Image: The microfluidic chip developed to detect proteins (Photo courtesy of National Chung Cheng University).
A compact microfluidic chip with integrated impedance biosensor for protein pre-concentration and detection has been developed.
The new technology can detect tumor markers in the bloodstream of cancer patients when they are still in the early stages of the disease. Furthermore, cancer screening in general hospitals usually takes at least one day to test different bodily substances, while the chip requires just five microliters of blood or urine.
Scientists at the National Chung Cheng University (Chiayi, Taiwan) have developed a low-cost, compact biochip is designed and fabricated for protein detection. Nanofractures formed by self-assembled gold nanoparticles at junction gaps are applied for ion enrichment and depletion to create a trapping zone when electroosmotic flow occurs in microchannels.
An impedance measurement module is implemented based on the lock-in amplifier technique to measure the impedance change during antibody growth on the gold electrodes, which is caused by trapped proteins in the detection region. The impedance measurement results confirm the presence of trapped proteins. Distinguishable impedance profiles measured at frequencies in the range of 10–100 kHz, for the detection area taken before and after the presence of proteins validate the performance of the proposed system. The chip works at a low voltage of about 36 volts, so that it can use general-purpose batteries or household electricity to analyze the sample.
Chun-Ping Jen, PhD, the leading study author, said, “People with cancer have some specific proteins in their bodies, which are called tumor markers. However, the proteins cannot usually be detected until they are in a large concentration during the middle and later stages of cancer. The chip, which took five years to develop, will be fitted into a handheld medical device than can also be used in the detection of other diseases. The study was originally published in the September 2018 issue of the journal Biomicrofluidics.
National Chung Cheng University