Detection of biomarkers in complex samples is a significant health plan strategy for medical diagnosis, therapy monitoring, and health management. However, high background noise resulting from impurities and other analytes in complex samples has hampered the improvement of detection sensitivity and accuracy. Herein, an ultralow background biochip based on time-gated luminescent probes supported by photonic crystals (PCs) was successfully developed for detection of bladder cancer (BC)-related miRNA biomarkers with high sensitivity and specificity in urine samples. Coupled with the time-gated luminescence of long-lifetime luminescence probes and the luminescence-enhanced capability of PCs, the short-lived autofluorescence can be efficiently removed; thus, the detection sensitivity will be significantly improved. Benefiting from these merits, a detection limit of 26.3 fM is achieved. Furthermore, the biochip exhibits excellent performance in urinary miRNA detection, and good recoveries are also obtained. The developed biochip possesses unique properties of ultralow background and luminescence enhancement, thus offering a suitable tool for the detection of BC-related miRNA in urine. With rational design of probe sequences, the biochip holds great potential for many other biomarkers in real patient samples, making it valuable in areas such as medical diagnosis and disease evaluation.
Keywords: autofluorescence; long-lifetime luminescence; miRNA detection; photonic crystals; urine.