Nanobiofunctionalized chitosan nanocomposite hydrogel as a highly biocompatible cancer drug carrier

A bio-inspired drug carrier was developed by dual functionalization of chitosan using L-glutamic acid (GA) and phyto-synthesized zinc oxide nanoparticles (ZNPs). A highly porous, three-dimensional network of nanocomposite hydrogel (GA-CHGZ) was obtained upon cross-linking chitosan using biomass-derived dialdehyde cellulose. The hydrogel was optimally loaded with naringenin (NRG) and further characterized using nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and swelling studies. An enhanced NRG loading efficiency of 85.23% was obtained using functionalized hydrogel compared to 52.54% using non-functionalized hydrogel. Delivery studies displayed a maximum release of 69.63% for 1.0 mg/ml of initial NRG concentration at pH 5, which is a highly preferred condition for cancer therapeutics. While ZNPs’ embedment was instrumental in improving the NRG loading and delivery rates, the GA conjugation increased the stability of NRG in the GA-CHGZ, aiding sustained NRG release, which followed a non-Fickian diffusion mechanism with polymer swelling. Antimicrobial potential was explored against Staphylococcus aureus and Trichophyton rubrum strains. The biocompatibility assay using L929 normal cells showed enhanced cell proliferation characteristics for the materials, revealing significant cell viability. The anticancer activity of NRG tested against A431 human skin carcinoma cells increased up to nine-fold with a reduced IC₅₀ value when a functionalized hydrogel was used instead of pure NRG without the nanocomposite carrier. Thus, the bio-functionalized drug–carrier system has a promising application for wound healing and topical skin cancer therapies.     

Growth mechanism and pH-regulation characteristics of composite latex particles prepared from Pickering emulsion polymerization of aniline/ZnO using different hydrophilicities of oil phases

A Pickering emulsion polymerization of aniline, using different hydrophilicities of oil phases, was stabilized by ZnO nanoparticles and performed to synthesize composite latex particles of polyaniline/ZnO. Ammonium peroxydisulfate (APS) was used as an oxidizing agent. The morphologies and growth mechanisms of the resulted composite latex particles were studied. The pH-regulation capacity of the composite latex particles was discussed. When toluene was used as the oil phase, the composite latex particles showed hollow structure, irregular morphology, and hundreds of nanometer in size. It was ascribed to the polymerization of aniline on the interfaces of droplets/water. ZnO nanoparticles, with 50-100 nm in size, acted as surfactants to stabilize the emulsion. When THF was used as an oil phase, the composite latex particles showed spherical morphology and enwrapping ZnO nanoparticles. It was attributed to the homogeneous nucleation of polyaniline in the aqueous phase. ZnO nanoparticles acted as templates for the polyaniline particles. The stability of the Pickering emulsion polymerization was affected by the volume ratio of the oil phase to water. The aqueous solution with pH 3-9 could simply be regulated to about pH 7 by the composite latex particles. It was contributed by the dissolution of ZnO nanoparticles and doping-dedoping of polyaniline in the acidic and alkaline aqueous solutions.     

An innovative approach to fabricate a thermosensitive melatonin-loaded conductive pluronic/chitosan hydrogel for myocardial tissue engineering

This study aimed at designing and fabrication of a novel injectable and thermosensitive melatonin-loaded pluronic/chitosan hydrogel containing gold nanoparticles (GNPs) and poly glycerol sebacate (PGS) for myocardial tissue engineering. The PGS nanoparticles were used as the melatonin (drug model) carrier. The gelation time, syringeability, stability, and swelling of the hydrogel were scrutinized. Rheological properties, chemical composition, and morphology of the samples were also investigated. The effect of GNPs addition on the electrical conductivity of hydrogel was assessed. The cytotoxicity of hydrogels was assessed through MTT assay in the exposure of H9C2 cells up to 7 days. Scanning electron microscopy was applied to evaluate the morphology of seeded cells. The synthesis parameters of PGS nanoparticles were optimized through which 2.5%w/v of PGS and 1:10 organic phase to aqueous phase (O/A) ratio were found desirable. The optimum hydrogel illustrated 2 min gelation time and was stable up to 20 days with 5% swelling in the first 12 h into phosphate buffered saline. The GNPs with a uniform distribution rendered the hydrogel electrically conductive (1500 μS/cm). According to the MTT assay results, 3.125 μM melatonin was considered as the suitable concentration by which a significant increase in the cell viability was observed. The results exhibited that the prepared hydrogel composed of pluronic/chitosan/GNPs, and 3.125 μM melatonin-loaded PGS nanoparticles could be applied as a promising scaffold for myocardial tissue engineering.     

