The concentration of tau protein in the patient's blood ranges from 0.46-4.6 pg/μL, while our current detection limit is 1 pg/μL. It is not difficult to understand that the limit of captamer method depends on the affinity of aptamer and tau protein. At present, the dissociation constant KD of the aptamer and tau protein we use is 13nm, which is not the limit that the aptamer can reach. If we can find an aptamer with a smaller Kd value, we can measure the protein content more accurately.

        Also ,because the reaction speed is too fast and the conventional qPCR needs initialization and temperature to rise, the data will be unstable. Therefore, we hope to directionally transform the recombinant enzyme used in the reaction to make it react after 39 ℃ thermal activation, which can make the data more stable.

        In the process of studying the influencing parameters, we chose the optimum temperature of 39 ℃. However, in fact, the decrease of temperature is conducive to the blocking effect of aptamer and reduce the background signal, and the increase of temperature is conducive to tau taking the aptamer away from the template chain and signal output. Although it is not at the optimum temperature of the enzyme, the effect may be better. So we plan to study the effect of temperature on the experimental results.

        Incubation time is also a very important parameter. We do not know how long the tau protein can fully take away the aptamer on the template chain. At present, the incubation time of the experiment is very short, basically only about 5 minutes, but there are also good experimental results. We hope to study the most reasonable incubation time - the shortest but can produce the best image.

        The most promising potential of this method is that it is not limited to tau protein. Our method can detect any pair of aptamers and target proteins with efficiency. Therefore, we will test more target protein aptamer combinations later, hoping to popularize this method.

        For safety reasons, we did not use human blood samples. We used simulated serum to verify the feasibility of our method in blood. Both the Institute of Biophysics and the Affiliated Hospital of China University of science and technology have expressed interest in our subject. We will cooperate after the competition. They will use our method to detect the tau protein content of volunteers, collect data, and establish a large database of tau content to prepare for the clarification of the mechanism of AD. We believe that with the joint efforts of scientific researchers all over the world, AD will eventually be defeated.