1
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Gould OC, Box SJ, Boott CE, Ward AD, Winnik MA, Miles MJ, Manners I. Manipulation and Deposition of Complex, Functional Block Copolymer Nanostructures Using Optical Tweezers. ACS NANO 2019; 13:3858-3866. [PMID: 30794379 PMCID: PMC6482436 DOI: 10.1021/acsnano.9b00342] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 02/22/2019] [Indexed: 05/23/2023]
Abstract
Block copolymer self-assembly has enabled the creation of a range of solution-phase nanostructures with applications from optoelectronics and biomedicine to catalysis. However, to incorporate such materials into devices a method that facilitates their precise manipulation and deposition is desirable. Herein we describe how optical tweezers can be used to trap, manipulate, and pattern individual cylindrical micelles and larger hybrid micellar materials. Through the combination of TIRF imaging and optical trapping we can precisely control the three-dimensional motion of individual cylindrical block copolymer micelles in solution, enabling the creation of customizable arrays. We also demonstrate that dynamic holographic assembly enables the creation of ordered customizable arrays of complex hybrid block copolymer structures. By creating a program which automatically identifies, traps, and then deposits multiple assemblies simultaneously we have been able to dramatically speed up this normally slow process, enabling the fabrication of arrays of hybrid structures containing hundreds of assemblies in minutes rather than hours.
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Affiliation(s)
- Oliver
E. C. Gould
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Stuart J. Box
- School
of Physics, University of Bristol, Bristol BS8 1TL, United Kingdom
| | - Charlotte E. Boott
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Andrew D. Ward
- Central
Laser Facility, Rutherford Appleton Laboratories, Oxford OX11 0QX, United Kingdom
| | - Mitchell A. Winnik
- Department
of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Mervyn J. Miles
- School
of Physics, University of Bristol, Bristol BS8 1TL, United Kingdom
| | - Ian Manners
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
- Department
of Chemistry, University of Victoria, Victoria, British Columbia V8W 3V6, Canada
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2
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Tomographic active optical trapping of arbitrarily shaped objects by exploiting 3D refractive index maps. Nat Commun 2017; 8:15340. [PMID: 28530232 PMCID: PMC5458125 DOI: 10.1038/ncomms15340] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 03/22/2017] [Indexed: 12/21/2022] Open
Abstract
Optical trapping can manipulate the three-dimensional (3D) motion of spherical particles based on the simple prediction of optical forces and the responding motion of samples. However, controlling the 3D behaviour of non-spherical particles with arbitrary orientations is extremely challenging, due to experimental difficulties and extensive computations. Here, we achieve the real-time optical control of arbitrarily shaped particles by combining the wavefront shaping of a trapping beam and measurements of the 3D refractive index distribution of samples. Engineering the 3D light field distribution of a trapping beam based on the measured 3D refractive index map of samples generates a light mould, which can manipulate colloidal and biological samples with arbitrary orientations and/or shapes. The present method provides stable control of the orientation and assembly of arbitrarily shaped particles without knowing a priori information about the sample geometry. The proposed method can be directly applied in biophotonics and soft matter physics. Controlling the three-dimensional behaviour of arbitrarily shaped and oriented particles with optical tweezers is a challenging task. Here, Kim and Park use tomographic active trapping to manipulate non-spherical particles and particle ensembles as well as biological cells.
