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1.
Pharm Dev Technol ; 25(7): 892-898, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32321344

ABSTRACT

Praziquantel (PZQ), a broad spectrum anthelmintic drug, cannot be found in acceptable dosage forms for elderly patients, paediatric patients, and for veterinary use. In fact, very little has been done up to now in the formulation of liquid dosage forms, being they always formulated for parenteral administration. To beat this important challenge, it was accomplished a comprehensive analysis of the influence of two elementary physicochemical aspects, i.e. surface thermodynamic and electrokinetic properties, on the colloidal stability of PZQ nanosuspensions. The hydrophobic character of the drug, intensely determining the flocculation curves, was confirmed by the thermodynamic characterization. The electrophoretic characterization, in combination with the sedimentation and relative absorbance versus time curves, highlighted that the electrical double layer thickness and the surface charge can play an essential role in the stability of the pharmaceutical colloid. Finally, it was demonstrated that controlling the pH values and the incorporation of electrolytes can help in formulating PZQ aqueous nanosuspensions with appropriate stability and redispersibility behaviours for pharmaceutical use.


Subject(s)
Anthelmintics/chemical synthesis , Drug Compounding/methods , Nanospheres/chemistry , Praziquantel/chemical synthesis , Anthelmintics/pharmacokinetics , Chemistry, Pharmaceutical/methods , Electrolytes/chemical synthesis , Electrolytes/pharmacokinetics , Hydrogen-Ion Concentration , Hydrophobic and Hydrophilic Interactions , Nanospheres/metabolism , Praziquantel/pharmacokinetics , Water/chemistry , Water/metabolism
2.
Int J Biol Macromol ; 155: 131-141, 2020 Jul 15.
Article in English | MEDLINE | ID: mdl-32224186

ABSTRACT

Carbon aerogel with various morphology and structural characteristics were prepared from chitosan by freeze drying-carbonization/activation process. The carbon aerogel obtained without activation (CNS-800) exhibited sheet structure and disordered micropores, N mostly existing in the forms of N-5 and N-6 groups. After phosphoric acid activation (CNSP-800), a 3D-honeycomb structure with long-range ordered pore channels was presented, with N-X being the main nitrogen-containing groups, some P-O/P=O and PC groups were also detected. KOH activation of CNS (CNSK-800) led to the formation of incomplete 3D-mesh structure and some graphite-like structure, which is the most unordered structure attributed to the high intense of KOH activation. All the samples showed micro-mesoporous structure, the specific surface area of CNS-800, CNSk-800 and CNSP-800 were 421, 1215 and 1475 m2/g, respectively. When used as electrode in the three-electrode supercapacitor, the capacitance values of 171, 318 and 416 F/g were obtained at 1 A/g in 1 M H2SO4 electrolyte for CNS-800, CNSK-800 and CNSP-800, with the pseudo capacitance contribution rates of 25.4%, 31.6% and 37.6% respectively. Additionally, the capacitance values were 98, 126 and 168 F/g in the two-electrode system respectively, and their energy densities reached 3.35, 4.69 and 6.36 Wh/kg at a power density of 25 W/kg accordingly.


Subject(s)
Carbon/chemistry , Chitosan/chemistry , Gels , Electric Capacitance , Electrolytes/chemical synthesis , Electrolytes/chemistry , Gels/chemical synthesis , Gels/chemistry , Porosity
3.
Macromol Rapid Commun ; 41(9): e2000047, 2020 May.
Article in English | MEDLINE | ID: mdl-32249484

ABSTRACT

A series of copolymers are prepared via cationic ring-opening polymerization with 1,3-dioxolane (DOL) and trioxymethylene (TOM) as monomers. The crystallization behaviors of the copolymers can be suppressed by adjusting the ratio of DOL/TOM. With LiBF4 as a source for a BF3 initiator, copolymer electrolytes (CPEs) can be prepared in situ inside cells without needing nonelectrolyte catalysts or initiators. The ionic conductivities and Li+ diffusion coefficients ( D Li + ) of the CPEs increase with a decreasing DOL/TOM ratio in a certain range. The CPE with a DOL/TOM ratio of 8/2 has the highest ionic conductivity as well as D Li + and shows excellent interfacial compatibility with lithium (Li) metal anodes. Li-Li symmetric cells can be uniformly plated/stripped for more than 1200 h. Furthermore, LiFePO4 -Li cells with 8/2-CPE display stable cycling performance for over 400 cycles. This strategy is a promising approach for the preparation of high-performance polymer electrolytes and is sure to promote their application in Li metal batteries.


