Bright and photo-stable luminescent nanoparticles held great potential for bioimaging, long-term molecular tracking. Rare-earth-doped upconversion nanoparticles (UCNPs) have been recently discovered with unique properties for Stimulated Emission Depletion (STED) super-resolution microscopy imaging. However, this system strictly requires optical alignment of concentric excitation and depletion beams, resulting in cost, stability, and complicity of the system. Taking the advantage of intermediate state saturation in UCNPs, emission saturation nanoscopy has been developed as a simplified modality by using a single doughnut excitation beam. In this work, we report that the emission saturation curve of fluorescence probes can modulate the performance of multi-photon emission saturation nanoscopy. With the precise synthesis of UCNPs, we demonstrate the resolution of this new imaging approach can be improved with five parameters, including emission band, activator doping, excitation power, sensitizer doping, core-shell. This approach opens a new strategy to a simple solution for super-resolution imaging and single molecule tracking at low cost, suggesting a large scope for materials science community to improve the performance of emission saturation nanoscopy.
The rapid development of a variety of molecular contrast agents makes the multimodality bioimaging highly attractive towards higher resolution, more sensitive, informative diagnosis. The key lies in the development of facile material synthesis that allows the integration of multiple contrast agents, ideally in a way that each of the components should be logically assembled to maximize their performances. Here, we report the one-pot programmable growth of multifunctional heterogeneous nanocrystal with tunable size, shape, composition, and properties. We demonstrated a facile one-pot hot-injection method to enable the highly selectively controlled growth of different sodium lanthanide fluoride nanomaterials in either longitudinal or transversal directions with atomic scale precision. This technique allows the upconversion luminescence signal, MRI signal and x-ray signal logically integrated and optimized within one single versatile nanoplatform for multimode bioimaging. These findings suggest that the facile strategy developed here have the promising to get the desired heterogeneous nanocrystals as an all-in-one contrast agent for integrated and self-correlative multimodal bioimaging.