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3
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Gould OEC, Qiu H, Lunn DJ, Rowden J, Harniman RL, Hudson ZM, Winnik MA, Miles MJ, Manners I. Transformation and patterning of supermicelles using dynamic holographic assembly. Nat Commun 2015; 6:10009. [PMID: 26627644 PMCID: PMC4686664 DOI: 10.1038/ncomms10009] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 10/22/2015] [Indexed: 11/26/2022] Open
Abstract
Although the solution self-assembly of block copolymers has enabled the fabrication of a broad range of complex, functional nanostructures, their precise manipulation and patterning remain a key challenge. Here we demonstrate that spherical and linear supermicelles, supramolecular structures held together by non-covalent solvophobic and coordination interactions and formed by the hierarchical self-assembly of block copolymer micelle and block comicelle precursors, can be manipulated, transformed and patterned with mediation by dynamic holographic assembly (optical tweezers). This allows the creation of new and stable soft-matter superstructures far from equilibrium. For example, individual spherical supermicelles can be optically held in close proximity and photocrosslinked through controlled coronal chemistry to generate linear oligomeric arrays. The use of optical tweezers also enables the directed deposition and immobilization of supermicelles on surfaces, allowing the precise creation of arrays of soft-matter nano-objects with potentially diverse functionality and a range of applications. Block copolymers can form micelles and assemblies of micelles (supermicelles) when placed in suitable solvents. Here, the authors use optical tweezers to control the arrangement and deposition of supermicelles into higher-order patterned nanostructures.
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Affiliation(s)
- Oliver E C Gould
- Bristol Centre for Functional Nanomaterials, HH Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, UK
| | - Huibin Qiu
- School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
| | - David J Lunn
- School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
| | - John Rowden
- School of Physics, University of Bristol, Bristol BS8 1TL, UK
| | | | | | - Mitchell A Winnik
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6
| | - Mervyn J Miles
- School of Physics, University of Bristol, Bristol BS8 1TL, UK
| | - Ian Manners
- School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
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4
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Armstrong JPK, Olof SN, Jakimowicz MD, Hollander AP, Mann S, Davis SA, Miles MJ, Patil AJ, Perriman AW. Cell paintballing using optically targeted coacervate microdroplets. Chem Sci 2015; 6:6106-6111. [PMID: 30090225 PMCID: PMC6054073 DOI: 10.1039/c5sc02266e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 07/20/2015] [Indexed: 01/06/2023] Open
Abstract
We present a new approach for the directed delivery of biomolecular payloads to individual cells with high spatial precision. This was accomplished via active sequestration of proteins, oligonucleotides or molecular dyes into coacervate microdroplets, which were then delivered to specific regions of stem cell membranes using a dynamic holographic assembler, resulting in spontaneous coacervate microdroplet-membrane fusion. The facile preparation, high sequestration efficiency and inherent membrane affinity of the microdroplets make this novel "cell paintballing" technology a highly advantageous option for spatially-directed cell functionalization, with potential applications in single cell stimulation, transfection and differentiation.
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Affiliation(s)
- James P K Armstrong
- Bristol Centre for Functional Nanomaterials , University of Bristol , BS8 1FD , UK
- Centre for Organized Matter Chemistry and Centre for Protolife Research , School of Chemistry , University of Bristol , BS8 1TS , UK . ;
- School of Cellular and Molecular Medicine , University of Bristol , BS8 1TD , UK
| | - Sam N Olof
- Bristol Centre for Functional Nanomaterials , University of Bristol , BS8 1FD , UK
- Centre for Organized Matter Chemistry and Centre for Protolife Research , School of Chemistry , University of Bristol , BS8 1TS , UK . ;
- HH Wills Physics Laboratory , University of Bristol , BS8 1TL , UK
| | - Monika D Jakimowicz
- Bristol Centre for Functional Nanomaterials , University of Bristol , BS8 1FD , UK
- Centre for Organized Matter Chemistry and Centre for Protolife Research , School of Chemistry , University of Bristol , BS8 1TS , UK . ;
- School of Cellular and Molecular Medicine , University of Bristol , BS8 1TD , UK
- HH Wills Physics Laboratory , University of Bristol , BS8 1TL , UK
| | - Anthony P Hollander
- School of Cellular and Molecular Medicine , University of Bristol , BS8 1TD , UK
| | - Stephen Mann
- Centre for Organized Matter Chemistry and Centre for Protolife Research , School of Chemistry , University of Bristol , BS8 1TS , UK . ;