Subject(s)
Dioxolanes/chemistry , Formaldehyde/chemistry , Polymers/chemistry , Electrolytes/chemical synthesis , Electrolytes/chemistry , Molecular Structure , Polymerization , Polymers/chemical synthesis
4.
Mol Inform ; 38(10): e1900014, 2019 10.
Article in English | MEDLINE | ID: mdl-31166649

ABSTRACT

We report the building, validation and release of QSPR (Quantitative Structure Property Relationship) models aiming to guide the design of new solvents for the next generation of Li-ion batteries. The dataset compiled from the literature included oxidation potentials (Eox ), specific ionic conductivities (κ), melting points (Tm ) and boiling points (Tb ) for 103 electrolytes. Each of the resulting consensus models assembled 9-19 individual Support Vector Machine models built on different sets of ISIDA fragment descriptors.(1) They were implemented in the ISIDA/Predictor software. Developed models were used to screen a virtual library of 9965 esters and sulfones. The most promising compounds prioritized according to theoretically estimated properties were synthesized and experimentally tested.


Subject(s)
Computer Simulation , Drug Evaluation, Preclinical , Electrolytes/chemistry , Electrolytes/chemical synthesis , Solvents/chemistry , Solvents/chemical synthesis , Electric Conductivity , Electric Power Supplies , Electrochemical Techniques , Electrolytes/analysis , Esters/chemical synthesis , Esters/chemistry , Lithium/chemistry , Models, Molecular , Molecular Structure , Quantitative Structure-Activity Relationship , Software , Solvents/analysis , Sulfones/chemical synthesis , Sulfones/chemistry , Support Vector Machine
5.
Molecules ; 24(6)2019 Mar 14.
Article in English | MEDLINE | ID: mdl-30875749

ABSTRACT

In recent years, the synthesis of polymer electrolyte systems derived from biopolymers for the development of sustainable green electrochemical devices has attracted great attention. Here electrolytes based on the red seaweeds-derived polysaccharide κ-carrageenan (κ-Cg) doped with neodymium triflate (NdTrif3) and glycerol (Gly) were obtained by means of a simple, clean, fast, and low-cost procedure. The aim was to produce near-infrared (NIR)-emitting materials with improved thermal and mechanical properties, and enhanced ionic conductivity. Cg has a particular interest, due to the fact that it is a renewable, cost-effective natural polymer and has the ability of gelling in the presence of certain alkali- and alkaline-earth metal cations, being good candidates as host matrices for accommodating guest cations. The as-synthesised κ-Cg-based membranes are semi-crystalline, reveal essentially a homogeneous texture, and exhibit ionic conductivity values 1⁻2 orders of magnitude higher than those of the κ-Cg matrix. A maximum ionic conductivity was achieved for 50 wt.% Gly/κ-Cg and 20 wt.% NdTrif3/κ-Cg (1.03 × 10-4, 3.03 × 10-4, and 1.69 × 10-4 S cm-1 at 30, 60, and 97 °C, respectively). The NdTrif-based κ-Cg membranes are multi-wavelength emitters from the ultraviolet (UV)/visible to the NIR regions, due to the κ-Cg intrinsic emission and to Nd3+, 4F3/2→4I11/2-9/2.


Subject(s)
Biopolymers/chemistry , Carrageenan/chemistry , Electrolytes/chemistry , Glycerol/chemistry , Biopolymers/radiation effects , Carrageenan/chemical synthesis , Electric Conductivity , Electrolytes/chemical synthesis , Gels/chemical synthesis , Gels/chemistry , Glycerol/chemical synthesis , Luminescence , Neodymium/chemistry , Ultraviolet Rays
6.
PLoS One ; 14(2): e0212066, 2019.
Article in English | MEDLINE | ID: mdl-30768616

