Decorated cellulose surfaces : opportunities for novel, sustainable ingredients for formulated products and tissue engineering scaffolds

• Main Author: Courtenay, James
• Other Authors: Scott, Janet ; Edler, Karen ; Sharma, Ram
• Published: University of Bath 2019
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.767611

Current demand for donor organs and tissues for transplantation vastly surpasses availability. To address this, tissue engineering is a rapidly advancing field, with much research directed towards the production of new biomaterial scaffolds, from sustainable and economically viable sources, with tailored properties to generate functional tissue for specific applications. Herein, a family of diverse cellulose scaffolds, with novel decorated surfaces, were developed through simple, robust and scalable chemical modifications, with the aim to facilitate cellular attachment and further tune, or regulate, cell response in tissue culture applications. Two-component systems (cell and scaffold) were achieved using 2D cellulose films derivitised with glycidyl trimethylammonium chloride, introducing a positive surface charge, which facilitated cellular attachment comparable to tissue culture plastic, without the addition of foetal bovine serum or other ligands. Surface properties were characterised and scaffold-cell interactions revealed that initial attachment was governed by electrostatic interactions between cellulose bearing a positive charge and the negatively charge phospholipid bilayer of the cell membrane. Micropatterned surfaces with cationic cellulose 'islands' were produced using reactive inkjet printing and cells shown to preferentially attach to these islands, thus demonstrating directed cell attachment. Crosslinking with glyoxal had the dual effect of enhancing cellular response, by increasing the cell microenvironment stiffness, and scaffold robustness, enabling more complex 3D structures to be produced. Applying this chemical modification to cellulose fibres resulted in dispersible cationic cellulose nanofibrils (CCNF), which led to the formation of hydrogels. The fundamental form and dimensions of the CCNF were probed and interfibrillar interactions, leading to gelation, investigated. Directionally freezing these hydrogels, followed by lyophilisation, produced 3D porous foams. Internal architectures were produced ranging from aligned smooth walled micro-channels, mimicking vascularised tissue, to pumice-like wall textures, reminiscent of porous bone. These exquisitely structured, yet robust foams, could provide biomaterial scaffolds suitable for industrial applications that require 3D cell culturing.