| | - Sean A Davis
- Centre for Organized Matter Chemistry and Centre for Protolife Research , School of Chemistry , University of Bristol , BS8 1TS , UK . ;
| | - Mervyn J Miles
- HH Wills Physics Laboratory , University of Bristol , BS8 1TL , UK
| | - Avinash J Patil
- Centre for Organized Matter Chemistry and Centre for Protolife Research , School of Chemistry , University of Bristol , BS8 1TS , UK . ;
| | - Adam W Perriman
- Centre for Organized Matter Chemistry and Centre for Protolife Research , School of Chemistry , University of Bristol , BS8 1TS , UK . ;
- School of Cellular and Molecular Medicine , University of Bristol , BS8 1TD , UK
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5
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Phillips DB, Gibson GM, Bowman R, Padgett MJ, Hanna S, Carberry DM, Miles MJ, Simpson SH. An optically actuated surface scanning probe. OPTICS EXPRESS 2012; 20:29679-93. [PMID: 23388796 DOI: 10.1364/oe.20.029679] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We demonstrate the use of an extended, optically trapped probe that is capable of imaging surface topography with nanometre precision, whilst applying ultra-low, femto-Newton sized forces. This degree of precision and sensitivity is acquired through three distinct strategies. First, the probe itself is shaped in such a way as to soften the trap along the sensing axis and stiffen it in transverse directions. Next, these characteristics are enhanced by selectively position clamping independent motions of the probe. Finally, force clamping is used to refine the surface contact response. Detailed analyses are presented for each of these mechanisms. To test our sensor, we scan it laterally over a calibration sample consisting of a series of graduated steps, and demonstrate a height resolution of ∼ 11 nm. Using equipartition theory, we estimate that an average force of only ∼ 140 fN is exerted on the sample during the scan, making this technique ideal for the investigation of delicate biological samples.
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Affiliation(s)
- D B Phillips
- H H Wills Physics Laboratories, University of Bristol, Bristol, England, UK.
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6
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Olof SN, Grieve JA, Phillips DB, Rosenkranz H, Yallop ML, Miles MJ, Patil AJ, Mann S, Carberry DM. Measuring nanoscale forces with living probes. NANO LETTERS 2012; 12:6018-23. [PMID: 23092335 DOI: 10.1021/nl303585w] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Optical trapping techniques have been used to investigate fundamental biological processes ranging from the identification of the processive mechanisms of kinesin and myosin to understanding the mechanics of DNA. To date, these investigations have relied almost exclusively on the use of isotropic probes based on colloidal microspheres. However, there are many potential advantages in utilizing more complex probe morphologies: use of multiple trapping points enables control of the interaction volume; increasing the distance between the optical trap and the sample minimizes photodamage in sensitive biological materials; and geometric anisotropy introduces the potential for asymmetric surface chemistry and multifunctional probes. Here we demonstrate that living cells of the freshwater diatom Nitzschia subacicularis Hustedt can be exploited as advanced probes for holographic optical tweezing applications. We characterize the optical and material properties associated with the high shape anisotropy of the silica frustule, examine the trapping behavior of the living algal cells, and demonstrate how the diatoms can be calibrated for use as force sensors and as force probes in the presence of rat B-cell hybridoma (11B11) cells.
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Affiliation(s)
- S N Olof
- H. H. Wills Physics Laboratory, School of Chemistry, University of Bristol, Bristol, BS8 1TL, United Kingdom
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7
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Vijayakumar A, Bhattacharya S. Design, fabrication, and evaluation of a multilevel spiral-phase Fresnel zone plate for optical trapping. APPLIED OPTICS 2012; 51:6038-6044. [PMID: 22945150 DOI: 10.1364/ao.51.006038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 07/17/2012] [Indexed: 06/01/2023]
Abstract
A compact optics configuration for the generation of donut beams for trapping atoms at the micrometer scale using a multilevel spiral-phase Fresnel zone plate (FZP) and a semiconductor laser is proposed. A FZP is designed and a multilevel spiral phase is integrated into it. A spiral-phase FZP with a radius of 1 mm and with more than 1300 half-period zones is designed with multiple angular levels for integer and fractional topological charges, and the device is fabricated using electron-beam lithography direct writing. The performance of the device is evaluated, and the generation of symmetric and asymmetric donut beams is successfully demonstrated.
