Simultaneous Visualization and Quantitation of Multiple Steroid Hormones Based on Signal‐Amplified Biosensing with Duplex Molecular Recognition

Abstract The simultaneous quantitation of multiple steroid hormones in real time is of great importance in medical diagnosis. In this study, a portable hormone biosensor based on duplex molecular recognition coupled with a signal‐amplified substrate was successfully developed for the simultaneous visualization and quantitation of multiple steroid hormones. Aptamer‐functionalized upconversion nanoparticles (UCNPs) with different emission peaks are immobilized on the photonic crystal (PC) substrate as the nanoprobes, leading to the specific and simultaneous assay of multiple steroid hormones. Coupled with the luminescence‐enhanced effect of the PC substrate, nanomolar quantification limits of multiple hormones are achieved. This well‐designed biosensor is also promising in the quantification of multiple hormones in serum samples. The amplified luminescence signals can be visualized with the naked eye and captured by an unmodified phone camera. This hormone quantitation biosensor exhibits the advantages of multi‐detection, visualization, high sensitivity, and selectivity for potential applications in clinical disease diagnosis.