Abstracts

Nanotechnology has significant promise for improving the generation of novel and beneficial imaging nanoprobes. Compared to traditional molecular-scale contrast agents, use of nanoparticles (NPs) as imaging probes has several benefits. These include: (1) high loading capacity, which allows the concentration of the imaging agent to be controlled within each nanoparticle during the synthesis process; (2) tunable surface, which may allow the contrast agent to be targeted to specific locations in the body or extend its circulation time in the blood; or (3) multimodal imaging capacities, which result from NPs' ability to combine two or more contrast properties and be used in multiple imaging techniques simultaneously.Nowadays, strong research efforts are drawn to the development of NPs with multiple capabilities (e.g., photoluminescent and magnetic resonance) because of their enormous potential to revolutionize biomedical imaging technology. A promising new class of optical contrast agents, colloidal metal semiconductor nanocrystals, or quantum dots, or QDs, have a large surface area for additional functionalization, strong resistance against photobleaching, adjustable emission colors, and broad absorption bands. Fluorescent QDs such as these can be used for in vivo imaging, but their use is limited by tissue auto-fluorescence, which causes low signal-to-noise ratios that make it difficult to identify them in biological contexts and lower contrast and clarity in the resulting image. There are several approaches to getting around this restriction. The creation of metal nanoparticles with NIR-spectrum excitation and emission is a strategy with strong potential. These innovative fluorescent labels hold great promise for bioanalysis since they combine the benefits of both QDs and NIR light. An alternative method involves incorporating transition metals, such as manganese (Mn), a chemical element that is also necessary for life, into nanocrystals. This provides the crystals with properties that are typical of phosphorescent emitters, such as longer luminescent lifetime and longer Stokes shift between excitation and emission wavelengths. Time-resolved photoluminescence (PL) studies offer the benefit of straightforwardly differentiating the luminescent emission from Mn-doped QDs from the sample's background fluorescence thanks to the ensuing phosphorescent emission. Furthermore, some of the potential doping ions—like Mn, for example—may be paramagnetic, making them good MRI contrast agents. Consequently, doping the photoluminescent nanocrystals with such components gives the QDs more MRI contrast capabilities. Because of their immense potential to revolutionize biomedical imaging technologies, research on the production of NPs with both optical and magnetic resonance functions is appealing. An overview of some of the cutting-edge research on this innovative kind of QDs for biomedical applications will be provided in this talk.