title: Microfluidic immunosensor design for the quantification of interleukin-6 in human serum samples.
abstract: Interleukin-6 (IL-6), an inflammatory cytokine, is one of the most important mediators of fever, the acute phase response, and inflammatory conditions. Described here is an integrated microfluidic immunosensor capable of detecting the concentration of IL-6 in human serum samples by use of an electrochemical method in a microfluidic biochip format. The detection of IL-6 was carried out using a sandwich immunoassay method based on the use of anti-IL-6 monoclonal antibodies, immobilized on a 3-aminopropyl-modified controlled-pore glass (APCPG) packet in a central channel (CC) of the microfluidic system. The IL-6 in the serum sample is allowed to react immunologically with the immobilized anti-IL-6 and biotin-labeled second antibodies specific to IL-6. After washing, the streptavidin-alkaline phosphatase conjugate is added. p-Aminophenyl phosphate is converted to p-aminophenol by alkaline phosphatase, and the electroactive product is quantified on a gold electrode at 0.10 V. For electrochemical detection and enzyme immunoassay, the LOD was 0.41 and 1.56 pg mL(-1), respectively. Reproducibility assays employed repetitive standards of IL-6, and the intra- and inter-assay coefficients of variation were below 6.5%. Compared with the traditional IL-6 sensing method, the integrated microfluidic immunosensor required smaller amounts of sample to perform faster detection.
authors.affiliation: INQUISAL, Department of Chemistry, National University of San Luis, CONICET, Chacabuco y Pedernera, D5700BWS, San Luis, Argentina.
authors.forename: Germán A
authors.initials: GA
authors.lastname: Messina
authors.forename: Nancy V
authors.initials: NV
authors.lastname: Panini
authors.forename: Noelia A
authors.initials: NA
authors.lastname: Martinez
authors.forename: Julio
authors.initials: J
authors.lastname: Raba
mesh_terms: D000469:Alkaline Phosphatase / Q000737:chemistry; D000911:Antibodies, Monoclonal / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods; D004563:Electrochemistry / Q000379:methods; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods*; D019809:Streptavidin / Q000737:chemistry
chemical_list: D000911:Antibodies, Monoclonal; D015850:Interleukin-6; D006046:Gold; D019809:Streptavidin; D000469:Alkaline Phosphatase