Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Achilles heel: Popular drug-carrying nanoparticles get trapped in bloodstream

Katawut Namdee, BME Ph.D. student, performs tests with different forms of drug carriers as part of the research done in ChE Professor Omolola Eniola Adefesco's lab in the GG Brown Building on North Campus Ann Arbor, MI on December 17, 2012. Image credit: Joseph Xu, Michigan Engineering Communications & Marketing
Katawut Namdee, BME Ph.D. student, performs tests with different forms of drug carriers as part of the research done in ChE Professor Omolola Eniola Adefesco's lab in the GG Brown Building on North Campus Ann Arbor, MI on December 17, 2012.

Image credit: Joseph Xu, Michigan Engineering Communications & Marketing

Abstract:
Many medically minded researchers are in hot pursuit of designs that will allow drug-carrying nanoparticles to navigate tissues and the interiors of cells, but University of Michigan engineers have discovered that these particles have another hurdle to overcome: escaping the bloodstream.

Achilles heel: Popular drug-carrying nanoparticles get trapped in bloodstream

Ann Arbor, MI | Posted on February 5th, 2013

Drug delivery systems promise precision targeting of diseased tissue, meaning that medicines could be more effective at lower doses and with fewer side effects. Such an approach could treat plaques in arteries, which can lead to heart attacks or strokes.

Drug carriers would identify inflamed vessel walls and deliver a drug that removes the deposits of calcium, cholesterol and other substances. Or, the carriers might seek out markers of cancer and kill off the small blood vessels in tumors, starving the malignant tissue of food and oxygen.

Nanoparticles, which have diameters under one micron, or one-thousandth of a millimeter, are thought to be the most promising drug carriers. Omolola Eniola-Adefeso, U-M professor of chemical engineering who studies nanoparticles in flowing blood, says the immune system can't get rid of them quickly.

"It's hard for a white blood cell to understand it has a nanoparticle next to it," she said.

Those same tiny dimensions allow them to slip through the cracks between cells and infiltrate cell membranes, where they can go to work administering medicine. But Eniola-Adefeso and her team found that these particles have an Achilles heel.

Blood vessels are the body's highways, and once nanoparticles get into the flow, they find it very difficult to reach the exits. In all vessels other than capillaries, the red cells in flowing blood tend to come together in the center.

"The red blood cells sweep those particles that are less than one micron in diameter and sandwich them," she said.

Trapped among the red cells, the nanoparticles can't reach the vessel wall to treat disease in the blood vessels or the tissue beyond.

With their recent work, including a study to be published recently in Langmuir, Eniola-Adefeso's team has shown that nanoparticle spheres face this problem in tiny arterioles and venules—one step up from capillaries—all the way up to centimeter-sized arteries.

They discovered this with the help of plastic channels lined with the same cells that make up the interiors of blood vessels. Human blood, with added nano- or microspheres, ran through the channels, and the team observed whether or not the spheres migrated to the channel walls and bound themselves to the lining. The researchers present the first visual evidence that few nanospheres make it to the vessel wall in blood flow.

"Prior to the work that we have done, people were operating under the assumption that particles will interact with the blood vessel at some point," Eniola-Adefeso said.

While a relatively small fraction of nanospheres filter out to the blood vessel walls, many more stay in the bloodstream and travel all over the body. Increasing the nanoparticle dose gives poor returns; after the team added five times more nanospheres to the blood samples, the number of spheres that bonded with the blood vessel lining only doubled.

"If localized drug delivery is an important goal, then nanospheres will fail," she said.

But it's not all bad news. The red blood cells tended to push microspheres with diameters of two microns or more toward the wall. Whether the blood flowed evenly, as it does in arterioles and venules, or in pulses, as occurs in arteries, the larger microspheres were able to reach the vessel wall and bind to it. When the team added more microspheres to the flow, they saw a proportional increase in microspheres on the vessel wall.

While microspheres are too large to serve as drug carriers into cell or tissue space on their own, the team suggested that microspheres could ferry nanospheres to the vessel wall, releasing them upon attachment. But the simpler approach may be nanoparticles of different shapes, which might escape the red blood cells on their own.