ABSTRACT

For the past decade, much attention was focused on polysaccharide natural resources for various purposes. Throughout the works, several efforts were reported to prepare new function of chitosan by chemical modifications for renewable energy, such as fuel cell application. This paper focuses on synthesis of the chitosan derivative, namely, O-nitrochitosan which was synthesized at various compositions of sodium hydroxide and reacted with nitric acid fume. Its potential as biopolymer electrolytes was studied. The substitution of nitro group was analyzed by using Attenuated Total Reflectance Fourier Transform Infra-Red (ATR-FTIR) analysis, Nuclear Magnetic Resonance (NMR) and Elemental Analysis (CHNS). The structure was characterized by X-ray Diffraction (XRD) and its thermal properties were examined by using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Whereas, the ionic conductivity of the samples was analyzed by electrochemical impedance spectroscopy (EIS). From the IR spectrum results, the nitro group peaks of O-nitrochitosan, positioned at 1646 and 1355 cm-1, were clearly seen for all pH media. At pH 6, O-nitrochitosan exhibited the highest degree of substitution at 0.74 when analyzed by CHNS analysis and NMR further proved that C-6 of glucosamine ring was shifted to the higher field. However, the thermal stability and glass transition temperatures were decreased with acidic condition. The highest ionic conductivity of O-nitrochitosan was obtained at ~10-6 cm-1. Overall, the electrochemical property of new O-nitrochitosan showed a good improvement as compared to chitosan and other chitosan derivatives. Hence, O-nitrochitosan is a promising biopolymer electrolyte and has the potential to be applied in electrochemical devices.


Subject(s)
Biopolymers/chemistry , Chitosan/chemistry , Dielectric Spectroscopy/methods , Electrolytes/chemistry , Dielectric Spectroscopy/instrumentation , Electric Conductivity , Electrolytes/chemical synthesis , Magnetic Resonance Spectroscopy , Spectroscopy, Fourier Transform Infrared , Temperature
7.
Carbohydr Polym ; 182: 81-91, 2018 Feb 15.
Article in English | MEDLINE | ID: mdl-29279130

ABSTRACT

A water soluble derivative in 98% yield with 23.1% incorporation of maleoyl groups was obtained by esterification of agarose with maleic anhydride. Graft copolymers were synthesized through vinyl groups of maleoylagarose with N-isopropylacrylamide using ceric ammonium nitrate or ammonium persulfate as initiator, by conventional method or microwave irradiation. High nitrogen content (4.6%) was obtained in the grafting process using ceric ammonium nitrate as initiator without microwave irradiation. Copolymers were characterized by FT-IR and NMR spectroscopies, TGA, DSC and morphological analysis by AFM and SEM microscopy, confirming the grafting of PNIPAAm onto polysaccharide backbone. Hydrogel films were obtained by ionic complexation between opposite charged groups of maleoylagarose-g-poly(N-isopropylacrylamide) and chitosan. The swelling of 1:1w/v maleoylagarose-g-PNIPAAm:chitosan film was higher than 2:1w/v film at 25 and 37°C. 53% release in vitro of diclofenac sodium from 1:1w/v maleoylagarose-g-PNIPAAm:chitosan was obtained at 37°C and pH 6.0 with <0.5 diffusional constant values.


Subject(s)
Acrylic Resins/chemistry , Chitosan/chemistry , Electrolytes/chemical synthesis , Electrolytes/chemistry
8.
ACS Appl Mater Interfaces ; 8(25): 15937-47, 2016 Jun 29.
Article in English | MEDLINE | ID: mdl-27267787

ABSTRACT

Near-infrared (NIR) fluorophores attract increasing attention as a molecular marker (or probe) for in vivo and in vitro biological fluorescence imaging. Three types of new NIR fluorescent conjugated oligoelectrolytes (COEs: Q-FlTBTTFl, Q-FlBBTFl, and Q-FlTBBTTFl) are synthesized with quaternized ammonium ionic groups in their side-chains for water solubility. The emission wavelength is modulated in the range 600-1300 nm, by adjusting the intramolecular charge transfer in the molecular backbone based on the electron-rich fluorene (and/or thiophene) and electron-deficient benzo[2,1,3]thiadiazole (or benzo[1,2-c:4,5-c']bis[1,2,5]thiadiazole) moieties. The COEs show a remarkably larger Stokes shift (147-276 nm) compared to commercial rhodamine and cyanine dyes in water, avoiding self-quenching and interference from the excitation backscattered light. The photoluminescence (PL) quantum efficiency is improved substantially by up to 27.8% in water by fabricating a vesicular complex, COE/v, with a block ionomer, poly[(ethylene oxide)-block-(sodium 2-acrylamido-2-methyl-1-propanesulfonate)]. In vitro cellular uptake images with the COEs are obtained with good biocompatibility by confocal single-photon and two-photon microscopy. The ex vivo and in vivo images of a mouse xenograft model treated with the Q-FlBBTFl/v exhibit a substantially stronger fluorescence signal at the tumor site than at the other organs, highlighting the potential of the COE/v as an NIR fluorescent imaging agent for the diagnosis of cancer.