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Affiliation(s)
- A Vijayakumar
- Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai 600036, India
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8
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Phillips DB, Simpson SH, Grieve JA, Gibson GM, Bowman R, Padgett MJ, Miles MJ, Carberry DM. Position clamping of optically trapped microscopic non-spherical probes. OPTICS EXPRESS 2011; 19:20622-20627. [PMID: 21997071 DOI: 10.1364/oe.19.020622] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We investigate the degree of control that can be exercised over an optically trapped microscopic non-spherical force probe. By position clamping translational and rotational modes in different ways, we are able to dramatically improve the position resolution of our probe with no reduction in sensitivity. We also demonstrate control over rotational-translational coupling, and exhibit a mechanism whereby the average centre of rotation of the probe can be displaced away from its centre.
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Affiliation(s)
- D B Phillips
- H. H. Wills Physics Laboratories, University of Bristol, Bristol, England, United Kingdom
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9
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Burnham DR, Schneider T, Chiu DT. Effects of aliasing on the fidelity of a two dimensional array of foci generated with a kinoform. OPTICS EXPRESS 2011; 19:17121-17126. [PMID: 21935073 PMCID: PMC3482895 DOI: 10.1364/oe.19.017121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 07/28/2011] [Accepted: 08/03/2011] [Indexed: 05/31/2023]
Abstract
This paper investigates, through simulation and experiment, the behavior of two dimensional foci arrays generated via phase-only holography where an iterative algorithm was used to produce the kinoforms. Specifically, we studied how aliasing of the signal on a spatial light modulator affects the quality of the foci array as the density and size of the array are varied. This study provides a reference for applications where it is important to understand how the fidelity and overall quality of the foci array changes as the number of foci increases and as the spacing between foci decreases.
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10
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Phillips DB, Grieve JA, Olof SN, Kocher SJ, Bowman R, Padgett MJ, Miles MJ, Carberry DM. Surface imaging using holographic optical tweezers. NANOTECHNOLOGY 2011; 22:285503. [PMID: 21646693 DOI: 10.1088/0957-4484/22/28/285503] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We present an imaging technique using an optically trapped cigar-shaped probe controlled using holographic optical tweezers. The probe is raster scanned over a surface, allowing an image to be taken in a manner analogous to scanning probe microscopy (SPM), with automatic closed loop feedback control provided by analysis of the probe position recorded using a high speed CMOS camera. The probe is held using two optical traps centred at least 10 µm from the ends, minimizing laser illumination of the tip, so reducing the chance of optical damage to delicate samples. The technique imparts less force on samples than contact SPM techniques, and allows highly curved and strongly scattering samples to be imaged, which present difficulties for imaging using photonic force microscopy. To calibrate our technique, we first image a known sample--the interface between two 8 µm polystyrene beads. We then demonstrate the advantages of this technique by imaging the surface of the soft alga Pseudopediastrum. The scattering force of our laser applied directly onto this sample is enough to remove it from the surface, but we can use our technique to image the algal surface with minimal disruption while it is alive, not adhered and in physiological conditions. The resolution is currently equivalent to confocal microscopy, but as our technique is not diffraction limited, there is scope for significant improvement by reducing the tip diameter and limiting the thermal motion of the probe.
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Affiliation(s)
- D B Phillips
- H H Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Clifton, Bristol BS8 1TL, UK
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11
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Mas J, Roth MS, Martín-Badosa E, Montes-Usategui M. Adding functionalities to precomputed holograms with random mask multiplexing in holographic optical tweezers. APPLIED OPTICS 2011; 50:1417-1424. [PMID: 21460909 DOI: 10.1364/ao.50.001417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this study, we present a method designed to generate dynamic holograms in holographic optical tweezers. The approach combines our random mask encoding method with iterative high-efficiency algorithms. This hybrid method can be used to dynamically modify precalculated holograms, giving them new functionalities-temporarily or permanently-with a low computational cost. This allows the easy addition or removal of a single trap or the independent control of groups of traps for manipulating a variety of rigid structures in real time.
