A Silver(I) Coordination Complex as a Reinforcing Antibacterial Agent for Cellulose Nanocrystal Cryogels

Cellulose nanocrystal (CNC)-based materials are promising sustainable alternatives for numerous applications, and enhancing their mechanical robustness while imparting antimicrobial activity could further broaden their utility. Here, the Ag(I) coordination complex [(ina)₂Ag]NO₃ (ina = isonicotinic acid) is introduced as a multifunctional additive for CNC materials. The complex was synthesized via a simple liquid-assisted grinding approach with full conversion and quantitative yield and incorporated into CNC suspensions under mild conditions. Its addition promotes attractive interparticle interactions, leading to a more cohesive CNC network. Consequently, the resulting cryogels exhibit a more compact morphology and a greater than 2-fold increase in compressive modulus compared to pristine CNC cryogels. In contrast, analogous systems containing AgNO₃ show negligible mechanical improvement, highlighting the importance of the coordination environment. Furthermore, CNC materials containing [(ina)₂Ag]NO₃ display broad-spectrum antimicrobial activity. These findings establish coordination compounds as multifunctional additives capable of reinforcing CNC materials while introducing non-native functionality.