Yijie Chen

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.

Quantum dots loaded nanogels for low cytotoxicity, pH-sensitive fluorescence, cell imaging and drug delivery

Nanogels (NGs) with drug tracking and delivery possess promising usage in clinical treatment. In this study, an available, low toxic and facile approach was developed to synthesize CdTe quantum dots loaded nanogels (QDs-NGs). The QDs-NGs retained the intrinsic pH sensitivity of the QDs with regard to the fluorescence intensity. The QDs-NGs were easily internalized by the cells as fluorescence probes, and acted as carriers for delivering methotrexate (MTX). The cellular uptake indicated that the QDs-NGs can protect QDs from decomposition in cytoplasm and retain the native fluorescence intensity. MTT assay demonstrated that the QDs-NGs greatly decreased the cytotoxicity of the QDs. The MTX loaded QDs-NGs exhibited slow release property in PBS buffer. Moreover, the MTX loaded QDs-NGs distinctly enhanced the availability of drug. The QDs-NGs are potential nanocarriers for the cell imaging and drug delivery.

Green-step assembly of low density lipoprotein/sodium carboxymethyl cellulose nanogels for facile loading and pH-dependent release of doxorubicin.

In this study, a simple and green approach was developed to produce a novel nanogel via self-assembly of low density lipoproteins (LDL) and sodium carboxymethyl cellulose (CMC), to efficiently deliver doxorubicin (DOX) to cancer cells. Under optimal conditions, the stable nanogels were of spherical shape with an average diameter of about 90 nm, PDI<0.3 and a zeta potential -35 mV. Furthermore, the cationic anticancer drug, doxorubicin (DOX) was effectively encapsulated into LDL/CMC nanogels with an exceptionally high encapsulation efficiency of ∼ 98%. The release of DOX from DOX-LDL/CMC nanogels was pH-dependent, and DOX was released at a quicker rate at pH 6.2 than at pH 7.4. Importantly, the DOX-LDL/CMC nanogels were shown to effectively kill cancer cells in vitro. The IC50 of the DOX-LDL/CMC nanogels in HeLa and HepG2 cells was approximately 2.45 and 1.72 times higher than that of free DOX. The slightly reduced antitumor efficacy was primarily due to the less cellular uptake of the DOX-LDL/CMC nanogels, which was confirmed by confocal laser scanning microscope (CLSM) and flow cytometry analysis. The high DOX payload and pH-dependent drug release rendered LDL/CMC nanogels as an efficient carrier for doxorubicin and possibly be used for other cationic drugs in different biomedical applications.

Construction of pH-sensitive lysozyme/pectin nanogel for tumor methotrexate delivery.

Novel nano-particles were developed from lysozyme-pectin through self-assembly, and the nanogels could be used as a carrier for the antitumor agent, methotrexate (MTX). The nanogels exhibited spherical with diameters about 109 ± 2 nm and narrow particle size distribution, as well as negative surface charge. Furthermore, the particle size and morphology of the nanogels hardly changed with the incorporation of MTX. The loading capacity of MTX in nanogels could reach 17.58 ± 0.85%. MTX-loaded nanogels were pH-dependent, accelerated release of MTX at a decreasing pH from 7.4 to 5.3. The MTT assay indicated that encapsulated MTX exhibited higher anticancer activity than free MTX. Meanwhile, MTX-loaded nanogels could be effectively endocytosed by HepG2 cells, resulting in enhanced cancer-cell apoptosis comparing to free MTX. It indicated that the nanogels had good biocompatibility and low toxicity. The obtained nanogels had great potential in the development of a new nanocarrier for anti-cancer drug delivery.

Supramolecular design of coordination bonding architecture on zein nanoparticles for pH-responsive anticancer drug delivery.

A pH-responsive system by constructing a designable coordination bonding-based metal-tannic acid (TA) architecture on zein nanoparticles (NPs) has been investigated. Film formation was initiated by the adsorption of the polyphenol and directed by pH-dependent, multivalent coordination bonding. The prepared metal-TA coated zein NPs (zein-TA/metal NPs) demonstrated good stability to maintain particle size in cell culture medium at 37 °C. The microstructure of the NPs was revealed by transmission electron microscopy (TEM). To confirm the surface chemical information of the NPs, XPS analysis was performed. Furthermore, in vitro viability studies revealed that the zein-TA/metal NPs showed no significant cytotoxicity against HepG2 cells for 24h. Because of the pH-responsive coordination bonding between TA and metal ions, the functional property of the metal-TA films was tailored for drug delivery. Biocompatible AuNPs were produced using zein-TA/metal NPs as reducing and stabilizing agents which were promising in the photothermal therapy of cancers and other diseases.

Nanogels fabricated from bovine serum albumin and chitosan via self-assembly for delivery of anticancer drug

In this study, bovine serum albumin (BSA) and chitosan (CS) were used to prepare BSA-CS nanogels by a simple green self-assembly technique. Then the nanogels were successfully used to entrap doxorubicin hydrochloride (DOX) with an entrapment ratio of 46.3%, aiming to realize the slow-release effect and lower the cytotoxicity of DOX. The IC50 values of DOX-loaded BSA-CS (DOX-BSA-CS) and free DOX obtained by MTT assay in SGC7901 cells were 0.22 and 0.05μg/mL, respectively. The cytotoxicity of DOX significantly decreased within 24h after encapsulation by the nanogels, indicating that the loaded drug could slowly release within 24h and the BSA-CS was a good slow release system. The cellular uptake experiments indicated DOX-BSA-CS diffused faster into the cancer cell than the bare drug. The flow cytometry and TUNEL assay proved DOX-BSA-CS could induce a larger apoptosis proportion of gastric cancer cells 7901 than the bare drug and it is promising to be used for curing gastric cancer.

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.

Self-assembled lysozyme/carboxymethylcellulose nanogels for delivery of methotrexate.

Nanogels (NGs) were fabricated with lysozyme and carboxymethylcellulose via a green self-assembly method. The prepared NGs were characterized by dynamic light scattering (DLS), zeta potential, Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). Pyrene and isothiocyanate were introduced as fluorescent probes to research the hydrophobic area of the NGs and cells endocytosis, respectively. Methotrexate (MTX) was used to investigate the drug encapsulation property of the NGs. It turned out to be that the drug loaded NGs were regular spherical shape with a hydrodynamic diameter of about 123 nm. The drug loading efficiency was about 14.2%. The NGs can slowly release the drug and increase the bioavailability of the loaded drug. The NGs are promising carriers for the delivery of drugs and other bioactive molecules.

Dissolution and rheological behavior of deacetylated konjac glucomannan in urea aqueous solution.

Deacetylation adversely affected the solubility of konjac glucomannan (KGM). Herein the dissolution behavior of deacetylated KGM (da-KGM) was studied in 10 wt% urea solution at various temperatures. KGM with different degrees of deacetylation (DD) could be well dissolved at -4°C. Low temperature was conducive to the dissolution of da-KGM. The result from steady shear showed that the zero-shear viscosity decreased with the increase of DD, with the rheological model being conformed to the Cross equation. Dynamic viscoelastic properties indicated the da-KGM gel formed more easily with increasing concentration, or decreasing temperature and DD. Temperature sweep revealed that gel process could be divided into two stages. The first stage was that both storage modulus (G) and loss modulus (G″) fell until the temperature reached 90°C. The second stage was that G and G″ increased abruptly, presenting the transition from sol to gel.

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.