traffick

Researchers have developed a new type of nanoparticle that can be
delivered orally. (Source: MIT)

Drugs delivered by nanoparticles hold promise for targeted treatment ... However, the particles have to be injected into patients, which has limited their usefulness so far.

Now, researchers from the Massachusetts Institute of Technology (MIT) and Brigham and Women’s Hospital (BWH) have developed a new type of nanoparticle that can be delivered orally and absorbed through the digestive tract, allowing patients to simply take a pill …The new nanoparticles are coated with antibodies that act as a key to unlock receptors found on the surfaces of cells that line the intestine, allowing the nanoparticles to break through the intestinal walls and enter the bloodstream.

 “The key challenge is how to make a nanoparticle get through this barrier of cells. Whenever cells want to form a barrier, they make these attachments from cell to cell, analogous to a brick wall Farokhzad said.

Researchers have previously tried to break through this wall by temporarily disrupting the tight junctions To build nanoparticles that can selectively break through the barrier, the researchers took advantage of previous work that revealed how babies absorb antibodies from their mothers’ milk, boosting their own immune defenses. Those antibodies grab onto a cell surface receptor called the FcRN, granting them access through the cells of the intestinal lining into adjacent blood vessels.

The researchers coated their nanoparticles with Fc proteins—the part of the antibody that binds to the FcRN receptor, which is also found in adult intestinal cells. “It illustrates that we can use these receptors to traffic nanoparticles that could contain pretty much anything. Any molecule that has difficulty crossing the barrier could be loaded in the nanoparticle and trafficked across,” Karnik said. .. including designing nanoparticles that can cross other barriers, such as the blood-brain barrier, which prevents many drugs from reaching the brain.

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Date: December 2, 2013

Source: MIT

Drug Delivery: Why Gold Nanoparticles Can Penetrate Cell Walls

Aug. 22, 2013 — Cells are very good at protecting their precious contents -- and as a result, it's very difficult to penetrate their membrane walls to deliver drugs, nutrients or biosensors without damaging or destroying the cell. One effective way of doing so, discovered in 2008, is to use nanoparticles of pure gold, coated with a thin layer of a special polymer. But nobody knew exactly why this combination worked so well, or how it made it through the cell wall.

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Now, researchers at MIT and the Ecole Polytechnique de Lausanne in Switzerland have figured out how the process works, and the limits on the sizes of particles that can be used. Their analysis appears in the journal Nano Letters,  by Reid Van Lehn,

Until now, says Van Lehn, the paper's lead author, "the mechanism was unknown. … In this work, we wanted to simplify the process and understand the forces" that allow gold nanoparticles to penetrate cell walls without permanently damaging the membranes or rupturing the cells.there is a limit concerning threshold  that depends on the composition of the particle's coating.

The coating applied to the gold particles consists of a mix of hydrophobic and hydrophilic components that form a monolayer -- a just one molecule thick -- on the particle's surface.

Since the nanoparticles themselves are completely coated, and shaped in such a way that allows the nanoparticles to pass through the membrane and than  seal the opening as soon as the particle has passed. "They would go through without allowing even small molecules to leak through behind them," Van Lehn says.

Irvine says that his lab is also interested in harnessing this cell-penetrating mechanism as a way of delivering drugs to the cell's interior, by binding them to the surface coating material. One important step in making that a useful process, he says, is finding ways to allow the nanoparticle coatings to be selective about what types of cells they attach to including  biosensing molecules on or into certain cells, Van Lehn says. In this way, scientists could detect or monitor specific biochemical markers including a person’s brainwaves