Biomimetic toolkit: Amino acids as modifiers for tunable cellulose nanofibril morphology

Cellulose, the most abundant biopolymer on Earth, is a premier, sustainable building block for advanced materials, prized for its renewability, low cost, and exceptional mechanical properties across various fields, including biomedicine and environmental remediation. However, achieving its full potential often demands the introduction of new functionalities—such as enhanced reactivity or tailored surface charges—through chemical modification. Herein, we present a groundbreaking, biomimetic reaction strategy for the tunable modification of cellulose nanofibrils (CNF) using amino acids as auxiliary reagents. This approach skillfully mimics nature's highly efficient functionalization pathways, enabling the simultaneous grafting of selective functional groups onto the CNF surface and the precise morphological tailoring of the fibrils. Transmission electron microscopy (TEM) analysis reveals that the chemical identity of the amino acid—specifically, imidazole- and guanidinium-bearing residues—drives distinct morphological transformations, yielding unique fibrillar topographies. Crucially, these morphology variations directly correlate with altered accessible surface areas, surface chemistries, and ionic interaction potentials. By selecting the appropriate amino acid mediators, we establish a rational design paradigm for creating CNF-based materials with customized morphology for specific applications. This work opens new avenues for developing advanced cellulose-based systems, particularly in environmental remediation, where superior control over surface functionality and morphology is essential for efficient pollutant capture and catalytic activity.

Dr. Daniel José da Silva is a Materials Engineer holding dual B.S. degrees (Materials Engineering, Science & Technology) from UFABC and a Ph.D. from the University of São Paulo, Brazil. His expertise features applied surface sciences and the development of functionalized polymers. Dr. da Silva is currently a postdoctoral researcher at Palacký University Olomouc (Czech Republic), leveraging nanostructured polymer systems from biomass for water remediation. This work is supported by his competitive MSCA-OP JAK grant (No. 22_010/0008685–01, Nano4Water), which aims to translate nanotechnology to solutions for environmental cleanup.