Colloquium: Selim Unlu

    Thursday, April 6, 2017 - 3:30pm - 5:00pm
    Meinel 307

    Interferometric Reflectance Imaging Sensor (IRIS) —Technology for Multiplexed Diagnostics and Digital Detection


     Optical biosensors are highly promising for future generation diagnostics by providing means to detect biomarkers in a highly sensitive, specific, quantitative and multiplexed fashion. We developed an optical sensing technology, Interferometric Reflectance Imaging Sensor (IRIS), and the relevant features of this multifunctional platform for quantitative, label-free and dynamic detection. We discuss two distinct modalities for IRIS: (i) low-magnification (ensemble biomolecular mass measurements) and (ii) high-magnification (digital detection of individual nanoparticles) along with their applications, including label-free detection of multiplexed protein chips, measurement of single nucleotide polymorphism, quantification of transcription factor DNA binding, and high sensitivity digital sensing and characterization of nanoparticles and viruses. [1]

    In high-magnification modality Single-Particle IRIS (SP-IRIS) has the ability to detect and characterize individual biological nanoparticles. In SP-IRIS, the interference of light reflected from the sensor surface is modified by the presence of particles producing a distinct signal that reveals the size of the particle that is not otherwise visible under a conventional microscope. Using this simple platform, we have demonstrated label-free identification of various viruses in multiplexed format in complex samples in a disposable cartridge [2]. Size discrimination of the imaged virions allows for rejection of non-specifically bound particles to achieve a limit-of-detection competitive with the state-of-the-art laboratory technologies. Recently, our technology was applied to detection of exosomes [3]. SP-IRIS has also shown promising results for detection of protein [4] and DNA molecules labeled with small Au nanoparticles – showing attomolar sensitivity and meeting the requirements for most in vitro tests. We are currently focusing on various biological applications as well as further improvement of the technique using pupil function engineering [5].

    [1]  O. Avci, N. Lortlar Ünlü, A. Yalcin, and M. S. Ünlü, "Interferometric Reflectance Imaging Sensor (IRIS)—A Platform Technology for Multiplexed Diagnostics and Digital Detection," Sensors, Vol. 15, No. 7, pp. 17649-17665, (2015)

    [2] S. M. Scherr, D. S. Freedman, K. N. Agans, A. Rosca, E. Carter, M. Kuroda, H. Fawcett, C. Mire, T. W. Geisbert, M. S. Ünlü, and J. H. Connor, "Disposable cartridge platform for rapid detection of viral hemorrhagic fever viruses," Lab Chip, Vol. DOI:, No. 10.1039/c6lc01528j, (2017)

    [3] G. G. Daaboul, P. Gagni, L. Benussi, P. Bettotti, M. Ciani, M. Cretich, D. S. Freedman, R. Ghidoni, A. Yalcin, C. Piotto, D. Prosperi, B. Santini, M. S. Ünlü, M. Chiari, "Digital Detection of Exosomes by Interferometric Imaging," Nature Scientific Reports, Vol. 6, 37246; DOI:, No. 10.1038/srep37246, (2016)

    [4]  M. R. Monroe, G. G. Daaboul, A. Tuysuzoglu, C. A. Lopez, F. F. Little, and M. S. Ünlü, "Single Nanoparticle Detection for Multiplexed Protein Diagnostics with Attomolar Sensitivity in Serum and Unprocessed Whole Blood," Analytical Chemistry, Vol. 85, No. 7, pp. 3698-3706, (2013)

    [5] O. Avci, M. I. Campana, C. Yurdakul, M. S. Ünlü, "Pupil function engineering for enhanced nanoparticle visibility in wide-field interferometric microscopy," Optica, 4(2) pp. 247-254, (2017)

    Speaker Bio(s): 

    M. Selim Ünlü received the B.S. degree from the Middle East Technical University, Ankara, Turkey, in 1986, and the M.S.E.E. (1988) and Ph.D. (1992) degrees from the University of Illinois at Urbana-Champaign, all in electrical engineering. Since 1992, he has been a professor at Boston University. He is currently a Distinguished Professor of Engineering appointed in electrical and computer engineering, biomedical engineering, physics, and graduate medical sciences. He has also served as the Associate Dean for Research and Graduate Programs in engineering. His research interests are in the areas of nanophotonics and biophotonics focusing on high-resolution solid immersion lens microscopy of integrated circuits and development of biological detection and imaging techniques, particularly in high-throughput digital biosensors based on detection of individual nanoparticles and viruses.

    Dr. Ünlü was the recipient of the NSF CAREER and ONR Young Investigator Awards in 1996. He has been selected as a Photonics Society Distinguished Lecturer for 2005-2007 and Australian Research Council Nanotechnology Network (ARCNN) Distinguished Lecturer for 2007. He has been elevated to IEEE Fellow rank in 2007 for his contributions to optoelectronic devices. In 2008, he was awarded the Science Award by the Turkish Scientific Foundation. He received the Boston University Charles DeLisi Distinguished Lecture Award in 2016. His professional service includes serving as the chair of the Annual Meeting for IEEE Photonics Society and Editor-in-Chief for IEEE Journal of Quantum Electronics.