Biomarker detection

Grant Number:     CMMI No. 1129727

Name:                  A Novel Multiplexed Multichannel Biosensor Chip for High-Throughput Detection of                                Macromolecular Biomarkers 

Start Date:           Sep 1st, 2011

Investigator(s):     Jiang Zhe (Principal Investigator)

                            Gang Cheng (Co-Principal Investigator)

Abstract

The rapid, sensitive and low-cost detection of macromolecular biomarkers is critical in clinical diagnostics, environmental monitoring, research and other scientific fields. Conventional assay methods usually require bulky, expensive and designated instruments and relative long assay time. For hospitals and laboratories lacking of immediate access of analytical instruments, fast and low-cost assay methods for the detection of macromolecular biomarkers are urgently needed. In this work, we developed a versatile microparticle (MP)-based immunoaggregation assay for the detection and quantification of macromolecular biomarkers. In this method, antibodies (Abs) were firstly conjugated to MP through streptavidin-biotin interaction and the addition of macromolecular biomarkers subsequently caused the aggregation of Ab-MPs, which were detected by an optical microscope and an optical particle sizer. Hence, the existence of invisible nanometer-scale macromolecular biomarkers (such as proteins) causes the change of detectable micrometer-scale particles. Goat anti-rabbit Ab and human ferritin were used as two model biomarkers to validated MP-based immunoaggregation assay in PBS and 10% FBS to mimic real biomarker assay in the complex medium. It was found that both the number ratio and the volume ratio of Ab-MP aggregates caused by biomarker to all particles were directly correlated to the biomarker concentration. In addition, we demonstrated that the detection range could be tuned by adjusting the Ab-MP concentration. We envision that this novel MP-based immunoaggregation assay can be readily combined with multiple detection methods to detect and quantify macromolecular biomarkers at the nanogram per milliliter level.