Subject(s)
Electrolytes/chemical synthesis , Fluorescent Dyes/chemical synthesis , Optical Imaging/methods , Water/chemistry , Animals , Electrolytes/chemistry , Fluorescent Dyes/chemistry , Mice , Neoplasms/diagnostic imaging
9.
Sci Rep ; 6: 24499, 2016 Apr 19.
Article in English | MEDLINE | ID: mdl-27091631

ABSTRACT

Electrochemical device with components having direct significance to biological life processes is a potent futuristic strategy for the realization of all-round green and sustainable development. We present here synthesis design, structural analysis and ion transport of a novel solid organic electrolyte (G7Li), a compound reminiscent of ion channels, derived from regioisomeric N7-guanine-carboxylate conjugate and Li-ions. G7Li, with it's in-built supply of Li(+)-ions, exhibited remarkably high lithium-ion transference number (= 0.75) and tunable room temperature ionic conductivity spanning three decades (≈10(-7) to 10(-3) Ω(-1) cm(-1)) as a function of moisture content. The ionic conductivity show a distinct reversible transition around 80-100 °C, from a dual Li(+) and H(+) (<100 °C) to a pure Li(+) conductor (>100 °C). Systematic studies reveal a transition from water-assisted Li-ion transport to Li hopping-like mechanism involving guanine-Li coordination. While as-synthesized G7Li has potential in humidity sensors, the anhydrous G7Li is attractive for rechargeable batteries.


Subject(s)
Electrolytes/chemistry , Guanine/chemistry , Lithium/chemistry , Electric Conductivity , Electrolytes/chemical synthesis , Guanine/analogs & derivatives , Guanine/chemical synthesis , Ion Channels/chemistry , Ion Transport , Ions/chemistry , Water/chemistry
10.
Macromol Rapid Commun ; 37(14): 1168-74, 2016 Jul.
Article in English | MEDLINE | ID: mdl-26924313

ABSTRACT

A diepoxy-functionalized 1,2,3-triazolium ionic liquid is synthesized in three steps and used in combination with a poly(propylene glycol) diamine to obtain ion-conducting epoxy-amine networks (EANs). The curing kinetics are followed by Fourier transform infrared spectroscopy, while the physical, mechanical, and ion-conducting properties of the resulting networks are studied by swelling experiments, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical thermal analysis, and broadband dielectric spectroscopy. The curing kinetics and thermomechanical properties of this system are relatively similar to those of conventional DGEBA- (bisphenol A diglycidyl ether)-based EANs with low glass transition temperature (Tg = -44 and -52 °C, respectively) characteristic of rubbery polymer networks. The anhydrous ionic conductivity of the pure network at 30 °C reaches a remarkably high value of 2 × 10(-7) S cm(-1) that could be further increased to 10(-6) S cm(-1) by the addition of 10 wt% LiTFSI.


Subject(s)
Amines/chemistry , Epoxy Compounds/chemistry , Ionic Liquids/chemistry , Polymers/chemistry , Triazoles/chemistry , Electrolytes/chemical synthesis , Electrolytes/chemistry , Ionic Liquids/chemical synthesis , Ions/chemistry , Kinetics , Molecular Structure , Polymers/chemical synthesis , Temperature , Triazoles/chemical synthesis
11.
Mater Sci Eng C Mater Biol Appl ; 58: 724-9, 2016 Jan 01.
Article in English | MEDLINE | ID: mdl-26478364

ABSTRACT

A new kind of polyelectrolyte complex (PEC) based on cationic chitosan (CS) and anionic poly(2-acry1amido-2-methylpropanesulfonic acid) (PAMPS) was prepared using a polymer-monomer pair reaction system. Chitosan was mixed with 2-acry1amido-2-methylpropanesulfonic acid) (AMPS) in an aqueous solution, followed by polymerization of AMPS. The complex was formed by electrostatic interaction of NH3(+) groups of CS and SO3(-) groups of AMPS, leading to a formation of complex nanoparticles of CS-PAMPS. A series of nanoparticles were obtained by changing the weight ratio of CS to AMPS, the structure and properties of nanoparticles were investigated. It was observed that the nanoparticles possessed spherical morphologies with average diameters from 255 nm to 390 nm varied with compositions of the nanoparticles. The nanoparticles were used as drug vehicles for doxorubicin, displaying relative high drug loading rate and encapsulation rate. The vitro release profiles revealed that the drug release could be controlled by adjusting pH of the release media. The nanoparticles demonstrated apparent advantages such as simple preparation process, free of organic solvents, size controllable, good biodegradability and biocompatibility, and they could be potentially used in drug controlled release field.


