Rong-Min Wang

One‐Step Synthesis of Thermosensitive Nanogels Based on Highly Cross‐Linked Poly(ionic liquid)s

A gel for all seasons: Thermosensitive nanogels based on highly cross-linked poly(ionic liquid)s (CLPNs) were prepared in one step by the copolymerization of imidazolium-based monomers with cross-linkers in selective solvents. Reversible nanogel-macrogel transitions of CLPNs in methanol could be achieved by changing the temperature.

Study on effective extraction of chicken feather keratins and their films for controlling drug release

We report the fabrication of keratin films with porosity using keratin, for controlled drug delivery systems. Feathers are currently an important waste product from the poultry industry, however abandoned down products cause an environmentally difficult disposal problem as they are not efficiently extracted and applied. In this paper, feather keratin was extracted using a high-efficiency method. The yield of pure keratin was up to 90%. Its molecular weight was 20 kDa with low dispersity. The films, based on the extracted keratin, were prepared using a simple method, and showed good mechanical properties. Furthermore, the feather keratin films were used to load and release drugs. The resultant feather keratin biopolymer films were pH-responsive and showed controllable drug-release behavior. In summary, we achieved a simple method to reutilize disused feathers. It could be an attractive candidate for applications in the biomedical field.

Poly(ethylene glycol)-conjugated human serum albumin including iron porphyrins : Surface modification improves the O2-transporting ability

Artificial O2-carrying hemoprotein composed of human serum albumin including tetrakis(o-amidophenyl)porphinatoiron(II) (Fe4P or Fe3P) [HSA-FeXP] has been modified by maleimide- or succinimide-terminated poly(ethylene glycol) (PEG), and the formed PEG bioconjugates have been physicochemically characterized. 2-Iminothiolane (IMT) reacted with the amino groups of Lys to create active thiol groups, which bind to alpha-maleimide-omega-methoxy PEG [Mw: 2-kDa (PEG(M2)), 5-kDa (PEG(M5))]. On the other hand, alpha-succinimidyl-omega-methoxy PEG [Mw: 2-kDa (PEG(S2)), 5-kDa (PEG(S5))] directly binds to Lys residues. MALDI-TOF MS of the PEG-conjugated HSA-FeXP showed distinct molecular ion peaks, which provide an accurate number of the PEG chains. In the case of PEG(MY)(HSA-FeXP), the spectroscopic assay of the thiol groups also provided the mean of the binding numbers of the polymers, and the degree of the modification was controlled by the ratio of [IMT]/[HSA]. The viscosity and colloid osmotic pressures of the 2-kDa PEG conjugates (phosphate-buffered saline solution, [HSA] = 5 g dL(-1)) were almost the same as that of the nonmodified one, whereas the 5-kDa PEG binding increased the rheological parameters. The presence of flexible polymers on the HSA surface retarded the association reaction of O2 to FeXP and stabilized the oxygenated complex. Furthermore, PEG(MY)(HSA-FeXP) exhibited a long circulation lifetime of FeXP in rats (13-16 h). On the basis of these results, it can be concluded that the surface modification of HSA-FeXP by PEG has improved its comprehensive O2-transporting ability. In particular the PEG(MY)(HSA-FeXP) solution could be a promising material for entirely synthetic O2-carrying plasma expander as a red cell substitute.

Preparation of low-molecular-weight chitosan derivative zinc complexes and their effect on the growth of liver cancer cells in vitro

Low-molecular-weight (LMW) chitosan salicylaldehyde Schiff-base and its zinc(II) complexes were synthesized and characterized by Fourier transform-infrared (FT-IR) spectra, transmission electron microscopy (TEM), dynamic light scattering (DLS), gel permeation chromatography-multiangle laser light scattering (GPC-MALLS), and elemental analysis. The results of electrophoretic analysis suggest that the Zn complexes bound to DNA by means of electrostatic interactions and intercalation. The effect of the Zn complexes on the growth of SMMC-7721 liver cancer cells was investigated by sulforhodamine B assay in vitro. The results reveal that the growth of liver cancer cells was inhibited by LMW-chitosan and their Zn complexes. The inhibition rate of the Zn complexes was higher than that of LMW-chitosan ligand. The LMW-chitosan Schiff-base Zn complex exhibited higher anticancer activity than the LMW-chitosan Zn complex. Combining LMW-chitosan with Schiff-base and Zn improved its anticancer activity, which we ascribe to the synergistic effect between the chitosan matrix and the planar construction of the Zn complexes.

One-pot facile synthesis of half-cauliflower amphiphilic Janus particles with pH-switchable emulsifiabilities

A facile synthesis strategy for generating two types of highly uniform amphiphilic polymer Janus particles, spherical seeds and half-cauliflower particles, is first presented. Both of the submicron particles possessing pH-switchable emulsifiabilities can change their amphiphilicities/shapes and induce phase inversion of emulsions in response to pH values of solution.

