SBIR-STTR Award

This research involves developing procedures to determine regional flow in tissues and organs at high resolution. Current methods for regional flow determinations are limited by microsphere size and counting statistics. This study tests the hypothesis that fluorescently-labeled antibodies, serving as "molecular microspheres", will attach to capillary binding sites in proportion to microregional flow. As compared to current microsphere-based measurements, the fluorescence intensity from bound dye molecules could potentially improve volume resolution of regional flow measurements by factors of 1,000 to 1,000,000. The project will develop fluorescence image analysis methods to measure microregional flow in whole organs. This project will provide physiological/medical researchers with a unique tool for quantifying regional flow at high resolution.. Phase I research will demonstrate the ability of fluorescent antibodies to serve as molecular flow markers in rat heart. Phase II will extend this methodology to studies of different colored fluorochromes attached to antibodies and to different antibodies specific to capillary endothelium. Phase II will also demonstrate the utility of the method for flow measurements in different organs and large animals and will develop high resolution flow display software. This technological innovation will advance the development of the Imaging CryoMicrotome/TM to perform integrative physiological studies in tissues and organs. PROPOSED COMMERCIAL APPLICATIONS: Potential markets include the hundreds of laboratories that currently do low resolution flow measurements, as well as researchers wishing to validate MRI methods on experimental animals. Increasing the resolution (decreasing tissue volume element size) could greatly expand the types of studies using this technology and increase demand for cytomicrotome imaging.

Thesaurus Terms:
blood flow measurement, digital imaging, fluorescent dye /probe, immunologic substance development /preparation, microcapsule, monoclonal antibody CD34 molecule, biomarker, capillary, vascular endothelium biotechnology, laboratory rat

This research involves the development of a method to quantify regional flow in tissues using automated instrumental procedures. Phase I results have demonstrated that fluorescent antibodies, specific to antigens in capillary endothelium, can be spatially located in sequential fluorescence images recorded from frozen tissue blocks during organ serial sectioning. Statistical limitations imposed on fluorescent and radioactive microsphere methods are removed by the use of molecules as flow markers (molecular microspheres), greatly expanding the details of organ-flow maps. During Phase I, fluorescent antibodies were identified that have excellent retention in heart vascular systems and regional deposition which correlates strongly with simultaneously injected 15 micron-diameter flourescent microspheres. Both the validity of the molecular microsphere approach and the feasibility of the imaging methodology have been demonstrated. Phase II will concentrate on in vivo studies in heart, development of analysis procedures and validation studies in lung and brain to be undertaken by collaborators. Methods will also be developed to conduct multiple flow measurements in the same organ. This project will provide researchers with methods and instrumentation to measure regional flow in tissue volumes much smaller than those possible with current techniques.

Thesaurus Terms:
blood flow measurement, digital imaging, fluorescent dye /probe, method development, monoclonal antibody biomarker, computer program /software, computer system design /evaluation, immunoconjugate, immunologic substance development /preparation, microcapsule, organ biotechnology, laboratory rat