Citrate Reduction Research Articles

Study the Effect of Polymers Type on Preparation and Characterization of Etoposide-loaded Gold Nanoparticles

In the last few years, the discoveries in pharmaceutical nanotechnology have triggered a revolution in the field of therapeutic, delivering an abundance of novel applications and actual approaches of metallic nanoformulations for the treatment and diagnosis of tenacious diseases. From this point of view, gold nanoparticles (GN) have been awarded an attractive platform for the development of efficient multifunctional therapeutic, controlled release systems, targeted delivery and diagnostic. The objective of this research was to prepare etoposide-loaded gold nanoparticles (E-GN) by incorporating of etoposide in to the functionalized GN by using different biocompatible polymers. In the present study, GN suspension was prepared by inverse citrate reduction method. Polymeric suspensions 19 (PGN 1-19) were prepared and characterized by atomic force microscopy measurement (AFM). The obtained results indicated that PGN10, PGN13, PGN17 and PGN19 with the preferable polymers and their concentration of (1-mg/mL HPMC-E5, 1-mg/mL PVA, 1.5 mg/mL gelatin and 0.5: 0.5 mg/mL of HPMC-E5: PVA combination) respectively, showed the better morphology, particles size (PS), and particles size distribution (PSD). Subsequently, eight formulas were prepared and optimized through the study of various variables as PS, PSD, etoposide loading efficiency (LE) and in-vitro dissolution profile. F7 revealed a greater LE of 99.39% with higher loading capacity (1 mg/mL) and in-vitro dissolution with controlled mode also, AFM results showed smooth surface nanoparticles, average PS (24.43 nm) with uniform PSD (9.84%). In addition, the result of transmission electron microscopy (TEM) revealed a spherical uniform shape with zeta potential of -34.13. In conclusion, polymeric functionalization of GN improved the etoposide loading efficiency and capacity and controlled the in-vitro dissolution profile and enhanced their colloidal stability.

Synergy of Adsorption and Plasmonic Photocatalysis in the Au-CeO2 Nanosystem: Experimental Validation and Plasmonic Modeling.

Adsorption-mediated water treatment leaves adsorbents as secondary pollutants in the environment. However, photocatalysis aids in decomposing the contaminant into its nontoxic forms. In this context, we demonstrate an adsorption-photocatalysis pairing in Au-CeO2 nanocomposites for a total methylene blue (MB) removal from water. We synthesized Au-CeO2 through the citrate (cit) reduction method at different Au loading and studied its adsorption capacity with kinetics and thermodynamic models. We observe that the high adsorption capacity of Au-CeO2 is primarily because of the presence of Ce3+ states in CeO2 and citrate ligands on Au NPs. The Ce3+ states interact and transfer their electrons to supported Au NPs, rendering a negative charge over Au. The negatively charged Au surface and the carboxyl (-COO-) group of citrate ligands mediate an electrostatic interaction/adsorption of cationic MB. The total removal of MB is expedited under white light and lasers. A control experiment with Au NPs shows less adsorption-photocatalysis. The size of Au NPs and Au-CeO2 interfacial interaction is responsible for the surface plasmon resonance spectral position at 550-600 nm. Linear sweep voltammetry (LSV) and plasmonic field simulation show surface plasmon-driven photocatalysis in Au-CeO2. LSV shows a 3-fold higher photocurrent density in Au-CeO2 than colloidal Au NPs under white light. The simulated electric field intensity in Au-CeO2 is maximum at SPR excitation and the closest interfacial separation (d = 0 nm). The plasmon-driven photocatalysis in colloidal Au NPs is mainly due to the interaction of hot electrons with the adsorbed MB molecule. Notably, near-field light concentration, hot electrons, and interfacial charge separation are responsible for excellent MB removal in the Au-CeO2 nanosystem. The total MB removal through adsorption-photocatalysis pairing is 99.3% (Au-CeO2), 30.7% (Au NPs), and 13% (CeO2).