Incorporated ZnO onto nano clinoptilolite particles as the active centers in the photodegradation of phenylhydrazine

ZnO was incorporated into nano particles of clinoptiloite by ion exchanging the zeolite in a zinc nitrate aqueous solution followed by calcinations process. All raw and modified samples were characterized by XRD, FT-IR, DRS, TG-DTG, SEM, BET and TEM. The prepared catalyst was used in the photocatalytic degradation of phenylhydrazine (PHZ) and the best experimental parameters were obtained as: 0.25 g L⁻¹ of the catalyst, 20 ppm pollutant concentration and pH = 8. The degradation extent was monitored by UV–vis spectroscopy and the results were confirmed by HPLC and the chemical oxygen demand (COD).     

壳聚糖/N-乙烯基吡咯烷酮接枝共聚物的制备及其性能

以壳聚糖（CS）和N-乙烯基吡咯烷酮（NVP）为原料,本文采用过氧化氢和抗坏血酸共引发剂引发,制备壳聚糖/N-乙烯基吡咯烷酮的接枝共聚物（CS-g-NVP）,研究了引发剂配比、反应温度和反应时间等因素对接枝共聚反应的影响。通过红外光谱、核磁共振和热重分析等对产物进行表征,并考察其吸湿性和亲水性能。结果表明,接枝共聚反应的最佳条件为：引发剂抗坏血酸/过氧化氢的摩尔比为1∶1、反应温度60℃、反应时间12h。接枝共聚产物的吸湿性优于壳聚糖,在饱和氯化钙和饱和硫酸铵环境下产物的吸湿率分别为3.68%和23.1%,高于原料壳聚糖的0.41%和9.77%,产物具有良好的亲水性和水溶性,能溶解于酸性和碱性水溶液中。     

Synthesis of non-collapsed hollow polymeric nanoparticles with shell thickness on the order of polymer gyration radius

The hollow polymeric nanoparticles of poly(styrene-co-divinylbenzene) of ultra-thin shell were synthesized by the interfacial RAFT miniemulsion polymerization with various particle sizes, void fractions and crosslinking degrees. With the void fraction increased, the hollow nanoparticles were more likely to collapse once dried. This collapse could be suppressed by simply increasing the level of crosslinker. The fraction of the collapsed hollow particles decreased nearly linearly with the increasing level of crosslinker. The non-collapsed hollow nanoparticles with a void fraction about 60% and shell thickness of 11.5 nm were fabricated with the crosslinker (divinylbenzene) of 0.67 mass fraction based on monomers. The resulted polymeric shell of the hollow nanoparticles was mesoporous, which had high surface area 514 m²/g, extremely large pore volume 2.74 ml/g and a most probable pore diameter of 9 nm. The structures of the hollow nanoparticles were mechanically stable not only in the solvent but also under harsh conditions like high temperature (200 °C) and strong shear. Additionally, the hollow nanoparticles were able to be fully re-dispersed in the solvent. The average hollow particle diameter was tuned from 70 nm to 199 nm by decreasing the level of the amphiphilic RAFT agent. The shell thickness was tuned from 10.6 nm to 19.3 nm by changing the core/shell ratios.     

NVP接枝壳聚糖水凝胶的合成与溶胀性能

合成了N-乙烯基吡咯烷酮（NVP）接枝壳聚糖（CHI）水凝胶,讨论了NVP/CHI、引发剂、交联剂、聚合温度、乙酸浓度等因素对接枝率及凝胶溶胀性能的影响,NVP∶CHI为6时,接枝率达到300%以上. 溶胀温度、pH值、盐浓度等对凝胶溶胀性能的影响实验表明,凝胶表现出温度敏感性,在40 ℃出现最大平衡溶胀率,并观察到一级相转变;在中性或弱酸性介质中溶胀性能较好;与PVP凝胶相比,NVP接枝CHI凝胶表现出反聚电解质效应. 溶胀动力学研究表明,在溶胀前期,CHI含量较高时,凝胶趋向于非Fick溶胀,说明除了溶剂扩散外,凝胶网络链段弛豫、水分子与凝胶网络间及凝胶高分子链段间相互作用对凝胶溶胀性能的影响至关重要;CHI含量较高时则趋向于Fick溶胀.     

