Controllability, antiproliferative activity, Ag⁺ release, and flow behavior of silver nanoparticles deposited onto cellulose nanocrystals

Silver nanoparticles (AgNPs)/carboxylated cellulose nanocrystals (Ag-cCNC) from Eucalyptus pulp were prepared using a three-step process. The cCNC were synthesized by oxidation of CNC from Eucalyptus pulp with ammonium persulfate, followed by a hydrothermal reaction to form Ag-cCNC. The Ag-cCNC was then characterized with respect to Ag⁺ release, flow behavior, and anticancer activity for potential applications in biomedicine and drug delivery. AgNPs with particle sizes in the range of 16.25 ± 7.83 to 21.84 ± 7.21 nm were uniformly embedded on the surface of the cCNC. The Ag-cCNC exhibited a slow and controllable release of Ag⁺ at a rate of 0.02 % per day for 28 days. Ag⁺ release was best described by the Korsmeyer-Peppas model based on non-Fickian diffusion. The Ag-cCNC at 200 μg/mL exerted antiproliferative activity in MCF-7 human breast cancer cells with 1.01 % ± 0.35 % cell viability and was non-toxic against normal Vero cells with 90 % viability. In contrast, the chemotherapeutic drug melphalan exhibited cytotoxic effects against both MCF-7 and Vero cells. The Ag-cCNC samples showed shear thinning properties with a pseudoplastic fluid behavior, indicating that Ag-cCNCs are suitable for drug delivery by injection.