Green and chemical reduction approaches for facile pH-dependent synthesis of gold nanoparticles

This study compares the green synthesis method using the Lycium ruthenicum (L. Ru) with wet chemical extraction using citrate reduction to synthesize stable gold nanoparticles (AuNPs). The effect of pH on the synthesized AuNPs has also been evaluated in the present investigation. AuNPs were synthesized successfully by both methods, as well; by the way, there were reported differences between the microstructure of resulting powders. For AuNPs synthesized using the green method, a pH value of 3 was reported to be the optimum pH due to the characteristics of synthesized AuNPs. In the mentioned pH, the AuNPs were spherical, mono-dispersed, and highly crystalline, characteristic of a well-done synthesis. Both chemo- and biosynthesized AuNPs revealed a relatively smaller particle size (33.92 and 55.65 nm, respectively) with well-dispersed spherical morphology under alkaline conditions. This study revealed that employing L. Ru extract could be considered a simple, facile, and green technique in stimuli-sensitive AuNPs synthesis.

MO437: Decreased Urinary Citrate Levels as a Marker of Progressive Deterioration of Glomerular Filtration in Patients With Autosomic Dominant Polycystic Kidney Disease (ADPKD)

Abstract BACKGROUND AND AIMS In a previous work we have found that there is a reduction in urinary citrate levels in autosomic dominant polycystic kidney disease (ADPKD) patients. Their levels are related to GFR but not serum bicarbonate levels. Our aim was to analyse whether there is any relationship between rate of GFR deterioration and citraturia in ADPKD patients. METHOD We collected routinary determinations of urine citrate in 24-h urine samples and analysed its predictive role for GFR deterioration with general linear modelling. RESULTS We included 94 patients, 42 ± 14 years old, 59.6% men and 40.4% women. Follow-up from citrate determination 55 ± 28 months (range 16–119). Baseline data: urea 40.2 ± 12.3, Cr 1.15 ± 0.38 mg/dL, GFR 78 ± 26 mL/min/1.73 m2. Bicarbonate 25.1 ± 2.5 (18.2–29.2) mEq/L. Final GFR: 69 ± 32 mL/min/1.73 m2. GFR variation: −2.23 ± 4.14 mL/min/year (range −13.7 to 10). We classified patients according to urinary citrate tertiles (≤117, 117 to ≤ 303, >303 mg/gCr). GFR was different at baseline (67.5 ± 27.9, 74.3 ± 24.3, 92.4 ± 19.7, respectively, P < 0.001) and at final observation (51.1 ± 31.8; 71.4 ± 30.1; 85.3 ± 24.9, respectively P < 0.001). There were no differences in albuminuria or proteinuria at baseline, but there were differences in uric acid serum levels and urine output. There were no differences in follow-up time. We observed that GFR rate was different according to tertiles: −4.62 ± 3.66, −0.58 ± 2.78 and −1.53 ​​± 4.74 mL/min/year, respectively (P < 0.001). When comparing CKD by stages, we found that patients with citrate ≤ 117 mg/gCr showed higher GFR rates than when they had higher levels: CKD1 −7.74 ± 3.37, CKD2 −4.5 ± 4.4, CKD3 −3.04 ± 1.79 versus citrate patients > 117 mg/gCr with deterioration < 2 mL/min/year (P < 0.05). With multivariate analysis, we found that final GFR was positively associated with baseline GFR and negatively with age, follow-up time and citrate levels ˂ 117 mg/gCr. CONCLUSION Urinary citrate levels decrease as GFR reduction is observed in ADPKD. The reduction of urinary citrate to values ≤ 117 mg/gCr is associated with faster deterioration of renal function in patients with ADPKD.

