A versatile new paradigm for the design of optical nanosensors based on enzyme‐mediated detachment of labelled‐reporters from hybrid nanoparticles: The example of urea detection
Antoni Llopis-Lorente, Reynaldo Villalonga, Maria Dolores Marcos, Ramón Martínez-Máñez, Félix Sancenon
Chemistry A European Journal
Here we present a novel bio‐inspired nanoarchitectonics approach for the design of optical probes. It is based on nanodevices that combine (i) an enzymatic receptor subunit, (ii) a signalling subunit (consisting of a labelled‐reporter attached to a silica surface), and (iii) a mechanism of communication between the two sites founded on the production of chemical messengers by the enzymatic subunit that induces the detachment of the reporter molecules from the silica surface. As a proof of concept, a urea nanosensor based on the release of Alexa Fluor 647‐labelled oligonucleotide from enzyme‐functionalized Janus Au‐MSNPs (gold‐mesoporous silica nanoparticles) has been developed. Janus Au‐MSNPs are functionalized on the silica face with amino groups to which the labelled oligonucleotide is attached by electrostatic interactions, whereas the gold face is used for grafting the urease enzyme. The nanodevice is able to release fluorescent‐oligonucleotide via enzyme‐mediated hydrolysis of urea to ammonia and the subsequent deprotonation of amino groups on the silica face. This simple nanodevice has been applied for the flurorimetric detection of urea in real human blood samples and for the identification of adulterated milk. Given the large variety of enzymes and reporter species that could be combined, we believe this is a general new paradigm that could applied to the design of a number of optical probes for the detection of target analytes.
Fluorescence, Nanostructures, Sensors, Chemical stability, Materials