Bin Zhou

Antibacterial multilayer films fabricated by layer-by-layer immobilizing lysozyme and gold nanoparticles on nanofibers

Negatively charged gold nanoparticles (GNP) and positively charged lysozyme (Lys) were alternately deposited on negatively charged cellulose mats via layer-by-layer (LBL) self-assembly technique. The fabricated multilayer films were characterized by energy-dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectra (FT-IR), and wide-angle X-ray diffraction (XRD). Morphology of the LBL film coated mats was observed by scanning electron microscopy (SEM). Thermal degradation properties were investigated by differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA). Additionally, the result of microbial inhibition assay indicated that the composite nanofibrous mats had excellent antibacterial activity against Escherichia coli and Staphylococcus aureus, which could be used for antimicrobial packing, tissue engineering, wound dressing, etc.

Fabrication of zein/quaternized chitosan nanoparticles for the encapsulation and protection of curcumin

In this article, we report the successful assembly of nanoparticles (NPs) from a water-soluble chitosan (CS) derivative (N-(2-hydroxyl)propyl-3-trimethyl ammonium chitosan chloride, HTCC) and zein via a low-energy phase separation method. The fabricated NPs were investigated for the first time to encapsulate and protect curcumin (Cur). The particle size and zeta potential of the zein–HTCC NPs varied from 66 to 170 nm and +36.3 to +62.5 mV, respectively. The encapsulation efficiency (EE) was greatly improved to 94.9% after HTCC coating, compared with 85.2% that using zein as a single encapsulant. The microstructure of the NPs was revealed by transmission electron microscopy (TEM). The physicochemical and structural analysis showed that the electrostatic interactions and hydrogen bonds were the major forces responsible for the formation of NPs. The encapsulation forms were evaluated for their efficiency in overcoming Curs heat and UV sensitivity, which improve the stability about 2.7 fold, 3.5 fold and 2.5 fold when disposed with 60 °C treatment for 30 min, 80 °C treatment for 1 min and ultraviolet radiation for 2 h, respectively at zein–HTCC1 = 1u2006:u20061. The results of the stability and DPPH assays indicated that the bioactivity was being protected upon encapsulation. Zein–HTCC NPs are believed to be promising delivery systems for the supplementation or treatment of hydrophobic nutrients or drugs.

Self-assembled zein–sodium carboxymethyl cellulose nanoparticles as an effective drug carrier and transporter

In this work, biodegradable nanoparticles (NPs) were assembled with sodium carboxymethyl cellulose (CMC) and zein to produce zein-CMC NPs. Paclitaxel (PTX) was 95.5% encapsulated at a zein-CMC weight ratio of 1u2009:u20093 and the NPs were spherical with an average particle size of approximately 159.4 nm, with the PTX concentration maintained at 80 μg mL-1. The NPs demonstrated good stability over a broad range of pH ranging from 3.7 to 11.0. The zein-CMC NPs were seen to provide a sustained release of PTX for up to 72 h, which led to an 80% release of the total loaded PTX in vitro. Confocal laser scanning microscopy (CLSM) and flow cytometry studies showed that the zein-CMC NPs could effectively transport encapsulated molecules into both drug-sensitive (HepG2 cells) and drug-resistant cancer cells (MCF-7 cells). Moreover, in vitro viability studies revealed that the PTX-loaded zein-CMC NPs had greater potency than free PTX in the PTX resistant MCF-7 cells at higher concentration. Furthermore, PTX-loaded NPs displayed obvious efficiency in the apoptosis of HepG2 cells. Zein-CMC NPs have shown significant potential as a highly versatile and potent platform for cancer therapy.

Vacuum-assisted layer-by-layer electrospun membranes: antibacterial and antioxidative applications

Layer-by-layer assembled films have been exploited for functional materials. Tannic acid with previously confirmed antibacterial and antioxidant potentials was deposited on cellulose nanofibrous mats. The LbL assembly technique allowed sufficient binding of TA and AgNPs–Lys to the supporting substrate via hydrogen bond and electrostatic interactions. The properties and morphology of the AgNPs–Lys/TA multilayer assembly membranes were characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectra (FT-IR), wide-angle X-ray diffraction (XRD), and scanning electron microscopy (SEM). The antibacterial and antioxidant activities were examined as well. The hybrid composite films have potential application in food packing and wound dressing, and tissue engineering, etc.

In situ synthesis of gold nanoparticles on LBL coated nanofibers by tannic acid for catalytic application

Electrospinning nanofibrous mats are extensively studied as efficient two-dimensional nanomaterials and applied in the fields of filtration, catalysis, and biosensors due to their flexibility and porosity. In this article, gold nanoparticle (AuNPs) loaded composite nanofibers were fabricated by a simple method, which consisted of the preparation of the nanofibers by electrospinning, the deposition of tannic acid (TA) on the surface of the nanofibers via layer-by-layer assembly and the reduction of the AuNPs on the nanofibrous mats. The as-prepared nanofibers were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), respectively. The results revealed that AuNPs were successfully generated on the nanofibers without aggregation. In addition, by adjusting the number of the bilayers in the assembly process, the content of gold supported on the nanofibrous mats could be easily controlled. The catalytic performance of the hybrid nanofibrous mats on the reduction of 4-nitrophenol (4-NP) with sodium borohydride was monitored by UV-visible spectroscopy (UV-vis). Notably, the hybrid composite nanofibrous mats could be easily separated from the reaction mixture.

Synergistic degradation of konjac glucomannan by alkaline and thermal method

The application of konjac glucomannan (KGM) in the food industry is always limited by its high viscosity. Hereby, low-viscosity KGM was prepared by alkaline-thermal degradation method. This process was demonstrated by the changes of average molecular weight and a kinetic model was developed. The results revealed that high alkalinity and high temperature had a synergetic effect on degradation. The structure of hydrolysates was evaluated by periodate oxidation and their fluidly properties were researched by rheology measurements. The degradation was divided into two regimes. The rate of the first regime (within 1h) is higher than that of the second one (last 1h). It is found that alkaline hydrolysis and deacetylation have a synergistic effect on the degradation under high alkalinity (pH 9.2) and low temperature condition (25 °C). Finally, rheology parameters showed alkaline-thermal degradation is a promising way that can be applied in practice to degrade KGM.

Phase separation in mixtures of ovalbumin and konjac glucomannan: Physicochemical and microscopic investigations

The phase behavior and microstructure of ovalbumin (OVA)/konjac glucomannan (KGM) mixtures were studied at pH 7.0. Phase diagrams were established by centrifugation and visual observation. Micro-phase separation of the OVA/KGM mixtures was quantified by measuring the turbidity. The microstructures of the phase separated mixtures were studied by measuring rheological property and confocal laser scanning microscopy (CLSM). The phase behavior of OVA/KGM mixtures appeared to be one single phase or two separated phases depending on the content of OVA and KGM. OVA had a pronounced effect on turbidity of OVA/KGM mixtures. The particle size of mixtures increased with increasing OVA and KGM concentration, which was the largest (119.1 μm) at 0.25 wt.% KGM and 5 wt.% OVA. The G and G″ cross-over at a mixture of 0.20 wt.% KGM and 4 wt.% OVA demonstrated the buildup of microstructure during phase separation. The association of OVA aggregates could be observed under CLSM.