RSC Advances
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2016
·Vol. 6
·期 38
·31934-31946
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IF 3.289
Wei-Wei Wang,Long Jiang,Wu-Yang Ren,Chun-Mei Zhang,Chang-Zhen Man,Thien-Phap Nguyen,Yi Dan
In this paper a series of di-block copolymers of L-lactide and (meth)acrylate [(M)A, representing methyl methacrylate, tert-butyl acrylate and 2-ethylhexyl acrylate] were synthesized by varying the molecular weight of the polylactide (PLLA) macroinitiator and the structure of the (meth)acrylate monomers. The glass transition temperature, crystallinity and thermal stability of copolymers with different poly(meth)acrylate [P(M)A] blocks were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results indicated that the glass transition temperature of the copolymers could be tuned by changing the chain structure and chain length of the P(M)A blocks. Besides, the crystallization of the copolymers was inhibited by the introduction of P(M)A blocks, and the toughness of the copolymers could be tuned. It is noted that the thermal stability of the copolymers depended on the type of P(M)A blocks and the PLLA/P(M)A blocks ratio. Furthermore, the microphase separation of copolymers in thin films was observed by atomic force microscopy (AFM) and scanning electron microscopy (SEM), and the results showed that the composition of copolymers significantly affected the surface morphology of the block copolymer thin films.
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RSC Advances
·
2016
·Vol. 6
·期 106
·104193-104200
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IF 3.289
Lili Lv,Lijuan Wang,Yanan Zou,Rui Chen,Jiaojiao Yu
A chiral nonaqueous capillary electrophoresis (NACE) method using L-sorbose–boric acid complexes as the chiral ion-pair selectors was developed for enantioseparation of nineteen chiral analytes including eight β-blockers, seven β-agonists, two phenothiazines antihistamines, and two fluoroquinolone antibiotics. The effects of L-sorbose and boric acid concentrations, triethylamine concentration, applied voltage, and capillary temperature on the enantioseparation were systematically investigated. Under the optimized conditions, thirteen pairs of enantiomers were baseline resolved and five pairs of enantiomers were partially enantioseparated. Salbutamol showed a sign of separation with a shoulder peak. A reversal of propranolol enantiomer migration orders took place in the case when different concentrations of triethylamine were added into the NACE running buffers. The mass spectrometry (MS) results confirmed that triethylamine could promote the formation of negatively charged L-sorbose–boric acid complex chiral counter ions with different complex ratios. The enantioseparation results were compared with the previous work. Calibration curves showed excellent linearity with square of correlation coefficients (r2) greater than 0.9994 over concentration ranges of 5.0–500.0 μg mL−1 for each enantiomer of clenbuterol and esmolol, and 12.5–500.0 μg mL−1 for that of metoprolol. The limits of detection (LODs) and limits of quantitation (LOQs) for each enantiomer were 0.4–1.25 μg mL−1 and 1.5–4.0 μg mL−1, respectively. The relative standard deviations (RSDs) of intra-day and inter-day precisions of migration times were ≤1.64% (n = 6), and ≤6.54% (n = 15), respectively. The peak areas were ≤4.03% (n = 6), and ≤3.92% (n = 15), respectively. This method can likely be applied to the determination of each enantiomer in pharmaceutical formulations.
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Journal of Food Measurement and Characterization
·
2016
·Vol. 11
·期 2
·548-555
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IF 0.521
Xiaohong Zhang,Zhidong Zhao,Xiongwei Lou,Jian Li,Guohua Hui
A maltose, L-rhamnose sensor based on porous Cu foam and electrochemical techniques was investigated in this paper. Cu foam material was prepared and characterized by scanning electron microscopy (SEM). The electro-oxidation reaction process of sweeteners occurred on Cu foam electrode was evaluated by cyclic voltammetry (CV) scanning. At an applied potential of 0.5 V, the linear range for maltose is 0.18–3.47 mM with sensitivity of 1.0492 mA cm −2 mM −1 . The limit of detection (LOD) was 15.86 μM (S/N = 3). The linear range for maltose is 0.18–3.47 mM with sensitivity of 0.6881 mA cm −2 mM −1 . The LOD was 24.18 μM (S/N = 3). Compared with Cu sheet electrode, Cu foam electrode showed higher current response towards maltose and L-rhamnose, leading to enhanced electrocatalytic activity, higher sensitivity, and lower LOD. Sweetener qualitative discrimination was carried out by stochastic resonance (SR) signal-to-noise ratio (SNR) spectrum eigen peak located noise intensities.