Subject(s)
Chitosan/chemistry , Doxorubicin/pharmacology , Drug Liberation , Electrolytes/chemistry , Nanoparticles/chemistry , Polymers/chemistry , Sulfonic Acids/chemistry , Calorimetry, Differential Scanning , Cell Death/drug effects , Electrolytes/chemical synthesis , Hydrogen-Ion Concentration , Molecular Weight , Nanoparticles/ultrastructure , Particle Size , Polymers/chemical synthesis , Sodium Chloride/chemistry , Spectrometry, Fluorescence , Spectroscopy, Fourier Transform Infrared , Static Electricity , Sulfonic Acids/chemical synthesis , Thermogravimetry
12.
ACS Appl Mater Interfaces ; 8(3): 1958-69, 2016 Jan 27.
Article in English | MEDLINE | ID: mdl-26709951

ABSTRACT

The design and development of fluorescent conjugated polyelectrolytes (CPEs) emitting in the red region of the visible spectrum is at present of great interest for bioimaging studies. However, despite the wide variety of CPEs available, stable bright red-emitters remain scarce due to their low solubility and instability in aqueous media, consequently limiting their applications. In this work, we have synthesized and characterized a new red-emitting cationic conjugated polyelectrolyte copoly-{[9,9-bis(6'-N,N,N-trimethylammonium)hexyl]-2,7-(fluorene)-alt-1,4-(naphtho[2,3c]-1,2,5-thiadiazole)} bromide (HTMA-PFNT), based on the incorporation of naphtha[2,3c][1,2,5] thiadiazole on fluorene backbone to increase the bathochromic emission, extending the conjugation length in the polymer backbone. Water stabilization was achieved by binding the polyelectrolyte to two different biological systems which are currently used as nanocarriers: human serum albumin (HSA) and lipid vesicles. Using both systems, stable nanostructures of different composition were obtained and their properties were characterized. The properties of the protein-based nanoparticles are consistent with polyelectrolyte aggregates covered with HSA molecules, while the liposome system is composed of lipid vesicles coated with polyelectrolyte chains partially inserted in the bilayer. Both protein and vesicle structural integrity were not affected after their interaction with HTMA-PFNT, as well as the carrier properties, allowing for the binding and transport of ligands. In addition, the nanoparticles displayed the ability of labeling the cell membrane of living cells. All these results extend the potential applications of these novel multifunctional nanoparticles as therapeutic carriers and bioimaging probes.


Subject(s)
Drug Carriers/chemistry , Electrolytes/chemistry , Light , Molecular Imaging/methods , Molecular Probes/chemistry , Buffers , Cell Line , Circular Dichroism , Electrolytes/chemical synthesis , Humans , Hydrodynamics , Liposomes/chemistry , Models, Theoretical , Nanoparticles/chemistry , Nanoparticles/ultrastructure , Particle Size , Serum Albumin/chemistry , Spectrometry, Fluorescence , Temperature
13.
Langmuir ; 31(41): 11249-59, 2015 Oct 20.
Article in English | MEDLINE | ID: mdl-26421938

ABSTRACT

The formation of fucoidan/chitosan-based polyelectrolyte multilayers (PEMs) has been studied with in situ Fourier transform infrared (FTIR) spectroscopy. Attenuated total reflectance (ATR) FTIR spectroscopy has been used to follow the sequential build-up of the multilayer, with peaks characteristic of each polymer being seen to increase in intensity with each respective adsorption stage. In addition, spectral processing has allowed for the extraction of spectra from individual adsorbed layers, which have been used to provide unambiguous determination of the adsorbed mass of the PEM at each stage of formation. The PEM was seen to undergo a transition in growth regimes during build-up: from supra-linear to linear. In addition, the wettability of the PEM has been probed at each stage of the build-up, using the captive bubble contact angle technique. The contact angles were uniformly low, but showed variation in value depending on the nature of the outer polymer layer, and this variation correlated with the overall percentage hydration of the PEM (determined from FTIR and quartz crystal microbalance data). The nature of the hydration water within the polyelectrolyte multilayer has also been studied with FTIR spectroscopy, specifically in situ synchrotron ATR FTIR microscopy of the multilayer confined between two solid surfaces. The acquired spectra have enabled the hydrogen bonding environment of the PEM hydration water to be determined. The PEM hydration water is seen to have an environment in which it is subject to fewer hydrogen bonding interactions than in bulk electrolyte solution.


