No abstract

The interpenetrating polymer network of fast temperature-responsive hydrogels based on soy protein and poly(N-isopropylacrylamide) were successfully prepared using sodium bicarbonate (NaHCO 3 ) solutions as the reaction medium. The structure and properties of the hydrogels were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry and thermal gravimetric analysis. The swelling and deswelling kinetics were also investigated in detail. The results showed that the proposed hydrogels had a highly porous structure, good miscibility and thermal stability, and a fast temperature response. The presence of NaHCO 3 had little effect on the volume phase transition temperature (VPTT) of the hydrogels, and the VPTTs were at about 32 °C. Compared with the traditional hydrogels, the proposed hydrogels had much faster swelling and deswelling rates. The swelling mechanism of the hydrogels was non-Fickian diffusion. These fast temperature-responsive hydrogels may have potential applications in the field of biomedical materials.

pH‐ and temperature‐responsive interpenetrating polymer network (IPN) hydrogels based on soy protein and poly(N‐isopropylacrylamide‐co‐sodium acrylate) were successfully prepared. The structure and properties of the hydrogels were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, and thermogravimetric analyzer. The equilibrium and dynamic swelling/deswelling behaviors and the drug release properties of the hydrogels responding to pH and/or temperature were also studied in detail. The hydrogels have the porous honeycomb structures, good miscibility and thermal stability, and good pH‐ and temperature‐responsivity. The volume phase transition temperature of the hydrogels is ca. 40°C. Changing the soy protein or crosslinker content could be used to control the swelling behavior and water retention, and the hydrogels have the fastest deswelling rate in pH 1.2 buffer solutions at 45°C. Bovine serum albumin release from the hydrogels has the good pH and temperature dependence. The results show that the proposed IPN hydrogels may have potential applications in the field of biomedical materials such as in drug delivery systems. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39781.

The purpose of this study was to fabricate and evaluate nanoparticles based on β‐conglycinin (7S) and chitosan (CS) to deliver 5‐fluorouracil (5‐FU). The nanoparticles were prepared with a self‐assembly method. Turbidity measurements performed at 600 nm were used to investigate the formation of the nanoparticles as a function of the pH, 7S‐to‐CS mass ratio, and total concentration of 7S and CS. The optimum conditions for the preparation of the nanoparticles were a pH of 5.5, a 7S‐to‐CS mass ratio of 4 : 1, and total concentration of 7S and CS of 9 mg/mL. Under these conditions, the nanoparticles in solution had a high turbidity and good stability. Fourier transform infrared spectroscopy revealed that the nanoparticles were formed mainly through electrostatic interactions between the amine groups (NH3+) of CS and the carboxyl groups (COO−) of 7S. Scanning electron microscopy micrographs and dynamic light scattering analysis showed that the nanoparticles had an approximately spherical morphology with a smooth surface, and the mean particle size was about 120 nm with a narrow size distribution. The release of 5‐FU showed an initial burst release followed by a sustained release, and the release was pH‐dependent. The release mechanism of 5‐FU was Fickian diffusion according to the Ritger–Peppas model. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41963.

The purpose of this work was to fabricate and evaluate glycinin nanoparticles for 7 delivery of phenolic compounds from Phyllanthus urinaria. The nanoparticles were prepared 8 using self-assembly method, and three variables, including pH (X 1 ), glycinin concentration 9 (X 2 ), and glycinin to phenolic compounds mass ratio (X 3 ), for the achievement of high 10 encapsulation efficiency of phenolic compounds were optimized using response surface 11 methodology. The statistical analyses show that the independent variables (X 1 , X 2 ) and the 12 quadratic terms (X 2 1 , X 2 2 and X 2 3 ) have significant effect on the encapsulation efficiency. The 13 optimized conditions are X 1 of 4.4, X 2 of 3.2 mg/mL, and X 3 of 6.2:1. Under these conditions, 14 the experimental value is 51.42% (n=3), which is well matched with the predicted value. 15 Scanning electron microscopy (SEM) micrograph and dynamic light scattering (DLS) 16 analyses show that the nanoparticles have an approximately spherical morphology with a 17 smooth surface, and the mean particle size was about 100 nm with a narrow size distribution 18 of 0.318. The release of phenolic compounds shows a faster release at pH 7.4 but a lower 19 release at pH 1.2, and the release mechanism at pH 1.2 and 7.4 is Fickian diffusion and 20 anomalous transport, respectively.21