Optical Imaging of Surface Chemistry and Dynamics in Confinement
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Quantitative Force Measurements with Optical Tweezers: the JPK Nanotracker™
Quantitative force measurements with optical tweezers: The JPK NanoTracker™ Introduction to optical tweezers manipulate biomolecules and cells, but also to directly and accurately measure the minute forces (on the order of Optical tweezers methodology has developed from proof-of- fractions of picoNewtons) involved. Most often, the principle experiments to an established quantitative biomolecules of interest are not trapped themselves technique in fields ranging from (bio)physics through cell directly, but manipulated through functionalized biology. As the name suggests, optical tweezers are a microspheres. means to manipulate objects with light. With this technique, The correct physical description of optical trapping depends microscopically small objects can be held and manipulated. on the size of the trapped object. One speaks of the ‘ray- At the same time, the forces exerted on the trapped objects optics’ regime when the object’s dimension d is much larger can be accurately measured. The basic physical principle than the wavelength of the trapping light: d>>λ. In this case, underlying optical tweezers is the radiation pressure diffraction effects can be neglected and the trapping forces exerted by light when colliding with matter. For macroscopic of the light can be understood in terms of ray optics. The objects, the radiation pressure exerted by typical light regime where d<<λ is called the Rayleigh regime. In this sources is orders of magnitude too small to have any case, the trapped particles can be treated as point dipoles, measurable effect: we do not feel the light power of the sun as the electromagnetic field is constant on the scale of the pushing us away. -
Second Harmonic Imaging Microscopy
170 Microsc Microanal 9(Suppl 2), 2003 DOI: 10.1017/S143192760344066X Copyright 2003 Microscopy Society of America Second Harmonic Imaging Microscopy Leslie M. Loew,* Andrew C. Millard,* Paul J. Campagnola,* William A. Mohler,* and Aaron Lewis‡ * Center for Biomedical Imaging Technology, University of Connecticut Health Center, Farmington, CT 06030-1507 USA ‡ Division of Applied Physics, Hebrew University of Jerusalem, Jerusalem 91904, Israel Second Harmonic Generation (SHG) has been developed in our laboratories as a high- resolution non-linear optical imaging microscopy (“SHIM”) for cellular membranes and intact tissues. SHG is a non-linear process that produces a frequency doubling of the intense laser field impinging on a material with a high second order susceptibility. It shares many of the advantageous features for microscopy of another more established non-linear optical technique: two-photon excited fluorescence (TPEF). Both are capable of optical sectioning to produce 3D images of thick specimens and both result in less photodamage to living tissue than confocal microscopy. SHG is complementary to TPEF in that it uses a different contrast mechanism and is most easily detected in the transmitted light optical path. It also does not arise via photon emission from molecular excited states, as do both 1- and 2-photon excited fluorescence. SHG of intrinsic highly ordered biological structures such as collagen has been known for some time but only recently has the full potential of high resolution 3D SHIM been demonstrated on live cells and tissues. For example, Figure 1 shows SHIM from microtubules in a living organism, C. elegans. The images were obtained from a transgenic nematode that expresses a ß-tubulin-green fluorescent protein fusion and Figure 1 also shows the TPEF image from this molecule for comparison. -
A Quantum Origin of Life?
