Polymer patches to ferry drugs, help in cancer diagnosis

November 7th, 2008 - 12:25 pm ICT by IANS  

Washington, Nov 7 (IANS) Human cells with tiny ‘backpacks’ could deliver chemotherapy agents, diagnose tumours or become building blocks for tissue engineering.Michael Rubner, director, Massachusetts Institute of Technology (MIT) Centre for Materials Science and Engineering and co-author of the study, said this is the first time anyone has attached such a synthetic patch to a cell.

The polymer backpacks allow researchers to use cells to ferry tiny cargoes and manipulate their movements using magnetic fields. Since each patch covers only a small portion of cell surface, it does not hamper its normal functions.

“The goal is to perturb the cell as little as possible,” said Robert Cohen, professor of chemical engineering at MIT and a co-author of the paper.

The researchers worked with B and T cells, two types of immune cells that can home on to various tissues in the body, including tumours, infection sites, and lymphoid tissues - a trait that could be exploited to achieve targeted drug or vaccine delivery.

“The idea is that we use cells as vectors (vehicles) to carry materials to tumours, infection sites or other tissue sites,” said Darrell Irvine, a co-author and MIT associate professor of materials science and engineering and biological engineering.

Cellular backpacks carrying chemotherapy agents could target tumour cells, while cells equipped with patches carrying imaging agents could help identify tumours by binding to protein markers expressed by cancer cells.

Another possible application is in tissue engineering. Patches could be designed that allow researchers to align cells in a certain pattern, eliminating the need for a tissue scaffold, according to MIT release.

The polymer patch system consists of three layers, each with a different function, stacked onto a surface. The bottom layer tethers the polymer to the surface, the middle layer contains the payload, and the top layer serves as a “hook” that catches and binds cells.

Once the layers are set up, cells enter the system and flow across the surface, getting stuck on the polymer hooks. The patch is then detached from the surface by simply lowering the temperature, and the cells float away, with backpacks attached.

These results were published online in Nano Letters Wednesday.

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