Preparation of chitosan-polyaspartic acid-5-fluorouracil nanoparticles and its anti-carcinoma effect on tumor growth in nude mice

AIM: To prepare chitosan-polyaspartic acid-5-fluorouracil (CTS-Pasp-5Fu) nanoparticles and investigate its anti-carcinoma effect and toxicity. METHODS: CTS-Pasp-5Fu nanoparticles were synthesized by ionic gelatification. Male BABL/c nude mice were injected with SGC-7901 gastric carcinoma cell line mass to establish a human gastric carcinoma model. They were randomly allocated into 4 groups: CTS-Pasp-5Fu (containing 5-Fu 1.25 mg/kg), 5-Fu (1.25 mg/kg), CTS-Pasp and normal saline groups. Tumor weight was measured and assay of colony forming unit-granulocyte and macrophage (CFU-GM) was performed. The structural change of cells and tissues was observed and the Bax and Bcl-2 genes were detected. RESULTS: Compared with normal saline, the inhibition rates of tumor growth for the CTS-Pasp, 5-Fu and CTS-Pasp-5Fu groups were 5.58%, 58.69% and 70.82%, respectively. The tumor inhibition rates for the CTS-Pasp, 5-Fu and CTS-Pasp-5Fu groups were 5.09%, 65.3% and 72.79%, respectively. There was a significant decrease in the number of CFU-GMformation and increase of total bilirubin, and alanine aminotransferase in the 5-Fu group, but no change in those of the other three groups. There was no change in white blood cell count and creatinine among the four groups. Pathological section of liver and nephridial tissues showed that the damage in the 5-Fu group was more severe than that in the CTS-Pasp-5Fu group. 5-Fu and CTS-Pasp-5Fu groups could both down-regulate the Bcl-2 expression and up-regulate the Bax expression to different extent, and the accommodate effect of CTS-Pasp-5Fu was more obvious than 5-Fu. CONCLUSION: The tumor inhibition rate of CTS-Pasp-5Fu nanoparticles is much higher than that of 5-Fu alone.

Selective depression of copper-activated sphalerite by polyaspartic acid during chalcopyrite flotation

Environmentally friendly flotation reagent,polyaspartic acid(PAPA),was tested as a potential selective depressant in the flotation separation of chalcopyrite and Cu-activated sphalerite.The depression mechanism of PAPA was revealed by contact angle measurements,Zeta potential measurements,Fourier transform infrared spectroscopy(FT-IR)analysis and inductively coupled plasma(ICP)measurement.The micro-flotation tests with single minerals showed that PAPA selectively depressed Cu-activated sphalerite,while chalcopyrite remained floatable.Moreover,a concentrate containing 31.40%Cu with a recovery of 92.43%was obtained in flotation tests of artificially mixed minerals.Results of contact angle measurements,Zeta potential measurements and FT-IR spectrum revealed that PAPA exerted a much stronger adsorption on Cu-activated sphalerite surface than on chalcopyrite surface,preventing the further adsorption of sodium diethyl dithiocarbamate(DDTC)on its surface.ICP measurements indicated that PAPA had an excellent complexing ability with Cu^(2+)in flotation pulp,weakening the activation of Cu species on sphalerite surface and producing selective depression.

Polyaspartic acid as a corrosion inhibitor for WE43 magnesium alloy

The inhibition behavior of polyaspartic acid(PASP)as an environment-friendly corrosion inhibitor for WE43 magnesium alloy was investigated in 3.5 wt.%NaCl solution by means for EIS measurement,potentiodynamic polarization curve,and scanning electron microscopy.The results show that PASP can inhibit the corrosion of WE43 magnesium alloy.The maximum inhibition efficiency is achieved when PASP concentration is 400 ppm in this study.

Synthesis of micro/meso porous carbon for ultrahigh hydrogen adsorption using cross-linked polyaspartic acid

In addition to the specific surface area,surface topography and characteristics such as the pore size,pore size distribution,and micro/mesopores ratio are factors that determine the performance of porous carbons(PCs)in the fields of energy,catalysis,and adsorption.Based on the mechanism of weight loss of polyaspartic acid at high temperatures,this study provided a new method for adjusting the surface morphology of PCs by changing the cross-linking ratio of the precursor,where cross-linked polyaspartic acid was used as precursor without additional activating agents.N2 adsorption analysis indicated that the specific surface area of the obtained PCs was as high as 1458 m2·g-1,of which I 200 m2·g-1was the contribution of the microporous area and the highest pore volume was 1.13 cm3·g-1,of which the micropore volume was 0.636cm3·g-1.The thermogravimetric analysis results of the precursor,and also the scanning electron microscopy and Brunauer-Emmet-Teller analysis results of the carboniza-tion product confirmed that the prepared PCs presented multilevel pore structure,and the diameters of most pores were 0.78 and 3.97 nm;moreover,the pore size distribution was relatively uniform.This conferred the PCs the ultrahigh hydrogen adsorption capacity of up to 4.52 wt-%at 77 K and 1.13 bar,in addition to their great energy storage and catalytic potental.

Synergistic scale inhibition of polyaspartic acid composite with magnetic field

Polyaspartic acid(PASP)composite,a scale inhibitor,was prepared from PASP,itaconic acid—acrylic acid—acrylic ester(IA-AA-AE)terpolymer and 2-phosphonobutane-1,2,4-tricarboxylic acid(PBTCA).The scale inhibition of PASP composite and the effect of its synergism with a magnetic field on scale inhibition were investigated.Calcium carbonate crystals in scale samples were characterized by means of SEM and XRD.The static and dynamic experiments show that the chelating function of PASP composite for Ca2+can be enhanced by synergism with a magnetic field.Under Ca2+650 mg/L,HCO3-1,300 mg/L and PASPcomposite 4 mg/L,the scale inhibition rate of PASP composite in magnetic water can increase by 10%in static state and by 20%in dynamic experiments.Scanning electron microscope(SEM)and X-ray diffraction(XRD)results show that calcite and aragonite can be completely transformed into vaterite by using PASP composite.

A novel green depressant for flotation separation of scheelite from calcite

Polyaspartic acid(PASP)was used as a novel environmental-friendly depressant,and its inhibition effect on flotation performance of scheelite and calcite using sodium oleate(NaOL)as a collector was investigated by ways of flotation experiments,zeta potential measurement,contact angle measurement and infrared spectroscopic analysis(IR).The results show that PASP exhibits stronger inhibition capability and selectivity than acidified water glass,and the flotation separation of scheelite from calcite can be realized in the presence of 6 mg/L PASP and 20 mg/L NaOL at pH>6.In the presence of PASP,the zeta potential of calcite surface almost keeps unchanged after adding NaOL,and the contact angle decreases sharply.Therefore,it is indicated that PASP significantly decreases the adsorption of NaOL on calcite surface.By contrast,it has no distinct effect on the adsorption of NaOL on the scheelite surface,which is further confirmed by IR results.