Prof. H. Daniel Ou-Yang Profile

Prof. H. Daniel Ou-Yang

Professor at Lehigh Univ

SPIE Involvement:

Conference Program Committee | Author

Publications (21)

Proceedings Article | 5 October 2023 Poster

Decoupling noises generated by active forces from noises generated by a combination of passive and active stochastic forces on an optically trapped particle

Chong Shen, Simin Xia, H. Daniel Ou-Yang

Proceedings Volume PC12649, PC1264901 (2023) https://doi.org/10.1117/12.2683979

KEYWORDS: Particles, Stochastic processes, Active optics, Optical tweezers, Numerical simulations, Chemical analysis, Biological research

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Proceedings Article | 20 August 2020 Presentation

Extract active fluctuations from total fluctuations of a confined active Brownian particle

Chong Shen, Zhiyu Jiang, Lanfang Li, H. Daniel Ou-Yang

Proceedings Volume 11463, 114631A (2020) https://doi.org/10.1117/12.2570663

KEYWORDS: Particles, Macromolecules, Thermal effects, Ions, Hydrogen, Time metrology, Spectroscopy, Motion measurement, Temperature metrology

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Proceedings Article | 9 September 2019 Paper

The far-from- equilibrium fluctuation of an active brownian particle in an optical trap

Chong Shen, H. Ou-Yang

Proceedings Volume 11083, 110831Q (2019) https://doi.org/10.1117/12.2531434

KEYWORDS: Particles, Optical tweezers, Thermodynamics, Diffusion, Glasses, Particle systems, Numerical simulations, Metals, Silica, Optical spheres

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Proceedings Article | 7 September 2018 Paper

Fluctuation-dissipation of an active Brownian particle under confinement

Chong Shen, H. D. Ou-Yang

Proceedings Volume 10723, 107230A (2018) https://doi.org/10.1117/12.2325011

KEYWORDS: Particles, Optical tweezers, Optical spheres, Silica, Diffusion, Metals, Thermodynamics

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Proceedings Article | 10 November 2016 Presentation

Dielectrophoresis force spectroscopy for colloidal nanoparticles (Conference Presentation)

H. Daniel Ou-Yang, Hao Huang

Proceedings Volume 9922, 99221E (2016) https://doi.org/10.1117/12.2239072

KEYWORDS: Dielectrophoresis, Nanoparticles, Particles, Spectroscopy, Confocal microscopy, Lab on a chip, Luminescence, Microscopy, Electrodes, Microfluidics

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Proceedings Article | 5 October 2015 Presentation

Noise, fluctuations, and nonlinear mechanical properties of living cells (Presentation Recording)

H. Daniel Ou-Yang, Ming Tzo Wei, Dimitrios Vavylonis, Sabrina Jedlicka

Proceedings Volume 9548, 95481K (2015) https://doi.org/10.1117/12.2191393

KEYWORDS: Proteins, Active optics, Thermography, Complex systems, Video, Optical tweezers, Optical micromanipulation, Current controlled current source

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Proceedings Article | 16 September 2014 Paper

Einstein's osmotic equilibrium of colloidal suspensions in conservative force fields

Jinxin Fu, H. Daniel Ou-Yang

Proceedings Volume 9164, 91641V (2014) https://doi.org/10.1117/12.2062169

KEYWORDS: Particles, Picosecond phenomena, Polymers, Optical tweezers, Nanoparticles, 3D image enhancement, Physics, Rhodium, Latex, Confocal microscopy

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Proceedings Article | 16 September 2014 Paper

Micro-particles self-arrangement in shapeable counter-propagating beams

Oto Brzobohatý, Jan Kaňka, Lukáš Chvátal, Pavel Zemánek, Daniel Ou-Yang

Proceedings Volume 9164, 91642L (2014) https://doi.org/10.1117/12.2060294

KEYWORDS: Particles, Waveguides, Gaussian beams, Optical tweezers, Beam shaping, Cameras, Lenses, Spatial light modulators, Telescopes, Mirrors

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Proceedings Article | 7 June 2013 Paper

