Biochip enables fast diagnosis of many diseases

In its Zurich research laboratory, IBM has developed a point-of-care diagnostic test device based on a silicon chip. A single device can detect up to sixteen pathogens, and it does this faster and with less material than conventional lab-on-chip devices. According to the researchers, the device is fabricated using largely the same process steps as for conventional semiconductor devices. The substrate material is silicon with a silicon dioxide passivation layer, on top of which a polymer layer is deposited to hold the indicator proteins.

The chip, which measures 1 × 5 cm, uses capillary forces to ingest the sample medium, which could be a patient's blood or a serum. It contains sets of micrometer-width channels that are filled by the sample medium in approximately 15 seconds, several times faster then traditional diagnostic devices. The filling speed can also be adjusted to several minutes if the chip needs additional time to read a more complex disease marker.

IBM claims its device needs much less sample fluid than other biochips – only 7 picolitres – and it provides results in less than one minute. According to IBM, this makes it ideal for emergency use, especially in situations where a patient's health condition can occur or deteriorate rapidly and the physician need a fast diagnosis. One example is cardiovascular disease, which is still one of the most frequent causes of death.

Depending on which indicator antibody proteins are used, the device can also detect a very broad range of bacterial and viral infections as well as markers for cancer or swine flu. It could also be used to test for chemical and biological hazards, the company said.

A sensor similar to the CMOS or CCD imaging sensors used in digital cameras is used to read out the results. To enable disposable use while keeping the device price low, the sensor is incorporated in a separate readout device instead of being integrated with the biochip.

IBM is collaborating with the Belgian firm Coris BioConcept (Gembloux, Belgium) to commercialise the biochip.