Abstract
Efforts to expand the precision science knowledge base and promote translation of findings to clinical care remain an important area of ongoing inquiry. Part of this effort includes quantification of proteins that can be used as biological markers (i.e., biomarkers) of pathophysiological processes and other important cellular and tissue activities. Potential applications for biological markers include disease or injury diagnosis, symptom prognosis, and therapy selection/evaluation. The increased understanding of the current and future utility of protein biomarkers, combined with the realization that many biomarkers normally exist in very low levels, has prompted efforts to develop new protein quantification systems with enhanced sensitivity, improved workflows, and shorter read times. Here, we provide an overview of an ultrasensitive immunoassay system and compatible interleukin-6 (IL-6) assays. This assay platform is bead-based, like many other commercially available systems; however, rather than quantifying the fluorescent signal in the spectral address of bead regions, the ultrasensitive immunoassay system quantifies free-floating fluorochromes using a rotating laser, charge-coupled device (CCD) camera, and avalanche photodiode (APD). This high-performance system can be used to quantify a myriad of protein biomarkers, in a variety of biological specimens collected from many species. In this article, quantification of IL-6 in human serum obtained from pediatric brain injury patients will be used as an exemplar.
