3d-printed-porous-cellulose-nanocomposite-hydrogel-scaffolds

3D Printed Porous Cellulose Nanocomposite Hydrogel Scaffolds

This work demonstrates the use of three-dimensional (3D) printing to produce porous cubic scaffolds using cellulose nanocomposite hydrogel ink, with ...

Stockholm University

Porous and non-porous cellulose acetate (CA) - cellulose nanocrystal (CNC) electrospun nanocomposite fibers and electrosprayed-electrospun composite membranes were fabricated using two different binary solvent systems. To evaluate the expression of CNC as the active entity in the membrane, dye adsorption studies were carried out using Victoria Blue. To overcome the low surface area of thick porous fibers, a porous electrosprayed-electrospun composite has developed which exhibited 98% dye removal compared to non-porous counterparts (67.9%). The porous membrane with CNC showed an increase of 38mV in surface zeta potential compared to 9mV increases in the case of the nonporous membrane and after the dye adsorption, it maintained the negative charge, indicating that further adsorption is feasible. Moreover, the mechanical properties of porous fibers were found to be ten-fold better than that of nonporous fibers. Creating porous CA-CNC composites is demonstrated as a tool for ensuring better exposure of active materials during the adsorption reaction.

Porous composite membranes based on cellulose acetate and cellulose nanocrystals via electrospinning and electrospraying.

3-Dimensional (3D) printing provides a unique methodology for the customization of biomedical scaffolds with respect to size, shape, pore structure and pore orientation useful for tissue repair and regeneration. 3D printing was used to fabricate fully bio-based porous scaffolds of a double crosslinked interpenetrating polymer network (IPN) from a hydrogel ink of sodium alginate and gelatin (SA/G) reinforced with cellulose nanocrystals (CNCs). CNCs provided favorable rheological properties required for 3D printing. The 3D printed scaffolds were crosslinked sequentially via covalent and ionic reactions resulting in dimensionally stable hydrogel scaffolds with pore sizes of 80-2125 μm and nanoscaled pore wall roughness (visible from scanning electron microscopy) favorable for cell interaction. The 2D wide angle X-ray scattering studies showed that the nanocrystals orient preferably in the printing direction; the degree of orientation varied between 61-76%. The 3D printing pathways were optimised successfully to achieve 3-dimensional scaffolds (Z axis up to 20 mm) with uniform as well as gradient pore structures. This study demonstrates the potential of 3D printing in developing bio-based scaffolds with controlled pore sizes, gradient pore structures and alignment of nanocrystals for optimal tissue regeneration.

3D printed scaffolds with gradient porosity based on a cellulose nanocrystal hydrogel.

Ultrathin graphene oxide (GO) layer was fabricated on cellulose nanofiber (CNF) membrane to achieve robust crosslinker free layered membrane with synergistic water flux and separation performance. Unlike pristine cellulosic or GO membranes, GO-CNF hybrid membranes exhibited significantly improved mechanical stability in both dry and wet states. All membranes showed negative surface zeta potential. GO: CNF membrane (1:100) exhibited significantly high water flux (18,123 ± 574 Lm h bar); higher than that of CNF membrane or the hydrophilic commercial reference membrane with comparable pore structure (Nylon 66, 0.2 μm). We hypothyse that a unique surface structure of "standing inserted GO nanosheets" observed at low concentrations of GO contributes enormously to its ultrafast water permeability through creation of numerous water transport nanochannels. The aniosptropic layered membranes exhibited >90% rejection of positively and negatively charged dyes through a combination of electrostatic interaction, hydrophobic interactions and molecular size exclusion. Construction of an ultrathin GO layer on CNF offers a unique and efficient way to prepare highly functional, economical and scalable water purification membranes having significant advantage with respect to flux, mechanical stability and rejection of dyes compared to isotropic membrane with GO nanosheets randomly dispersed in the cellulose nanofibrous network.

Article	Year
Porous composite membranes based on cellulose acetate and cellulose nanocrystals via electrospinning and electrospraying. Carbohydrate polymers\| PubMed ID: 28917850	2017
3D printed scaffolds with gradient porosity based on a cellulose nanocrystal hydrogel. Nanoscale\| PubMed ID: 29451572	2018
Mechanically robust high flux graphene oxide - nanocellulose membranes for dye removal from water. Journal of hazardous materials\| PubMed ID: 30875575	2019

Aji P. Mathew

Biography

JoVE Journal Publications

Other Publications