Sodium Polyaspartate Research Articles

Preparation and application of new polycarboxylic acid for scale inhibition

In oilfield, scaling caused by water injection is becoming increasingly serious by blocking the gathering and transmission pipelines of the oilfield and resulting in a decline in oilfield production and a great loss of production. Oil and gas leakage caused by pipeline scaling, corrosion and perforation has caused irreversible damage to the surrounding environment. In this paper, citric acid and sodium pyrophosphate are used as the main agents, and hydrolytic polymaleic anhydride, polyaspartic sodium and polyepoxysuccinic acid are respectively compounded to establish polycarboxylic acid scale inhibitor. The scale inhibition experiments of CaCO3, CaSO4 and BaSO4 were carried out to obtain a new type of highly effective polycarboxylic acid scale inhibitor formula. For CaCO3, the best formula is 200 ppm citric acid + 30 ppm hydrolyzed polymaleic anhydride. For CaSO4, the best formula is 100 ppm citric acid + 5 ppm sodium polyaspartate.

Characterization of isoniazid incorporation into chitosan-poly(aspartic acid) nanoparticles

The incorporation of the drug Isoniazid (an anti-tuberculosis drug) into nanoparticles of polyelectrolyte chitosan-poly(aspartic acid) complexes was carried out by the ionotropic gelation technique, adding a sodium polyaspartate solution containing the drug to a chitosan solution in different proportions in a mass ratio (mg/mg) Isoniazid/Chitosan. This was confirmed by MALDI-TOF/MS, ESI/MS, FTIR, and UV-Vis. The lowest average particle diameter (PD), estimated by DSL, was 148.5 ± 1 nm corresponding to an Isoniazid/chitosan ratio (mg/mg) of 0.5:1. FE-SEM showed nanoparticles in the order of 100–300 nm; whereas AFM showed semi-spherical particle morphology.

Antimicrobial and anticancer potential of novel polyaspartate derivatives synthesized via quaternary ammonium grafting

AbstractThree novel polyaspartate derivatives with antibacterial properties and low hemolytic effects are synthesized by the reaction of sodium polyaspartate (PAspNa) with different quaternary ammonium salts with a carboxylic end‐group, subsequently these are tested in vitro against different cancer and normal cell lines. 1‐(carboxypentyl) pyridinium bromide, 1‐(carboxypentyl) benzalkonium bromide, and 1‐(carboxypentyl) quinolinium bromide are synthesized from a quaternization reaction between 6‐bromohexanoic acid and the respective tertiary amines (pyridine, N,N‐dimethylbenzylamine, and quinoline). Then, these ammonium salts are chemically grafted along the sodium polyaspartate macromolecular chains through an acid–base reaction. Three different polyaspartate derivatives are obtained and their chemical structures analyzed and confirmed by FT‐IR and 1H NMR, the corresponding thermal stability is analyzed by thermogravimetric analysis. The antibacterial efficiency of these PAspNa derivatives against Escherichia coli is determined by measuring the minimum inhibitory concentration and the minimum bactericidal concentration. Hemolysis assays are performed on isolated human erythrocytes and finally the cell proliferation is studied by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) analysis. All the PAspNa derivatives show antibacterial activities, low hemolytic effects, and antiproliferative effect in some concentrations evaluated in murine fibroblast (3T3), and cancer cell lines of cervix (HeLa), breast (4T1), and liver (HepG2) cells lines.

Selective depression of galena by sodium polyaspartate in chalcopyrite flotation

• PASP (Sodium polyaspartate) is a kind of biodegradable and available polyamino acid. • PASP can depress the flotation of galena under weakly alkaline conditions. • PASP has a greater impact on galena than on chalcopyrite . • The competitive adsorption on the mineral surface results in the selective depression. In the flotation separation of copper-lead–zinc complex polymetallic sulphide ores, the separation of chalcopyrite from galena is difficult because both of them have good floatability. Therefore, the development of a green, eco-friendly and selective galena depressant is highly required. In this work, sodium polyaspartate (PASP) was used as a galena depressant in the separation of chalcopyrite from galena. Single mineral flotation experiments showed that PASP could selectively depress galena. With 10 mg/L PASP addition at pH = 10, the recovery of chalcopyrite remained 91.9%, but the recovery of galena decreased to 1.1%. The selective depression mechanism of PASP was studied by collector adsorption measurements, FT-IR and XPS analysis.

