Reducing fluorescence interference for improved Raman spectroscopic analysis of plant cell walls

Abstract

Lignin fluorescence in plant cell walls significantly interferes with Raman spectroscopic signals, resulting in compromised analytical accuracy and resolution. To address this issue, a strategy was implemented to both reduce the absolute lignin content in samples and prepare thinner plant tissue sections. This approach involved embedding plant samples in LR White resin, complemented by an ultrathin sectioning technique. Additionally, algorithms were developed to eliminate the impact of resin spectra on the imaging process. These advancements collectively enhanced the performance of Raman spectroscopy by effectively diminishing the disruptive effects of lignin fluorescence. Further analysis with confocal laser scanning microscopy (CLSM) elucidated the presence of aggregation-induced luminescence (AIE) in plant tissues, revealing a direct correlation with lignin concentration. These findings not only offer a new perspective for the application of Raman spectroscopy in plant science, but also pave the way for advancements in tip-enhanced Raman spectroscopy (TERS) detection.