Subject(s)
Chitosan/chemistry , Polymers/chemical synthesis , Polysaccharides/chemistry , Electrolytes/chemical synthesis , Electrolytes/chemistry , Molecular Structure , Polymers/chemistry , Spectroscopy, Fourier Transform Infrared , Water/chemistry
14.
ACS Chem Neurosci ; 6(9): 1526-35, 2015 Sep 16.
Article in English | MEDLINE | ID: mdl-26114931

ABSTRACT

Finding new optical probes to detect and track amyloid protein aggregates is key to understanding and defeating the myriad of neurodegenerative and other diseases associated with these misfolded proteins. Herein we report that a series of fluorescent, soluble oligo(p-phenylene ethynylene)s (OPEs) are able to detect amyloids in vitro by massive binding-activated superluminescence, with low micromolar affinity and high selectivity for the amyloid conformer. The OPEs track the kinetics of amyloid fibril formation from native hen egg white lysozyme (HEWL) similarly to thioflavin T (ThT), and the dependence of binding affinity on OPE length supports the theory of a linear binding groove. We hypothesize, based on spectral properties, induced circular dichroism, and previous work in analogous systems, that the fluorescence turn-on mechanism is a combination of the reduction of static solvent-mediated quenching at the ethyl ester end groups of the phenylene ethynylene fluorophore and the formation of chiral J-type aggregates templated on the amyloid fibril surface.


Subject(s)
Amyloid/metabolism , Electrolytes , Fluorescent Dyes , Optical Imaging/methods , Polymers , Amyloid/chemistry , Benzothiazoles , Circular Dichroism , Electrolytes/chemical synthesis , Electrolytes/chemistry , Fluorescent Dyes/chemical synthesis , Fluorescent Dyes/chemistry , Kinetics , Microscopy, Atomic Force , Microscopy, Electron, Transmission , Molecular Structure , Muramidase/chemistry , Muramidase/metabolism , Optical Imaging/instrumentation , Polymers/chemical synthesis , Polymers/chemistry , Spectrophotometry , Thiazoles/chemistry , Thiazoles/metabolism
15.
Molecules ; 20(3): 4369-82, 2015 Mar 09.
Article in English | MEDLINE | ID: mdl-25759954

ABSTRACT

In this work, we describe the fabrication of self-assembled polyelectrolyte nanoparticles that provide a multicolor optical imaging modality. Poly(γ-glutamic acid)(γ-PGA) formed self-assembled nanoparticles through electrostatic interactions with two different cationic polymers: poly(L-lysine)(PLL) and chitosan. The self-assembled γ-PGA/PLL and γ-PGA/chitosan nanoparticles were crosslinked by glutaraldehyde. Crosslinking of the ionic self-assembled nanoparticles with glutaraldehyde not only stabilized the nanoparticles but also generated a strong autofluorescence signal. Fluorescent Schiff base bonds (C=N) and double bonds (C=C) were generated simultaneously by crosslinking of the amine moiety of the cationic polyelectrolytes with monomeric glutaraldehyde or with polymeric glutaraldehyde. The unique optical properties of the nanoparticles that resulted from the crosslinking by glutaraldehyde were analyzed using UV/Vis and fluorescence spectroscopy. We observed that the fluorescence intensity of the nanoparticles could be regulated by adjusting the crosslinker concentration and the reaction time. The nanoparticles also exhibited high performance in the labeling and monitoring of therapeutic immune cells (macrophages and dendritic cells). These self-assembled nanoparticles are expected to be a promising multicolor optical imaging contrast agent for the labeling, detection, and monitoring of cells.


Subject(s)
Chitosan/chemistry , Contrast Media/chemical synthesis , Electrolytes/chemical synthesis , Fluorescent Dyes/chemical synthesis , Nanoparticles/chemistry , Polyglutamic Acid/analogs & derivatives , Polylysine/chemistry , Animals , Cell Line , Cell Survival , Contrast Media/chemistry , Electrolytes/chemistry , HeLa Cells , Humans , Mice , Molecular Structure , Optical Imaging , Particle Size , Polyglutamic Acid/chemistry , Spectrometry, Fluorescence , Static Electricity
16.
Carbohydr Polym ; 115: 160-9, 2015 Jan 22.
Article in English | MEDLINE | ID: mdl-25439881