Mapping two-dimension trapping potential of nanoparticles in an optical trap

Jinxin Fu, Yi Hu, Liangcheng Zhou, Min Yao Lim, Melissa Goleb, Qiwen Zhan, H. Daniel Ou-Yang

Proceedings Volume 8883, 88830J (2013) https://doi.org/10.1117/12.2027057

KEYWORDS: Particles, Optical tweezers, Nanoparticles, Luminescence, Quantum dots, Optical spheres, Gaussian beams, Microscopes, Confocal microscopy, Objectives

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Proceedings Article | 10 October 2012 Paper

Transverse force profiles of individual dielectric particles in an optical trap

Ming-Tzo Wei, Jack Ng, C. T. Chan, Arthur Chiou, H. Daniel Ou-Yang

Proceedings Volume 8458, 84580Z (2012) https://doi.org/10.1117/12.930079

KEYWORDS: Particles, Optical tweezers, Transducers, Mie scattering, Dielectrics, Nonlinear optics, Gaussian beams, Calibration, Objectives, Geometrical optics

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Proceedings Article | 28 August 2010 Paper

Thermal and non-thermal fluctuations of the mechanical properties in living cells

Ming-Tzo Wei, H. Daniel Ou-Yang

Proceedings Volume 7762, 77621L (2010) https://doi.org/10.1117/12.860697

KEYWORDS: Particles, Optical tweezers, Cytoskeletons, CCD cameras, Proteins, Optical tracking, Objectives, Calibration, Ferroelectric materials, Phase shifts

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Proceedings Article | 28 August 2010 Paper

Measurements of charged colloidal bulk moduli using optical bottles

Joseph Junio, H. D. Ou-Yang

Proceedings Volume 7762, 776226 (2010) https://doi.org/10.1117/12.860953

KEYWORDS: Particles, Optical testing, Optical spheres, Optical tweezers, Scattering, Nanoparticles, Latex, Calibration, Light scattering, Sodium

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Proceedings Article | 28 August 2010 Paper

Fluorescence correlation spectroscopy in an optical trap

Yi Hu, Xuanhong Cheng, H. Daniel Ou-Yang

Proceedings Volume 7762, 776229 (2010) https://doi.org/10.1117/12.860791

KEYWORDS: Particles, Fluorescence correlation spectroscopy, Diffusion, Optical tweezers, Nanoparticles, Luminescence, Correlation function, Molecules, Calibration, Laser optics

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Proceedings Article | 28 August 2010 Paper

Optical tweezers as a force sensor for separating dielectrophoresis and AC electroosmosis forces

Jingyu Wang, H. Daniel Ou-Yang

Proceedings Volume 7762, 77621U (2010) https://doi.org/10.1117/12.860831

KEYWORDS: Dielectrophoresis, Particles, Optical tweezers, Electrodes, Sensors, Microfluidics, Liquids, Interfaces, Ions, Amplitude modulation

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Proceedings Article | 20 August 2009 Paper

Depletion-enhanced optical trapping in nanoparticle suspensions

Joseph Junio, H. Daniel Ou-Yang

Proceedings Volume 7400, 74001C (2009) https://doi.org/10.1117/12.826386

KEYWORDS: Particles, Polymers, Optical spheres, Nanoparticles, Optical tweezers, Luminescence, Signal detection, Objectives, Collimation, Optical amplifiers

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Proceedings Article | 20 August 2009 Paper

Measurement of optical binding force between two colloidal particles

Ming-Tzo Wei, Jack Ng, C. T. Chan, H. Daniel Ou-Yang

Proceedings Volume 7400, 74001E (2009) https://doi.org/10.1117/12.826398

KEYWORDS: Particles, Optical binding, Optical tweezers, Dielectric polarization, Dielectrics, Mie scattering, Optical testing, Optical spheres, Polarization, Objectives

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Proceedings Article | 29 August 2008 Paper

Measurements of the compressibility of colloidal suspensions by radiation pressure

