High-resolution study of garlic and agave cellulose nanoparticles crystalline structures using transmission electron microscopy (TEM)

Currently, the use of high-resolution microscopic techniques has become popular due to their accessibility and accuracy in the information obtained from a micrograph. Transmission Electron Microscopy (TEM) can achieve nanometric spatial resolution, and further, elucidate the crystalline structure of a material such as cellulose nanoparticles (CNP). The objective of this work was the molecular characterization of the crystalline structure of CNP obtained from garlic and agave residues. Gatan microscopy (GM3), ImageJ, and CrystalOgraph software were used to analyze TEM images, measure distances (d₁, d₂, d₃), angles (α, β, γ) and simulate their respective cellulose allotropes. CNP sizes were smaller for garlic than agave, and a triclinic structure (Iα) exists for garlic CNP but a monoclinic (Iβ) one for agave CNP. The crystallographic study by TEM allows the elucidation of crystal structures with enough precision using only an image, and it provides insight into molecular arrangements in biological material that are rarely studied. Graphic abstract: [Figure not available: see fulltext.].