June 26, 2008 11:1 World Scientific Book - 9in x 6in quantum Chapter 1 A Quantum Origin of Life? Paul C. W. Davies The origin of life is one of the great unsolved problems of science. In the nineteenth century, many scientists believed that life was some sort of magic matter. The continued use of the term “organic chemistry” is a hangover from that era. The assumption that there is a chemical recipe for life led to the hope that, if only we knew the details, we could mix up the right stuff in a test tube and make life in the lab. Most research on biogenesis has followed that tradition, by assuming chemistry was a bridge—albeit a long one—from matter to life. Elucidat- ing the chemical pathway has been a tantalizing goal, spurred on by the famous Miller-Urey experiment of 1952, in which amino acids were made by sparking electricity through a mixture of water and common gases [Miller (1953)]. But this concept turned out to be something of a blind alley, and further progress with pre-biotic chemical synthesis has been frustratingly slow. In 1944, Erwin Schr¨odinger published his famous lectures under the ti- tle What is Life? [Schr¨odinger (1944)] and ushered in the age of molecular biology. Sch¨odinger argued that the stable transmission of genetic infor- mation from generation to generation in discrete bits implied a quantum mechanical process, although he was unaware of the role of or the specifics of genetic encoding. The other founders of quantum mechanics, including Niels Bohr, Werner Heisenberg and Eugene Wigner shared Schr¨odinger’s belief that quantum physics was the key to understanding the phenomenon Received May 9, 2007 3 QUANTUM ASPECTS OF LIFE © Imperial College Press http://www.worldscibooks.com/physics/p581.html June 26, 2008 11:1 World Scientific Book - 9in x 6in quantum 4 Quantum Aspects of Life of life. -
Depth-Resolved Measurement of Optical Radiation-Pressure Forces with Optical Coherence Tomography
Vol. 26, No. 3 | 5 Feb 2018 | OPTICS EXPRESS 2410 Depth-resolved measurement of optical radiation-pressure forces with optical coherence tomography NICHALUK LEARTPRAPUN, RISHYASHRING R. IYER, AND STEVEN G. ADIE* Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA *[email protected] Abstract: A weakly focused laser beam can exert sufficient radiation pressure to manipulate microscopic particles over a large depth range. However, depth-resolved continuous measurement of radiation-pressure force profiles over an extended range about the focal plane has not been demonstrated despite decades of research on optical manipulation. Here, we present a method for continuous measurement of axial radiation-pressure forces from a weakly focused beam on polystyrene micro-beads suspended in viscous fluids over a depth range of 400 μm, based on real-time monitoring of particle dynamics using optical coherence tomography (OCT). Measurements of radiation-pressure forces as a function of beam power, wavelength, bead size, and refractive index are consistent with theoretical trends. However, our continuous measurements also reveal localized depth-dependent features in the radiation- pressure force profiles that deviate from theoretical predictions based on an aberration-free Gaussian beam. The combination of long-range radiation pressure and OCT offers a new mode of quantitative optical manipulation and detection with extended spatial coverage. This may find applications in the characterization of optical tractor beams, or volumetric optical manipulation and interrogation of beads in viscoelastic media. © 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement OCIS codes: (110.4500) Optical coherence tomography; (350.4855) Optical tweezers or optical manipulation. -
New Light on Hidden Surfaces
