Advanced printable hydrogels from pre-crosslinked alginate as a new tool in semi solid extrusion 3D printing process

Giovanni Falcone; Pierluigi Mazzei; Alessandro Piccolo; Tiziana Esposito; Teresa Mencherini; Rita P Aquino; Pasquale Del Gaudio; Paola Russo

doi:10.1016/j.carbpol.2021.118746

Advanced printable hydrogels from pre-crosslinked alginate as a new tool in semi solid extrusion 3D printing process

Carbohydr Polym. 2022 Jan 15:276:118746. doi: 10.1016/j.carbpol.2021.118746. Epub 2021 Oct 20.

Authors

Giovanni Falcone¹, Pierluigi Mazzei², Alessandro Piccolo³, Tiziana Esposito², Teresa Mencherini², Rita P Aquino², Pasquale Del Gaudio², Paola Russo⁴

Affiliations

¹ Department of Pharmacy, University of Salerno, Fisciano, SA, Italy; PhD Program in Drug Discovery and Development, University of Salerno (SA), Italy.
² Department of Pharmacy, University of Salerno, Fisciano, SA, Italy.
³ Interdepartmental Research Center on Nuclear Magnetic Resonance for the Environment, Agro-food and New Materials (CERMANU), University of Naples Federico II, Portici, NA, Italy; Department of Agriculture, University of Naples Federico II, Portici, NA, Italy.
⁴ Department of Pharmacy, University of Salerno, Fisciano, SA, Italy. Electronic address: paorusso@unisa.it.

PMID: 34823778
DOI: 10.1016/j.carbpol.2021.118746

Abstract

With the aim to overcome alginate shape fidelity issue during the semisolid extrusion 3D printing and matrix collapsing after drying, we speculated that a pre-crosslinking step of the alginate ink-gel with low amount of Ca⁺² could improve the hydrogel performance. To verify this, the influence of pre-crosslinker concentration (10-25 mM) on the ink gel rheological properties were studied and flow behaviour and viscoelastic properties were determined. The developed ink gels were fully characterised by DSC and Magnetic Resonance Imaging (MRI). Moreover, extrudability and the shape retention of extruded forms after printing and after drying were studied. The rheological and MRI data, combined with the morphological analysis of printed forms allowed us to identify the relationship between printability, shape retention and shear thinning behaviour of gels, showing good extrudability for all the pre-crosslinked gels with a calcium concentration between 0.15 and 0.25, corresponding to both egg-box dimers and multimers interactions.

Keywords: Alginate ionotropic gelation; Hydrogel printability; Magnetic Resonance Imaging; Rheological requirements; Semi solid extrusion 3D printing.