Photocatalytic performance of alkali metal doped graphitic carbon nitrides and Pd-alkali metal doped graphitic carbon nitride composites

Although there are several reports about the beneficial performance of metal doped graphitic carbon nitrides (g-C3N4) in various photocatalytic reactions, the effect of different alkali metal dopants has not been studied systematically. Series of undoped, Li-, Na- and K-doped samples was synthetized and used for the preparation of novel type of photocatalysts, composed of palladium nanoparticles supported on alkali metals-doped graphitic carbon nitride. Palladium loading was achieved via citrate reduction of palladium precursor in the presence of the carbon nitride material. Several physicochemical characterization methods such as attenuated total reflection infrared-(ATR-IR), diffuse reflectance UV–visible spectroscopy, high-resolution transmission microscopy (HRTEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), and thermogravimetric analysis (TGA) were used to get information about the morphology and composition of the novel composites. According to the optical characterization results, the band gap of g-C3N4 decreased upon Na- and K doping but increased after Li-doping. The palladium nanoparticles were distributed over the support and appeared in dispersed (undoped g-C3N4, Li-g-C3N4) or agglomerated (Na-g-C3N4, K-g-C3N4) form with individual particle size below 5 nm. The catalytic performance of these composite materials was tested in two processes: (i) photodegradation of methyl orange and (ii) hydrogen production from methanol. The Na- doping of graphitic carbon nitride was found to be a key issue to enhance hydrogen production. The carbon nitride matrix was found to be stable during the photocatalytic experiments, while the Pd component underwent certain changes during the photocatalytic reforming reaction of methanol. Our results indicated that the really acting metallic Pd cocatalyst was formed mainly in situ.

An ultrasensitive electrochemical immunosensor based on in-situ growth of CuWO4 nanoparticles on MoS2 and chitosan-gold nanoparticles for cortisol detection

In this paper, a sensitive immunosensor was designed using copper tungstate@molybdenum sulfide (CuWO4@MoS2) and chitosan-gold (Chit-Au) nanocomposites to detect cortisol. CuWO4@MoS2 nanocomposites was synthesized by hydrothermal synthesis, gold nanoparticles (AuNPs) were synthesized by a sodium citrate reduction, and Chit-Au was synthesized by ultrasonic method. The manifestation platform of x-ray diffraction (XRD), transmission electron microscopy (TEM), and energy disperse spectroscopy (EDS), and scanning electron microscopy (SEM) were devoted to characterizing morphologies and structures of the obtained nanocomposites. Then, Chit-Au and CuWO4@MoS2 were modified in GCE to obtain the Chit-Au/CuWO4@MoS2/GCE electrode. Cortisol antibody (C-Mab) was successfully combined with Chit-Au/CuWO4@MoS2/GCE electrode using 1-Ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N–H-hydroxy succinimide (NHS). Furthermore, the immunosensor was characterized using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques, and the cortisol levels were evaluated by square wave voltammetry (SWV) technique in a PBS (pH 7.0, 0.9% NaCl) solution comprising 5 mM [Fe(CN)6]3−/4−. The results demonstrate that the immunosensor exhibited a wide ranges from 0.1 fg/mL to 1 μg/mL and a low detection limit of 0.014 fg/mL in cortisol detection.

Synthesis, In Vitro Testing, and Biodistribution of Surfactant-Free Radioactive Nanoparticles for Cancer Treatment.

New forms of cancer treatment, which are effective, have simple manufacturing processes, and easily transportable, are of the utmost necessity. In this work, a methodology for the synthesis of radioactive Gold-198 nanoparticles without the use of surfactants was described. The nuclear activated Gold-198 foils were transformed into H198AuCl4 by dissolution using aqua regia, following a set of steps in a specially designed leak-tight setup. Gold-198 nanoparticles were synthesized using a citrate reduction stabilized with PEG. In addition, TEM results for the non-radioactive product presented an average size of 11.0 nm. The DLS and results for the radioactive 198AuNPs presented an average size of 8.7 nm. Moreover, the DLS results for the PEG-198AuNPs presented a 32.6 nm average size. Cell line tests showed no cytotoxic effect in any period and the concentrations were evaluated. Furthermore, in vivo testing showed a high biological uptake in the tumor and a cancer growth arrest.

