Argonne National Laboratory is reporting that its scientists have designed a novel type of biochip. Based on the polymerase chain reaction, an old technology by now (isn't it?), the lab-on-a-chip should offer rapid diagnostic testing capabilities for a variety of diagnostic needs:
The biochip system can identify infectious disease strains in less than 15 minutes when testing protein arrays and in less than two hours when testing nucleic acid arrays. The system can be used in hospitals and other laboratories as well as in the field. The technology provides a point-of-care diagnostic system that would save time and money compared to current systems, which require sending samples to a centralized lab for confirmatory diagnosis.
Each biochip has hundreds to thousands of gel drops, each about 100 microns in diameter -- 100 microns is about the width of an average human hair. A segment of a DNA strand, protein, peptide or antibody is inserted into each drop, tailoring it to recognize a specific biological agent or biochemical signature. These drops are in known positions so when a sample reacts, the reaction position can be detected, identifying the sample.
"The array of gel drops can be tailored to detect specific strains of infectious diseases or other biological organisms," said Schabacker. "Each drop can detect trace quantities of the agents for which they are specific."
The biochip can also be used to identify biological warfare agents. Easy sample preparation, standard operating protocols and a portable biochip reader that is smaller than a lunchbox make the system suitable for use in the field by first responders, military personnel and medical technicians.
The system makes use of the polymerase chain reaction (PCR), a universal method for replicating billions of copies from one piece of genetic material. PCR allows trace quantities of DNA to be replicated to a level where they can be detected in the biochip system.
A sample to be tested is applied to a biochip, which is then put in a reader and scanned using patented side illumination laser technology to detect reaction sites. Automated algorithms determine the agents present in the sample...
The biochip system also has great potential as a discovery tool. Current research aimed at the development of proteome chips has shown great promise. Proteome chips, which are biochips displaying all the proteins expressed by an organism at a specific time, provide the ability to screen for new cancer biomarkers, vaccine targets and therapeutic targets, as well as provide a means of characterizing disease states.
