Penn Radioimmunoassay and Biomarkers Core
The Radioimmunoassay and Biomarkers Core offers a large number of high quality immunoassay services to basic, translational, and clinical investigators performing diabetes and related metabolic disease research. The RIA/Biomarkers Core is housed within in a new state of the art-laboratory within the Institute for Diabetes, Obesity & Metabolism (IDOM) located on the 12th floor of the Smilow Center for Translational Research. This new location places the Core on the same floor and in close proximity to the Islet Cell Biology Core, Functional Genomics Core, and Mouse Phenotyping, Physiology & Metabolism Core that enhances the already close interactions among these DRC Scientific Cores.
IDOM is also home to the Metabolic Tracer Resource directed by Dr. John Millar which offers gas chromatography-mass spectrometry of stable isotope tracers, and so provides a “one-stop” shop for DRC investigators requiring metabolic assays of both hormone levels and metabolite fluxes derived from human, animal, and cell culture experiments. The integrated delivery of assay services provided by the RIA/Biomarkers Core is further enhanced by informatics infrastructure for ordering, tracking, billing and delivery of service. The performance of a large number of immunoassay services in a central core facility rather than in scattered locations throughout the University provides a significant overall savings in equipment, personnel effort, and supplies for investigators, while importantly allowing for the generation of results with superior quality due to our enhanced quality control/quality assurance/quality management (QA/QC/QM) processes.
Approximately 100 different diabetes, obesity and metabolism-related biomarkers can be assayed and the number of assay services offered continues to increase. Current services include radioimmunoassay (RIA), enzyme-linked immunosorbent assay (ELISA), and multiplex ELISA on the Luminex platform for an expanding variety of diabetes and metabolism related hormones and cytokines derived from blood, urine, and tissue samples.
Samples generated for assay in the DRC Islet Cell Biology, Mouse Phenotyping, Physiology & Metabolism, and Functional Genomics Cores are delivered directly to the RIA/Biomarker Core for analysis, ensuring proper collection, handling, reporting, and interpretation of data generated from the DRC Scientific Cores.
New services anticipated in the near future include the development of assays on a more sensitive multiplex platform based on digital ELISA (Simoa; Single Molecule Array).
RIA services at Penn are unique to the RIA/Biomarkers Core and offer high-volume, rapid turnaround of affordably priced insulin, C-peptide and glucagon assays for human and rodent blood and tissue samples.
ELISA services are also available to assay insulin from low sample volume mouse studies, and for non-human primate studies to assay monkey insulin and C-peptide.
Multiplex ELISA services are available on the Luminex IS100 platform which uses cell-sorting technology to measure multiple proteins simultaneously on bead based immunoassays. This technology can be particularly useful to investigators studying mouse models and those with repeated sampling human protocols, where sample volumes are often low.
In all cases, we use commercial kits and commercial quality control material. In order to minimize cost, insulin, C-peptide and glucagon are grouped in batches and processed within two weeks. Other hormones are processed within two weeks of kit arrival.
The RIA/Biomarkers Core director, Dr. Michael Rickels, and technical director, Dr. Heather Collins, advise investigators on determining the best assay method, proper collection strategy, and the costs involved to address their scientific question. This consultation starts at the time of preparation of research grants to assist investigators with appropriately budgeting for assay costs, as well as the supplies and reagents necessary for the proper collection of samples for particular assays.
Training and Education
The RIA/Biomarkers Core is dedicated to providing outreach and training for the DRC research community in order to support the highest standard of biomarker research for diabetes, obesity and related metabolic disorders. As part of the education and training function of the core, Drs. Collins and Rickels meet with investigators, coordinators and nurses to train them on the procedures for collecting samples for reliable measurement, including the addition of chemicals and/or proteases as may be required for the protection of intact peptide hormones. Where study subjects are evaluated cross-sectionally or prospectively before and after intervention, samples are batched with representation across groups and with longitudinal samples from the same subjects assayed simultaneously to minimize inter-assay variation from affecting effect sizes. Thus, collection and storage conditions for samples are critical. As Director of the Translational Research Program for IDOM, and Associate Director of the Penn Center for Human Phenomic Science (CHPS), Dr. Rickels supervises clinical research and nursing staff who contribute to investigator training and facilitate the implementation of appropriate sample collection and processing procedures in the CHPS units where the clinical and translational research studies in diabetes and obesity are conducted.