2007: The Year in Technology

Electric Pulses Destroy Cancer Cells

California at Berkeley have developed a new minimally invasive method of treating cancer. Called irreversible electroporation (IRE), the process was invented by two engineers, Rafael V. Davalos of Virginia Tech and Boris Rubinsky of UC Berkeley. Electroporation is a phenomenon that increases the permeability of a cell from none, to a reversible opening, to an irreversible opening. With the latter, the cell will die. The researchers applied this irreversible concept to the targeting of cancer cells.

“IRE removes tumors by irreversibly opening tumor cells through a series of short, intense electric pulses from small electrodes placed in or around the body,” said Davalos. “This application creates permanent openings in the pores in the cells of the undesirable tissue. The openings eventually lead to the death of the cells without the use of potentially harmful chemotherapeutic drugs. We did not use any drugs, the cells were destroyed, and the vessel architecture was preserved.”

Oncologists already use a variety of methods to destroy tumors using heat or freezing processes, but these current techniques can damage healthy tissue or leave malignant cells. The difference with IRE is the ability adjust the electrical current and reliably kill the targeted cells.

“IRE shows remarkable promise as a minimally invasive, inexpensive surgical technique to treat cancer. It has the advantages that it is easy to apply, is not affected by local blood flow, and can be monitored and controlled using electrical impedance tomography,” Davalos explained.

For more information on the cancer treatment process, click here.

Self-Healing Materials Mimic Human Skin

The next generation of self-healing materials has been invented by researchers at the University of Illinois. The material mimics human skin by healing itself time after time. The new materials rely upon embedded, 3D microvascular networks that emulate biological circulatory systems. In the same manner that a cut in the skin triggers blood flow to promote healing, a crack in the new materials will trigger the flow of healing agent to repair the damage.

To create the self-healing materials, the researchers built a scaffold using a robotic deposition process called direct-write assembly. The process employs a concentrated polymeric ink, dispensed as a continuous filament, to fabricate a 3D structure, layer by layer. Once the scaffold has been produced, it is surrounded with an epoxy resin. After curing, the resin is heated and the ink, which liquefies, is extracted, leaving behind a substrate with a network of interlocking microchannels. In the final steps, the researchers deposited a brittle epoxy coating on top of the substrate, and filled the network with a liquid healing agent.

In tests, the coating and substrate were bent until a crack formed in the coating. The crack propagated through the coating until it encountered one of the fluid-filled “capillaries” at the interface of the coating and substrate. The healing agent moved from the capillary into the crack, where it interacted with catalyst particles. If the crack reopened under additional stress, the healing cycle was repeated.

Currently, the material can heal cracks in the epoxy coating — analogous to small cuts in skin. The researchers’ next step is to extend the design to where the network can heal “lacerations” that extend into the material’s substrate.

For more information on the self-healing materials, click here.