Biomimetic Mineralization of Tannic Acid-Supplemented HEMA/SBMA Nanocomposite Hydrogels

Abstract

This study developed a tannic acid (TA)-supplemented 2-hydroxyethyl methacrylate-co-sulfobetaine methacrylate (HEMA-co-SBMA) nanocomposite hydrogel with mineralization and antibacterial functions. Initially, hybrid hydrogels were synthesized by incorporating SBMA into the HEMA network and the influence of SBMA on the chemical structure, water content, mechanical properties, and antibacterial characteristics of the hybrid HEMA/SBMA hydrogels was examined. Then, nanoclay (Laponite XLG) was introduced into the hybrid HEMA/SBMA hydrogels and the effects evaluated of the nanoclay on the chemical structure, water content, and mechanical properties of these supplemented hydrogels. The 50/50 hybrid HEMA/SBMA hydrogel with 30 mg/mL nanoclay showed outstanding mechanical properties (3 MPa) and water content (60%) compared to pure polyHEMA hydrogels. TA then went on to be incorporated into these hybrid nanocomposite hydrogels and its effects investigated on biomimetic mineralization. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) showed that bone-like spheroidal precipitates with a Ca/P ratio of 1.67% were observed after 28 days within these mineralized hydrogels. These mineralized hydrogels demonstrated an almost 1.5-fold increase in compressive moduli compared to the hydrogels without mineralization. These multifunctional hydrogels display good mechanical and biomimetic properties and may have applications in bone regeneration therapies.