Synthesis of methacrylic acid-styrene block copolymers by living radical polymerization in the presence of chitosan

The existence of living growing end radicals in the radical polymerization of sodium methacrylate (MAA·Na) in the presence of chitosan acetate salt has been ascertained by preparing block copolymers with styrene as secondary comonomer. When polymerization of MAA·Na eventually reached 93.4% conversion after 144 h at 30°C, secondary comonomer styrene added to the system undergoes further polymerization. Solvent extraction was performed to separate the homopolymers and block copolymers in order to determine the properties of the product. The results of the solubilities, of gel permeation chromatography and of ¹H nuclear magnetic resonance showed the characteristics of the block copolymers.     

In situ preparation of nano ZnO/hyperbranched polyimide hybrid film and their optical properties

Novel hybrid films of fluorinated hyperbranched polyimide (HBPI) and zinc oxide (ZnO) were prepared via the in situ sol-gel polymerization technique, in which mono-ethanolamine (MEA) was used as the coupling agent between the termini of HBPI and the precursor of ZnO. The hybrid films were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) absorption, ultraviolet-visible (UV-vis) absorption, and fluorescent excitation/emission spectroscopy. The films, which originated from the colourless fluorinated HBPI structure and homogeneously dispersed ZnO nanoparticles, exhibited good optical transparency. Furthermore, two kinds of model compounds with and without ZnO and a HBPI film blended with ZnO microparticles were prepared to clarify the fluorescence mechanism in the pristine HBPI and in situ hybrid films. Efficient energy transfer from the ZnO nanoparticles to the aromatic HBPI main chains was observed in the in situ hybrid films, whereas energy transfer occurred only from the locally excited (LE) states to the charge-transfer (CT) state in the HBPI film. These facts demonstrate that the peripheral termini of HBPI are covalently bonded to ZnO particles via the MEA function, which operates as an effective pathway for energy transfer to give intense fluorescent emission.     

Sponge-like chitosan-based nanostructured antibacterial material as a topical hemostat

In this study, chitosan/alginic acid/zinc oxide (CHI/AA/ZnO) nanostructured hydrogel sponges were fabricated by incorporating ZnO nanoparticles (<100 nm) into polymer matrix to develop a new potential biomaterial for hemorrhage control. For this purpose, the crosslinked CHI/AA/ZnO nanostructured sponges were synthesized by freeze-drying technique. Genipin was used as a crosslinker. The prepared chitosan-based sponges were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy—energy-dispersive spectroscopy analysis. The effects of ZnO content on the physicochemical characteristics of sponge-like nanostructured hydrogels were evaluated by swelling ratio in two different pH values. Physical immobilization of dexamethasone as a model drug in hydrogel matrix resulted sustained release of drug more than 3 days. Antibacterial activity of hydrogel sponges was assessed against Staphylococcus aureus. The cytotoxicity and hemostatic efficacy of crosslinked CHI/AA/ZnO sponge like-nanostructured hydrogels was evaluated in vitro and in vivo, respectively. The results of this study demonstrated that the prepared CHI/AA/ZnO nanostructured sponge had the potential to be an antibacterial topical hemostat. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47522.     

Removal of boron from aqueous solution by composite chitosan beads

Various metal-oxide nanoparticles and chitosan were blended to form new adsorbents (M-Oxide-CTS) for removing boron from aqueous solutions in a batch system. The maximum boron adsorption capacity (q = 7.8 mg/g) was reached at pH = 4 within 5 min. Calculations based on Langmuir, Freundlich, and Dubinin–Radushkevich models showed the heterogeneous and physical nature of boron adsorption on M-Oxide-CTS. Modeling of the thermodynamic date indicated the nonspontaneous and exothermic process. The pseudo-second-order model adequately described the boron adsorption on M-Oxide-CTS. Desorption by means of alkaline solution at pH = 12 was carried out successfully.     

