Colloidal suspensions of iron oxide magnetic nanoparticles are known to dissipate energy when exposed to an oscillating magnetic field. Such energy dissipation can be employed to locally raise ...temperature inside a tumor between 41°C and 45°C (hyperthermia) to promote cell death, a treatment known as magnetic fluid hyperthermia (MFH). This work seeks to quantify differences between MFH and hot-water hyperthermia (HWH) in terms of reduction in cell viability using two cancer cell culture models, Caco-2 (human epithelial colorectal adenocarcinoma) and MCF-7 (human breast cancer). Magnetite nanoparticles were synthesized via the co-precipitation method and functionalized with adsorbed carboxymethyl dextran. Cytotoxicity studies indicated that in the absence of an oscillating magnetic field, cell viability was not affected at concentrations of up to 0.6 mg iron oxide/mL. MFH resulted in a significant decrease in cell viability when exposed to a magnetic field for 120 minutes and allowed to rest for 48 hours, compared with similar field applications, but with shorter resting time. The results presented here suggest that MFH most likely induces apoptosis in both cell types. When compared with HWH, MFH produced a significant reduction in cell viability, and these effects appear to be cell-type related.
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•CM-dextrans of various Mws are synthesized and used as FO draw solutes.•CM-dextran draw solution has high osmotic pressure for desalination.•Low solute leakage and nontoxicity make ...CM-dextran suitable for protein enrichment.•FO process shows low membrane fouling propensity and low energy consumption.•Diluted CM-dextran draw solution can be used in daily chemical industries.
In this study, a series of anionic polyelectrolytes, sodium carboxymethyl dextrans with different molecular weights (CM-dextran-1000/5000/20,000), are facilely prepared via a one-step reaction and applied as novel draw solutes in forward osmosis (FO) process. Various characterizations (FTIR, NMR, conductivity titration and cytotoxicity test) are performed to investigate the chemical structure, degree of substitution (DS) and toxicity of synthesized CM-dextrans. Effects of the solution concentration and solute molecular weight on physicochemical properties (relative viscosity, conductivity and osmotic pressure) of CM-dextran draw solutions as well as their corresponding FO performances are investigated systematically. In comparison with FO performance of 1 M NaCl draw solution (water flux of 22.1 LMH; reverse solute flux of 9.8 gMH), 40 wt% CM-dextran-1000 draw solution shows a higher water flux (24.9 LMH) and a much lower reverse solute flux (0.97 gMH) in PRO mode. Furthermore, CM-dextran solution with the low reverse solute diffusion, nontoxicity, and the high osmotic pressure, can be potentially used as draw solution for desalination and protein enrichment via FO. The theoretical calculation also confirms that FO process shows lower special energy consumption than UF process in the application of protein concentration.
•Oleic acid in combination with low dosage carboxymethyl dextran coated superparamagnetic iron oxide nanoparticles was prepared by chemical coprecipitation method.•The obtained nanoparticles with ...good water dispersion and relatively high saturation magnetization can efficiently become the transversal relaxation times (T2) contrast agent.•The obtained nanoparticles can actively target to human lung adenocarcinoma (A549) cells after conjugating with monoclonal antibody CD44v6, which would be conducive to the detection of lung cancer.
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To improve the sensitive and specific detection of metastasis of lung cancer, this study fabricated immune superparamagnetic iron oxide nanoparticles (SPIONs) used in magnetic resonance (MR) immumoimaging. These SPIONs were coated with oleic acid and carboxymethyl dextran, and then conjugated to mouse anti-CD44v6 monoclonal antibody. The physicochemical properties of magnetic nanoparticles without monoclonal antibody were characterized by X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). The sizes of the nanoparticles were determined by dynamic light scattering measurements (DLS) and transmission electron microscope (TEM). Coated nanoparticles could well disperse in water with low dosage of CMD as the Fe/CMD ratio is 1/1 and 2/1 (w/w). Importantly, these SPIONs have relatively high saturation magnetization, as measured by vibrating sample magnetometer (VSM). They could efficiently become the transversal relaxation times (T2) contrast agent to improve detection limit through measured in vitro magnetic resonance imaging (MRI) and actively target human lung adenocarcinoma (A549) cells in vitro cell culture. Thus, these immune SPIONs are potentially useful for lung tumor-targeting diagnosis.
► CM-dextran coated MNPs were prepared by a two-step method. ► CM-dextran coated MNPs showed superparamagnetism and were stable over the entire range of pH and NaCl concentration in water. ► ...CM-dextran coated MNPs exhibited excellent MRI property and could potentially be used as MRI contrast agents for magnetic resonance molecular imaging.
Superparamagnetic nanoparticles functionalized with carboxymethyl dextran (CM-dextran) were synthesized by a two-step method. First, the magnetic nanoparticles (MNPs) coated with dextran (
M
w
≈
20000) were prepared by co-precipitation of Fe
2+ and Fe
3+ ions. Then, dextran on the surface of MNPs reacted with monochloroacetic acid (MCA) in alkaline condition. The influences of temperature and reactant concentration on the amount of –COOH on the surface of nanoparticles were systematically studied. The obtained MNPs coated with CM-dextran were stable over the entire range of pH and NaCl concentration. The MRI experiment indicated that the CM-dextran MNPs could potentially be used as MRI contrast agents for magnetic resonance molecular imaging.
