Abstract: Pancreatic cancer (PC) has a high mortality rate with poor prognosis. The poor prognosis is partially due to the late detection of PC. At present, tissue biopsy, imaging, and blood testing are three major diagnostic methods for PC. Among these, blood testing is cheaper and more convenient for patients, but the sensitivity of existing blood testing tools is insufficient to screen early-stage PC patients. Now in the market, blood testing for the pancreatic cancer glycan biomarker CA 19-9 uses 1116NS19.9 antibody, but the sensitivity is challenging. Developing a high-sensitivity blood testing tool to detect early-stage PC is urgently needed. Aptamers hold promise as an alternative to antibodies and have the potential to be applied in biosensors along with the antibodies against multiple biomarkers. Here, we report an aptamer SELEX to select out aptamers which could be used in a PC aptasensor. We firstly expressed asprosin, one of the early-stage pancreatic cancer biomarkers. Then, a natural DNA aptamer SELEX was performed against asprosin. We discovered two classes of asprosin aptamer sequence. Class I was A rich sequences, which contains over 50% of A in random regions. And Class II is C rich sequences. Ten asprosin aptamer candidates showed a nanomolar level of binding to our expressed asprosin, and three candidates have high specificity and binding affinity in flow cytometry and ELONA data. Other characterization assays including electrochemical assays are ongoing. In the longer term we aim to develop these asprosin aptamers into aptasensors with potential combination with CA19-9 detection for pancreatic cancer.
