Whole-Bacterium SELEX Aptamer Selection of Fusobacterium nucleatum and Application to Colorectal Cancer Noninvasive Screening in Human Feces

In terms of cancer diagnoses and cancer-related deaths worldwide, colorectal cancer (CRC) is now the third most common malignancy. The drawbacks of current screening methods are their exorbitant costs, difficult procedures, and lengthy implementation timelines. The benefits of fecal screening for CRC are ease of operation, noninvasiveness, cost-effectiveness, and superior sensitivity. As a result of its enrichment in the malignant tissues and feces of CRC patients, Fusobacterium nucleatum (F. nucleatum) has emerged as a crucial biomarker for the incipient detection, identification, and prognostic prediction of CRC. Here, for the first time, the whole-bacterium SELEX method was used to screen the highly specific and affinity aptamers against F. nucleatum by 13 cycles of selection. The Apt-S-5 linear correlation equation is y = 0.7363x2.8315 (R2 = 0.9864) with a limit of detection (LOD) of 851 CFU/mL. The results of the experiment using fecal samples revealed a substantial disparity between the microorganisms in the CRC patients' feces and those in the feces of healthy individuals and were consistent with those of qPCR. The aptamers may therefore offer a crucial approach to identifying F. nucleatum and hold tremendous promise for CRC diagnosis and prognostic prediction.