Hyaluronic Acid/Laponite Clay Nanocomposites‐Based Hydrogels for 3D Bioprinting Applications

Abstract

Hyaluronic acid (HA) is a glycosaminoglycan with excellent physicochemical and biological properties and represents a potential component to constitute inks used in tissues and organs 3D bioprinting process. On the other hand, it does not have an adequate degree of rigidity necessary for the structural maintenance of printed components. Laponite (Lap) is a synthetic nanoclay capable of increasing the rheological properties of polymeric hydrogels. The present study aimed to develop and characterize HA/Lap clay nanocomposites-based hydrogels for the constitution of inks for 3D bioprinting, considering the Lap potential to improve the rheological characteristics of HA. For this, HA (12 mg/mL) and Laponite-XLG (50 mg/mL) hydrogels were initially produced. Three additional hydrogels, composed from the association of different percentages of HA and Lap samples (w/w), were manufactured (HA/Lap 75:25%, 50:50%, and 25:75%). After constitution, all hydrogels samples were characterized by rheological and spectrophotometric analysis (Fourier-Transform Infrared Spectroscopy-FTIR). Finally, they were submitted to an in vitro cytotoxicity test, with cell viability (human fibroblasts-GM07492) established by a spectrophotometric Resazurin/Resorufin method. The rheological analysis results demonstrate a directly proportional increase in hydrogel viscosity concerning the increase in Lap percentage. The values of HA, Lap, and experimental HA/Lap clay nanocomposites-based hydrogels samples (75:25%, 50:50%, and 25:75%) were 4.9, 12.7, 4.0, 9.4, and 12.0 Pa.s, respectively. In FTIR analysis, bands (wavenumber 1000.7 cm-1) were identified in the Lap and HA/Lap samples, corresponding to the stretching of the Si-O interaction of Lap's tetrahedral layer. The viability tests demonstrated the non-toxic profile of the HA, Lap, and the hydrogels resulting from their associations. Such results demonstrate the biological safety of HA/Lap samples and the rheological modifying role from Lap on developed hydrogels. The viscosity levels achieved, especially in the proportions of HA/Lap of 50:50% and 25:75%, demonstrate its potential in the constitution of inks for use in 3D bioprinting. Further research should contribute to establishing the ideal composition (percentage of HA and Lap) and the printability characteristics of the HA/Lap clay nanocomposites-based hydrogels.