Singapore, May 12, 2008: Scientists at Institute of Bioengineering and Nano Technology (IBN) have succeeded in developing an all-in-one rapid gene diagnosis device that integrates biological sample preparation with polymerase chain reaction (PCR) on a chip.

 

Using this device, the IBN research team led by senior research scientist Dr Juergen Pipper achieved miniaturized PCR gene detection in only 17 minutes, which is radically faster than conventional laboratory methods, a prepared release by the company said.

 

The release said PCR involves multiple cyclical processes of heating and cooling called thermocycling. It is widely used in molecular biology to amplify small amounts of DNA in a biological sample for a wide variety of clinical and medical diagnostic applications. Conventional PCR requires hours due to the fairly high thermal mass of the PCR thermocyclers, tube materials that are low conductors of heat and large PCR volumes. Most chips for PCR analysis reported so far also require biological samples to be prepared separately using conventional methods.

 

In contrast, IBN’s lab-on-a-chip can perform the entire process starting with an actual biological sample to completion of PCR much faster than available methods. Unlike other miniaturized approaches, IBN’s device also allows the biological sample to be introduced directly onto the chip to be prepared for PCR.

 

IBN’s integrated platform harnesses droplets containing magnetic nanoparticles to rapidly complete the entire process. A blood sample can be mixed with a droplet on the chip that contains magnetic nanoparticles. Antibodies on the surface of this droplet will bind with the specific cells to be tested in the blood. Once the blood sample is introduced to the droplet, it is prepared for PCR on the chip.

 

The droplet loaded with the magnetic nanoparticles is first moved with a permanent magnet to separate cells from the drop of blood. Next the droplet is moved along the chip to combine with washing solution in order to isolate the cellular materials to be tested. The cell contents in the droplet are then combined with enzymes and reagents for PCR. The sub-µl cellular solution in the droplet is then ready for PCR. It is manipulated through four temperature zones in cycles of 8 seconds for PCR. A fluorescence detector monitors the PCR process and indicates if and in what amount a particular gene is present.

 

Using IBN’s lab-on-a-chip, 30 cells implanted with the genetic information of a marker protein were successfully isolated from 25 µl of blood. The cells were concentrated 100 times, washed, and the gene of the marker protein was detected using real-time PCR. This entire process was completed in 17 minutes.

 

The IBN lab-on-a-chip requires no other equipment and can be easily adapted for new biochemical assay tests for diverse applications, such as medical diagnostics, food quality testing and forensics. The IBN-developed device is cheap and designed for single-use or disposable application. Its only cost arises from the tiny quantities of chemical reagents required.