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JOURNAL OF POLYMER SCIENCE
·
2024
·
IF 3.9
Kun Li,Shaojuan Chen,Shaohua Wu
An approach that combines a modified electrospinning method with thermal stretching post-treatment is designed to fabricate poly(l-lactide-co-ε-caprolactone) (PLCL) electrospun nanofiber yarns (ENYs). The nanofiber diameter in the PLCL ENYs is found to present an increasing trend with the increasing of polymeric concentration. When the PLCL concentration reaches 13% (w/v), the as-generated ENYs show bead-free and uniform nanofibrous structure. Then, a thermally stretching technique is applied to process the primarily-obtained PLCL ENYs. When the stretching temperature is set as 60 °C, the thermally-stretched PLCL ENYs present superior fiber orientation and notably enhanced crystallinity, thus resulting in dramatically increased mechanical properties. Finally, the thermally stretched PLCL ENYs are further processed into braided fabrics, and their mechanical properties are found to possess an obviously increased trend with the increasing of ENY numbers, demonstrating the adjustment feasibility of the mechanical properties of ENY-based textiles by controlling the ENY numbers. Importantly, the in vitro cell studies demonstrate that the ENY-based braided textiles significantly support the adhesion and proliferation of human dermal fibroblasts (HDFs). In all, the present study provides an easily-handling strategy to fabricate high performance PLCL ENYs, which shows promising future for the generation of advanced biomedical textiles. Graphical
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Journal of Science-Advanced Materials and Devices
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2024
·
IF 6.7
Tien Dung Nguyen,Thuy Chinh Nguyen,Xuan Thai Nguyen,Thi Kim Anh Nguyen,Thao Linh Bui,Thanh Thuy Tran,Hoang Thai
Hydrotalcite-Ag nanoparticles (HT-Ag NPs) have garnered significant attention in research due to their remarkable antibacterial activity and excellent photocatalytic properties. Consequently, they have been utilized in various fields, such as pharmaceuticals, medicine, electronics, and environmental treatment. However, the synthesis of HT-Ag nanoparticles often involves the use of NaBH 4 , a chemical reducing agent, to reduce Ag (I) ions and form Ag NPs on HT. Nevertheless, the residue of chemical reducing agents can lead to environmental pollution as above mentioned. The approach of utilizing plant extracts for the synthesis of Ag NPs decorated on HT has captivated many scientists due to its eco-friendly and environmentally sustainable process. Additionally, the plant extract plays a crucial role in stabilizing Ag NPs within HT-Ag structures. This paper presents a green synthesis of hydrotalcite-silver (HT-Ag) nanosheets using an AgNO 3 salt solution as a precursor and areca ( Areca catechu L.) nut extract as a reducing agent. The HT nanosheets, synthesized by a co-precipitation method combined with a hydrothermal method, exhibited an ordered lamellar layer structure. The areca seed extract in 99.5 % ethanol solvent acts as a reducing agent to convert Ag(I) ions into silver nanoparticles (Ag NPs). The presence of Ag NPs on the surface of HT nanosheets was confirmed using UV–Vis spectroscopy, XRD, AAS, HR-TEM, and SEM methods. The results indicated that Ag NPs are spherical in shape and uniformly dispersed on the surface of HT. The particle size of Ag NPs ranged from 15 nm to 40 nm. The yield of the Ag NPs synthesis process on HT ranged from 60.79 % to 85.89 %, depending on the concentration of AgNO 3 salt solution. The antibacterial properties, including their effectiveness against E. coli and S. aureus , were tested using the agar well diffusion method to determine the zone of inhibition. The minimum inhibitory concentration (MIC) value of HT-Ag nanosheets has also been evaluated. Specifically, the study focused on evaluating the antibacterial activity of HT-Ag nanosheets using a marine Gram-negative bacterium, P. stutzeri B27, to explore their potential applications in materials designed for use in marine environments. Furthermore, the durability of HT-Ag nanosheets was assessed. The obtained results demonstrated that the Ag NPs decorated on HT exhibited excellent antibacterial activity against E. coli , S. aureus , and P. stutzeri B27, making them suitable for applications as antibacterial and enhancing additives for polymer systems, particularly in materials used in marine environments.
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MICROCHEMICAL JOURNAL
·
2024
·
IF 4.9
Juan Hou,Qinqin Chen,Xiangzhi Meng,Donghan Wang,Huiling Liu,Wei Feng
The increasing presence of heavy metals and amino acids in environmental and pharmaceutical samples necessitates the development of effective and sensitive detection methods. Traditional analytical techniques often lack the specificity and sensitivity required for simultaneous detection of multiple analytes, leading to a need for novel approaches. In this study, we developed a ratiometric fluorescence probe based on a physical mixture of red and blue carbon dots (R/BCDs) for the selective detection of lead ions (Pb 2+ ) and L-cysteine (L-Cys). The probe was synthesized through hydrothermal methods and characterized by various spectroscopic techniques. The R/BCDs probe exhibited a remarkable 11.6-fold fluorescence quenching in response to Pb 2+ , with a detection limit of 15 nM, while subsequent addition of L-Cys showed a 9.6-fold restored fluorescence signal, achieving a detection limit of 75 nM. Additionally, we demonstrated the feasibility of fabricating colorimetric test paper and hydrogels, enabling rapid on-site analysis. This dual-analyte detection capability was demonstrated through successful application in real water and pharmaceutical samples. The R/BCDs probe offers a novel, simple, and effective strategy for environmental monitoring and biological assessments, highlighting its potential for practical applications.