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Affiliation(s)
- Josep Mas
- Optical Trapping Lab--Grup de Biofotònica, Departament de Física Aplicada i Òptica, Universitat de Barcelona (UB), Martí i Franqués 1, Barcelona 08028, Spain
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12
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Hörner F, Woerdemann M, Müller S, Maier B, Denz C. Full 3D translational and rotational optical control of multiple rod-shaped bacteria. JOURNAL OF BIOPHOTONICS 2010; 3:468-475. [PMID: 20455214 DOI: 10.1002/jbio.201000033] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The class of rod-shaped bacteria is an important example of non-spherical objects where defined alignment is desired for the observation of intracellular processes or studies of the flagella. However, all available methods for orientational control of rod-shaped bacteria are either limited with respect to the accessible rotational axes or feasible angles or restricted to one single bacterium. In this paper we demonstrate a scheme to orientate rod-shaped bacteria with holographic optical tweezers (HOT) in any direction. While these bacteria have a strong preference to align along the direction of the incident laser beam, our scheme provides for the first time full rotational control of multiple bacteria with respect to any arbitrary axis. In combination with the translational control HOT inherently provide, this enables full control of all three translational and the two important rotational degrees of freedom of multiple rod-shaped bacteria and allows one to arrange them in any desired configuration.
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Affiliation(s)
- Florian Hörner
- Institute for Applied Physics, Westfälische Wilhelms-Universität, Münster, Germany
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13
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Carberry DM, Simpson SH, Grieve JA, Wang Y, Schäfer H, Steinhart M, Bowman R, Gibson GM, Padgett MJ, Hanna S, Miles MJ. Calibration of optically trapped nanotools. NANOTECHNOLOGY 2010; 21:175501. [PMID: 20368683 DOI: 10.1088/0957-4484/21/17/175501] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Holographically trapped nanotools can be used in a novel form of force microscopy. By measuring the displacement of the tool in the optical traps, the contact force experienced by the probe can be inferred. In the following paper we experimentally demonstrate the calibration of such a device and show that its behaviour is independent of small changes in the relative position of the optical traps. Furthermore, we explore more general aspects of the thermal motion of the tool.
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Affiliation(s)
- D M Carberry
- H H Wills Physics Laboratory, University of Bristol, Bristol, UK
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14
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Curran A, Yao AM, Gibson GM, Bowman R, Cooper JM, Padgett ML. Real time characterization of hydrodynamics in optically trapped networks of micro-particles. JOURNAL OF BIOPHOTONICS 2010; 3:244-251. [PMID: 20301124 DOI: 10.1002/jbio.201000003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The hydrodynamic interactions of micro-silica spheres trapped in a variety of networks using holographic optical tweezers are measured and characterized in terms of their predicted eigenmodes. The characteristic eigenmodes of the networks are distinguishable within 20-40 seconds of acquisition time. Three different multi-particle networks are considered; an eight-particle linear chain, a nine-particle square grid and, finally, an eight-particle ring. The eigenmodes and their decay rates are shown to behave as predicted by the Oseen tensor and the Langevin equation, respectively. Finally, we demonstrate the potential of using our micro-ring as a non-invasive sensor to the local environmental viscosity, by showing the distortion of the eigenmode spectrum due to the proximity of a planar boundary.
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Affiliation(s)
- Arran Curran
- Department of Physics and Astronomy, University of Glasgow, Glasgow, UK.
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15
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Carberry DM, Picco L, Dunton PG, Miles MJ. Mapping real-time images of high-speed AFM using multitouch control. NANOTECHNOLOGY 2009; 20:434018. [PMID: 19801760 DOI: 10.1088/0957-4484/20/43/434018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Conventional AFM is highly restricted by its scan rate, a problem that has been overcome by the development of high-speed AFM systems. As the technology to produce higher scan rates has developed it has pushed forward the design of control software. However, the user interface has not evolved at the same rate, limiting the user to sequential control steps. In this paper we demonstrate the integration of HSAFM with a multitouch interface to produce a highly intuitive and responsive control environment. This enables nanometre resolution to be maintained whilst scanning the sample over tens of microns, and arbitrary paths to be traversed. We illustrate this by scanning around two chromosomes in water, before scanning on top of the chromosome, showing the surface structure.
