Abstract 3199: Miniaturized, multiplexed, highly sensitive protein NanoArray assay for measuring biomarkers in dried blood spot (DBS) samples

Abstract

Abstract As the utility of new biomarkers for diagnosis and treatment of disease become better understood, physicians and researchers are faced with increasingly critical decisions regarding how to best distribute their valuable patient samples. While simply taking more blood would seem a reasonable solution, a recent publication in the Archives of Internal Medicine (Salisbury, et.al., Arch Intern Med. 2011;171(18):1646-1653) addresses the very real problem of hospital-acquired anemia (HAA) brought on by blood loss resulting from blood drawn for clinical assays. Also in many resource constrained countries, the lack of adequate infrastructure such as hospitals, laboratories, transportation systems as well as qualified personnel pose major obstacles for patient access to clinical testing. This has revived interest in collecting dried blood spots (DBS) for clinical testing. DBS samples provide a number of benefits when compared with drawing venous blood: they require minimal blood volume (usually 50µl per spot), they can easily be collected from infants and children, and they can be used to collect blood samples where collection and storage of serum or plasma is not feasible. However for DBS samples to be a viable solution for clinical assay, the assay method must be sensitive and yet require very small sample volumes. NanoInk, Inc. has developed a highly sensitive assay based on dip-pen nanolithography (DPN™) using the NanoArrayer3000™. Utilizing a 48 subarray slide platform printed with a nano-scale antibody array we have created a miniaturized multiplexed sandwich ELISA with sensitivities as low as the 100's of femtograms/ml while using sample volumes that range from 2-4µl/well. Using our proprietary elution protocol, we are able to elute biomarkers from a standard 3.2mm DBS card punch sufficient to provide triplicate assay values while still keeping the samples concentrated enough to measure lower concentration biomarkers. Our NanoInk DBS cytokine assay has been validated using eluted blood standards and QC samples and shows good well-to-well and slide-to-slide variability. NanoInk's multiplexed assay format can also be customized to include a wide array of biomarkers. This multiplex capability, in combination with our proprietary sample and standard elution protocol, now allows clinicians to accurately measure the concentration of multiple biomarkers using convenient small-volume DBS samples. The results of an ongoing study for measuring biomarker levels in patient samples using our 5-cytokine DBS assay will be presented. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3199. doi:1538-7445.AM2012-3199