title: Sensitive, rapid and quantitative detection of substance P in serum samples using an integrated microfluidic immunochip.
abstract: Miniaturized diagnostic devices hold the promise of accelerate the specific and sensitive detection of various biomarkers, which can translate into many areas of medicine - from cheaper clinical trials, to early diagnosis and treatment of complex diseases. Therefore, we report on a disposable integrated chip-based capillary immunoassay featuring a microfluidic ELISA format combining electrochemical detection and low-cost fabrication employing a dry film photoresist, Vacrel(®) 8100. The readily accessible carboxylate groups on the material surface allow fast and high yield immobilization of biomolecules using amine-specific coupling via reactive esters requiring no laborious surface pretreatment. The integrated microfluidic system provides a convenient platform for a flow-through immunoassay. Capillary force is used for easy reagent delivery and loading the chip channel. We performed rapid quantification of serum level of substance P, a potential biomarker of acute neuroinflammation, using the developed microfluidic immunochip. Our miniaturized assay demonstrated a sensitive electrochemical detection of the antigen at 15.4pgml(-1) (11.5pM) using only 5µl of the biological fluid while cutting the total assay preparation time in half and the read-out time to 10min. Combining microfluidics and fabrication suitable for mass production with the capability of testing clinically relevant samples creates conditions for the construction of low-cost and portable point of care diagnostic devices with minimal auxiliary electronics.
authors.affiliation: University of Freiburg, Department of Microsystems Engineering, Laboratory for Sensors, Georges-Koehler Allee 103, 79110 Freiburg, Germany. Electronic address: josef.horak@imtek.uni-freiburg.de.
authors.forename: Josef
authors.initials: J
authors.lastname: Horak
authors.affiliation: University of Freiburg, Department of Microsystems Engineering, Laboratory for Sensors, Georges-Koehler Allee 103, 79110 Freiburg, Germany.
authors.forename: Can
authors.initials: C
authors.lastname: Dincer
authors.affiliation: University of Freiburg, Department of Microsystems Engineering, Laboratory for Sensors, Georges-Koehler Allee 103, 79110 Freiburg, Germany.
authors.forename: Hüseyin
authors.initials: H
authors.lastname: Bakirci
authors.affiliation: University of Freiburg, Department of Microsystems Engineering, Laboratory for Sensors, Georges-Koehler Allee 103, 79110 Freiburg, Germany.
authors.forename: Gerald
authors.initials: G
authors.lastname: Urban
mesh_terms: D003217:Conductometry / Q000295:instrumentation*; D004797:Enzyme-Linked Immunosorbent Assay / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007118:Immunoassay / Q000295:instrumentation*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D008904:Miniaturization; D013373:Substance P / Q000097:blood*; D018511:Systems Integration
chemical_list: D013373:Substance P
keywords: Biochip; Electrochemical detection; Immunoassay; Microfluidics; Substance P