Selective separation of smithsonite from quartz by using sodium polyaspartate as a depressant

This study introduced an easily degradable depressant, sodium polyaspartate (PASP), into the selective separation of smithsonite and Zn2+-activated quartz with sodium oleate (NaOL) as a collector. The flotation recovery of smithsonite significantly improved in the presence of PASP, and quartz and smithsonite were separated at pH 9–10. The flotation and depression mechanisms of smithsonite and quartz were studied by applying zeta potential measurements, total organic carbon analysis, scanning electron microscopy–energy spectrometry, and X-ray photoelectron spectroscopy. The results of various measurements indicated that PASP complexed with Zn2+ to cause the desorption of Zn2+ from the quartz surface, thus reducing the adsorption of NaOL on the quartz surface and depressing the flotation of quartz. However, although PASP could adsorb onto the smithsonite surface, it had little effect on the adsorption of NaOL. Therefore, PASP could be used as a quartz depressant in conventional smithsonite–quartz flotation circuits.

A nanogel based oral gene delivery system targeting SUMOylation machinery to combat gut inflammation.

Poor success rates and challenges associated with the current therapeutic strategies of inflammatory bowel disease (IBD) have accelerated the emergence of gene therapy as an alternative treatment option with great promise. However, oral delivery of nucleic acids (NAs) to an inflamed colon is challenged by multiple barriers presented by the gastrointestinal, extracellular and intracellular compartments. Therefore, we screened a series of polyaspartic acid-derived amphiphilic cationic polymers with varied hydrophobicity for their ability to deliver NAs into mammalian cells. Using the most effective TAC6 polymer, we then engineered biocompatible and stable nanogels composed of polyplexes (TAC6, NA) and an anionic polymer, sodium polyaspartate, that were able to deliver the NAs across mammalian cells using caveolae-mediated cellular uptake. We then utilized these nanogels for oral delivery of PIAS1 (protein inhibitor of activated STAT1), a SUMO 3 ligase, encoding plasmid DNA since PIAS1 is a key nodal therapeutic target for IBD due to its ability to control NF-κB-mediated inflammatory signaling. We show that plasmid delivery using TAC6-derived nanogels diminished gut inflammation in a murine colitis model. Therefore, our study presents engineering of orally deliverable nanogels that can target SUMOylation machinery to combat gut inflammation with very high efficacy.

Anisotropic Proton Conductivity of Poly(aspartic acid) Thin Films

Abstract Anisotropic proton conductivity was investigated in 60-nm-thick spin-coated thin films of partially protonated poly(aspartic acid)/sodium polyaspartate (P-Asp). The film showed large conductivity difference between in-plane and through-plane directions. The in-plane and through-plane conductivities to the substrate are 2.7 × 10−6 and 3.4 × 10−9 S cm−1, respectively, at the same relative humidity (RH) of 50% and 298 K. The proton conductivity for the in-plane direction was three orders of magnitude greater than that for the through-plane direction. The anisotropic origin is derived from the reported highly oriented structure of the P-Asp thin film. The proton conductivity exhibits no difference for the two in-plane directions between radial and circumferential directions, which can be expected as anisotropic main chain orientation by a centrifugal force during spin-coating.

Cell Permeating Nano-Complexes of Amphiphilic Polyelectrolytes Enhance Solubility, Stability, and Anti-Cancer Efficacy of Curcumin.

