Thermosensitive Hydrogel for Encapsulation and Controlled Release of Biocontrol Agents to Prevent Peanut Aflatoxin Contamination

Abstract

Starch, alginate, and poly(N-isopropylacrylamide) (PNIPAAm) were combined to prepare a semi-interpenetrating network (IPN) hydrogel with temperature sensitivity. Calcium chloride was used as cross-linking agent, the non-toxigenic Aspergillus flavus spores were successfully encapsulated as biocontrol agents by the method of ionic gelation. Characterization of the hydrogel was performed by Fourier-transform infrared spectroscopy (FTIR), scanning electron micrograph (SEM), and thermogravimetry analysis (TGA). Formulation characteristics, such as entrapment efficiency, beads size, swelling behavior, and rheological properties were evaluated. The optical and rheological measurements indicated that the lower critical solution temperature (LCST) of the samples was about 29–30 °C. TGA results demonstrated that the addition of kaolin could improve the thermal stability of the semi-IPN hydrogel. Morphological analysis showed a porous honeycomb structure on the surface of the beads. According to the release properties of the beads, the semi-IPN hydrogel beads containing kaolin not only have the effect of slow release before peanut flowering, but they also can rapidly release biocontrol agents after flowering begins. The early flowering stage of the peanut is the critical moment to apply biocontrol agents. Temperature-sensitive hydrogel beads containing kaolin could be considered as carriers of biocontrol agents for the control of aflatoxin in peanuts.

Effect of Different Surface-charged Lamellar Materials on Swelling Properties of Nanocomposite Hydrogels

“…The 13 C nuclear magnetic resonance (NMR) spectra of precursor materials (MC and AAm) used in the synthesis of hydrogels are shown in Figs. 4a and 4b.…”

“…In addition, assignments of Am were observed at δ = 128.09, 130.45 and 169.47 ppm, which refer to the C2, C1 and C3 carbons, respectively. Figure 4c shows the 13 C NMR spectra of the pure hydrogel, HG300 (1:1) and HG550 (1:1). The most intense peaks at δ = 41.92 and 180.50 ppm were found in all spectra and refer to C1, C2 and C3, C5 carbons from polyacrylamide structure, respectively.…”

Rational Design of Thermoresponsive Microgel Templates with Polydopamine Surface Coating for Microtissue Applications

“…Hydrogels made from this polymer exhibit a reversible volume phase transition (VPT) in the physiological temperature range and undergo changes in solubility and swelling, which facilitates the imitation of the structure, properties, and microenvironment of native tissue. [ 6–8 ] By incorporation of comonomers into the PNIPAAm network, the VPT temperature can be further tuned to higher or lower values depending on the hydrophilicity and the amount of the comonomer. [ 9 ] Since PNIPAAm‐based microgels can be easily shaped via droplet‐based microfluidics, various temperature‐dependent microgels can be obtained, which differ in size, mechanical strength, and opacity.…”

Characterization of Biocompatible Hydrogel Lenses Using Methacrylic Acid with Neodymium Oxide Nanoparticles

“…This advantage has been used to mainly use it as a biomechanical material for treatment of wounds. The development of therapeutic material, which uses antimicrobial substances such as thaizole to form hydrogel materials, is still underway [ 13 , 14 , 15 , 16 , 17 ]. In this case, unlike the contact lens, it is not necessary to ensure the transparency of the material [ 18 ].…”