? DESCRIPTION (provided by applicant) There is a critical need for a blood sample preparation and processing method that can preserve integrity and improve downstream analysis, while being completely free of cold storage requirements. Such a technology would allow clinicians and patients to collect blood samples for cancer screening, monitoring and/or diagnosis comfortably from patient's homes, obviating the need for outpatient lab visits. Vaxess Technologies is developing a set of biomaterial-based approaches that improves the stability of a wide range of samples using a novel silk protein matrix. The objective of this proposal is to characterize the ability of a silk matrix to stabilize a panel of metabolomic prostate cancer biomarkers in a blood sample. The enhanced performance of silk- based protection will be compared to other similar methods (dried blood spot (DBS) cards) and the gold standard (frozen storage). We anticipate that the use of silk will allow for minimally- or non-invasive sample collection routes, and will provide comparable analyte retention to the current gold standard, frozen storage, while improving recovery as compared to commercially-available DBS cards. Vaxess has extensive preliminary data demonstrating the use of silk to stabilize antibodies, plasma proteins and nucleic acids from complex fluids such as whole blood, plasma, serum, and saliva. We anticipate being able to do the same with blood analytes, as proposed here. In the first aim, we will form serum-laden silk matrices and quantitate metabolomic prostate cancer marker levels. This will be accomplished by using mass spectrometry to measure analyte recovery from silk matrices and comparing the yields directly to frozen controls or DBS cards. Modifications of silk molecular weight and its net charge can systematically change proteomic interactions, and thus provides a route to study the mechanistic underpinnings of silk stabilization in the context of sample recovery. In a second aim, we will compare the stability of markers identified in Aim 1 to frozen control samples and DBS cards when all have been treated at various temperatures and humidity levels. The expected outcome of these studies will be the development of a silk-based sample preparation method for cancer-specific analytes that will improve downstream sample processing. The rationale for the proposed research is that, once recovery and stability of these biomarkers is proven to be augmented by a silk encapsulate, diagnostic kits can be outfitted with various silk formats, which can then be used as a platform system for full validation in follow-on studies. Success with the planned approach can positively impact many areas of need in the field of cancer diagnostics, including early detection, screening, and clinical diagnosis, by increasing overall access to precise analytics and by reducing pre-analytical variations that affect sample quality. Furthermore, by offering methods to interface with finger-prick volumes of whole blood, a silk-based stabilization system could be used without a phlebotomist and thus circumvent the resource requirements of the outpatient clinic.