ABSTRACT

Polyelectrolyte complex (PEC) is formed when polymers with opposite charges are combined in solution. PECs are recently gaining attention as carriers for controlled release of drugs and proteins. Herein, bone morphogenetic protein-2 (BMP-2) was immobilized in a PEC of natural polymers, chitosan and hyaluronic acid. Charge-to-charge stoichiometry of the formed PEC was estimated based on turbidity of combined chitosan and hyaluronic acid solutions. Free amino groups in chitosan were crosslinked with different amounts of genipin. The degree of crosslinking, consequently its effects in vitro in terms of swelling, degradation and cytocompatibility were analyzed. Immobilization of three different amount of BMP-2 in chitosan-hyaluronic acid PEC scaffold resulted sustained release of the growth factor for more than 30 days. Immobilization efficacies varied from 61% to 76% depending on the amount of BMP-2. Finally effects in osteogenic differentiation of the PEC with BMP-2 to MC3T3-E1 cells were determined by reverse transcriptase PCR.


Subject(s)
Bone Morphogenetic Protein 2/metabolism , Chitosan/chemistry , Cross-Linking Reagents/chemistry , Electrolytes/chemistry , Hyaluronic Acid/chemistry , Immobilized Proteins/metabolism , Iridoids/chemistry , Polymers/chemistry , Animals , Bone Morphogenetic Protein 2/chemistry , Cell Differentiation , Cell Proliferation , Cells, Cultured , Delayed-Action Preparations , Electrolytes/chemical synthesis , Immobilized Proteins/chemistry , Mice , Osteoblasts/cytology , Polymers/chemical synthesis
17.
Soft Matter ; 10(2): 312-9, 2014 Jan 14.
Article in English | MEDLINE | ID: mdl-24651903

ABSTRACT

Gel electrolytes have usually been prepared by adding gelators or polymers to the liquid organic solvent-based electrolytes. In this study, we proposed a method to prepare gel electrolytes using gelators in liquid (low molecular weight) polymer-based electrolytes. Inexpensive 1,3:2,4-dibenzylidene-D-sorbitol (DBS) was chosen as a gelator for poly(ethylene glycol) (PEG)-based electrolytes at relatively low DBS concentrations. A series of gel electrolytes was produced by varying the DBS amounts, PEG molecular weights and PEG end groups. First, we found that DBS molecules self-assembled into 3-D networks consisting of nanofibrils that were approximately 10 nm in diameter, as measured by transmission electron microscopy; they exhibited spherulite-like morphologies under polarizing optical microscopy. Second, the dynamic rheological measurements demonstrated that the elastic modulus and the dissolution temperature of DBS-PEG gels increased with the increasing DBS content. The thermal degradation temperature of these gels also increased when the DBS concentration increased, as determined by thermogravimetric analysis. In addition, adding DBS may help to facilitate the dissolution of iodide and iodine in PEG due to its ether groups. Furthermore, the conductivity of the prepared DBS-PEG gel electrolytes was similar to that of the liquid PEG electrolytes (without DBS). When used in dye-sensitized solar cells (DSSC), the PEG-based electrolytes having inactive methyl end groups achieved the highest energy conversion efficiency among the tested cells. The efficiency of DSSC filled with our gel electrolytes remained basically the same over a one-month period, implying that the materials were relatively stable.


Subject(s)
Polyethylene Glycols/chemistry , Sorbitol/analogs & derivatives , Electrolytes/chemical synthesis , Electrolytes/chemistry , Gels/chemical synthesis , Gels/chemistry , Molecular Structure , Polyethylene Glycols/chemical synthesis , Sorbitol/chemistry
18.
J Am Chem Soc ; 136(10): 3736-9, 2014 Mar 12.
Article in English | MEDLINE | ID: mdl-24575841

ABSTRACT

A near-IR-emitting conjugated oligoelectrolyte (COE), ZCOE, was synthesized, and its photophysical features were characterized. The biological affinity of ZCOE is compared to that of an established lipid-membrane-intercalating COE, DSSN+, which has blue-shifted optical properties making it compatible for tracking preferential sites of accumulation. ZCOE exhibits diffuse staining of E. coli cells, whereas it displays internal staining of select yeast cells which also show propidium iodide staining, indicating ZCOE is a "dead" stain for this organism. Staining of mammalian cells reveals complete internalization of ZCOE through endocytosis, as supported by colocalization with LysoTracker and late endosome markers. In all cases DSSN+ persists in the outer membranes, most likely due to its chemical structure more closely resembling a lipid bilayer.


