Sensitive Detection of Biomarker Using Multifunctional Aptamer-Modified Fluorescent E. coli O157:H7
TL;DR
Low-abundance PSA analysis may expand the utility of PSA in female-related diseases, as a small-scale clinical study illustrated that the serum PSA levels were significantly elevated in patients with polycystic ovary syndrome compared to healthy controls.
Abstract
Highly sensitive quantification of biomarkers is essential for disease diagnosis, treatment monitoring, and prognosis evaluation. Recently, nanomaterial-based immunosensors have attracted increasing attention due to their high sensitivity. However, the preparation of nanomaterials is often complex, costly, and environmentally unfriendly. Here, we employed Escherichia coli O157:H7 as a nanoreporting probe, leveraging its dyeable genomic DNA to achieve direct signal amplification of target biomarkers. A multifunctional hairpin-shaped aptamer was designed to convert the target into measurable fluorescence signals from E. coli O157:H7 through bispecific binding and allosteric effects of the aptamer. Under optimized conditions, the E. coli O157:H7-based biosensor could detect 0.05 pg/mL prostate-specific antigen (PSA), with a linear relationship ranging from 0.1 to 50 pg/mL (correlation coefficient R2 = 0.988). The method also demonstrated excellent specificity and recovery rates (93–107%), confirming its applicability for real-sample detection. A small-scale clinical study illustrated that the serum PSA levels were significantly elevated in patients with polycystic ovary syndrome compared to healthy controls. Hence, low-abundance PSA analysis may expand the utility of PSA in female-related diseases.