A novel pectin from Akebia trifoliata var. australis fruit peel and its use as a wall-material to coat curcumin-loaded zein nanoparticle.

In this study, a pectin was extracted from Akebia trifoliata var. australis fruit peel waste using water solution, and its physicochemical properties were evaluated. The pectin was rich in galacturonic acid (GalA) content (76.68%). The degree of esterification (DE) and molecular weight (Mw) were 37.60% and 29,890 Da, respectively. The pectin structure was determined using Fourier transform-infrared (FT-IR) and Hydrogen nuclear magnetic resonance (H-NMR). The pectin exhibited an amorphous nature, negative charge, and good solubility. The pectin was then used as a wall-material to coat curcumin-loaded zein nanoparticles for the first time. The obtained nanoparticles (curcumin-loaded core-shell nanoparticle, CLCSNs) exhibited a core (zein)-shell (pectin) structure and a spherical shape with an average diameter of 230 nm. The electrostatic attraction, hydrogen bonding, and intermolecular interaction were involved in the CLCSNs formation. A high encapsulation efficiency (EE, 89.65%) and loading capacity (LC, 10.35%) of the CLCSNs were obtained for the curcumin. The solubility, stability, antioxidant activity, and in vitro bioavailability of the curcumin were significantly increased after loading into the CLCSNs. Therefore, this sustainable pectin from Akebia trifoliata var. australis fruit peel waste represents a promising natural macromolecule for use in the pharmaceutical and food industries.

New pectin-induced green fabrication of Ag@AgCl/ZnO nanocomposites for visible-light triggered antibacterial activity.

The pectin (CEP) was used as matrix material to prepare Ag@AgCl/ZnO nanocomposites with a green method for photocatalytic antibacterial activity in visible-light. Briefly, Ag@AgCl plasmonic hybrids were prepared in the CEP macromolecule matrix with size control, which was attributed to the stability of carboxyl and hydroxyl groups on the CEP. Subsequently, an effective and green two-steps approach was explored for the fabrication of CEP-Ag@AgCl/ZnO nanocomposites with resource saving and environment friendly. Interestingly, more Ag+ was converted into metallic Ag in the CEP-Ag@AgCl/ZnO than that in the CEP-Ag@AgCl. This phenomenon was attributed that the reducibility of free hemiacetal hydroxyl groups on CEP was realized with the help of NaOH in the preparation of CEP-ZnO. In addition, the CEP chains were not obviously destroyed except for the change in the crystallinity after the preparation of the CEP-Ag@AgCl/ZnO nanocomposites, indicating that the method was non-destructive. Moreover, the pH triggered release of Zn2+ and low release of Ag+ in CEP-Ag@AgCl/ZnO nanocomposites with excellent photocatalytic antibacterial activity were confirmed in this work. The proposed green process provides a new idea for the large-scale production of antibacterial pectin-based nanocomposites in industry with a low-cost.

A novel antibacterial agent based on AgNPs and Fe3O4 loaded chitin microspheres with peroxidase-like activity for synergistic antibacterial activity and wound-healing.

In this study, a novel antibacterial agent was developed based on chitin nanofibrous microspheres loaded with AgNPs and Fe3O4 nanoparticles (Ag-Fe3O4-NMs) for synergistic antibacterial activity and wound healing. Ag-Fe3O4-NMs was prepared via an in situ synthetic method which showed an excellent porosity and wettability. Moreover, Ag-Fe3O4-NMs were capable of sustained release of Ag+ and catalysed the decomposition of low H2O2 concentrations to generate hydroxyl radical (OH). The OH and Ag+ showed higher antibacterial activity and inhibited the toxicity with high dose of AgNPs and H2O2. In vitro biocompatibility results suggested that Ag-Fe3O4-NMs have low toxicity and low hemolysis. Thus, a novel antibacterial agent with enhanced synergistic antibacterial activity was obtained by combination of Ag-Fe3O4-NMs and H2O2 at a low and biologlically safe dosage, which could facilitate fibroblast growth, accelerate epithelialization, and promote the healing rate of infected wounds.