serum Albumin / Q000737:chemistry
D012709:Serum Albumin