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

Light-Based Communication Within Cells Enabled by Hydrogel Implant

By BiotechDaily International staff writers
Posted on 12 Nov 2013
Image: Light passing through an optical fiber (left) can either carry in a signal that stimulates the activity of cells embedded in the hydrogel implant or bring back a signal generated by cells responding to something in their environment (Photo courtesy of the Harvard Bio-Optics Lab/Wellman Center for Photomedicine, Massachusetts General Hospital).
Image: Light passing through an optical fiber (left) can either carry in a signal that stimulates the activity of cells embedded in the hydrogel implant or bring back a signal generated by cells responding to something in their environment (Photo courtesy of the Harvard Bio-Optics Lab/Wellman Center for Photomedicine, Massachusetts General Hospital).
American scientists have developed a way to deliver a light signal to specific tissues deep within the body.

For researchers developing unique therapies based on inducing specific cells to do precise things, getting accurate communication to the right group of cells at the precise time remains a major challenge. The use of light to communicate with cells has been limited by its restricted ability to pass through tissues. Now, researchers at the Wellman Center for Photomedicine at Massachusetts General Hospital (MGH; Boston, USA) published findings of their accomplishment in the October 20, 2013, issue of the journal Nature Photonics.

“Scientists only began investigating light-activated therapy a few years ago, but it is generating huge interest,” said Wellman investigator Seok Hyun Yun, PhD, senior author of the study. “One of the best known examples is use of optogenetics—activation or deactivation of brain cells by illumination with different colors of light to treat brain disorders. But how to deliver light deep within the brain or other tissues has been a common problem. The implant we have developed may help solve this problem.”

The technology is called a light-guiding hydrogel. The implant is made from polymer-based scaffolding capable of supporting living cells and contains cells genetically modified either to perform a specific activity in response to light or to emit light in response to a specific metabolic signal. An optical fiber connects the implant to either an external light source or a light detector.

The investigators first determined the characteristics of the hydrogel scaffolding, including flexibility, transparency, and stability, that would be most appropriate for delivering or detecting a light signal. After figuring out how many cells could be implanted into the hydrogel without significantly reducing its ability to transmit a light signal, they developed and evaluated in mice two different systems, both involving implantation of a 4-cm hydrogel beneath the animal’s skin.

The first system’s implants contained cells genetically engineered to express light-emitting green fluorescent protein (GFP) upon contact with a toxin. After validating in vitro the hydrogels’ response to nanoparticles containing the toxic metal cadmium, the researchers implanted the hydrogels beneath the skin of three groups of mice. One group was then injected with the cadmium nanoparticles, the second received nanoparticles encased in a polymer shell that shielded cells from the toxin, and the third received a control saline injection. The implants only generated a GFP-signal in response to the unshielded nanoparticles, indicating their ability to sense a change, in this case, the presence of a toxin in the cellular environment.

To investigate a possible therapeutic application for the system, the investigators used a hydrogel implant containing cells that respond to blue light by producing glucagon-like peptide-1 (GLP-1), a protein playing an essential role in glucose metabolism. After the implants were placed under the skin of mice with diabetes, the blue light signal was delivered for 12 hours. One day and a half later (48 hours after the implant) the animals that received the light signal had twice the level of GLP-1 in their blood, combined with considerably better results in a glucose tolerance test, than did implanted mice not treated with light.

“This work combines several existing technologies well known in their respective fields, such as drug delivery, genetic engineering, biomaterial science, and photonics, to build a new implant system that enables the delivery of photomedicine deep in the body,” said Dr. Yun, an associate professor of dermatology at Harvard Medical School (Boston, MA, USA) and director of the Harvard Bio-Optics Lab. “This is the first time anyone has shown the ability to talk optically—by means of light—with cells deep within the body, both to sense the presence of a toxin and to deliver a cell-based therapy.”

The researchers added that the next phase of research should examine how altering the shape and structure of the hydrogel can improve the implant’s light-guiding properties, ways to enhance the generation and delivery of a therapeutic protein, how the immune system would react to long-term implantation and ways to deliver or identify the light signal that would not require passing a fiber through the skin.

Related Links:

Massachusetts General Hospital



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.