Bioinspired sensor chip for detection of miRNA-21 based on photonic crystals assisted cyclic enzymatic amplification method.

Cancer, as the most invasive disease in the world, has led to an increasing amount of death year by year, so it is highly desired to develop a portable device to monitor the aberrant expression of biomarker in cancer patient. Here, we present a bio-photonic periodic nanostructures sensor chip assisted cyclic enzymatic amplification method to detect miRNA-21 with a detection limit of 55 fM. By employing biocompatible polydopamine nanospheres (PDANs) and DNaseⅠto construct an target-recycling amplification process on the photonic crystals, the output fluorescence signal can be strengthened selectively and short amplification time is needed. Benefiting from the synergy of the enhancement of photonic crystals and enzymatic cycle amplification, we realize high sensitivity detection of miRNA-21 with a detection range of 1 pM-10 nM and a detection limit of about four orders of magnitudes lower than the method employs no amplification, showing an expectable prospect in the early diagnosis of cancer.