New light on hidden surfaces New light on hidden surfaces PROEFSCHRIFT TER VERKRIJGING VAN DE GRAAD VAN DOCTOR AAN DE UNIVERSITEIT LEIDEN, OP GEZAG VAN DE RECTOR MAGNIFICUS DR.D.D.BREIMER, HOOGLERAAR IN DE FACULTEIT DER WISKUNDE EN NATUURWETENSCHAPPEN EN DIE DER GENEESKUNDE, VOLGENS BESLUIT VAN HET COLLEGE VOOR PROMOTIES TE VERDEDIGEN OP WOENSDAG 15 SEPTEMBER 2004 KLOKKE 15.15 UUR DOOR SYLVIE ROKE GEBOREN TE DE BILT IN 1977 Promotiecommissie Promotor: Prof. Dr. A. W. Kleyn Co-promotor Dr. M. Bonn Referent Prof. Dr. H. J. Bakker Overige leden: Prof. Dr. J. Reedijk Prof. Dr. J. W. M. Frenken Prof. Dr. G. J. Kroes Prof. Dr. A. van Blaaderen The work described in this thesis was made possible by financial support from the Foundation for Fundamental Research on Matter (FOM), which is financially supported by the Netherlands Organization for Scientific Research (NWO). ”...Thereisnoproblemknowntosciencethatcannotbecured by the liberal application of chocolate.” RICHARD BUTTERWORTH Contents 1Introduction 1 1.1Surfaces................................. 1 1.2Second-ordersumfrequencygeneration............... 3 1.3Femtosecondsumfrequencygeneration............... 4 1.4Thisthesis................................ 6 2 Experimental 9 2.1Introduction............................... 9 2.2Thelasersystem............................ 9 2.3Second-orderprocesses........................ 10 2.4Generatinginfraredpulses....................... 12 2.5Thesumfrequencyexperiment.................... 12 3 Time vs. frequency domain sum frequency generation 15 3.1Introduction.............................. -
Optical Micromachines for Biological Studies
micromachines Review Optical Micromachines for Biological Studies Philippa-Kate Andrew 1 , Martin A. K. Williams 2,3 and Ebubekir Avci 1,3,* 1 Department of Mechanical and Electrical Engineering, Massey University, Palmerston North 4410, New Zealand; [email protected] 2 School of Fundamental Sciences, Massey University, Palmerston North 4410, New Zealand; [email protected] 3 MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand * Correspondence: [email protected] Received: 21 January 2020; Accepted: 9 February 2020; Published: 13 February 2020 Abstract: Optical tweezers have been used for biological studies since shortly after their inception. However, over the years research has suggested that the intense laser light used to create optical traps may damage the specimens being studied. This review aims to provide a brief overview of optical tweezers and the possible mechanisms for damage, and more importantly examines the role of optical micromachines as tools for biological studies. This review covers the achievements to date in the field of optical micromachines: improvements in the ability to produce micromachines, including multi-body microrobots; and design considerations for both optical microrobots and the optical trapping set-up used for controlling them are all discussed. The review focuses especially on the role of micromachines in biological research, and explores some of the potential that the technology has in this area. Keywords: optical tweezers; multi-component micromanipulators; radiation damage; life sciences; optical microrobots 1. Introduction Improvements in tools for the visualisation of objects at the micro- and nano- scale have given researchers the ability to investigate materials and processes previously out of reach. -
Optical Sectioning in Fluorescence Microscopy by Confocal and 2
Optical Sectioning in Fluorescence achieved with this methodology, Calcium sparks are microscopic calcium release Downloaded from events inside living muscle cells and their properties are giving new insight into Microscopy by Confocal and how excitation leads to contraction (Cannell et al., 1995; Lopez-Lopez et al,, 2-Photon Molecular Excitation 1995; Gomez et al., 1997). Although the wide field microscope had been applied to calcium imaging since about 1985, calcium sparks had not been observed Techniques previously. This is probably because the presence of fluorescence from outside https://www.cambridge.org/core M.B. Cannell & C.Soeller the focal plane results in a marked loss of in-plane contrast for wide field St. George's Hospital Medical School, microscopy. (Note also that fluo-3 was used as the calcium indicator in these Cranmer Terrace, London SW17 ORE experiments as it has low fluorescence in the absence of calcium which also improves image contrast.) The calcium spark illustrates the high sensitivity of Confocal Microscopy current confocal optical methods - the calcium spark finally occupies about 10 fl Fluorescence microscopy has proved to be an invaluable tool for 14 4 (10" l) and represents calcium binding to only -10 indicator molecules, Until biomedical science since it is possible to visualise small quantities of labeled recently, the laser scanning confocal microscope has been the only instrument materials (such as intracellular ions and proteins) in both fixed and living that could measure fluorescence with a spatial resolution of about 0.4 x 0.4 x 0.8 cells, However, the conventional wide field fluorescence microscope suffers . -