Many hydrophobic drugs encounter severe bioavailability issues owing to their low aqueous solubility and limited cellular uptake. We have designed a series of amphiphilic polyaspartamide polyelectrolytes (PEs) that solubilize such hydrophobic drugs in aqueous medium and enhance their cellular uptake. These PEs were synthesized through controlled (∼20 mol %) derivatization of polysuccinimide (PSI) precursor polymer with hydrophobic amines (of varying alkyl chain lengths, viz. hexyl, octyl, dodecyl, and oleyl), while the remaining succinimide residues of PSI were opened using a protonable and hydrophilic amine, 2-(2-amino-ethyl amino) ethanol (AE). Curcumin (Cur) was employed as a representative hydrophobic drug to explore the drug-delivery potential of the resulting PEs. Unprecedented enhancement in the aqueous solubility of Cur was achieved by employing these PEs through a rather simple protocol. In the case of PEs containing oleyl/dodecyl residues, up to >65000× increment in the solubility of Cur in aqueous medium could be achieved without requiring any organic solvent at all. The resulting suspensions were physically and chemically stable for at least 2 weeks. Stable nanosized polyelectrolyte complexes (PECs) with average hydrodynamic diameters (DH) of 150-170 nm (without Cur) and 220-270 nm (after Cur loading) were obtained by using submolar sodium polyaspartate (SPA) counter polyelectrolyte. The zeta potential of these PECs ranged from +36 to +43 mV. The PEC-formation significantly improved the cytocompatibility of the PEs while affording reconstitutable nanoformulations having up to 40 wt % drug-loading. The Cur-loaded PECs were readily internalized by mammalian cells (HEK-293T, MDA-MB-231, and U2OS), majorly through clathrin-mediated endocytosis (CME). Cellular uptake of Cur was directly correlated with the length of the alkyl chain present in the PECs. Further, the PECs significantly improved nuclear transport of Cur in cancer cells, resulting in their death by apoptosis. Noncancerous cells were completely unaffected under this treatment.

Influence of sodium polyaspartate added to the negative active material on the electrochemical behavior of lead-acid batteries

This article investigates the influence of sodium polyaspartate (PASP), used as an additive in the negative active material (NAM) on the performance of lead-acid batteries, including battery capacity at different discharge/charge rates, fast charge performance, high rate discharge performance, and cycling performance. The addition of PASP to NAM can prevent lead sulfate accumulation and refine the size of lead sulfate crystals making them easier to restore during the charging process, thus enhancing the utilization of NAM. Consequently, the charge and discharge capacity and the cycling performance are also improved. Many remarkable improvements of the performance of lead-acid batteries have been observed during the battery tests. The obtained results show that addition of 0.4–0.9 % PASP additive to NAM yields highest discharge capacity compared to that of regular batteries, exceeding by about 21–29 % of the 3-h rate capacity on average. Other performance parameters also show a high superiority trend as compared to batteries without additive and the additive loading level ranges between 0.4 and 4 %.

Enhancement of Proton Transport in an Oriented Polypeptide Thin Film

Proton transport properties of a partially protonated poly(aspartic acid)/sodium polyaspartate (P-Asp) were investigated. A remarkable enhancement of proton conductivity has been achieved in the thin film. Proton conductivity of 60-nm-thick thin film prepared on MgO(100) substrate was 3.4 × 10(-3) S cm(-1) at 298 K. The electrical conductivity of the oriented thin film was 1 order of magnitude higher than the bulk specimen, and the activation energies for the proton conductivity were 0.34 eV for the oriented thin film and 0.65 eV for the pelletized sample, respectively. This enhancement of the proton transport is attributable to the highly oriented structure on MgO(100) substrate. This result proposes great potential for a new strategy to produce a highly proton-conductive material using the concept of an oriented thin film structure without strong acid groups.

A double blind randomised controlled clinical trial comparing a novel anti-stain and calculus reducing dentifrice with a standard fluoride dentifrice

ObjectivesThis clinical trial tested the anti-stain efficacy at 3 and 6 months of a novel, sodium polyaspartate-containing, anti-stain dentifrice. In addition, the efficacy of the new dentifrice in controlling gingival inflammation and inhibition of calculus deposition was tested. MethodsParticipants were recruited to this double blind randomised control clinical trial, and allocated to either test or control groups. The presence of stain and calculus were entry criteria. Measurements of stain, calculus and gingival inflammation were recorded using the Shaw and Murray Stain score, Volpe-Manhold Calculus score and the Modified Gingival Index respectively. Measurements were made at baseline, prior to the removal of stain and calculus, and after 3 and 6 months. Missing data were imputed by and the outcomes were analysed using univariate analysis. ResultsAt three months, toothpaste containing sodium polyaspartate was better (difference of mean 1.13 with SEM 0.57) than control for the control of dental stain (p<0.05). Stain scores also showed a trend in favour of the test product (difference of mean 1.03 with SEM 0.78) at six months (p>0.05). There was no difference between toothpastes with respect to calculus deposition or gingival inflammation. ConclusionsToothpaste containing sodium polyaspartate was more effective than a control toothpaste at preventing deposition of dental stain for 3 months after professional tooth cleaning but showed no significant effect at 6 months. Clinical relevanceSodium polyaspartate toothpaste was more effective than a control toothpaste at preventing dental stain formation and maybe helpful in controlling staining between episodes of scaling and polishing.