Eniola-Adefeso and her team are experimenting with rod-shaped nanoparticles.

"A sphere has no drift," she said, so nanospheres won't naturally move sideways out of the red cell flow. "When a rod is flowing, it drifts, and that drift moves it closer to the vessel wall."

####

For more information, please click here

Contacts:
Kate McAlpine

734-763-4386

Copyright © University of Michigan

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

The newest paper titled "Margination Propensity of Vascular-Targeted Spheres from Blood Flow in a Microfluidic Model of Human Microvessels" is published online at:

The Cell Adhesion and Drug Delivery Lab:

Related News Press

News and information

University of Manchester selects Anasys AFM-IR for coatings and corrosion research July 30th, 2014

Nature inspires a greener way to make colorful plastics July 30th, 2014

Analytical solutions from Malvern Instruments support University of Wisconsin-Milwaukee researchers in understanding environmental effects of nanomaterials July 30th, 2014

FEI Unveils New Solutions for Faster Time-to-Analysis in Metals Research July 30th, 2014

Govt.-Legislation/Regulation/Funding/Policy

Nature inspires a greener way to make colorful plastics July 30th, 2014

Tough foam from tiny sheets: Rice University lab uses atom-thick materials to make ultralight foam July 29th, 2014

A new way to make microstructured surfaces: Method can produce strong, lightweight materials with specific surface properties July 29th, 2014

Seeing is bead-lieving: Rice University scientists create model 'bead-spring' chains with tunable properties July 28th, 2014

Nanomedicine

Zenosense, Inc. July 29th, 2014

Optimum inertial design for self-propulsion: A new study investigates the effects of small but finite inertia on the propulsion of micro and nano-scale swimming machines July 29th, 2014

FEI adds Phase Plate Technology and Titan Halo TEM to its Structural Biology Product Portfolio: New solutions provide the high-quality imaging and contrast necessary to analyze the 3D structure of molecules and molecular complexes July 28th, 2014

New imaging agent provides better picture of the gut July 25th, 2014

Discoveries

Flexible Metamaterial Absorbers July 29th, 2014

Zenosense, Inc. July 29th, 2014

Optimum inertial design for self-propulsion: A new study investigates the effects of small but finite inertia on the propulsion of micro and nano-scale swimming machines July 29th, 2014

A new way to make microstructured surfaces: Method can produce strong, lightweight materials with specific surface properties July 29th, 2014

Announcements

University of Manchester selects Anasys AFM-IR for coatings and corrosion research July 30th, 2014

Nature inspires a greener way to make colorful plastics July 30th, 2014

Analytical solutions from Malvern Instruments support University of Wisconsin-Milwaukee researchers in understanding environmental effects of nanomaterials July 30th, 2014

FEI Unveils New Solutions for Faster Time-to-Analysis in Metals Research July 30th, 2014

Safety-Nanoparticles/Risk management

Analytical solutions from Malvern Instruments support University of Wisconsin-Milwaukee researchers in understanding environmental effects of nanomaterials July 30th, 2014

NNCO Announces an Interactive Webinar: Progress Review on the Coordinated Implementation of the National Nanotechnology Initiative 2011 Environmental, Health, and Safety Research Strategy July 23rd, 2014

Development of an interactive tool for the implementation of environmental legislation for nanoparticles manufacturers July 4th, 2014

FDA issues guidance on use of nanotechnology in foods July 1st, 2014

Grants/Awards/Scholarships/Gifts/Contests/Honors/Records

New imaging agent provides better picture of the gut July 25th, 2014

Hysitron is Awarded TWO R&D 100 Awards for Highly Innovative Technology Developments in the Areas of Extreme Environments and Biological Mechanical Property Testing July 23rd, 2014

Researchers create vaccine for dust-mite allergies Main Page Content: Vaccine reduced lung inflammation to allergens in lab and animal tests July 22nd, 2014

EPFL Research on the use of AFM based nanoscale IR spectroscopy for the study of single amyloid molecules wins poster competition at Swiss Physics Society meeting July 22nd, 2014

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE