3D Printing of Antimicrobial Alginate/Bacterial-Cellulose Composite Hydrogels by Incorporating Copper Nanostructures

Novel antimicrobial 3D printed alginate/bacterial-cellulose hydrogels with in situ synthesized copper nanostructures were developed having improved printability. Prior 3D printing, two methods were tested for the development of the alginate hydrogels: a) ionic crosslinking with calcium ions followed by an ion exchange with copper ions (Method A); and b) ionic crosslinking with copper ions (Method B). A solution containing sodium borohydride, used as reducing agent, was subsequently added to the hydrogels, producing in situ clusters of copper nanoparticles embedded in the alginate hydrogel matrix. The method used and the concentrations of copper and reducing agent were found to affect the stability of the alginate/copper hydrogels, with Method A producing more stable materials. By increasing the alginate concentration from 1 to 4 wt% and by using Method A, alginate/bacterial-cellulose/copper hydrogel structures were 3D printed having excellent printability as compared with pure alginate hydrogels. Notewort...