In situ observation of molecular diffusion in solid supports using two-photon fluorescence microscopy

Area of Science:

• Materials Science
• Chemical Engineering
• Biophysics

Background:

• Understanding molecular diffusion in polymeric materials is crucial for applications in drug delivery, catalysis, and sensing.
• Polymeric solid supports, such as TentaGel beads, are widely used in various scientific fields.
• Real-time monitoring of diffusion dynamics within these supports remains a challenge.

Purpose of the Study:

• To establish two-photon fluorescence microscopy as a viable technique for observing molecular diffusion within polymeric solid supports.
• To quantify the diffusion rates of specific molecules through individual TentaGel beads.
• To investigate the heterogeneity of diffusion properties across a population of TentaGel beads.

Main Methods:

• Utilized two-photon fluorescence microscopy for real-time observation.
• Immobilized TentaGel beads onto a cover slip for stable sample preparation.
• Tracked the diffusion of Rhodamine 6G molecules through individual beads.

Main Results:

• Successfully demonstrated the capability of two-photon fluorescence microscopy to monitor molecular diffusion in real-time.
• Observed and quantified the diffusion of Rhodamine 6G through single TentaGel beads.
• Identified considerable bead-to-bead heterogeneity in diffusion rates across 40 tested beads.

Conclusions:

• Two-photon fluorescence microscopy is a powerful tool for studying diffusion in polymeric matrices.
• TentaGel beads exhibit significant variations in their diffusion properties, impacting their performance in applications.
• Further research is warranted to understand the origins of this heterogeneity and its implications.