title: Microfabricated photocrosslinkable polyelectrolyte-complex of chitosan and methacrylated gellan gum.
abstract: Chitosan (CHT) based polyelectrolyte complexes (PECs) have been receiving great attention for tissue engineering approaches. These hydrogels are held together by ionic forces and can be disrupted by changes in physiological conditions. In this study, we present a new class of CHT-based PEC hydrogels amenable to stabilization by chemical crosslinking. The photocrosslinkable anionic methacrylated gellan gum (MeGG) was complexed with cationic CHT and exposed to light, forming a PEC hydrogel. The chemical characterization of the photocrosslinkable PEC hydrogel by Fourier transform infrared spectroscopy (FTIR) revealed absorption peaks specific to the raw polymers. A significantly higher swelling ratio was observed for the PEC hydrogel with higher CHT content. The molecular interactions between both polysaccharides were evaluated chemically and microscopically, indicating the diffusion of CHT to the interior of the hydrogel. We hypothesized that the addition of MeGG to CHT solution first leads to a membrane formation around MeGG. Then, migration of CHT inside the MeGG hydrogel occurs to balance the electrostatic charges. The photocrosslinkable feature of MeGG further allowed the formation of cell-laden microscale hydrogel units with different shapes and sizes. Overall, this system is potentially useful for a variety of applications including the replication of microscale features of tissues for modular tissue engineering.
authors.affiliation: 3B's Research Group - Biomaterials, Biodegradables and Biomimetics, Dept. of Polymer Engineering, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, Taipas, 4806-909 Guimarães, Portugal ; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal ; Center for Biomedical Engineering, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA 02139, USA ; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Daniela F
authors.initials: DF
authors.lastname: Coutinho
authors.forename: Shilpa
authors.initials: S
authors.lastname: Sant
authors.forename: Mojdeh
authors.initials: M
authors.lastname: Shakiba
authors.forename: Ben
authors.initials: B
authors.lastname: Wang
authors.forename: Manuela E
authors.initials: ME
authors.lastname: Gomes
authors.forename: Nuno M
authors.initials: NM
authors.lastname: Neves
authors.forename: Rui L
authors.initials: RL
authors.lastname: Reis
authors.forename: Ali
authors.initials: A
authors.lastname: Khademhosseini