Development of a microfluidic chip for a label-free impedance biosensor
Date Issued
2011
Date
2011
Author(s)
Chang, Ku-Ning
Abstract
With the rapid development of medical technology, average life span of human has greatly increased over the years. The trend of fast approach to an aging society for most developed countries has raised the demand for better medical cares. To improve the health care, it is vital to diagnose the diseases such as cancers and cardiovascular disease in an early stage. All of which have driven the concept of point-of-care testing (POCT) to small clinics and typical families. To achieve the above-mentioned vision, many portable biosensors are to be developed. Since cardiovascular disease (CVD) induced death remains on the top 3 death causes in Taiwan over the years, we hope to develop a biosensor for the detection of CVD biomarkers. The newly developed POCT utilized biomarkers such as CRP and S100 for diagnosis.
Since typical optical biosensors have problems such as miniaturization difficulty, high cost and light alignment difficulty, etc., we adopted electrochemical methods for our biosensor development. A good biosensor developed for POCT implementation should have advantages such as small size, low cost, and ease of operation. Therefore, we miniaturized the three-electrodes onto a biochip, and combined it with microfluidics to construct a microfluidic biochip system. Here we used Cysteamine and ATP as our bio-linkers to perform the antibody-antigen interaction tests for the verifications of the microfluidic biochip’s feasibility. The proteins we used here are CRP and S100. The results showed that the change of electron transfer resistance grows linearly with the protein concentrations. The detection range was identified to be from 10 ng/ml to10 μg/ml, and the detection limit was 10ng/ml. This is two orders of magnitude lower than the concentration of a person faces a low risk of developing cardiovascular disease (AHA). Besides, we did the fluorescence test and the impedance measurement on a novel conductive linker, AS2SAc. This linker is stable and easy to preserve; therefore, we hope to improve the sensor stability by the use of the linker. From the experimental results, we found that the AS2SAc has a sufficient binding ability and a low Ret, which is suitable for the protein detection. Hence, we believe that by combining the microfluidic biochip and AS2SAc, the biosensor we developed can be very useful for POCT implementation.
Subjects
Point-of care
Microfluidic biochip
Impedance biosensor
Label-free
SDGs
Type
thesis
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