Press Release Archive

  • home_icon HOME
  • News
  • Press Release Archive

KAIST researchers published an article on the development of a novel technique to precisely track the 3-D positions of optically-trapped particles having complicated geometry in high speed in the April 2015 issue of Optica.

 

Optical tweezers have been used as an invaluable tool for exerting micro-scale force on microscopic particles and manipulating three-dimensional (3-D) positions of particles. Optical tweezers employ a tightly-focused laser whose beam diameter is smaller than one micrometer (1/100 of hair thickness), which generates attractive force on neighboring microscopic particles moving toward the beam focus. Controlling the positions of the beam focus enabled researchers to hold the particles and move them freely to other locations so they coined the name “optical tweezers.”

 

To locate the optically-trapped particles by a laser beam, optical microscopes have usually been employed. Optical microscopes measure light signals scattered by the optically-trapped microscopic particles and the positions of the particles in two dimensions. However, it was difficult to quantify the particles’ precise positions along the optic axis, the direction of the beam, from a single image, which is analogous to the difficulty of determining the front and rear positions of objects when closing an eye due to a lack of depth perception. Furthermore, it became more difficult to measure precisely 3-D positions of particles when scattered light signals were distorted by optically-trapped particles having complicated shapes or other particles occlude the target object along the optic axis.

 

Professor YongKeun Park and his research team in the Department of Physics at the Korea Advanced Institute of Science and Technology (KAIST) employed an optical diffraction tomography (ODT) technique to measure 3-D positions of optically-trapped particles in high speed. The principle of ODT is similar to X-ray CT imaging commonly used in hospitals for visualizing the internal organs of patients. Like X-ray CT imaging, which takes several images from various illumination angles, ODT measures 3-D images of optically-trapped particles by illuminating them with a laser beam in various incidence angles.

 

The KAIST team used optical tweezers to trap a glass bead with a diameter of 2 micrometers, and moved the bead toward a white blood cell having complicated internal structures. The team measured the 3-D dynamics of the white blood cell as it responded to an approaching glass bead via ODT in the high acquisition rate of 60 images per second. Since the white blood cell screens the glass bead along an optic axis, a conventionally-used optical microscope could not determine the 3-D positions of the glass bead. In contrast, the present method employing ODT localized the 3-D positions of the bead precisely as well as measured the composition of the internal materials of the bead and the white blood cell simultaneously.

 

Professor Park said, “Our technique has the advantage of measuring the 3-D positions and internal structures of optically-trapped particles in high speed without labelling exogenous fluorescent agents and can be applied in various fields including physics, optics, nanotechnology, and medical science.”

 

Kyoohyun Kim, the lead author of this paper (“Simultaneous 3D Visualization and Position Tracking of Optically Trapped Particles Using Optical Diffraction Tomography”), added, “This ODT technique can also apply to cellular-level surgeries where optical tweezers are used to manipulate intracellular organelles and to display in real time and in 3-D the images of the reaction of the cell membrane and nucleus during the operation or monitoring the recovery process of the cells from the surgery.”

 

The research results were published as the cover article in the April 2014 issue of Optica, the newest journal launched last year by the Optical Society of America (OSA) for rapid dissemination of high-impact results related to optics.

 

 

Figure 1: This picture shows the concept image of tweezing an optically-trapped glass bead on the cellular membrane of a white blood cell.

Concept%20image%20of%20tweezing%20an%20optically-trapped%20glass%20bead.jpg


 

Figure 2:High-speed 3-D images produced from optical diffraction tomography technique


High-speed%203-D%20images%20produced%20by%20ODT.jpg


List of Articles
No. Category Subject Author Date Views
36 KINC Graphene-based Transparent Electrodes for Highly Efficient Flexible OLEDs [2016-06-07] file KAIST_INSTITUTE 2016.06.18 890
35 KIHST Next-generation Holographic Microscope for 3D Live Cell Imaging [2016-03-29] file KAIST_INSTITUTE 2016.06.18 835
34 KINC KAIST Researchers Develop a Technology to Enable Unzipping of the Graphene Plane [2016-03-22] file KAIST_INSTITUTE 2016.06.18 807
33 Others A Firefighter Drone That Flies and Crawls Up Walls [2016-01-20] file KAIST_INSTITUTE 2016.06.18 814
32 Others 융합연구기획과제 성과 - 대학 캠퍼스 내 실내외 통합 내비게이션 개발 [2015-09-17] file KAIST_INSTITUTE 2016.06.10 1325
31 KIR BBC News Channel's Technology Program "Click"Aired KAIST's Jellyfish Robot [2015-08-06] file KAIST_INSTITUTE 2016.06.10 1517
» KIHST Fast and Accurate 3-D Imaging Technique to Track Optically-Trapped Particles [2015-08-06] file KAIST_INSTITUTE 2016.06.10 815
29 KIHST Anti-Cancer Therapy Delivering Drug to an Tumor Developed by KAIST Researchers [2015-08-06] file KAIST_INSTITUTE 2016.06.10 1239
28 KINC KAIST Develope a Credit-Card-Thick Flexible Lithium Ion Battery [2015-08-06] file KAIST_INSTITUTE 2016.06.10 965
27 I-Space KAIST Open a Mobile Healthcare Showroom on Campus [2015-08-06] file KAIST_INSTITUTE 2016.06.10 910
26 KINC 조병진, 임성갑, 유승협 교수 휘어지는 10나노미터 고분자 절연막 개발 [2015-08-05] file KAIST_INSTITUTE 2016.06.10 898
25 KIITC 박인규 교수, 공기오염 측정 센서 원천기술 개발 [2015-08-05] file KAIST_INSTITUTE 2016.06.10 1071
24 KINC 최성율 교수 도장 찍듯이 자유롭게 그래핀 옮기는 기술 개발 [2015-08-05] file KAIST_INSTITUTE 2016.06.10 1261
23 KIHST KIOST 김승우 연구소장 올해 국가과학자 선정 [2012-09-20] KAIST_INSTITUTE 2016.06.10 771
22 KIHST 이제는 세포 내부도 훤히 들여다본다 [2012-01-27] file KAIST_INSTITUTE 2016.06.10 717
21 KINC 전기적 자기적 성질 동시에 갖는 신물질 물성 규명 [2012-01-17] file KAIST_INSTITUTE 2016.06.10 911
20 KINC LED의 새로운 발견, 형광체 없이 다양한 색깔의 빛 낸다 [2012-01-17] file KAIST_INSTITUTE 2016.06.10 926
19 KIITC KAIST's Smart E-book System More Convenient than Paper-based Books [2012-02-19] file KAIST_INSTITUTE 2016.06.10 822
18 KINC 보다 태양빛에 가까운 LED 개발 [2012-01-12] file KAIST_INSTITUTE 2016.06.10 944
17 KIITC 초슬림 휴대폰 나온다 [2012-01-12] file KAIST_INSTITUTE 2016.06.10 703
Board Pagination Prev 1 2 Next
/ 2

KAIST 291 Daehak-ro, Yuseong-gu, Daejeon (34141)
T : +82-42-350-2381~2384
F : +82-42-350-2080
Copyright (C) 2015. KAIST Institute