Features | Partner Sites | Information | LinkXpress
Sign In
PZ HTL SA
GLOBETECH PUBLISHING
GLOBETECH PUBLISHING

3-Photon Microscopy Breaks Depth Limit of Current Biological Tissue Imaging

By BiotechDaily International staff writers
Posted on 07 Feb 2013
Image:  A horizontal frame from 3D reconstructed 3-photon microscopy images in a mouse brain. Red: neurons, blue: blood vessels, dark holes: nonfluorescent neurons (Photo courtesy of Prof. Xu’s laboratory, Cornell University).
Image: A horizontal frame from 3D reconstructed 3-photon microscopy images in a mouse brain. Red: neurons, blue: blood vessels, dark holes: nonfluorescent neurons (Photo courtesy of Prof. Xu’s laboratory, Cornell University).
In a proof-of-concept study of a live mammalian brain, scientists have now shown that 3-photon microscopy enables high-resolution, noninvasive in vivo imaging at unprecedented depths of complex biological tissue, breaking the fundamental depth limit of standard 2-photon microscopy.

The team of scientists, at Cornell University (Ithaca, NY, USA), have demonstrated a three-fold improvement in the depth limit of fluorescence-based biological tissue imaging over the widely used 2-photon microscopy (2PM) based technology (invented at Cornell in 1990). Tissue scattering limits the maximum imaging depth of 2PM to the cortical layer of the mouse brain, and imaging subcortical structures currently requires the removal of overlying brain tissue or the insertion of optical probes. Senior investigator Chris Xu, associate professor of applied and engineering physics, and colleagues have now demonstrated high-resolution, 3D imaging of the subcortical region of a live, intact mouse brain using 3-photon microscopy (3PM) based imaging technology (invented at Cornell in 1995).

The study, published online January 20, 2013, in the journal Nature Photonics, describes 3-photon fluorescence combined with a longer excitation wavelength of the laser pulse to overcome obstacles such as tissue scattering and absorption, which have prohibited high-resolution imaging deep within biological tissues. Dyes and transgenic mice were used to test the 3PM on different fluorescent signals. Using the live mouse brain model, the researchers have proved the principle of 3PM operating at a wavelength of 1,700 nanometers and this, in combination with the new laser developed specifically for 3-photon excitation, allowed for the high-resolution imaging at unprecedented depths within the brain—vascular structures as well as neurons within the mouse hippocampus were imaged.

"With MRI, we can see the whole brain but not with the resolution we have demonstrated. The optical resolution is about 100 to 1,000 times higher and allows us to clearly visualize individual neurons," said Prof. Xu. Pushing these depth limits is important for basic science and could also prove useful clinically, Prof. Xu noted. Depression and diseases like Parkinson's and Alzheimer's are associated with changes deep inside the brain, and finding the cures could be helped by subcortical neural imaging—below the gray matter, into the white matter and beyond, if the brain is visualized as stacked layers. If 3-photon microscopy can be used to map the entire brain, it could pave the way to new breakthroughs in neuroscience as well as other clinically relevant areas.

Related Links:

Cornell University



Channels

Genomics/Proteomics

view channel
Image: The TheraCyte cell encapsulation device (Photo courtesy of TheraCyte, Inc.).

Encapsulated Human-Insulin-Producing Progenitor Cells Cure Diabetes in Mouse Model

A breakthrough system that allows subcutaneous implantation of encapsulated immature pancreatic cells (beta progenitor cells) was shown to produce enough insulin to correct the symptoms of diabetes in a mouse model.... Read more

Drug Discovery

view channel
Image: Chitosan is derived from the shells of shrimp and other sea crustaceans, including Alaskan pink shrimp, pictured here (Photo courtesy of NOAA - [US] National Oceanic and Atmospheric Administration).

Chitosan Treatment Clears the Way for Antibiotics to Eliminate Recurrent Urinary Tract Infections

Recurrent urinary tract infection was successfully resolved in a mouse model by treatment with the exfoliant chitosan followed by a round of antibiotics. Bacterial urinary tract infection (UTI), most... Read more

Biochemistry

view channel

Mitochondrial Cause of Aging Can Be Reversed

Researchers have found a cause of aging in lab animals that can be reversed, possibly providing an avenue for new treatments for age-related diseases including type 2 diabetes, cancer, muscle wasting, and inflammatory diseases. The researchers plan to begin human trials late 2014. The study, which was published December... Read more

Therapeutics

view channel

Cytokine Identified That Causes Mucositis in Cancer Therapy Patients

The action of the cytokine interleukin 1-beta (IL-1beta) has been found to underlie the onset of mucositis, a common, severe side effect of chemotherapy and irradiation of cancer patients. Mucositis occurs as a result of cell death in reaction to chemo- or radiotherapy. The mucosal lining of the mouth becomes thin, may... Read more

Business

view channel

Analytical Sciences Trade Fair Declared a Rousing Success

Organizers of this year's 24th "analytica" biosciences trade fair have reported significant increases in both the number of visitors and exhibitors compared to the 2012 event. The analytica trade fair for laboratory technology, analysis, and biotechnology has been held at the Munich (Germany) Trade Fair Center every... Read more
 
Copyright © 2000-2014 Globetech Media. All rights reserved.