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Summary:Biophotonics is at the intersection of photonics and biology where light is used to image, detect, and manipulate biological materials. This project addresses several factors that are critical for the successful development and integration of biophotonic applications in bioscience research and medicine: diagnostic and clinical standards for validating the efficacy of biophotonics-based applications, imaging standards to ensure high fidelity, a thorough understanding of the fundamental physics underlying new biophotonics-based therapeutic techniques, and measurement and science standards for improving manufacturing quality, promoting acceptance of biophotonics technology,and advancing the understanding of the interaction between biological systems and photons. Description:Nano-biophotonics consists of four broad areas: molecular bioimaging; nano-biosensors; multiplexed bioassays; and nanotechnology-based medical practices for diagnosis and therapy. Success in these areas is challenged by the underlying complexity of biological systems. Major levels of complexity and associated technical barriers appear at all levels of biology including the molecular, cellular, and tissue and organism levels. To address these challenges, our research strategies are based on the following approaches.
Major Accomplishments:
At the Molecular Level: A multimodality molecular imaging technique integrating atomic force, polarized Raman, and fluorescence lifetime microscopies, together with 2D autocorrelation image analysis is applied to the study of a mesoscopic heterostucture of nanoscale materials. This approach enables simultaneous measurement of fluorescence emission and Raman shifts from a quantum dot (QD)—single-wall carbon nanotube (SWCNT) complex. Nanoscale physical and optoelectronic characteristics are observed including local QD concentrations, orientation-dependent polarization anisotropy of the SWCNT Raman intensities, and charge transfer from photo-excited QDs to covalently conjugated SWCNTs. Our measurement approach bridges the properties observed in bulk and single nanomaterial studies. This methodology provides fundamental understanding of the charge and energy transfer between nanoscale materials in an assembly. Areas of related measurement science and techniques include:
At the Cellular Level: With current concerns of antibiotic-resistant bacteria and biodefense, it has become important to rapidly identify infectious bacteria. Traditional technologies involving isolation and amplification of the pathogenic bacteria are time-consuming. In collaboration with NIH, we have achieved a rapid and simple method that combines in vivo biotinylation of engineered host-specific bacteriophage and conjugation of the phage to streptavidin-coated quantum dots. The method provides specific detection of as few as 10 bacterial cells per milliliter in experimental samples, with a 100-fold amplification of the signal over background in 1 hour. This method can be applied to any bacteria susceptible to specific phages and would be particularly useful for detection of bacterial strains that are slow growing, e.g., Mycobacterium, or are highly infectious, e.g., Bacillus anthracis. In more recent collaboration with Naval Medical Research Center, we further refined this technique for a more sensitive and quantitative assay. Areas of related measurement science and techniques include:
At the Tissue and Organism Level: Enumeration of bacterial colonies in an agar plate is simple in concept, but automated colony counting is difficult due to variations in colony color, size, shape, contrast, and density, as well as colony overlap. Furthermore, in applications where high throughput is essential, it is critical to employ a fast and user-friendly automated technique that does not compromise counting accuracy. While commercial oproducts exist that can count bacterial colonies, they can be cost-prohibitive for small laboratories. We have developed a colony counting program, NIST’s Integrated Colony Enumerator (NICE), designed to count dark colonies from multiple regions of interests on an agar plate. Images can be cost effectively acquired by a digital camera or a desktop scanner and imported into NICE. High throughput standardized assay formats such as the multiplexed opsonophagocytic killing (MOPA4) assay can be readily counted by NICE. Areas of related measurement science and techniques include:
Selected Publications
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Lead Organizational Unit:pmlCustomers/Contributors/Collaborators:
Michael Emmert-Buck, National Cancer Institute, NIH
Moon Nahm, University of Alabama Medical Center Shanmuga Sozhamannan, Navy Medical Research Center Fuyuki Tokumasu and Thomas Wellems, National Institute of Allergy and Infectious Disease, NIH Contractors/Guest Researchers:Facilities/Tools Used:
Associated Products:Contact
Nano-biophontics for quantitative biophysics and molecular imaging: 100 Bureau Drive, M/S 8443 |