Work

808 nm-excited upconversion single-particle imaging for long-term tracking of cargo transport in live neurons

Year: 2025

Type: article

Abstract: Upconversion nanoparticles (UCNPs) activated by 808 nm excitation hold promise for bioimaging due to minimized water absorption and tissue heating. However, their luminescence efficiency and single-particle performance in complex biological systems remain limited. Here, we present a rationally designed core-multishell UCNP structure (NaYbF 4 : x%Er@NaYF 4 : y%Yb@NaYF 4 : z%Nd, 10 %Yb@NaYF 4 ) optimized for enhanced upconversion luminescence (UCL) at the single-particle level under 808 nm excitation. By systematically tuning Er 3+ concentration in the emissive core, Yb 3+ in the energy migration shell, and Nd 3+ in the energy-harvesting layers, we achieved efficient energy spatial management. Single-particle analysis revealed power-dependent UCL saturation, with 12 % Er 3+ doping in the core, 10 % Yb 3+ doping in the migration shell, and 30 % Nd 3+ doping in the energy-harvesting layer yielding maximal brightness. These UCNPs were further surface-functionalized for live-cell imaging and enabled continuous cargo tracking in hippocampal neurons for over 30 min under 808 nm excitation. Trajectory analysis revealed hitchhiking-like transport dynamics within axons. This work highlights the potential of UCNPs for advanced biological imaging and mechanistic insights into nanoscale cargo dynamics in neurons.

Source: Journal of Luminescence

DOI: 10.1016/j.jlumin.2025.121483