ABSTRACT
We report the efficacy of the Iron nanoparticles (IONPs) and assessed two different approaches for the synthesis of IONPs i.e. Polyol and co-precipitation method and further, evaluate their antimicrobial properties. Ferrous sulphate heptahydrate salts were reduced with ethylene glycol to obtain IONP and Fe+2 and Fe+3 co-precipitation reaction was performed with KOH at optimum heating. Further, synthesized (IONPs) were characterized by hydrodynamic radii measurement done by DLS clearly indicating the size of IONPs is 79.75nm in polyol based and 135.1 nm in co-precipitation method. The biological efficacy in terms of antimicrobial activity was assessed by the Kirby Bauer method, applied for both Gram-positive and Gram-negative bacteria such as Staphylococcus aureus and Escherichia coli, respectively. The ZOI values i.e. Zone of inhibition diameter was found to be clearly visible in both S. aureus and E. coli, indicating bactericidal activity. Further growth kinetics studies and bacterial genotoxicity was also assessed. Hence, IONPs synthesized are proposed to have great potential as an antibacterial agent and can be used in drug delivery.
ABSTRACT
Objective: The redox-responsive drug delivery system of MSN-SS-PEG@As2O3 was constructed based on mesoporous silica nanoparticle (MSN), which was modified by both redox-sensitive disulfide bonds and non-toxic, non-immunogenic polyglycols (PEG), and loaded the arsenic trioxide (As2O3) by electrostatic adsorption and evaluated in vitro. Methods: Silica was synthesized by coprecipitation method. The redox-responsive carrier (MSN-SS-PEG) was synthesized on the basis of silica, (3-mercaptopropyl) trimethoxysilane, 2-(2-pyridyldithio) ethylamine hydrochloride and methoxy terminated PEG. The particle size and Zeta potential of MSN-SS-PEG were measured by Malvern particle size analyzer; The structure of the carrier was verified by infrared spectroscopy; The morphology and physical and chemical properties of the carrier were investigated by transmission electron microscopy (TEM) and small angle powder diffraction; The drug loading efficiency of MSN-SS-NH2@As2O3 and MSN-SS-PEG@As2O3 were investigated by inductively coupled plasma emission spectrum (ICP). The drug loading was further verified by thermogravimetry (TGA). In vitro release characteristics of the drug delivery system under different pH conditions were investigated by dialysis bag method. MTT assay was used to investigate the toxicity of carrier and delivery system to human normal hepatocytes (L02) or human hepatocarcinoma (HepG2) cells. Results: The potential of MSN, MSN-SS-NH2, MSN-SS-PEG was (-13.40 ± 0.87), (31.63 ± 0.90), (27.70 ± 5.60) mV, respectively. The final potential of modified carrier was positive. The particle size of MSN-SS-PEG was (159.60 ± 3.10) nm. The results of TEM showed that MSN, MSN-SS-NH2 and MSN-SS-PEG were all round or quasi round; The drug loading of MSN-SS-PEG@As2O3 was 4.38%, which measured by ICP; The release in vitro showed that MSN-SS-PEG@As2O3 was redox sensitive response. Compared with L02 cells, HepG2 cells were more sensitive to the toxicity of the carrier, and with the increase of the carrier concentration, the cell survival rate of MSN-SS-PEG was higher than that of MSN-SS-NH2, suggesting that PEG modification can further reduce the cytotoxicity of the carrier and improve the biocompatibility of the carrier. In addition, MTT results showed that the inhibitory effect of MSN-SS-PEG@As2O3 on HepG2 cell was significantly higher than that of other groups. Conclusion: The carrier prepared in this paper had a round and uniform particle size. The modified silica can release under the special microenvironment of the tumor and increase the accumulation of the drug in the tumor site. The delivery system has a good application in tumor therapy as a tumor micro-environment responsive carrier.
ABSTRACT
@#Ophthalmic solution of organic-inorganic layered double hydroxides hybrid nanocomposites based on layered double hydroxides(LDH)intercalated with pirenoxine sodium(PRN)and chitosan-glutathione(CG)was prepared, characterized and evaluated using rabbit precorneal retention. Mg-Al-PRN-LDH, Zn-Al-PRN-LDH and CG-PRN-LDH were synthesized by co-precipitation. The nanocomposites were characterized by laser particle sizer, powder X-ray diffraction(X-RD), fourier transform infrared spectra(FTIR)and transmission electron micrographs(TEM). The release of PRN from Mg-Al-PRN-LDH, Zn-Al-PRN-LDH, and CG-PRN-LDH nanocomposites and API in artificial tear was compared. Based on in vivo precorneal retention studies, PRN-LDH and CG-PRN-LDH nanocomposite dispersions showed significantly higher AUC(3. 72-, 7. 59-folds)and MRT(2. 18-, 2. 60-folds)than that of the commercial eye drops group. Organic-inorganic layered double hydroxides hybrid nanocomposites CG-PRN-LDH dispersions could remarkably improve precorneal retention of PRN.
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Objective: To investigate the properties of zirconia toughened glass infiltrated nanometer-ceramic composite (Al 2O 3/nZrO 2) . Methods: Zirconia toughened glass infiltrated nanometer-ceramic composite(Al 2O 3/nZrO 2)powder was prepared with combination of chemical co-precipitation method and ball milling. The shape, size, partical distribution, crystal phase and chemical composition were measured and analyzed. Results: (1) The crystal phase composition of the studied nanometer ceramic composite powder was made up with ?-Al 2O 3, t-ZrO 2 and m-ZrO 2 examined by XRD?(2) The density of the powder was 4.12 g/cm 3?(3) The particle distribution of the powder ranged 0.02～3.0 ?m?(4)Observed with SEM, the particle profile of the powder was regular, the ratio of length and width of the particles was about 1.2. Conclusion: The studied nanometer ceramic composite powder owns good homogeneity, stable chemical composition, reasonable powder-size gradation and may be favourable in the improvement of the packing density of ceramics.