CLAY MINERALS AS FUNCTIONAL INGREDIENTS OF CHITOSAN/PVA INKS FOR PRESSURE-ASISTED MICRO-SYRINGE 3D PRINTING OF MEDICAL DEVICES.

Abstract

Hydrogel-based formulations are promising platforms for chronic wound management since they maintain a moist environment and enable controlled drug delivery. The advancements in 3D printing (3DP) enables the development of medical devices and medicines based on polymers, but their low printability is a limitation to overcome. This study explores chitosan/PVA/clay hydrogels as inks for Pressure-Assisted Micro-syringe 3DP, focusing on the influence of different clay minerals. Chitosan (4% w/w), PVA (2.3% w/w) and triethanolamine (2% w/w) were the basic ingredients, while clays (0.45% w/w laponite, 0.9% w/w montmorillonite, 1.81% w/w sepiolite and halloysite) were added as functional ingredients. The addition of clays made the polymeric mixture printable: Laponite provided the highest printing resolution, sepiolite reported great reproducibility after post-printing and montmorillonite prevented filament collapsing most effectively. FTIR and XRD confirmed interactions among components, such as polymer/clay intercalation, which could explain the printability and compressive Young Modulus improvements. The stability of the printed devices in simulated fluid can be controlled by the type of clay, which can be predicted by the wetting angle of hydrogels. In vitro cytocompatibility studies revealed a cell viability > 90% in all cases, confirming their biocompatibility. This exploratory study demonstrates that clays can modulate the behaviour of polymer mixtures and optimize their 3DP performance, thus enabling the production of personalized and tunable medical devices and/or medicines.

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