Chitosan/Hyaluronic Acid/Zinc Oxide Carbohydrate-Based Nanocomposite Modulates Inflammatory and Functional Responses in β-Cell Spheroids

Zinc oxide nanoparticles (ZnO-NPs) offer attractive bioactivity for pancreatic β-cell interfaces because zinc is central to insulin storage and secretion, but uncontrolled nanoparticle exposure can also induce oxidative and inflammatory responses. Here, we developed a carbohydrate-based nanocomposite in which ZnO-NPs were incorporated within conformal chitosan/hyaluronic acid (Cs/HA) multilayers assembled by layer-by-layer deposition around MIN6 β-cell spheroids. Multilayer formation and ZnO incorporation were characterized by confocal microscopy, quartz crystal microbalance with dissipation monitoring, and atomic force microscopy, while molecular transport was assessed using FITC–dextran probes.

The Cs/HA multilayers formed hydrated, size-selective interfaces that maintained high relative transport of low-molecular-weight probes while attenuating larger macromolecules. Incorporation of ZnO generated distinct nanoscale domains within the polymer matrix and altered the biological response to the nanoparticles. Compared with dispersed ZnO-NPs, multilayer-incorporated ZnO-NPs were associated with reduced acute cytotoxicity, lower oxidation-sensitive fluorescence following oxidative challenge, and reduced macrophage TNF-α secretion. At 25 µg mL⁻¹, ZnO incorporation altered basal insulin secretion while preserving glucose responsiveness and was accompanied by strong upregulation of zinc transporters and metallothioneins, consistent with activation of endogenous zinc-handling pathways.

These findings demonstrate that the biological effects of an inorganic nanomaterial can be modulated by its presentation within a hydrated polysaccharide interphase. This short-term proof of concept establishes Cs/HA–ZnO multilayers as a promising materials strategy for integrating inorganic functionality at the β-cell interface while limiting the acute adverse responses associated with freely dispersed ZnO nanoparticles.