Loess clay based copolymer for removing Pb(II) ions.

Functional monomers, such as acrylic acid and 2-hydroxyethyl methacrylate were supported into loess clay in situ polymerization, which afforded loess clay based copolymer (LC/PAAHM), a new kind of polymer adsorbent for removing Pb(II) ions from aqueous solution. Characterization of the polymer adsorbent was carried out by different sophisticated methods, such as Fourier transformation infrared spectrometry (FTIR), scanning electron microscopy (SEM), X-ray diffractometry (XRD), thermogravimetric analysis (TGA), and Zetasizer. Batch experiments were carried out to evaluate the factors affecting the removal efficiency, in which the pH, the adsorbent dosage, temperature and initial Pb(II) concentration all found in positive relevance to the increase of Pb(II) removal efficiency. The removal rate of Pb(II) got to 99% at room temperature and the adsorption capacity got to 356.9 mg/g. The pseudo-first-order and pseudo-second-order kinetic models were applied to test the experimental data, and Langmuir and Freundlich models have been applied to study the adsorption equilibrium, respectively.

Keratin films from chicken feathers for controlled drug release.

Abstract summaryDuring the past two decades significant advances have been made in the development of biomaterials for biomedical applications, especially biomaterials based on natural polymers. In this paper, we report the preparation of protein films for controlled drug release applications. This

Novel redox-responsive nanogels based on poly(ionic liquid)s for the triggered loading and release of cargos

The unique disulfide chemistry has been widely explored for novel and versatile delivery systems addressing both intracellular and extracellular barriers. In this study, novel redox-responsive nanogels were fabricated by radical copolymerization of ionic liquid (IL)-based monomers, 1,n-butanediyl-3,3′-bis-1-vinylimidazolium dibromide ([CnVIm]Br, n = 4, 6), and disulphide dimethacrylate (DSDMA) in selective solvents. The as-synthesized nanogels were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analyses (TG), dynamic laser scattering (DLS) and zeta (ζ)-potential measurements. The results demonstrated that the sizes of poly(ionic liquid) (PIL)-based nanogels can be tuned by the feed ratio of the monomers and DSDMA. Moreover, the redox-response performances of these nanogels were evaluated through the size variation in the presence of dithiothreitol (DTT) and benzoyl peroxide (BPO). The capability of PIL-based nanogels for controlled release was also investigated by using rhodamine B (RhB) as prototype model drug. It was found that DTT-triggered release of RhB could be achieved. Therefore, a redox-triggered loading and release matrix can be conveniently fabricated via PIL-based nanogels. And it can also be potentially used as a controlled carrier in biological medicine.

A facile fabrication of amphiphilic Janus and hollow latex particles by controlling multistage emulsion polymerization

In this paper, we found that morphology controllable compound latex particles could be prepared by controlling the multistage emulsion polymerization. Influences of the content of methacrylic acid (MAA) on preparing the hydrophilic cores and the particles were investigated with the observation of dynamic light scattering (DLS) and transmission electron microscope (TEM) results. The acorn-like latex particles were synthesized by partially encapsulated with hydrophobic polystyrene (PSt)-layer. With adding moderate polarity polymethylmethacrylate (PMMA) interlayer, the hydrophilic cores could be fully encapsulated by the hydrophobic PSt-layer, and the core-shell structure formed. After alkali treatment, the acorn-like and core-shell latex particles evolved into amphiphilic Janus and hollow latex particles, respectively. The morphology of latex particles was investigated by TEM, and the forming mechanism of amphiphilic Janus and hollow latex particles was proposed.

Functional poly(ethylene terephthalate) materials prepared by condensation copolymerization with ionic liquids

In this study, ionic liquid-modified polyethylene terephthalate was prepared for the first time via the condensation copolymerization of 1,3-bis(2-hydroxyethyl) imidazolium chloride (tetrafluoroborate, hexafluorophosphate) with dimethyl terephthalate and ethylene glycol using stannous chloride as the catalyst. The obtained functional materials were characterized using viscosity, infrared spectra, thermogravimetric analysis, scanning electron microscopy, and conductivity measurement. The wettabilities of the materials with different counterions were also tested by static water contact angle measurement. The results revealed that both the thermal stability and the hydrophilicity of functional material were enhanced greatly due to the introduction of ionic liquids. In addition, the antibacterial performances of the copolymers were also evaluated by in vitro assay, and the results proved that the ionic liquid-modified materials presented good antibacterial property. As a result, an effective and feasible method for the modification of polyethylene terephthalate was developed.