Thursday, February 12, 2009
Engineers at National Taiwan University have developed an implantable system-on-a-chip (SoC) capable of drug delivery within a living person that has shown potential for improving the effectiveness of drug therapy through precision control, according to a paper presented here Tuesday (Feb. 10) at the IEEE's International Solid State Circuits Conference.
The implantable CMOS SoC features monolithic integration of a wireless controller/actuation circuitry and a drug delivery array, according to the paper. The authors describe the device as the first of its kind.
By releasing drugs such as nonapeptide leuprolide acetate or nitroglycerin, the SoC could be used for applications such as the localized diagnosis and therapy of cancers or providing immediate treatment for heart attack victims, researchers say. The system can be implanted through minimally invasive surgery, and the wireless capability and doctors to make non-invasive therapy modification, they say.
The proposed SoC would offer lower system cost, smaller device size and lower power consumption than existing technologies, according to the paper.
The device is realized in standard 0.35-micron CMOS technology with a die size of 1.77 x 1.4mm2. Drug reservoirs within the device are fabricated by CMOS-compatible post-IC processing and addressable by an on-chip microcontroller. An on-off-keying (OOK) wireless circuit is also integrated in the same die for receiving external commands. Drugs are released into the body by the rupturing of membranes covering the drug reservoir following receipt of the wireless commands.
National Taiwan University's Yu-Jie Huang, who presented the paper on the drug-delivery SoC Tuesday, said the rupture of the membranes for drug delivery occurs by heating those membranes to the point of failure. The temperature required for this rupture to occur, about 1,500 Kelvin, is "very high," raising concerns about the exposure of human tissue that comes in contact with the device or the drug contained within.
However, the device is "not the first to use this electroactivation technique," and there is precedent for devices heated to this temperature without damage to the tissue or drug, Huang said.
So far, the device has been studied in laboratory conditions outside a living organism but has not yet been implanted within a living organism, Huang said.
By: DocMemory
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