Proteins

Researchers: Shuai Nie
Past Members: David Rissin, Timothy Blicharz, and Tres Brazell

Protein assays provide access to biologically relevant information, including qualitative and quantitative information about specific proteins in a given sample matrix. Highly target specific monoclonal antibodies were immobilized on microspheres to create an individually addressed fiber optic array capable of single microsphere interrogation for the simultaneous measurement of multiple proteins. A microsphere based sandwich immunoassay was developed to simultaneously detect two innate immune system proteins found in human saliva. Preliminary results suggest that the degree of multiplexing on our fiber optic platform can be amplified, as the cross-reactivity between detection antibodies and their non-specific targets is relatively low in comparison to the signal generated by the specific binding of detection antibodies with their target.

Figure 1 Duplexed Europium encoding image (left; 600nm emission) and signal image from tagged detection antibody (right; 570nm). Dimmer encoded beads are probes to the target, while brighter encoded beads are probes to a target not present in the sample.

Figure 2 Detection of various concentrations of lactoferrin target protein using a duplexed array. Specific capture to lactoferrin probes shown in red and non-specific capture to Immunoglobulin probes shown in blue

“Duplexed sandwich immunoassays on a fiber-optic microarray”, D.M. Rissin, D.R. Walt. Analytica Chimica Acta , 2006

"Fiber-Optic Microsphere-Based Antibody Array for the Analysis of Inflammatory Cytokines in Saliva", Blicharz, Timothy M.; Siqueira, Walter L.; Helmerhorst, Eva J.; Oppenheim, Frank G.; Wexler, Philip J.; Little, Frederic F.; Walt, David R. Analytical Chemistry (2009), 81(6), 2106-2114.