Multifunctional Dendrimer-templated Antibody Presentation on Biosensor Surfaces for Improved Biomarker Detection.
Dendrimers, with their well-defined globular shape and a high density of functional groups, are ideal nanoscale materials for templating sensor surfaces. This work exploits dendrimers as a versatile platform for capturing biomarkers with improved sensitivity and specificity. Synthesis, characterization, fabrication, and functional validation of the dendrimer-based assay platform are described. Bifunctional hydroxyl/thiol functionalized G4-polyamidoamine (PAMAM) dendrimer is synthesized and immobilized on to the polyethylene-glycol (PEG)-functionalized assay plate by coupling PEG-maleimide and dendrimer thiol groups. Simultaneously, part of the dendrimer thiol groups are converted to hydrazide functionalities. The resulting dendrimer-modified surface is coupled to the capture antibody in the Fc region of the oxidized antibody. This preserves the orientation flexibility of the antigen binding region (Fv) of the antibody. To validate the approach, the fabricated plates are further used as a solid phase for developing a sandwich type ELISA to detect IL-6 and IL-1β, important biomarkers for early stages of chorioamnionitis. The dendrimer-modified plate provides assays with significantly enhanced sensitivity, lower nonspecific adsorption, and a detection limit of 0.13 pg ml-1for IL-6 luminol detection and 1.15 pg ml-1for IL-1β TMB detection, which are significantly better than those for the traditional ELISA. The assays were validated in human serum samples from normal (non-pregnant) woman and pregnant women with pyelonephritis. The specificity and the improved sensitivity of the dendrimer-based capture strategy could have significant implications for the detection of a wide range of cytokines and biomarkers since the capture strategy could be applied to multiplex microbead assays, conductometric immunosensors and field effect biosensors.
Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, Michigan 48202 (U. S. A.) and Eunice Kennedy Shriver National Institute of Child Health and Human Development, NICHD, NIH, DHHS, Detroit, MI 48201 (U. S. A.).
Hye Jung
HJ
Han
Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, Michigan 48202 (U. S. A.) and Eunice Kennedy Shriver National Institute of Child Health and Human Development, NICHD, NIH, DHHS, Detroit, MI 48201 (U. S. A.).
Rangaramanujam M
RM
Kannan
Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, Michigan 48202 (U. S. A.).
Sunxi
S
Wang
Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, Michigan 48202 (U. S. A.).
Guangzhao
G
Mao
Perinatology Research Branch NICHD/NIH/DHHS, Department of Obstetrics and Gynecology, Wayne State University, Hutzel Women's Hospital, Detroit, MI 48201 (U. S. A.).
Juan Pedro
JP
Kusanovic
Eunice Kennedy Shriver National Institute of Child Health and Human Development, NICHD, NIH, DHHS, Detroit, MI 48201 (U. S. A.).
Roberto
R
Romero
IL-1β; Interleukin-6; antibody conjugation; biosensors; cytokine; dendrimers