Filling behavior of ZnO nanoparticles into opal template via electrophoretic deposition and the fabrication of inverse opal

Combining colloidal crystal template (artificial opal) and electrophoretic deposition (EPD) process, well-ordered ZnO inverse opal can be formed by finding the optimum driving potential of EPD. Through providing the various driving potentials from −25 V, −10 V, −5 V to −2.5 V, the different mechanism of electrophoretically depositing ZnO nanoparticles into the colloidal crystal template was determined by the SEM observation of the filled templates. Because the nano-channels of colloidal crystal template are the network type, the results of surface jam, incomplete filling and perfect filling are found under specific applied voltages. The high-quality ZnO inverse opal can be only fabricated under the perfect nano-channel-filling condition. The filling behavior can be monitored dynamically by tracing the current transients, and the optimum conditions for filling the interstitial spaces of templates constructed from colloidal particles with 180 nm and 300 nm diameter can be obtained by applying a voltage of −5 V and −15 V, respectively. After the complete filling of ZnO nanoparticles into the colloidal crystal template consisting of 300 nm colloids, high-quality ZnO photonic crystal possessing an absorptive peak at the wavelength of 560 nm can be fabricated by removing the template. It is expected that the EPD can find extensive applications for preparing photonic crystals of various oxides only if their nanoparticles are available.     

A microwave‐assisted process for coating polymer and glass surfaces with semiconducting ZnO submicron particles

A new method for coating glass slides with ZnO particles with an average size of 200 nm is proposed in the current article. The coating was performed under microwave radiation. Two main morphologies are found for the ZnO crystals that are deposited on glass slides. The first morphology is that of a very dense coating of ZnO hexagonal rods growing perpendicular to the glass surface. The second is the growth of ZnO flower‐like particles. In addition to coating the glass by ZnO particles, we also report on coating other polymers [poly(methyl methacrylate) plate, polycarbonate beads, Nylon 6,6 beads, and polypropylene beads) by ZnO. The morphology obtained for ZnO coated on polymers is different from that detected for coating ZnO on glass. The unorganized coating of ZnO rods on polymers has been observed. The coated glass slides were characterized by X‐ray diffraction, volumetric titration, EDS, scanning electron microscope, and optical measurements (DRS and transmittance spectroscopy). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Ferulic acid as a comonomer in the synthesis of a novel polymeric chain with biological properties

In this study, ferulic acid was copolymerized with methacrylic acid to obtain a useful material with both antioxidant and antifungal properties. An ascorbic acid/hydrogen peroxide redox pair was used as a water‐soluble and biocompatible initiator system to prime the one‐pot polymerization reaction. The obtained material was characterized with gel permeation chromatography, Fourier transform infrared spectroscopy, ultraviolet spectroscopy, and fluorescence analyses, and the disposable phenolic group content was determined to verify the insertion of ferulic acid into the polymeric backbone. Finally, the antioxidant and antifungal activities were demonstrated toward the hydroxyl radical and Aspergillus niger, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

壳聚糖烷基化改性及其纳米微球负载扑热息痛的研究

将低分子量壳聚糖经长链烷基在碱性条件下改性制得烷基化壳聚糖衍生物 ,红外光谱研究表明取代反应主要发生在壳聚糖的氨基上 ,透射电镜研究表明该衍生物在水中可自动形成粒径分布在 1 0 0nm左右的纳米微粒。以扑热息痛为模型药物 ,对烷基壳聚糖纳米微球在磷酸缓冲液 (pH =7 4)中体外释放的研究表明 ,在取代度接近的情况下 ,随着烷基链的增长 ,扑热息痛在磷酸缓冲液中的缓释作用得到改善 ,累积达到平衡时的浓度降低。     

Shape control synthesis of polymeric hybrid nanoparticles via surface‐initiated atom‐transfer radical polymerization