Subject(s)
Electrolytes/analysis , Optical Imaging/methods , Staining and Labeling/methods , Animals , COS Cells/cytology , Cell Survival , Chlorocebus aethiops , Electrolytes/chemical synthesis , Electrolytes/metabolism , Endocytosis , Escherichia coli/cytology , Microscopy, Confocal/methods , Yeasts/cytology
19.
Langmuir ; 30(12): 3441-7, 2014 Apr 01.
Article in English | MEDLINE | ID: mdl-24593694

ABSTRACT

Chronic wounds continue to be a global healthcare concern. Thus, the development of new nanoparticle-based therapies that treat multiple symptoms of these "non-healing" wounds without encouraging antibiotic resistance is imperative. One potential solution is to use chitosan, a naturally antimicrobial polycation, which can spontaneously form polyelectrolyte complexes when mixed with a polyanion in appropriate aqueous conditions. The requirement of at least two different polymers opens up the opportunity for us to form chitosan complexes with an additional functional polyanion. In this study, chitosan:pectin (CS:Pec) nanoparticles were synthesized using an aqueous spontaneous ionic gelation method. Systematically, a number of parameters, polymer concentration, addition order, mass ratio, and solution pH, were explored and their effect on nanoparticle formation was determined. The size and surface charge of the particles were characterized, as well as their morphology using transmission electron microscopy. The effect of polymer concentration and addition order on the nanoparticles was found to be similar to that of other chitosan:polyanion complexes. The mass ratio was tuned to create nanoparticles with a chitosan shell and a controllable positive zeta potential. The particles were stable in a pH range from 3.5 to 6.0 and lost stability after 14 days of storage in aqueous media. Due to the high positive surface charge of the particles, the innate properties of the polysaccharides used, and the harmless disassociation of the polyelectrolytes, we suggest that the development of these CS:Pec nanoparticles offers great promise as a chronic wound healing platform.


Subject(s)
Chitosan/chemistry , Nanoparticles/chemistry , Pectins/chemistry , Polymers/chemical synthesis , Electrolytes/chemical synthesis , Electrolytes/chemistry , Hydrogen-Ion Concentration , Molecular Conformation , Particle Size , Polymers/chemistry , Surface Properties
20.
Langmuir ; 30(9): 2470-9, 2014 Mar 11.
Article in English | MEDLINE | ID: mdl-24568261

ABSTRACT

We report the controlled formation of internally porous polyelectrolyte particles with diameters ranging from tens to hundreds of micrometers through selective solvent extraction using microfluidics. Solvent-resistant microdevices, fabricated by frontal photopolymerization, encapsulate binary polymer (P)/solvent (S1) mixtures by a carrier solvent phase (C) to form plugs with well-defined radii and low polydispersity; the suspension is then brought into contact with a selective extraction solvent (S2) that is miscible with C and S1 but not P, leading to the extraction of S1 from the droplets. The ensuing phase inversion yields polymer capsules with a smooth surface but highly porous internal structure. Depending on the liquid extraction time scale, this stage can be carried out in situ, within the chip, or ex situ, in an external S2 bath. Bimodal polymer plugs are achieved using asymmetrically inverted T junctions. For this demonstration, we form sodium poly(styrenesulfonate) (P) particles using water (S1), hexadecane (C), and methyl ethyl ketone (S2). We measure droplet extraction rates as a function of drop size and polymer concentration and propose a simple scaling model to guide particle formation. We find that the extraction time required to form particles from liquid droplets does not depend on the initial polymer concentration but is rather proportional to the initial droplet size. The resulting particle size follows a linear relationship with the initial droplet size for all polymer concentrations, allowing for the precise control of particle size. The internal particle porous structure exhibits a polymer density gradient ranging from a dense surface skin toward an essentially hollow core. Average particle porosities between 10 and 50% are achieved by varying the initial droplet compositions up to 15 wt % polymer. Such particles have potential applications in functional, optical, and coating materials.


Subject(s)
Alkanes/chemistry , Butanones/chemistry , Microfluidic Analytical Techniques , Polystyrenes/chemical synthesis , Water/chemistry , Electrolytes/chemical synthesis , Electrolytes/chemistry , Electrolytes/isolation & purification , Particle Size , Polystyrenes/chemistry , Polystyrenes/isolation & purification , Porosity , Solvents/chemistry , Surface Properties
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