Effect of hyaluronan molecular weight on the stability and biofunctionality of microfibers assembled by interfacial polyelectrolyte complexation

Abstract

Nervous system disorders are characterized by a progressive loss of function and structure of neurons that ultimately leads to a decline in cognitive and motor functions. In this study, we used interfacial polyelectrolyte complexation (IPC) to produce fibers for neural tissue regeneration. IPC is a processing method that allows spinning of sensitive biopolymers. The rate of spinning and the properties of the used biopolymers (charge and molecular weight) influence different characteristics of the fibers such as size and stability, among others. We used two major components of the neuronal stem cell niche, the polycationic collagen (Col) and the polyanionic hyaluronic acid (HA), to obtain bioactive fibers. We tested HA with different molecular weights and found that HA with medium and high molecular weights (350 and 1200 kDa, respectively) enabled drawing of microfibers with a homogeneous distribution of Col and HA, whereas low-molecular-weight HA (40 kDa) did not allow spinning. The obtained microfibers showed high swelling ability in a physiological buffer: their diameters increased more than 5-fold from their dry state. At these conditions, the tensile storage moduli of the fibers were similar to nervous tissues. Collagenase and hyaluronidase did not change the morphology of the fibers for up to 3 days but reduced their moduli 2- to 3-fold. Assays with PC12 neuronal-like cells showed that IPC microfibers support cell adhesion and viability regardless of the molecular weight of the used HA.This work was supported by the Fundação para a Ciência e Tecnologia (project OncoNeoTreat, grant number PTDC/CTM-REF/0022/2020), cofinanced by FCT─OE component (DOI: 10.54499/PTDC/CTM-REF/0022/2020), Funding “Base” (DOI: 10.54499/UIDB/50026/2020), Funding “Programático” (DOI: 10.54499/UIDP/50026/2020), and Funding “Complementar─LA” (DOI: 10.54499/LA/P/0050/2020). R.R.C. acknowledges FCT for support through grant 2022.00764.CEECIND/CP1718/CT0020 (DOI: 10.54499/2022.00764.CEECIND/CP1718/CT0020). D.S.C. acknowledges FCT for support through grant DL57/2016/CP1377/CT0092 (DOI: 10.54499/DL57/2016/CP1377/CT0092). C.C. acknowledges FCT for support through grant SFRH/BD/143209/2019. The authors would like to thank the contributions to this research from the project “TERM RES Hub–Scientific Infrastructure for Tissue Engineering and Regenerative Medicine,” reference PINFRA/22190/2016 (Norte-01-0145-FEDER-022190), funded by the Portuguese National Science Foundation (FCT) in cooperation with the Northern Portugal Regional Coordination and Development Commission (CCDR-N), for providing relevant lab facilities, state-of-the art equipment, and highly qualified human resources