Rapid detection of theophylline using an aptamer-based nanopore thin film sensor

Abstract

<p>This paper reports, for the first time, an aptamer-based nanopore thin film sensor for detecting the ophylline in buffer and complex fluids. In my experiments, I created the sensor and found that it could help us to better test theophylline than an antibody-based detection sensor. The following is a detailed explanation of the sensor creation and the experimental process.</p> <p>Anodic aluminum oxide (AAO) has been investigated and applied in numerous products since the 1970s. It is a highly-arrayed porous nanostructure as shown in Figure 1. The pore size normally ranges from tens to hundreds of nanometers, and the aspect ratio could be higher than 40:1. Application areas of AAO include biomedical sensing, energy storage, template-based nanofabrication, electronics, etc. In my experiment, I applied AAO to the process of creating a sensor.</p> <p>In my experiments, I chose RNA aptamer rather than antibodies because its molecules</p> <p>overcome the weakness of antibodies. The 33 nts RNA aptamer sequences used were found to recognize and selectively bind theophylline (Figure 2) [1]. Moreover, aptamers are easy to synthesize, have both excellent heat stability and a wide tolerance range of PH and salt concentration, and is much less costly than antibodies.</p> <p>The first study used an aptamer-based nanopore thin film sensor to detect theophylline in the buffer and complex fluids. I first fabricated the nanopore thin film sensors with a microfluidic interface, then demonstrated the surface functionalization procedure of the sensor. I then used optical transducing signals to detect the fringes followed by using the sensor as a reference sensor to further cancel out the non-specific binding effect; theophylline in low concentration (0.2μM), caffeine, theobromine, and plant extract were successfully detected. The experiment showed that this aptamer-based sensor had good specificity and selectivity, allowing me to further test theophylline in serum.</p> <p>The second study used an optical aptamer-based plant hormone sensor with a microfluidics capillary interface. I adopted the exact same methodology and sensor from themy first study and further designed an optical aptamer-based sensor with a microfluidics capillary interface to upgrade the testing process. Such a microfluidics capillary interface film censor was created and how my two successful experiments were performed. The research outcome is that an aptamer-based label-free sensor for optically detecting theophylline has been demonstrated for the first time. It performs much better than its competitors and has a promising future in further</p> <p>applications in similar experiments.</p>