Work

Super‐Resolving Particle Diffusion Heterogeneity in Porous Hydrogels via High‐Speed 3D Active‐Feedback Single‐Particle Tracking Microscopy

Year: 2025

Type: article

Abstract: Nanoparticle diffusion in 3D porous structures is critical to understanding natural and synthetic systems but remains underexplored due to limitations in traditional microscopy methods. Here, we use 3D Single-Molecule Active-feedback Real-time Tracking (3D-SMART) microscopy to resolve nanoparticle dynamics in agarose gels with unprecedented spatiotemporal resolution. We highlight 'hopping diffusion', where particles intermittently escape confinement pockets, providing insights into hydrogel microstructure. Long, highly sampled trajectories enable extraction of kinetic parameters, confinement sizes, and thermodynamic barriers. This study demonstrates 3D-SMART's ability to probe particle-environment interactions at super-resolution (~10 nm in XY and ~30 nm in Z) in 3D, offering new perspectives on nanoparticle diffusion and the structural dynamics of porous materials, with implications for drug delivery, material science, and biological systems.

Source: Small

DOI: 10.1002/smll.202505319

Authors: Yuxin Lin, Haoting Lin, Kevin D. Welsher

Institution: Duke University

Language: English

Topic: Advanced Fluorescence Microscopy Techniques

Subfield: Biophysics

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: green

Funder: National Institute of General Medical Sciences

Award: G80269827