Effect of Various Cations on the Formation of Calcium Carbonate and Barium Sulfate Scale with and without Scale Inhibitors

High pressure dynamic tube blocking tests have been conducted to determine the effect of iron (divalent and trivalent), calcium, magnesium, and sodium ions on the formation of calcium carbonate and barium sulfate scale with and without added scale inhibitors. Scale inhibitors were chosen to represent the three main functional groups used in commercial oilfield scale inhibitors: the phosphonate group (found in sodium diethylenetriaminepentaphosphonate), the carboxylate group (in sodium polyaspartate), and the sulfonate group (in sodium polyvinysulfonate). A fourth proprietary inhibitor with phosphonate and carboxylate groups was also used in some studies.

TGA/FTIR/MS study on thermal decomposition of poly(succinimide) and sodium poly(aspartate)

The thermal degradation of sodium polyaspartate (PAspNa) and of its precursor - polysuccinimide (PSI) - was investigated using three different techniques: thermal analysis (TA), Fourier transform infrared spectroscopy (FTIR) and mass spectrometry (MS). These online coupled techniques can comprise a very useful tool for the investigation of the thermal decomposition and its mechanisms and allow having simultaneous information about the decomposition process itself as well as of the evolving substances. PSI and sodium-polyaspartate present complex thermal decomposition processes (two to five stages). Also, thermal stability of PSI is low in comparison to that of PAspNa. Finally, weight losses were 72.53% for PSI and 46.73% in the case of PAspNa.

Biodegradable polymeric template for magnetic composites on its base

Modified starch and sodium polyaspartate blend was used as a polymeric template for the preparation of a magnetic composites. Their structural and magnetic properties (by SEM, magnetometry, IR), as well as thermal stability and particle size distributions were characterized. The dependence between the magnetite content and magnetic susceptibility values is stressed. The study confirms the possibility to obtain magnetic composites from magnetite (Fe3O4) and the polymeric composite template based on carboxymethyl starch and sodium polyaspartate. The importance of these magnetic composites derives from the biodegradability of the template as well as the possibilities given by functional groups able to couple both magnetite and further bioactive substances.

Synthesis and Proton Transport Property of Poly(aspartic acid) Thin Film on MgO(100) Substrate

An enhancement in proton conductivity for poly(aspartic acid)/sodium polyaspartate (P-Asp) by synthesizing thin film on MgO substrate was investigated. The average degrees of polymerization and molecular weight were ~70 and ~9400, respectively. The degree of protonation in the carboxylic acid groups was 10 %. The proton conductivities of the pelletized P-Asp and thin film were 6.4 x 10-4 and 3.4 x 10-3 S cm-1, respectively, under a relative humidity of 70 % and 298 K. The proton conductivity of the thin film was found to be five times higher than that of the pelletized P-Asp. The activation energy for the proton conduction of the pelletized P-Asp was 0.89 eV. The activation energy of P-Asp thin film was smaller than that of the pelletized sample. Application of this phenomenon may lead to a new method for producing highly proton-conductive material.

Heterogeneous polymerization with polyaspartate macromonomer having vinyl pendant groups. II. Control of particle diameter and diameter distribution in dispersion copolymerization

AbstractTo control particle diameter and particle diameter distribution in dispersion copolymerization of styrene and sodium polyaspartate macromonomer containing vinylbenzyl pendant groups, effects of some polymerization parameters, water contents, initiator concentration, styrene monomer concentration, reaction temperature, and type of initiator on the particle diameter and the diameter distribution were investigated. Variation of the water contents from 20 to 80 vol % controls the resultant particle diameter from 0.066 to 0.47 μm. The diameter increased with increasing initiator concentration. This tendency is similar to dispersion polymerization system using a nonpolymerizable stabilizer. Particle diameter distribution broadened with increasing styrene monomer concentration. This trend was attributed to the increase of a period of particle formation. This result indicated that the period of particle formation affected the resultant particle diameter distribution. Particle diameter distribution was successfully improved (CV = 9.1 from 23.6%) by shortening of decomposition time of initiator. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2281–2288, 2009