Two-Photon Excitation Fluorescence Microscopy
P1: FhN/ftt P2: FhN July 10, 2000 11:18 Annual Reviews AR106-15 Annu. Rev. Biomed. Eng. 2000. 02:399–429 Copyright c 2000 by Annual Reviews. All rights reserved TWO-PHOTON EXCITATION FLUORESCENCE MICROSCOPY PeterT.C.So1,ChenY.Dong1, Barry R. Masters2, and Keith M. Berland3 1Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; e-mail: [email protected] 2Department of Ophthalmology, University of Bern, Bern, Switzerland 3Department of Physics, Emory University, Atlanta, Georgia 30322 Key Words multiphoton, fluorescence spectroscopy, single molecule, functional imaging, tissue imaging ■ Abstract Two-photon fluorescence microscopy is one of the most important re- cent inventions in biological imaging. This technology enables noninvasive study of biological specimens in three dimensions with submicrometer resolution. Two-photon excitation of fluorophores results from the simultaneous absorption of two photons. This excitation process has a number of unique advantages, such as reduced specimen photodamage and enhanced penetration depth. It also produces higher-contrast im- ages and is a novel method to trigger localized photochemical reactions. Two-photon microscopy continues to find an increasing number of applications in biology and medicine. CONTENTS INTRODUCTION ................................................ 400 HISTORICAL REVIEW OF TWO-PHOTON MICROSCOPY TECHNOLOGY ...401 BASIC PRINCIPLES OF TWO-PHOTON MICROSCOPY ..................402 Physical Basis for Two-Photon Excitation ............................ -
Innovations of Wide-Field Optical-Sectioning
Innovations of wide-field optical-sectioning fluorescence microscopy: toward high-speed volumetric bio-imaging with simplicity Thesis by Jiun-Yann Yu In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy California Institute of Technology Pasadena, California 2014 (Defended March 25, 2014) ii c 2014 Jiun-Yann Yu All Rights Reserved iii Acknowledgements Firstly, I would like to thank my thesis advisor, Professor Chin-Lin Guo, for all of his kind advice and generous financial support during these five years. I would also like to thank all of the faculties in my thesis committee: Professor Geoffrey A. Blake, Professor Scott E. Fraser, and Professor Changhuei Yang, for their guidance on my way towards becoming a scientist. I would like to specifically thank Professor Blake, and his graduate student, Dr. Daniel B. Holland, for their endless kindness, enthusiasms and encouragements with our collaborations, without which there would be no more than 10 pages left in this thesis. Dr. Thai Truong of Prof. Fraser's group and Marco A. Allodi of Professor Blake's group are also sincerely acknowledged for contributing to this collaboration. All of the members of Professor Guo's group at Caltech are gratefully acknowledged. I would like to thank our former postdoctoral scholar Dr. Yenyu Chen for generously teaching me all the engineering skills I need, and passing to me his pursuit of wide-field optical-sectioning microscopy. I also thank Dr. Mingxing Ouyang for introducing me the basic concepts of cell biology and showing me the basic techniques of cell-biology experiments. I would like to pay my gratefulness to our administrative assistant, Lilian Porter, not only for her help on administrative procedures, but also for her advice and encouragement on my academic career in the future. -
Pulsed Optical Tweezers for Levitation and Manipulation of Stuck Biological
2005 Conference on Lasers & Electro-Optics (CLEO) CFN3 Pulsed optical tweezers for levitation and manipulation of stuck biological particles Amol Ashok Ambardekar and Yong-qing Li Department ofPhysics, East Carolina University, Greenville, North Carolina 27858 acube3(1!yahoo. covm,livrnail.ecu. ec/ Abstract: We report on optical levitation and manipulation of microscopic particles that are stuck on a glass surface with a pulsed optical tweezers. Both the stuck dielectric beads and biological cells are demonstrated to be levitated. ©2005 Optical Society of America OCIS codes: (170.4520) Optical confinement and manipulation; (140.7010) Trapping Optical tweezers has