Membrane analytical test system for highly sensitive determination of Hg2+ ions in natural waters

Abstract. A membrane test system has been developed for sensitive and specific detection of Hg2+ ions in natural waters. The test system uses gold nanoparticles synthesized by citrate reduction and a nitrocellulose membrane with a band of the conjugate of mercaptosuccinic acid (MSA) and bovine serum albumin (BSA). In the presence of Hg2+ ions, they are reduced by citrate and adsorbed on the surface of gold nanoparticles. The resulting product moves along the membrane of the test strip under the action of capillary forces and specifically binds to the MSA-BSA conjugate with the formation of a visually detectable colored band. The analysis takes 20 minutes without requiring additional manipulations or instrumentation. Under optimized conditions, the detection limit for Hg2+ ions was 0.13 ng/mL. The efficiency of the proposed approach was confirmed by its approbation for the control of natural waters; Hg2+ recovery ranged from 70 to 120%.

Transparent glass coated with silver colloid nanoparticles candidate as an antiCoronavirus surface - Perspective

Silver nanoparticles have a wide range of anti-bacterial, anti-fungal, and anti-viral effects due to their unique properties. In this work, citrate reduction has been employed to fabricate silver colloidal nanoparticles with 12 nm. The plasmon resonance spectra of nanoscopic silver particles adsorbed onto transparent electrodes in contact with various electrolyte solutions and concentrations of NaC1O4, KPF6, and NaCl were studied. Potentials were controlled with a galvanostat, and UV/visible spectrophotometer was employed to obtain the optical spectra. The results showed the electrolyte identity, potential-induced redshifts, and damping is most pronounced for NaCl, whereas spectral changes are weaker in the cases of NaC1O4 and KPF6 solutions. Hence, due to the noble physical and biological properties of silver colloid nanoparticles, it becomes a great candidate and promising in the future to be used as an anti-coronavirus surface.

Synthesis of large and stable colloidal gold nanoparticles (AuNPs) by seeding-growth method

Colloidal gold nanoparticles (AuNPs) have been used in various applications, mainly in biomedical sciences for therapeutic and diagnostic purposes. These AuNPs can be conjugated with biomolecules and chemical substances due to their unique physical and chemical properties. The AuNPs are usually synthesized by a chemical method; namely Turkevich method or reduction method. However, this synthesis method is not suitable for synthesis of large AuNPs due to aggregation and instability of AuNPs suspension. Thus, the aim for this study is to evaluate the seeding-growth method for synthesis of large AuNPs. The seed of 15 nm AuNPs was initially produced using the citrate reduction method, then further grown to 40, 60, and 80 nm AuNPs using the mild reduction agent, hydroxylamine. Transmission electron microscopy (TEM), dynamic light scattering (DLS), and UV–vis- NIR spectroscopy were used to characterize the as-synthesized AuNPs. The narrow particle size distribution and low polydispersity index value (PDI) for all AuNPs revealed the presence of monodisperse AuNPs. The as-synthesized AuNPs are nearly spherical as shown by the degree of ellipticity (G) close to 1.00. This result showed no agglomeration of AuNPs in the colloidal suspension. The UV–vis-NIR spectra showed peaks shifted to a longer wavelength that confirmed increasing size of AuNPs. The synthesis of different sizes of AuNPs using the seeding-growth method was successful and stable with no aggregation and agglomeration.