Synthesis of polyaspartate macromonomer having a vinyl end group and application to dispersion copolymerization of styrene

Sodium polyaspartate (PAspNa) macromonomer with an acryloyl end group was synthesized for dispersion polymerization. At first, a poly(succinimide) (PSI) derivative with a hydroxyphthalimide end group was synthesized by polycondensation of l-aspartic acid and 4-hydroxyphthalic acid. Then, the PSI derivative was end-capped with an acryloyl group by a reaction with acrlyloyl chloride. Finally, a PAspNa derivative with a vinyl end group was synthesized by a hydrolysis of succinimide units by sodium hydroxide. The synthesized macromonomer was applied as a polymerizable stabilizer in dispersion copolymerization of styrene in a mixture of ethanol and water. The PAspNa macromonomer acted as an effective stabilizer and gave sub-micron-sized polymeric particles in dispersion polymerization in polar medium.

Effects of dispersion stabilizer and reaction solvent on forming monodisperse polystyrene microspheres by dispersion polymerization

We used poly(aspartic acid) (PAsp) synthesized by ion exchange with sodium polyaspartate (PAspNa) as a dispersion stabilizer. PAsp improved the dispersion stability and the solubility in the medium for dispersion polymerization. The effects of the stabilizer hydrophobicity on particle formation, conversion, particle diameter, and its distribution of polystyrene microspheres were investigated by using both biodegradable polymers as a dispersion stabilizer. According to these results, we concluded that the polymerization rate of the styrene with PAsp was higher than that of styrene with PAspNa. That is why, smaller and more monodisperse microspheres were prepared with PAsp, compared to those with PAspNa.

Synthesis of monodisperse polystyrene microspheres by dispersion polymerization using sodium polyaspartate

We prepared monodisperse polystyrene microspheres by dispersion polymerization using sodium polyaspartate (PAspNa) as a dispersion stabilizer in an ethanol/water medium. The influence of reaction parameters, i.e., the volume fraction of ethanol in the medium, stabilizer concentration, and the monomer concentration, on the average diameter of the prepared polystyrene microspheres and its distribution were investigated. Polystyrene microspheres were successfully prepared, and the average diameter of the prepared monodisperse polystyrene microspheres was controlled by adjusting the reaction parameters. The zeta potential of the microspheres and the time course of conversion, the particle diameter and its distribution, and particle numbers were also examined. It was found that PAspNa as a dispersion stabilizer provides an environmentally benign process for the preparation of monodisperse polymer microspheres by dispersion polymerization.

Synthesis of tri-calcium phosphate sponges by interfacial deposition and thermal transformation of self-supporting calcium phosphate films

Porous films of β- or α-tri-calcium phosphate (TCP) were prepared by thermal transformation at 1000 °C or 1200 °C, respectively, of thin calcium phosphate/calcium carbonate precursor films precipitated at the air/water interface of a supersaturated carbonic acid solution containing 60 ppm sodium polyaspartate and a [PO43−] : [CO32−] ratio of ca. 2 : 1. The β-Ca3(PO4)2 and α-Ca3(PO4)2 films were typically 10 µm in thickness, consisted of sponge-like interiors with 0.5–1 µm sized macropores, and exhibited surface areas of 10 and 12 m2 g−1 respectively. The thickness and morphology of the TCP flakes were related to the time-dependent structure of the self-supporting composite precursor films, which ranged from highly porous 2-D networks to densely packed agglomerates. Similar films consisting only of calcium phosphate, as well as calcium carbonate films of more complex architecture and up to 150 µm in thickness, were also prepared by polyaspartate-mediated controlled crystallization at the air/water interface. The novel combination of carbonic acid solution and bulk-precipitation inhibitor is described in the preparation of porous minerals that have potential applications as supports for catalysts, for drug delivery, protein adsorption and release, or as bone implant materials.