Navigation Links
MIT: Removable 'cloak' for nanoparticles helps them target tumors
Date:5/3/2011

CAMBRIDGE, Mass. -- MIT chemical engineers have designed a new type of drug-delivery nanoparticle that exploits a trait shared by almost all tumors: They are more acidic than healthy tissues.

Such particles could target nearly any type of tumor, and can be designed to carry virtually any type of drug, says Paula Hammond, a member of the David H. Koch Institute for Integrative Cancer Research at MIT and senior author of a paper describing the particles in the journal ACS Nano.

Like most other drug-delivering nanoparticles, the new MIT particles are cloaked in a polymer layer that protects them from being degraded by the bloodstream. However, the MIT team, including lead author and postdoctoral associate Zhiyong Poon, designed this outer layer to fall off after entering the slightly more acidic environment near a tumor. That reveals another layer that is able to penetrate individual tumor cells.

In the ACS Nano paper, which went online April 23, the researchers reported that, in mice, their particles can survive in the bloodstream for up to 24 hours, accumulate at tumor sites and enter tumor cells.

The new MIT approach differs from that taken by most nanoparticle designers. Typically, researchers try to target their particles to a tumor by decorating them with molecules that bind specifically to proteins found on the surface of cancer cells. The problem with that strategy is that it's difficult to find the right target a molecule found on all of the cancer cells in a particular tumor, but not on healthy cells. Also, a target that works for one type of cancer might not work for another.

Hammond and her colleagues decided to take advantage of tumor acidity, which is a byproduct of its revved-up metabolism. Tumor cells grow and divide much more rapidly than normal cells, and that metabolic activity uses up a lot of oxygen, which increases acidity. As the tumor grows, the tissue becomes more and more acidic.

To build their targeted particles, the researchers used a technique called "layer-by-layer assembly." This means each layer can be tailored to perform a specific function.

When the outer layer (made of polyethylene glycol, or PEG) breaks down in the tumor's acidic environment, a positively charged middle layer is revealed. That positive charge helps to overcome another obstacle to nanoparticle drug delivery: Once the particles reach a tumor, it's difficult to get them to enter the cells. Particles with a positive charge can penetrate the negatively charged cell membrane, but such particles can't be injected into the body without a "cloak" of some kind because they would also destroy healthy tissues.

The nanoparticles' innermost layer can be a polymer that carries a cancer drug, or a quantum dot that could be used for imaging, or virtually anything else that the designer might want to deliver, says Hammond, who is the Bayer Professor of Chemical Engineering at MIT.

Other researchers have tried to design nanoparticles that take advantage of tumors' acidity, but Hammond's particles are the first that have been successfully tested in living animals.

The researchers are planning to further develop these particles and test their ability to deliver drugs in animals. Hammond says she expects it could take five to 10 years of development before human clinical trials could begin.

Hammond's team is also working on nanoparticles that can carry multiple payloads. For example, the outer PEG layer might carry a drug or a gene that would "prime" the tumor cells to be susceptible to another drug carried in the particle's core.


'/>"/>

Contact: Caroline McCall
cmccall5@mit.edu
Massachusetts Institute of Technology
Source:Eurekalert

Related biology news :

1. All wrapped up: K-State researchers graphene cloak protects bacteria, leading to better images
2. Moths cloaked in color
3. Invisibility cloak could protect against earthquakes
4. Common nanoparticles found to be highly toxic to Arctic ecosystem
5. Nanoparticles offer hope for common skin allergy
6. Rice scientist recognized for stellar work on nanoparticles, cell membranes
7. Growth-factor-containing nanoparticles accelerate healing of chronic wounds
8. With chemical modification, stable RNA nanoparticles go 3-D
9. Cinnamon can replace harmful chemicals used to create nanoparticles
10. Drugs encased in nanoparticles travel to tumors on the surface of immune-system cells
11. Probing the nanoparticle: Predicting how nanoparticles will react in the human body
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:5/12/2016)... WearablesResearch.com , a brand of Troubadour ... from the Q1 wave of its quarterly wearables survey. ... receptivity to a program where they would receive discounts ... company. "We were surprised to see that ... LaColla , CEO of Troubadour Research, "primarily because there ...
(Date:4/26/2016)... and LONDON , ... Finacle, part of EdgeVerve Systems, a product subsidiary ... Onegini today announced a partnership to integrate the ...      (Logo: http://photos.prnewswire.com/prnh/20151104/283829LOGO ) ... provide their customers enhanced security to access and ...
(Date:4/14/2016)... TEL AVIV, Israel , April 14, 2016 /PRNewswire/ ... in Behavioral Authentication and Malware Detection, today announced the ... has already assumed the new role. Goldwerger,s ... for BioCatch, on the heels of the deployment of ... In addition, BioCatch,s behavioral biometric technology, which discerns unique ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... , June 23, 2016  Blueprint Bio, a ... discoveries to the medical community, has closed its Series ... Matthew Nunez . "We have received a ... the capital we need to meet our current goals," ... provide us the runway to complete validation on the ...
(Date:6/23/2016)... ... June 23, 2016 , ... ... of intelligent tools designed, tuned and optimized exclusively for Okuma CNC machining centers ... The result of a collaboration among several companies with expertise in toolholding, cutting ...
(Date:6/22/2016)... YORK , June 22, 2016  According ... growing next generation sequencing (NGS) market include significant ... of smaller sequencers.  More accessible and affordable sequencers, ... to growing demand for consumables including sample prep ... The Market for Sample Preparation for Next Generation ...
(Date:6/22/2016)... ... June 22, 2016 , ... The ... immigrant achievements and contributions to North Texas and the nation, recently held its ... immigrant community to the civic and economic vitality of North Texas. Proceeds from ...
Breaking Biology Technology: