Inorganic fluorescent nanoprobes for cellular and subcellular imaging

Abstract The imaging of essential events and physiological states at cellular and subcellular levels plays key roles in studies of biological mechanism and applications of clinical diagnostics. Fluorescent imaging is a powerful technique for cell imaging due to its unique advantages. However, traditional fluorescent dye probes for imaging face significant challenges in investigating spatiotemporal dynamics of molecules or biological structures in cells. With the rapid development of nanotechnology, inorganic nanoparticle (NP)-based fluorescent probes are being constructed and show great improvements in photophysical properties and bioavailability, which enable more sensitive, longer-term imaging in cells. This review introduces several types of inorganic fluorescent nanoprobe, including dye-containing silica NPs, quantum dots, metal nanoclusters and upconversion NPs, and then discusses the cellular uptake process and applications of these nanoprobes for cellular and subcellular imaging. We also cover the ongoing challenges of NPs in clinical applications.