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JOURNAL OF HAZARDOUS MATERIALS
·
2024
·
IF 12.2
Wenyu Li,Wei Ma,Yang Yang,Huan He,Baiyang Chen
Concerns have recently arisen regarding the formation of carcinogenic and genotoxic iodinated haloacetic acids (HAAs), such as monoiodoacetic acid (MIAA), during the disinfection of iodine-containing water with chloramine. Existing detection methods for MIAA rely on either labor-intensive derivatization operations or expensive instruments, making analysis challenging. To bypass these issues, this study proposed a novel two-step liquid-liquid extraction strategy to enrich MIAA and then pioneered the integration of common ion chromatography (IC) with an ultraviolet detector to measure trace MIAA precisely. This novel approach achieved a remarkable 155.6-fold enrichment of MIAA and significantly reduced the need for water and chemicals, hence enhancing its efficiency and environmental friendliness. Besides, this method effectively removed coexisting anions and separated MIAA from other interferents by adjusting IC column and eluent conditions. The method detection limit of MIAA is an impressive 21.44 ng/L, and the recoveries in synthetic and real water samples ranged from 85 to 113%, with maximum deviations of 7.59%. We validated the reliability of our approach by comparing it with the USEPA 552.3 method. In conclusion, this IC-based method proves to be a robust and environment-benign solution for detecting trace MIAA in complex water components.
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Journal of Functional Foods
·
2017
·
IF 3.144
Chongyang Jin,Hualin Wang,Minmin Chen,Suwei Jiang,Qiusheng Song,Min Pang,Shaotong Jiang
A facile strategy was developed to fabricate zinc (II) functionalized l -phenylalanine in situ grafted starch (Zn(II)@ l -Phe-g-St). The structure of Zn(II)@ l -Phe-g-St was proposed and well characterized, and the assays of antibacterial activity against typical bacteria ( Bacillus subtilis and Escherichia coli ) and cytotoxicity of Hela cell were focused on. Boc- l -phenylalanine was used to achieve l -Phe-g-St by in situ grafting onto starch through esterification reaction after removal of Boc. It was confirmed that around 71.02% of NH 2 of l -Phe complexed with Zn(II) by σ-coordinate bonds and the coordination number of Zn(II) approximated to 2. Zn(II)@ l -Phe-g-St exhibited a good antibacterial activity against both Bacillus subtilis and Escherichia coli with increasing its concentration, and a relatively more effective antibacterial activity against Bacillus subtilis than Escherichia coli . Furthermore, Zn(II)@ l -Phe-g-St was found to be very low toxicity towards Hela cells especially at the concentration below 40 μg ml −1 .
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Materials Science & Engineering C-Materials for Biological Applications
·
2017
·
IF 4.164
Le Pan,Yanjie Li,Lin Zhu,Buchang Zhang,Yuhua Shen,Anjian Xie
In this study, the poly (ethylene glycol) double acrylates (PEGDA) was first initiated by Spinacia oleracea L. extract (SOLE) to in situ form a polymer hydrogel shell on Hela cells with near infra-red irradiation. The SOLE was also a natural photosensitizer for photodynamic therapy of tumor. The use of SOLE is simple, eco-friendly, low cost, and convenient. More importantly, the PEGDA/SOLE composite hydrogel shell on Hela cells not merely prevents SOLE from diffusing to normal tissue for reducing the side effects, but also keeps high SOLE concentration on tumor cell for improving the antitumor effect. Such a hydrogel system has good biocompatibility and exhibits high therapeutic efficacy. This study extended the application of the SOLE/PEGDA gel in photodynamic therapy.
