Microneedle ArrayEncapsulated with Programmed DNAHydrogels for Rapidly Sampling and Sensitively Sensing of SpecificMicroRNA in Dermal Interstitial Fluid

Author: Please verify that the changes made to improve the English still retain your original meaning.Detection of microRNA (miRNA) in dermal interstitial fluid (ISF) has emerged as clinically useful in health status monitoring. However, it remains a great challenge owing to the difficult sampling and low abundance. Here, we report a DNA hydrogel microneedles (MNs) array to realize rapid enrichment and sensitive detection of miRNA in ISF. The MNs' patch consists of methacrylate hyaluronic acid (MeHA) equipped with a smart DNA circuit hydrogels' system (MeHA/DNA), in which an appropriate miRNA input enables triggering a cascading toehold-mediated DNA displacement reaction to catalytically cleave cross-linking points to generate amplified fluorescence (FL) for miRNA detection. The MeHA/DNA-MNs patch with high mechanical strength can extract adequate ISF in a short time (0.97 ± 0.2 mg in 5 min) in vivo because of its supreme water affinity. Additionally, the cascading toehold-mediated DNA displacement signal amplification reaction allows for sensitive detection of the low-abundant miRNAs down to 241.56 pM. The DNA hydrogels' MNs present potential for minimally invasive personalized diagnosis and real-time health monitoring in clinical applications.