Enhanced Cell Affinity of Chitosan Membranes Mediated by Superficial Cross-Linking: A Straightforward Method Attainable by Standard Laboratory Procedures

Abstract

It is well accepted that the surface modification of biomaterials can improve their biocompatibility. In this context, techniques like ion etching, plasma-mediated chemical functionalization, electrospinning, and contact microprinting have successfully been employed to promote the cell adhesion and proliferation of chitosan (CH) substrates. However, they prove to be time-consuming, highly dependent on environmental conditions, and/or limited to the use of expensive materials and sophisticated instruments not accessible to standard laboratories, hindering to a high extent their straightforward application. Filling this gap, this paper proposes the superficial cross-linking of CH as a much simpler and accessible means to modify its superficial properties in order to enhance its cellular affinity. CH membranes were prepared by solvent casting followed by a cross-linking step mediated by the chemical vapor deposition (CVD) of glutaraldehyde (GA). The membranes were characterized against non- and solution cross-linked membranes in terms of their mechanical/surface properties and biological performance. Among others, the CVD membranes proved (i) to be more mechanically stable against cell culture and sterilization than membranes cross-linked in solution and (ii) to prompt the adherence and sustained proliferation of healthy cells to levels even superior to commercial tissue culture plates (TCPs). Accordingly, the CVD cross-linking approach was demonstrated to be a simple and cost-effective alternative to the aforementioned conventional methods. Interestingly, this concept can also be applied to other biomaterials as long as GA (or other volatile components alike) can be employed as a cross-linker, making possible the cross-linking reaction at mild experimental conditions, neither requiring sophisticated lab implements nor using any potentially harmful procedure.

Photocrosslinked Alginate-Methacrylate Hydrogels with Modulable Mechanical Properties: Effect of the Molecular Conformation and Electron Density of the Methacrylate Reactive Group

“…Figure 5 shows the obtained stress-strain curves and the mechanical properties thereby derived. It can be observed from the curves (panel A) that all samples displayed the typical evolution of brittle materials subjected to stress, involving the elastic (ε ≤ 0.15), plastic (0.15 < ε ≤ ε F ), and fracture deformations (ε > ε F ), as described for other polysaccharide-based hydrogels [3]. In good agreement with other reports on hydrogels of similar nature [17,22], the Young's moduli of the H-ALGMx hydrogels were determined to amount to ca.…”

“…These apparently contradictory results can be understood if the fracture mechanism of crosslinked materials is analyzed. As explained in previous publications [3,41], during the elastic deformation, which is reversible, non-crosslinked chains (non-spatially restricted chains) align with the direction of the stress, compensating its effect to avoid a permanent deformation of the bulk material. If the imposed stress is maintained, then not only non-crosslinked, but hitherto motionless crosslinked chains also start to undergo spatial restructuring, up to a certain point in which a plastic deformation is reached (permanent deformation).…”

“…Hydrogels are hydrophilic networks formed upon crosslinking of polymer chains, capable of absorbing water or biological fluids while maintaining their crosslinked structure [2]. The interest in these materials, both as 2D and 3D systems, stems from the fact that they closely resemble the natural environment of cells, allowing them to replicate and unravel diverse cell-extracellular matrix (cell-ECM) interactions [3][4][5].…”

“…Hydrogels for biomedical applications can be produced from natural polysaccharides [6], such as cellulose [7], chitosan (CH) [3,4], sodium alginate (ALG) [5,8], and dextran [9], and also from some synthetic polymers such as poly(acrylamide) (PAM) [10], poly(ethylene glycol) (PEG) [11,12], and poly(vinyl alcohol) (PVA) [13], among others. With respect to the synthesis methodologies, they can be produced by either physical or chemical crosslinking or even by the combination of both [14].…”

Evaluating the potential of chitosan/poly(vinyl alcohol) membranes as alternative carrier material for proliferation of Vero cells

“…Hence higher specific growth rate indicates comparatievly faster growth (22). Reports have shown improved cell adhesion and proliferation on the CS membrane on surface modification (38). Existing reports suggest that apart from physicochemical properties, surface properties play an important role in cell adhesion and spreading on substrates (33).…”