We use cookies to understand how you use our site and to improve your experience. This includes personalizing content and advertising. To learn more, click here. By continuing to use our site, you accept our use of cookies. Cookie Policy.

Features Partner Sites Information LinkXpress hp
Sign In
Advertise with Us
LGC Clinical Diagnostics

Download Mobile App




Exploring Microscopic Structures Using Holographic Video

By LabMedica International staff writers
Posted on 04 Aug 2009
Print article
Image: Colored transmission electron micrograph (TEM) of lipid droplets in a developing fat cell (Photo courtesy of Steve Gschmeissner / SPL).
Image: Colored transmission electron micrograph (TEM) of lipid droplets in a developing fat cell (Photo courtesy of Steve Gschmeissner / SPL).
Physicists have developed a technique to record three-dimensional (3D) movies of microscopic systems, such as biologic molecules, through holographic video. The study has potential to improve medical diagnostics and drug discovery.

The technique, developed in the laboratory of New York University (NYU; NY, USA) physics professor David Grier, comprises two components: making and recording the images of microscopic systems and then analyzing these images. To generate and record images, the researchers created a holographic microscope, which is based on a traditional light microscope. However, instead of relying on an incandescent illuminator, which conventional microscopes employ, the holographic microscope uses a collimated laser beam that consists of a series of parallel rays of light and similar to a laser pointer.

When an object is placed into path of the microscope's beam, the object scatters some of the beam's light into a complex diffraction pattern. The scattered light overlaps with the original beam to create an interference pattern reminiscent of overlapping ripples in a pool of water. The microscope then magnifies the resulting pattern of light and dark and records it with a conventional digital video recorder (DVR). Each snapshot in the resulting video stream is a hologram of the original object. Unlike a conventional photograph, each holographic snapshot stores data about the three-dimensional structure and composition of the object that created the scattered light field.

The recorded holograms appear as a pattern of concentric light and dark rings. This resulting pattern contains a wealth of information about the material that originally scattered the light--where it was and its composition. Analyzing the images provided a different set of challenges. To do so, the researchers based their research on a quantitative theory explaining the pattern of light that objects scatter. The hypothesis, the Lorenz-Mie theory, maintains that the way light is scattered can reveal the size and composition of the object that is scattering it.

"We use that theory to analyze the hologram of each object in the snapshots of our video recording,” explained Prof. Grier, who is part of NYU's Center for Soft Matter Research. "Fitting the theory to the hologram of a sphere reveals the three-dimensional position of the sphere's center with remarkable resolution. It allows us to view particles a micrometer in size and with nanometric precision--that is, it captures their traits to within one billionth of a meter. That's a tremendous amount of information to obtain about a micrometer-scale object, particularly when you consider that you get all of that information in each snapshot. It exceeds other existing technology in terms of tracking particles and characterizing their make-up--and the holographic microscope can do both simultaneously.”

Because the analysis is computationally intensive, the researchers employ the number-crunching power of the graphic processing unit (GPU) used in high-end computer video cards. Originally developed to provide high-resolution video performance for computer games, these cards possess capabilities suitable for the holographic microscope.

The investigators have already employed the technique for a range of applications, from research in basic statistical physics to analyzing the composition of fat droplets in milk. More broadly, the technique creates a fundamental level; research in these areas seeks to understand whether or not certain molecular components, i.e., the building blocks of pharmaceuticals, stick together.

One approach, called a bead-based assay, creates micrometer-scale beads whose surfaces have active groups that bind to the target molecule. Because of their small size, the challenge for researchers is to determine if these beads actually adhere to the target molecules. The way this is traditionally done is to create yet another molecule--or tag--that binds to the target molecule. This tag molecule, time-consuming, and costly to produce, is typically identified by making it fluorescent or radioactive.

The holographic imaging technique, with its magnification and recording capabilities, allows researchers to observe molecular-scale binding without a tag, saving both time and money. Requiring just one microscopic bead to detect one type of molecule, holographic video microscopy promises a previously unachievable level of miniaturization for medical diagnostic tests and creates possibilities for running very large numbers of sensitive medical tests in parallel.

The study was reported in the July 7, 2009, issue of the journal Optics Express.

Related Links:
New York University

Gold Member
Pharmacogenetics Panel
VeriDose Core Panel v2.0
Verification Panels for Assay Development & QC
Seroconversion Panels
New
Troponin I Test
Quidel Triage Troponin I Test
New
Total 25-Hydroxyvitamin D₂ & D₃ Assay
Total 25-Hydroxyvitamin D₂ & D₃ Assay

Print article

Channels

Molecular Diagnostics

view channel
Image: Researcher Kanta Horie places a sample in a mass spectrometer that measures protein levels in blood plasma and other fluids (Photo courtesy of WashU Medicine)

Highly Accurate Blood Test Diagnoses Alzheimer’s and Measures Dementia Progression

Several blood tests are currently available to assist doctors in diagnosing Alzheimer's disease in individuals experiencing cognitive symptoms. However, these tests do not provide insights into the clinical... Read more

Immunology

view channel
Image: The findings were based on patients from the ADAURA clinical trial of the targeted therapy osimertinib for patients with NSCLC with EGFR-activated mutations (Photo courtesy of YSM Multimedia Team)

Post-Treatment Blood Test Could Inform Future Cancer Therapy Decisions

In the ongoing advancement of personalized medicine, a new study has provided evidence supporting the use of a tool that detects cancer-derived molecules in the blood of lung cancer patients years after... Read more

Microbiology

view channel
Image: Schematic representation illustrating the key findings of the study (Photo courtesy of UNIST)

Breakthrough Diagnostic Technology Identifies Bacterial Infections with Almost 100% Accuracy within Three Hours

Rapid and precise identification of pathogenic microbes in patient samples is essential for the effective treatment of acute infectious diseases, such as sepsis. The fluorescence in situ hybridization... Read more
Copyright © 2000-2025 Globetech Media. All rights reserved.