Polymeric hybrid nanoparticles were synthesized via surface‐initiated atom‐transfer radical polymerization (SI‐ATRP) method on the surface of gold nanoparticles in cyclohexanone. Tetraoctyl ammonium bromide (TOAB) as a phase transfer agent was used to transfer the gold nanoparticles into cyclohexanone, which will be replaced by disulfide initiator on the surface of gold nanoparticles. Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and UV–vis spectroscopy were utilized to characterize the product to make sure the experiment had been conducted. The results showed that the polymeric gold hybrid nanoparticles with different structures could be controlled by adjusting the ratio of initiator and gold nanoparticles in ATRP. If the ratio is very little, asymmetric polystyrene–gold hybrid nanoparticles were synthesized, and a single gold nanoparticle was attached with a polystyrene sphere. If the ratio becomes larger, core–shell polystyrene–gold nanocomposite particles were obtained resulting in gold nanoparticle encapsulated by a uniform polymer shell. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43584.     

Incorporation of high oil content in polyvinyl acetate nanoparticles produced by batch miniemulsion polymerization stabilized with a polymeric stabilizer

Nanoparticles (NPs) have been widely applied in the biomedical area. In order to satisfy the requirements for biomedical applications, sodium lauril sulfate (SLS) and hexadecane, widely used as anionic surfactant and co‐stabilizer, were successfully replaced by biocompatible compounds, in order to obtain poly(vinyl acetate) (PVAc) NPs via miniemulsion polymerization. The incorporation of high oil content in PVAc NPs was investigated, using different poly(vinyl alcohol) (PVOH) concentrations as polymeric surfactant. Besides the polymeric surfactant, lecithin and Miglyol 812, a triacylglycerol of saturated fatty acids obtained from coconut oil, were used as surfactant and co‐stabilizer, respectively. A high Miglyol 812 content was incorporated in the PVAc NPs and the morphology was investigated by TEM. The influence of PVOH concentration on the droplet nucleation mechanism and final morphology of PVAc NPs was evaluated. High PVOH concentration favored micellar particle nucleation. According to the TEM images, hemispheres nanoparticles were obtained. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41365.     

Synthesis, surface modification and photocatalytic property of ZnO nanoparticles

ZnO nanoparticles were synthesized by calcination of precursor prepared by the precipitation method. Polystyrene was grafted onto the surface of ZnO nanoparticles to improve the dispersion of the particles and to reduce their photocatalytic activity. The obtained particles were characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction, and transmission electron microscopy. The photocatalytic activity of bare and modified ZnO nanoparticles was studied. The influence of surface modification on the photocatalytic degradation of methyl orange has been analyzed. The composition of residual solution was determined through high performance liquid chromatography. Experimental results show that well dispersed ZnO nanoparticles were obtained after surface modification. ZnO nanoparticles possess high photocatalytic activity, whereas the photocatalytic activity can be significantly reduced when polystyrene was grafted onto the particle surface.     

Preparation of nanoparticles composed of chitosan and its derivatives as delivery systems for macromolecules

Three different kinds of nanoparticles for paracellular transport were prepared using a simple and mild ionic‐gelation method. Sodium tripolyphosphate (TPP) as crosslinking agent was added into three kinds of solutions, which were chitosan solution, physical blending solution of chitosan, and glycidyl trimethylammonium chloride (GTMAC), and O‐(2‐hydroxyl) propyl‐3‐trimethyl ammonium chitosan chloride (O‐HTCC) solution respectively. O‐HTCC was synthesized by coupling of GTMAC to chitosan whose functional groups of the NH₂ groups were protected. The nanoparticles were characterized by transmission electron microscopy, atomic force microscopy, photon correlation spectroscopy, and zeta potential measurement. The results showed that increasing TPP concentration promoted the size of chitosan nanoparticles, a decrease in the size of O‐HTCC nanoparticles incurred on the contrary. The size of O‐HTCC nanoparticles is slightly bigger than that of pure chitosan nanoparticles, and smaller than that of physical blending nanoparticles (PBN). Bovine serum albumin (BSA), as a model protein drug, was incorporated into the nanoparticles. Compared with chitosan nanoparticles and PBN, high BSA loading efficiency (87.5%) and loading capacity (99.5%) are achieved by quaternized chitosan (O‐HTCC) nanoparticles, and the release profile of BSA from nanoparticles has an obvious burst effect and a slowly continuous release phase followed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007