Tracking Molecular Diffusion across Biomaterials’ Interfaces Using Stimulated Raman Scattering

Abstract

The determination of molecular diffusion across biomaterial interfaces, including those involving hydrogels and tissues remains important, underpinning the understanding of a broad range of processes including, for example, drug delivery. Current techniques using Raman spectroscopy have previously been established as a method to quantify diffusion coefficients, although when using spontaneous Raman spectroscopy, the signal can be weak and dominated by interferences such as background fluorescence (including biological autofluoresence). To overcome these issues, we demonstrate the use of the stimulated Raman scattering technique to obtain measurements in soft tissue samples that have good signal-to-noise ratios and are largely free from fluorescence interference. As a model illustration of a small metabolite/drug molecule being transported through tissue, we use deuterated (d 7-) glucose and monitor the Raman C–D band in a spectroscopic region free from other Raman bands. The results show that although mass transport follows a diffusion process characterized by Fick’s laws within hydrogel matrices, more complex mechanisms appear within tissues.

Review of optical methods for noninvasive imaging of skin fibroblasts—From in vitro to ex vivo and in vivo visualization

“…Studying the diffusion of fibroblasts during early healing in vivo has not yet been conducted. However, the process of glucose diffusion into biological tissue was studied in [178], the glucose diffusion imaging technique can be adapted to study the movement of fibroblasts in living organisms. Viruses often manipulate the host fibroblasts lipid metabolism to facilitate their replication and spread [179].…”

Microbial interaction-induced siderophore dynamics lead to phenotypic differentiation of Staphylococcus aureus

“…Raman spectroscopy can be used to analyze the effects of interactions of microbial phenotypes at the molecular level (Cui et al, 2022). We collected Raman spectra representing the phenotype of SA that altered with iron levels and co-culturing with bacterial types and visualized by DAPC, as depicted in Figure 4.…”