Joseph Junio, H. Daniel Ou-Yang

Proceedings Volume 7038, 70380I (2008) https://doi.org/10.1117/12.794193

KEYWORDS: Particles, Luminescence, Optical tweezers, Infrared lasers, Signal detection, Microscopes, Objectives, Optical amplifiers, Light scattering, Fluorescence spectroscopy

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Proceedings Article | 5 September 2007 Paper

The Kerr effect produced by optical trapping of nanoparticles in aqueous suspensions

Joseph Junio, Eric Blanton, H. Ou-Yang

Proceedings Volume 6644, 664408 (2007) https://doi.org/10.1117/12.739784

KEYWORDS: Particles, Luminescence, Infrared lasers, Kerr effect, Optical tweezers, Signal detection, Microscopes, Nanoparticles, Laser induced fluorescence, Optical amplifiers

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Proceedings Article | 19 February 2007 Paper

Development and applications of an optical tweezer-based microrheometer: case studies of biomaterials and living cells

Jing Wang, Huseyin Yalcin, Angela Lengel, Corey Hewitt, H. Daniel Ou-Yang

Proceedings Volume 6441, 644112 (2007) https://doi.org/10.1117/12.701324

KEYWORDS: Particles, Confocal microscopy, Anisotropy, Microscopes, Imaging systems, Optical tweezers, Phase shifts, Silica, Calibration, Mirrors

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The investigation of mechanical properties of living biological cells and biomaterials is challenging because they are inhomogeneous and anisotropic at microscopic scales, and often time-dependent over a broad time scale. Through three case studies of biomaterials and living cells, we demonstrate that a novel, oscillating optical tweezer-based imaging microrheometer developed recently in our laboratory has overcome many technical barriers posed by the complexity of biological systems. In this paper, we present the working principle, system setup and calibration of the imaging microrheometer, and report the groundbreaking results of the three applications: gelation dynamics of cross-linkable hyaluronan acid (HA) hydrogels; Mechanical in-homogeneity and anisotropy in purified microtubule networks; and effects of drug treatment and temperature variation on the mechanical properties of in vitro human alveolar epithelial cells. In each case, micro beads inserted in the materials, or attached to the cell membrane were used as probes for optical trapping. The probe particle was set into a forced harmonic oscillation by oscillating optical tweezers. Position sensing optics and phase lock-in signal processing allow the determination of the amplitude and phase shift of the particle motion at high sensitivity. The complex mechanical modulus G^* is then calculated from the amplitude and the phase shift. The rheometer system is capable of measuring dynamic local mechanical moduli in the broad frequency range of 1.3-1000 Hz at a sampling rate of 2 data point per second across a wide dynamic range (1~20,000 dyne/cm²). Integration of the rheometer system with spinning disk confocal microscopy enables the study of micromechanical properties and the microstructure of the sample simultaneously. Combination of dual-axis, piezo-electric activated mirror and 2-D position sensing detector gives the rheometer system the capability of investigating mechanical anisotropy in highly structured biological samples.

Proceedings Article | 11 September 2006 Paper

The design and biological applications of dual-beam oscillating optical tweezer-based imaging cytorheometer

H. D. Ou-Yang, J. Wang

Proceedings Volume 6326, 63261O (2006) https://doi.org/10.1117/12.681266

KEYWORDS: Particles, Optical tweezers, Confocal microscopy, Lung, Optical amplifiers, Polymers, Spatial resolution, Objectives, Microscopes, Calibration

