Abstract: The present disclosure is directed to optical probes. An optical probe can include a plasmonic core, a buffer layer on the plasmonic core, and a composite shell comprising a fluorophore embedded in a transparent metal oxide matrix. An optical probe can include a plasmonic core, a transparent shell encapsulating the core, and a plurality of Raman dyes proximate to the core and embedded in the transparent shell. An optical probe can include a plasmonic core comprising a nanoparticle; and a plurality of secondary nanoparticles proximate to the plasmonic core selected to provide plasmonic coupling to the plasmonic core by charge transfer. The optical probes can be useful in various detection systems, for example paper-based lateral flow strip assemblies, particularly where it is necessary to detect low levels of an analyte.

Abstract: A first embodiment is a quantum dot-DNA-metallic ensemble that can be used as a fluorescent nanosensor for multiplexed detection of the presence and the quantity of one or more target ions in a single assay. In this design, DNA-functionalized multi-colored quantum dots are used as energy donors and god nanoparticles are used as energy acceptors. This design allows for flexibility and a selective binding of a target ion to oligonucleotides, drives the formation of DNA helixes, which bring a quantum dot and metallic nanoparticle into close proximity, leading to a fluorescence emission energy transfer. The energy transfer is detected and the presence and the quantity of the target ion can be confirmed.

Abstract: The present invention details a nanostructured electrochemical biosensor based on aptamer as the molecular recognition probe. The biosensor is comprised of an electrochemical cell that can be plugged into an electric controller. This electrochemical biosensor contains a working electrode made of the micro-/nano-scale gold dot array pattern, on which aptamer is immobilized on the surface of the dot array as the molecular recognition probe. The aptamer is labeled with an electrochemical indicator. Reversible binding of an analyte to the aptamer causes the change in the conformation of aptamer, consequently brings the electrochemical indicator close to the electrode surface. This results in the electron transfer from the electrochemical indicator to the electrode, which can be read as a change in output current or potential.