Zein-Tea Saponin Complex Nanoparticles (ZTCNP) Preparation and Characterization

Sigma-Aldrich, Inc. (St. Louis, MO, USA) provided Zein (purity ≥ 92%), Nile Red, and Nile Blue A, while Xi'an Yihe Biotechnology Co., Ltd (Xi'an, China) supplied the tea saponin (TS, 98% purity). Dow Corning Co. (Midland, MI, USA) provided the Sylgard 184 curable silicone elastomer (polydimethylsiloxane, PDMS). Sunflower oil was purchased from a local supermarket, and all other chemicals used were of analytical grade. To obtain ZTCNP, a mixture of Zein powder (1 g) and TS solutions (2.5, 5, 7.5 mM) was homogenized using a Microfluidizer (M110EH model, Microfluidics International Corporation, Newton, MA) for one pass at a pressure level of 50 MPa after being dissolved in a 100 mL TS solution and stirred magnetically at 25 °C for 2 h.