An Eco-Friendly Antheraea Pernyi Silk Gland Protein/Sodium Alginate Multiple Network Hydrogel as Potential Drug Release Systems

Sodium alginate/gelatin hydrogel spheres loaded with Fructus Ligustri Lucidi essential oil: Preparation, characterization and biological activity

The application of plant essential oils in the food industry is often hindered by their poor water solubility and high volatilize. Encapsulation has emerged as an effective solution to this problem. This study focuses on the preparation of Fructus Ligustri Lucidi essential oil gel spheres (FEOH) based sodium alginate and gelatin. The optimum formulation for FEOH was established by Box-Behnken Design response surface testing, resulting in a composition of 10 % FEO, 5 % TW20 and 2 % CaCl2. This formulation achieved an encapsulation efficiency of 85.56 %. FTIR and SEM results indicated the successful encapsulation of FEO within the gel spheres. Furthermore, DSC and TGA results showed that encapsulation enhanced the thermal stability of the essential oil. At room temperature, the water content of FEOH exceeded 90 %, and it showed the highest swelling ratio of 62.5 % in an alkaline medium at different pH conditions. The in vitro release behavior showed that FEOH was released up to 85.28 % in oil-based food simulants within 2 h. FEOH showed strong antibacterial activity, with a Minimum Inhibitory Concentration (MIC) of 128 mg/mL against Staphylococcus aureus and 256 mg/mL against Escherichia coli. The gel spheres obtained in this research show significant potential as food preservatives in food matrices.

Microfluidic Preparation of pH-Responsive Microsphere Fibers and Their Controlled Drug Release Properties

In this study, a capillary microfluidic device was constructed, and sodium alginate solution and a pH-sensitive hydrophobic polymer (p(BMA-co-DAMA-co-MMA)) solution were introduced into the device for the preparation of hydrogel fibers loaded with polymer microspheres. The structure of the microsphere fiber, including the size and spacing of the microspheres, could be controlled by flow rate, and the microspheres were able to degrade and release cargo responding to acidic pH conditions. By modification with carboxymethylcellulose (CMC), alginate hydrogel exhibited enhanced pH sensitivity (shrunk in acidic while swollen in basic condition). This led to an impact on the diffusion rate of the molecules released from the inner microspheres. The microsphere fiber showed dramatic and negligible degradation and drug release in tumor cell (i.e., A431 and A549 cells) and normal cell environments, respectively. These results indicated that the microsphere fiber prepared in this study showed selective drug release in acidic environments, such as tumor and inflammation sites, which could be applied as a smart surgical dressing with normal tissue protective properties.