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RSC Advances
·
2017
·Vol. 7
·期 24
·14888-14901
·
IF 3.108
Shifeng Yan,Yuanyuan Sun,An Chen,Lei Liu,Kunxi Zhang,Guifei Li,Yourong Duan,Jingbo Yin
A novel class of pH-responsive hollow poly(L-glutamic acid)/chitosan (PLGA/CS) nanogels was fabricated by a templating approach, which was mild and surfactant free, and combined with a “grafting from” method and intermacromolecular crosslinking technique. The surface grafting, crosslinking reaction, nanogel fabrication and microstructure were investigated by FTIR, 1H NMR, XRD, TGA, light scattering, and electron microscopy. The size of the resultant PLGA/CS nanogels could be accurately controlled by simply changing the size of the silica template. The nanogels responded to changes in environmental pH, elucidated according to the variation of the size of the nanogels and zeta potential at different pH values. Taking water-soluble antineoplastic agent mitoxantrone (MTX) as a model drug, the nanogels presented high loading ability at high-pH environment and rapid MTX release behavior under acidic conditions. MTT assays used to study the in vitro cytotoxicity of PLGA/CS nanogels showed a negligible cytotoxicity in mouse fibroblast L929 cells. Compared with bare MTX, MTX loaded PLGA/CS nanogels exhibited an enhanced inhibition effect to human gastric carcinoma SGC7901 cells. Fluorescence microscopy and flow cytometry analysis results demonstrated efficient cellular uptake of the PLGA/CS nanogels into the cells. These studies suggest that such pH-responsive PLGA/CS hollow nanogels might have great potential in controlled drug delivery systems.
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Journal of Materials Chemistry B
·
2024
·Vol. 12
·期 45
·11696-11707
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IF 6.1
Songyan Guo,Youbei Qiao,Chaoli Wang,Yuming Zhang,Tiehong Yang,Hong Wu
Nanoparticles (NPs) derived from branched copolymers of poly (β-L-malic acid) (PMLA) have been extensively investigated for drug delivery due to their high density of pendant carboxyl groups. This abundant functional group availability enhances their potential as effective drug delivery systems; however, the strong negative charge of PMLA poses a challenge in its uptake by cancer cells due to electrostatic repulsion. In this study, we developed novel enzyme- and pH-sensitive nanoparticles (EP-NPs) based on PMLA, demonstrating tumor-specific behavior and selective activation within tumor tissues. To enhance the cellular internalization of the nanoparticles, we incorporated transactivator of transcription (TAT). In summary, long-chain polyethylene glycol (PEG) was conjugated to PMLA to confer specificity to the TAT peptide. This was achieved using a tetrapeptide linker: alanine–alanine–asparagine–leucine (AANL), which serves as a substrate for legumain. Legumain is a highly conserved cysteine protease primarily found in lysosomes and blood vessels, initially discovered in legumes. It is markedly overexpressed in numerous solid tumors, as well as in endothelial cells and tumor-associated macrophages. The release of doxorubicin in tumor cells was sustained due to the low pH (5.0–5.5) and degradation of PMLA. The PEG modification optimized the particle size and shielded the nanoparticles from plasma proteins and detection by the reticuloendothelial system, thereby prolonging their long circulation time. Once the nanoparticles reached the tumor microenvironment, the AANL was cleaved by legumain, exposing the TAT peptide on the surface, which enhances cellular internalization. Both in vitro and in vivo efficacy studies demonstrated that these EP-NPs significantly inhibited tumor growth while exhibiting negligible systemic toxicity, thereby suggesting that the developed enzyme/pH-sensitive PMLA-based nanoparticle holds great promise as an anti-tumor drug delivery system.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Rui Luo,Dongyi Xian,Feng Li,Guiling Zhou,Ling Jiang,Jieyi Wu,Liming Lin,Yuwei Zheng,Guanyu Liu,Qian Xu,Xin Pan,Chuanbin Wu,Tingting Peng,Guilan Quan,Chao Lu
The development of antibiotic-loaded microneedles has been hindered for years by limited excipient options, restricted drug-loading space, poor microneedle formability, and short-term drug retention. Therefore, this study proposes a dissolving microneedle fabricated from the host-defense peptide ε-poly- l -lysine (EPL) as an antibacterial adjuvant system for delivering antibiotics. EPL serves not only as a major matrix material for the microneedle tips, but also as a broad-spectrum antibacterial agent that facilitates the intracellular accumulation of the antibiotic doxycycline (DOX) by increasing bacterial cell membrane permeability. Furthermore, the formation of physically crosslinked networks of EPL affords microneedle tips with improved formability, good mechanical properties, and amorphous nanoparticles (approximately 7.2 nm) of encapsulated DOX. As a result, a high total loading content of both antimicrobials up to 2319.1 μg/patch is achieved for efficient transdermal drug delivery. In a Pseudomonas aeruginosa -induced deep cutaneous infection model, the EPL microneedles demonstrates potent and long-term effects by synergistically enhancing antibiotic activities and prolonging drug retention in infected lesions, resulting in remarkable therapeutic efficacy with 99.91 % (3.04 log) reduction in skin bacterial burden after a single administration. Overall, our study highlights the distinct advantages of EPL microneedles and their potential in clinical antibacterial practice when loaded with amorphous DOX nanoparticles.
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