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Affiliation(s)
- D M Carberry
- H H Wills Physics Laboratory, University of Bristol, Bristol, UK
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16
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Simpson SH, Hanna S. Thermal motion of a holographically trapped SPM-like probe. NANOTECHNOLOGY 2009; 20:395710. [PMID: 19726835 DOI: 10.1088/0957-4484/20/39/395710] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
By holding a complex object in multiple optical traps, it may be harmonically bound with respect to both its position and its orientation. In this way a small probe, or nanotool, can be manipulated in three dimensions and used to measure and apply directed forces, in the manner of a scanning probe microscope. In this paper we evaluate the thermal motion of such a probe held in holographic optical tweezers, by solving the Langevin equation for the general case of a set of spherical vertices linked by cylindrical rods. The concept of a corner frequency, familiar from the case of an optically trapped sphere, is appropriately extended to represent a set of characteristic frequencies given by the eigenvalues of the product of the stiffness matrix and the inverse hydrodynamic resistance matrix of the tool. These eigenvalues may alternatively be interpreted as inverses of a set of characteristic relaxation times for the system. The approach is illustrated by reference to a hypothetical tool consisting of a triangular arrangement of spheres with a lateral probe. The characteristic frequencies and theoretical resolution of the device are derived; variations of these quantities with tool size and orientation and with the optical power distribution, are also considered.
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Affiliation(s)
- Stephen H Simpson
- H H Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK
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17
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Wills JB, Butler JR, Palmer J, Reid JP. Using optical landscapes to control, direct and isolate aerosol particles. Phys Chem Chem Phys 2009; 11:8015-20. [DOI: 10.1039/b908270k] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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18
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Gibson GM, Leach J, Keen S, Wright AJ, Padgett MJ. Measuring the accuracy of particle position and force in optical tweezers using high-speed video microscopy. OPTICS EXPRESS 2008; 16:14561-70. [PMID: 18794991 DOI: 10.1364/oe.16.014561] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We assess the performance of a CMOS camera for the measurement of particle position within optical tweezers and the associated autocorrelation function and power spectrum. Measurement of the displacement of the particle from the trap center can also be related to the applied force. By considering the Allan variance of these measurements, we show that such cameras are capable of reaching the thermal limits of nanometer and femtonewton accuracies, and hence are suitable for many of the applications that traditionally use quadrant photodiodes. As an example of a multi-particle measurement we show the hydrodynamic coupling between two particles.
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Affiliation(s)
- Graham M Gibson
- Department of Physics and Astronomy, University of Glasgow, Glasgow, UK.
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19
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Benito DC, Carberry DM, Simpson SH, Gibson GM, Padgett MJ, Rarity JG, Miles MJ, Hanna S. Constructing 3D crystal templates for photonic band gap materials using holographic optical tweezers. OPTICS EXPRESS 2008; 16:13005-13015. [PMID: 18711539 DOI: 10.1364/oe.16.013005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A simple and robust method is presented for the construction of 3-dimensional crystals from silica and polystyrene microspheres. The crystals are suitable for use as templates in the production of three-dimensional photonic band gap (PBG) materials. Manipulation of the microspheres was achieved using a dynamic holographic assembler (DHA) consisting of computer controlled holographic optical tweezers. Attachment of the microspheres was achieved by adjusting their colloidal interactions during assembly. The method is demonstrated by constructing a variety of 3-dimensional crystals using spheres ranging in size from 3 microm down to 800 nm. A major advantage of the technique is that it may be used to build structures that cannot be made using self-assembly. This is illustrated through the construction of crystals in which line defects have been deliberately included, and by building simple cubic structures.
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Affiliation(s)
- D C Benito
- HH Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK
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