We work on the wet-synthesis techniques of different type of nanoparticles: rare earth based nanoparticles (RENPs), quantum dots (i.e. CuInS2), chalcogenide nanoparticles (i.e. CuS), noble metal nanoparticles (i.e. Au nanorods).
Among the above listed nanomaterials, the RENPs are the "bread and butter" of the Vetrone Group. Primarily focusing on the thermal decomposition synthesis of RENPs (LiREF4 or NaREF4) from metal-trifluoroacetate precursors, we are constantly improving and developing new methods to obtain RENPs of various sizes, compositions, morphologies, and core/shell architectures.
We study the optical properties various nanostructures we create. Of particular interest to us are the unique photoluminescence properties of RENPs. RENPs are notorious for their ability to absorb low energy near-infrared (NIR) light and convert it to high energy UV and visible light via a process of upconversion. At the same time a downshifting process of NIR-to-NIR photoluminescence occurs. Hence RENPs under a single wavelength of excitation can cover the majority of the optical spectral range (from UV to NIR). Our research focuses on the manipulation of upconversion and downshifting processes by tailoring the chemical composition and architecture of RENPs. We try to understand the fundamentals that govern these processes, as well as how to straightforwardly harness this emission for various applications.
One of the major research lines of our group is optical nanothermometry. We explore how various nanostructures can act as photoluminescence thermometer. Different upconversion or downshifting emission bands of RENPs can serve to measure surrounding temperature in a completely contactless manner. These nanothermometers allow us to extract thermal information at the micro/nanoscale, which is pertinent for fundamental thermodynamic studies or nanoparticle application within biomedical context. The latter takes advantage of nanothermometers as diagnostic tools, or thermal control agents that help to avoid overheating of tissues during heat based treatments.
Besides fundamental interest, a major driving force in Vetrone Group behind nanoparticle research is their application in biomedicine, as potential theranostic tools for the betterment of imaging, diagnosis, and therapy. By tailoring their morphologies, composition and surface coatings we ensure water dispersibility of our nanoparticles and investigate their compatibility with live objects. Different nanoparticles are studied as photoluminescence contrast agents for deep-tissue optical biopsy, drug delivery vehicles, photothermal agents and mediators of secondary photochemical processes (i.e. energy donors in the context of photodynamic therapy of cancer).
When envisioning nanostructures for specific task in mind it is not always possible to conceive a single type of nanoparticle with all-in-one features. Yet, through surface chemistry or synthesis manipulation we can create more intricate nanoplatforms that are composed of different type of nanomaterials. For instance, in the context of photothermal therapy it can be advantageous to combine heaters with optical thermometers - Au nanorodos + RENPs - taking advantage of prominent heat generation properties of Au nanorods and those of temperature sensing of RENPs. These sort of hybrid photothermal agents provide a real-time temperature monitoring in situ, allowing to provide controlled eradication of malignant tissues and to avoid overheating and damage to the healthy ones.