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Because of its non-invasive nature, optical tweezers have emerged as a popular tool for the studies of complex fluids and biological cells and tissues. The capabilities of optical tweezer-based experimental instruments continue to evolve for better and broader applications, through new apparatus designs and integrations with microscopic imaging techniques. In this paper, we present the design, calibration and applications of a powerful microrheometer that integrates a novel high temporal and spatial resolution dual-beam oscillating optical tweezer-based cytorheometer (DOOTC) with spinning disk confocal microscopy. The oscillating scheme detects the position of micron-size probe particles via a phase-sensitive lock-in amplifier to greatly enhance sensitivity. The dual-beam scheme ensures that the cytorheometer is insensitive to sample specimen background parameter variances, and thus enables the investigation of micromechanical properties of biological samples, which are intrinsically inhomogeneous. The cytorheometer system is demonstrated to be capable of measuring dynamic local mechanical moduli in the frequency range of 0.1-150 Hz at up to 2 data point per second and with nanometer spatial resolutions, while visualizing and monitoring structural properties in situ. We report the results of system applications in the studies of bovine skin gelatin gel, purified microtubule assemblies, and human alveolar epithelial cells. The time evolution of the storage moduli G' and the loss moduli G'' of the gel is recorded for undisturbed gel-forming process with high temporal resolution. The micromechanical modulus G* of polymerized microtubule network as a function of frequency are shown to be both inhomogeneous and anisotropic consistent with local structures revealed by confocal imaging. The mechanical properties of A549 human lung cells as a function of temperature will be reported showing significant decrease in cell stiffness at higher temperature.

Proceedings Article | 18 August 2005 Paper

Oscillating optical tweezer-based 3-D confocal microrheometer for investigating the intracellular micromechanics and structures

H. Ou-Yang, E. Rickter, C. Pu, O. Latinovic, A. Kumar, M. Mengistu, L. Lowe-Krentz, S. Chien

Proceedings Volume 5930, 593004 (2005) https://doi.org/10.1117/12.618108

KEYWORDS: Optical tweezers, Particles, Confocal microscopy, Optical amplifiers, Cytoskeletons, Microscopes, Proteins, Mirrors, Phase shifts, Motion measurement

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Mechanical properties of living biological cells are important for cells to maintain their shapes, support mechanical stresses and move through tissue matrix. The use of optical tweezers to measure micromechanical properties of cells has recently made significant progresses. This paper presents a new approach, the oscillating optical tweezer cytorheometer (OOTC), which takes advantage of the coherent detection of harmonically modulated particle motions by a lock-in amplifier to increase sensitivity, temporal resolution and simplicity. We demonstrate that OOTC can measure the dynamic mechanical modulus in the frequency range of 0.1-6,000 Hz at a rate as fast as 1 data point per second with submicron spatial resolution. More importantly, OOTC is capable of distinguishing the intrinsic non-random temporal variations from random fluctuations due to Brownian motion; this capability, not achievable by conventional approaches, is particular useful because living systems are highly dynamic and often exhibit non-thermal, rhythmic behavior in a broad time scale from a fraction of a second to hours or days. Although OOTC is effective in measuring the intracellular micromechanical properties, unless we can visualize the cytoskeleton in situ, the mechanical property data would only be as informative as that of "Blind men and the Elephant". To solve this problem, we take two steps, the first, to use of fluorescent imaging to identify the granular structures trapped by optical tweezers, and second, to integrate OOTC with 3-D confocal microscopy so we can take simultaneous, in situ measurements of the micromechanics and intracellular structure in living cells. In this paper, we discuss examples of applying the oscillating tweezer-based cytorheometer for investigating cultured bovine endothelial cells, the identification of caveolae as some of the granular structures in the cell as well as our approach to integrate optical tweezers with a spinning disk confocal microscope.

Showing 5 of 21 publications

Conference Committee Involvement (18)

Optical Trapping and Optical Micromanipulation XXII

3 August 2025 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation XXI

18 August 2024 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation XX

20 August 2023 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation XIX

21 August 2022 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation XVIII

2 August 2021 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation XVII

24 August 2020 | Online Only, California, United States

Optical Trapping and Optical Micromanipulation XVI

11 August 2019 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation XV

19 August 2018 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation XIV

6 August 2017 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation XIII

28 August 2016 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation XII

9 August 2015 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation IX

12 August 2012 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation VIII

21 August 2011 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation VII

1 August 2010 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation VI

2 August 2009 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation V

10 August 2008 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation IV

26 August 2007 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation III

13 August 2006 | San Diego, California, United States

Showing 5 of 18 Conference Committees

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