Design of geometric structures of hydrogel via 3D printing to regulate release kinetics and bioaccessibility of β-carotene

Abstract

The aim of the present study was to investigate release kinetics and bioaccessibility of β-carotene from four key geometric structures of hydrogel tablets, total porosity, filling porosity, average pore size and specific surface area, which constructed by 3D printing four shapes and three internal filling patterns. The results indicated that circle samples had the lowest filling porosity, average pore size and specific surface area, which showed the highest cumulative intestinal release amounts of β-carotene (CIA). While diagonal samples exhibited the higher total porosity, resulting in the higher cumulative gastric release amounts of β-carotene (CGA). Disintegration of hexagon and circle samples were clearly delayed compared square and pentagon samples. The β-carotene release was best fitted in the first order model in gastrointestinal digestion (r2, 0.9176–0.9915). The β-carotene release mechanism for all samples was Fickian diffusion and frame erosion in gastric digestion, while the predominant release mechanism of β-carotene for samples was Fickian diffusion in intestinal digestion except for hexagon and circle samples with orthogonal pattern. Positive correlations between CGA and negative correlations between CIA and geometric structural parameters of samples were obtained, and the correlation coefficients were found to be in the order: specific surface area > average pore size > total porosity > filling porosity. Circle samples and orthogonal samples had the higher β-carotene bioaccessibility of the printed tablets (38.75% ∼ 50.64%), and SVM model illustrated a better performance for predicting the β-carotene bioaccessibility of printing tablets based on structural parameters (R2 > 0.80).