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DhITACT: DNA Hydrogel Formation by Isothermal Amplification of Complementary Target in Fluidic Channels

 

by Prof. Hyukjin Lee (hyukjin@ewha.ac.kr)

Department of Pharmaceutical Sciences, College of Pharmacy

 

 

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The recent outbreaks of Ebola and Middle East respiratory syndrome were worldwide issues. Infectious diseases such as Ebola, Middle East respiratory syndrome, and severe acute respiratory syndrome spread very quickly and easily. When outbreaks become pandemic, societies and their economies fall into chaos. It is necessary to detect these diseases early to prevent them from reaching epidemic status.


MERS, for instance, made numerous infectious people in Korea especially making second most death by infection. Major reason was lack of technique detecting disease in early period. RT-PCR is the most widely used method to diagnose infectious diseases. However, this method has multiple drawbacks. It need special equipment and skilled person due to thermal cycling. This result in high prices and electricity needs, time consuming. Therefore, this device is useless in developing countries and not easy to be portable device.
 
Here, we report a novel platform to detect viral or bacterial pathogens named as DhITACT: DNA h ydrogel formation by Iso thermal amplification of complementary targets in microfluidic channels. Unlike other detection methods, an infectious pathogen is readily detectable by human eye in DhITACT system, not requiring any equipment such as fluorescence and/or chemiluminescence analyzers. During operation of DhITACT, single-stranded (ss) RCA products are generated on the surface of microfluidic channels by the isothermal amplifycation process upon the selective binding of target nucleic acids from the biological fluids. In particular, DhITACT allows ss RCA products to self-assemble forming an in situ DNA hydrogel within the microchannels. As a result, the volume of the DNA hydrogel gradually enlarges during the incubation period, growing sufficiently large enough to block the channels.


Thus, an operator can easily tell the presence of target pathogens by observing the blockage of flow in the microfluidic array chip. Depending on the number of channels in DhITACT system, a simple on/off optical detection by the naked eye can provide multiple and simultaneous phenotyping of various infectious pathogens from the biological specimens.

Our device can be applied to numerous fields such as cancer diagnosis, animal diseases etc. We are now contacting companies for transferring our technique and commercializing DhITACT. We are always struggling to develop faster, more sensitive detection system than before and extend apply fields.
 
* Related Article
DhITACT: DNA Hydrogel Formation by Isothermal Amplification of Complementary Target in Fluidic Channels
Advanced Materials, 2015, 27(23), 3513–3517