become a powerful tool for capturing and manipulation of micron-sized particles, typically by using continuous-wave (cw) lasers [1, 2]. It has been routinely applied to manipulate living cells, bacteria, viruses, chromosomes and other organelles [3, 4], To reduce the photodamage to the trapped particles, the average power of the trapping lasers is usually limited to below hundreds of mW and near-infrared (NIR) or infrared lasers were used for trapping [3, 6]. The trapping force generated by the cw optical tweezers is typically in the order of 10-12 N [4, 5]. This weak force is efficient to confine micro-particles suspended in liquids, but not sufficient to levitate the particles that are stuck on the glass surface, where it has to overcome the binding force. Therefore, the stuck particles cannot be manipulated with the optical tweezers that only employs cw lasers. In this paper, we describe a pulsed optical tweezers that employs a pulsed laser for levitation of the stuck particles and a low-power cw laser for successive trapping and manipulation. -
Diving Into Surfaces
Sylvie Roke cycles in the foyer of the Max Planck Institute for Metals Research for demonstration purposes only, but she loves cycling in the Swabian hills and dales around Stuttgart. xxxxxxxxxxxx MATERIAL & TECHNOLOGY_Personal Portrait Diving into Surfaces The experiments for her doctoral studies did not work out quite as planned the first time around. After switching gears and continued work, however, Sylvie Roke opened up a completely new perspective on soft matter. At the Max Planck Institute for Metals Research, she also uses this method to investigate potential new drugs and biological materials. A PORTRAIT BY UTA DEFFKE ometimes it is the small, ev- many more charges, which have an at- In spite of her delicate appearance and eryday things that still hide tractive or repulsive effect on each oth- her mere 32 years, it does not sound as big secrets. Take some oil, for er and on their surroundings. But what if Sylvie Roke is intimidated by this. On example, and pour it into a exactly do these molecules look like? the contrary. The young researcher bowl of water. The two liq- How are they arranged and why? Is loves such challenges and knows what S uids won’t mix, as everyone knows there a difference between a curved she can do and what she wants. When from an oil and vinegar vinaigrette. surface and a planar interface? she talks about her work and her plans, Only a vigorous shake makes the oil she makes vivid gestures, demonstrates floating on top disperse into the water CHALLENGING TEXTBOOK the motion of molecules with the aid in the form of fine droplets. -
Imaging with Second-Harmonic Generation Nanoparticles
1 Imaging with Second-Harmonic Generation Nanoparticles Thesis by Chia-Lung Hsieh In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy California Institute of Technology Pasadena, California 2011 (Defended March 16, 2011) ii © 2011 Chia-Lung Hsieh All Rights Reserved iii Publications contained within this thesis: 1. C. L. Hsieh, R. Grange, Y. Pu, and D. Psaltis, "Three-dimensional harmonic holographic microcopy using nanoparticles as probes for cell imaging," Opt. Express 17, 2880–2891 (2009). 2. C. L. Hsieh, R. Grange, Y. Pu, and D. Psaltis, "Bioconjugation of barium titanate nanocrystals with immunoglobulin G antibody for second harmonic radiation imaging probes," Biomaterials 31, 2272–2277 (2010). 3. C. L. Hsieh, Y. Pu, R. Grange, and D. Psaltis, "Second harmonic generation from nanocrystals under linearly and circularly polarized excitations," Opt. Express 18, 11917–11932 (2010). 4. C. L. Hsieh, Y. Pu, R. Grange, and D. Psaltis, "Digital phase conjugation of second harmonic radiation emitted by nanoparticles in turbid media," Opt. Express 18, 12283–12290 (2010). 5. C. L. Hsieh, Y. Pu, R. Grange, G. Laporte, and D. Psaltis, "Imaging through turbid layers by scanning the phase conjugated second harmonic radiation from a nanoparticle," Opt. Express 18, 20723–20731 (2010). iv Acknowledgements During my five-year Ph.D. studies, I have thought a lot about science and life, but I have never thought of the moment of writing the acknowledgements of my thesis. At this moment, after finishing writing six chapters of my thesis, I realize the acknowledgment is probably one of the most difficult parts for me to complete.