•Poly(ethylene glycol) was attached to reducing end of carboxymethyl-dextran (CMD).•Protein complex formation occurred at pH 5.9 for PEGylated CMD vs. pH 5.5 for CMD.•Phase separation of complexes ...not influenced by amount of PEGylated CMD.•Spheroidal complexes possessed hydrodynamic radius of 11–40nm.
Electrostatic interactions between α-lactalbumin (α-lac) and carboxymethyldextran (CMD) in acidic solutions lead to phase-separated complexes. By adding a non-ionic poly(ethylene glycol) (PEG) chain onto the reducing end of CMD, forming carboxymethyl-dextran-block-poly(ethylene glycol) (CMD-b-PEG), the PEG block was hypothesized to reduce interactions with α-lac and promote formation of a micelle-like complex structure. Formation of complexes between α-lac and CMD-b-PEG or α-lac and CMD was determined following acidification by light scattering and electrophoretic mobility. Phase separation, size, and structure of α-lac/CMD-b-PEG complexes were characterized by turbidimetry, dynamic light scattering, and electron microscopy, respectively. Complexes of α-lac/CMD-b-PEG formed at pH values near pH 6, while α-lac/CMD complexes formed at pH 5.5. Both CMD and CMD-b-PEG decreased the charge of α-lac below pH 5.5 and led to phase separation below pH 5. Shift in charge and the critical pH of phase separation were both sensitive to the α-lac to CMD ratio, while the relative amount of CMD-b-PEG did not significantly influence either. Hydrodynamic radii of α-lac/CMD-b-PEG complexes was between 11 and 20nm, which increased with increasing α-lac to CMD-b-PEG ratio and with decreasing pH. Spheroidal structures of ∼10nm were also observed in micrographs that were attributed to α-lac/CMD-b-PEG complexes.
Abstract Peritoneal adhesions are serious sequelae of surgery, and can cause significant morbidity and/or mortality due to pain, infertility, and bowel obstruction. We have designed and synthesized ...novel dextran (DX)-based injectable hydrogels for adhesion prevention, which are formed by mixing hydrazide-modified carboxymethyldextran (CMDX–ADH) with aldehyde-modified DX (DX–CHO) or carboxymethylcellulose (CMC–CHO). At high polymer concentrations, hydrogels formed very quickly upon mixing, e.g. 5% CMDX–ADH with 6% DX–CHO ( CMDX–DX; 1.8 s) and 5% CMDX–ADH with 6% CMC–CHO ( CMDX–CMC; 5.8 s). CMDX–DX shrank after gelling, while CMDX–CMC swelled. CMDX–ADH and CMC–CHO showed minimal to mild cytotoxicity to mesothelial cells and macrophages in vitro , while DX–CHO was very cytotoxic. However, all cross-linked gels had very mild cytotoxicity. When applied in a rabbit sidewall defect-bowel abrasion model of adhesion formation, CMDX–CMC greatly reduced the formation of adhesions while CMDX–DX worsened them.
The formation of a stable spatial arrangement of protein A ligands is a great challenge for the development of high‐capacity polymer‐grafted protein A adsorbents due to the complexity in interplay ...between coupled ligands and polymer chain. In this work, carboxymethyl dextrans (CMDs) with different molecular weight were introduced to provide stable spatial ligand arrangement in CMD‐grafted protein A gels to improve IgG adsorption. The result showed that coupling of protein A ligand in CMD‐grafted layer had no marked influence on pore size and dextran layers coupled with the ligands were stable in experimental range of salt concentrations. The result of IgG adsorption revealed that carboxymethyl dextran T10, a short CMD, was more suitable as a scaffold for the synthesis of high‐capacity protein A gels. Moreover, the maximal adsorption capacity for IgG was obtained to be 96.4 mg/g gel at ionic capacities of 300–350 mmol/L and a ligand density of 15.2 mg/g gel. Dynamic binding capacity for IgG exhibited a higher capacity utilization in CMD‐grafted protein A gels than non‐grafted protein A gel. The research presented a tactics to establish a stable dextran layer coupled with protein A ligands and demonstrated its importance to improve binding capacity for IgG.
Rapid, sensitive, and reliable detection of high mobility group box 1 (HMGB1) is essential for medical and diagnostic applications due to its important role as a biomarker of chronic inflammation. ...Here, we report a facile method for the detection of HMGB1 using carboxymethyl dextran (CM-dextran) as a bridge molecule modified on the surface of gold nanoparticles combined with a fiber optic localized surface plasmon resonance (FOLSPR) biosensor. Under optimal conditions, the results showed that the FOLSPR sensor detected HMGB1 with a wide linear range (10
to 10
g/mL), fast response (less than 10 min), and a low detection limit of 43.4 pg/mL (1.7 pM) and high correlation coefficient values (>0.9928). Furthermore, the accurate quantification and reliable validation of kinetic binding events measured by the currently working biosensors are comparable to surface plasmon resonance sensing systems, providing new insights into direct biomarker detection for clinical applications.
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