A universal dual-readout viscosity flow sensor based on biotarget-triggered hyaluronidase release from aptamer-capped metal-organic frameworks

Abstract

Paper-based sensors are particularly appealing for on-site detection owing to the avoidance of expensive and complex instruments. A dual-readout viscosity flow sensor based on biotarget-triggered hyaluronidase (HAase) release from aptamer-capped metal-organic frameworks (MOFs) was designed for on-site detection. The aptamer-capped MOFs (HAase@MOF) were fabricated using UiO-67-NH2 as a nanocarrier for HAase and the double-stranded DNA (dsDNA) as a gatekeeper. The dsDNA structure of HAase@MOF was unlocked to release HAase in the presence of the target; thus, HAase hydrolyzed the hyaluronic acid hydrogel, changing the viscosity and acidity. The reaction solutions were pipetted onto the pH paper strips and the changes in the diffusion distance and the color signal were used to quantify the biotarget concentration. In this context, cytochrome c (cyt c) was selected as the model biotarget. The proposed sensor exhibited excellent specificity and reproducibility for detection of cyt c in human serum and bacterial biofilms. Overall, this study provides a low-cost, rapid workflow, and simple method for biotarget detection with dual-readout signal. Notably, other biotargets could be detected via directly changing the capping dsDNA structure of the MOFs. Thus, the dual-readout viscosity flow sensor possesses great promising in developing commercial products for on-site detection and sensing.