Tip-Enhanced Raman Spectroscopy of Cell Wall Heterogeneity for Aspergillus Fumigatus

TL;DR

This study applies tip-enhanced Raman spectroscopy to map and analyze the chemical heterogeneity of Aspergillus fumigatus spores' cell walls at the nanoscale, revealing detailed biochemical compositions and differences between wild-type and mutant strains.

Contribution

It demonstrates the use of TERS for detailed chemical mapping of fungal cell walls, including melanin, overcoming challenges of biological sample fragility and complex spectral interpretation.

Findings

Mapped chemical components including melanin, polysaccharides, lipids, and proteins.

Identified spectral features specific to Dihydroxynaphthalene melanin.

Compared biochemical differences between wild-type and mutant spores.

Abstract

Tip-enhanced Raman spectroscopy (TERS) enables nanoscale chemical mapping of biological structures, providing high-resolution, high-signal-to-noise ratio imaging into molecular distribution and interactions beyond the capabilities of conventional Raman imaging. However, challenges such as the deformation of fragile biological cells and the complexity of signal interpretation would increase the difficulty in investigating biological samples with TERS. Here, we demonstrate using TERS to investigate the cell wall heterogeneity of Aspergillus fumigatus spores. Using TERS imaging and spectral analysis, we map the chemical components including melanin within the fungal cell wall. The results reveal distinct spectral features associated with polysaccharides, lipids, and proteins. Furthermore, by comparing the wild-type and albino mutant spores, we illuminate the biochemical characteristics of Dihydroxynaphthalene melanin (DHN-melanin) in the fungal cell wall.