Preparation and properties study of F-SiO2@MPDA-AuNPs drug nanocarriers

Photothermal material was one of the hot topics in nanomedicine in recent years, which had aroused widespread attention of scholars. In this paper, a kind of core-shell drug nanocarriers with good photothermal properties were prepared, and its photothermal therapeutic effect on tumor cells in vitro was studied. First, fluorescein isothiocyanate (FITC) was encapsulated in silica nanoparticles to form silica fluorescent (F-SiO2) nanoparticles. Then mesoporous dopamine (MPDA) layer were built on the F-SiO2 nanoparticles, the core-shell nanoparticles (F-SiO2@MPDA) with mesoporous shell structure were obtained. Finally, Au nanoparticles (AuNPs) were wrapped on the surface of the layer of MPDA shell by the citrate reduction method, and the F-SiO2@MPDA-AuNPs composite nanoparticles were formed. Then, the fluorescence property, adsorption performance, sustained release property, photothermal property and cytotoxicity of the F-SiO2@MPDA-AuNPs nanoparticles were researched. It was found that F-SiO2@MPDA-AuNPs nanoparticles had good fluorescence performance, high adsorption capacity (DOX, 111.275 mg/g) and pH responsive release performance. When pH = 5.2, the DOX release rate was 39.5% within 7 h under the action of near-infrared light (NIR). In addition, it also had a high photothermal conversion rate (36.95%), and the DOX loaded F-SiO2@MPDA-AuNPs nanoparticles had obvious inhibitory effect on tumor cells in vitro. As a kind of mesoporous drug nanocarriers with photothermal properties, it has potential application value.

Determination of fenamidone residues by surface-enhanced Raman spectroscopy

The purpose of this study is to establish a novel, simple and rapid surface-enhanced Raman spectroscopy (SERS) detection technology for fenamidone. Fenamidone is a fungicide widely used with curative activity against oomycete diseases. Gold nanoparticles (AuNPs) were prepared by improved trisodium citrate reduction method of chloroauric acid. As a surface-enhanced Raman scattering (SERS) active colloid, the optimized product had the advantages of high sensitivity, reproducibility and chemical stability. The Results showed that the detection limit of fenamidone adsorbed on AuNPs was 0.01 mg/kg. The linear response between SERS intensity and logarithmic concentration was R2 = 0.9562. The method was preliminary applied in tobacco sample and showed its potential to serve as an alternative rapid quantification method of fenamidone residues with simplicity, efficiency, high accuracy and precision.

Tyndall-effect-based colorimetric assay with colloidal silver nanoparticles for quantitative point-of-care detection of creatinine using a laser pointer pen and a smartphone.

Herein, this paper initially reports a new colorimetric Tyndall effect-inspired assay (TEA) for simple, low-cost, sensitive, specific, and point-of-care detection of creatinine (an important small biomolecule) by making use of silver nanoparticles (AgNPs) as model colloidal nanoprobes for visual light scattering signaling. The naked-eye TEA method adopts negatively-charged citrate-capped AgNPs (Cit-AgNPs) prepared by sodium citrate reduction. In the presence of alkaline conditions, the creatinine analyte can form carbanion/oxoanion amino tautomers which in turn crosslink with carboxylate groups on the Cit-AgNPs via a hydrogen bonding network to mediate the aggregation of such colloidal nanoprobes showing a significantly-enhanced TE signal that was created and quantified by a hand-held laser pointer pen and a smartphone, respectively. The results demonstrate that the resulting equipment-free method with the TE readout could enable the portable quantification of creatinine with a detection limit of ∼55 nM, which was ∼90–2334 times lower than that obtained from AgNP-based colorimetric approaches with the most common localized surface plasma resonance signaling. Moreover, it shows a larger analytical sensitivity up to ∼580.8227 signal per nM, offering ∼2.4–232-fold improvement in comparison with many of the recent instrumental creatinine nanosensors. The accuracy and practicality of the developed nanosensing system was additionally confirmed with satisfactory recovery results ranging from ca. 98.52 to 100.36% when analyzing a set of real complex human urine samples.

A magnetically induced self-assembled and label-free electrochemical aptasensor based on magnetic Fe3O4/Fe2O3@Au nanoparticles for VEGF165 protein detection

Based on magnetic Fe3O4/Fe2O3@Au nanoparticles (Fe3O4/Fe2O3@Au NPs), to detect an important tumor screening marker, vascular endothelial growth factor 165 (VEGF165), a label-free electrochemical aptasensor was constructed. Magnetic glassy carbon electrode (MGCE) after Fe3O4/Fe2O3@Au NPs surface modification by a magnetic-induced self-assembly technique was the platform. Fe3O4/Fe2O3@Au NPs were used as the signal amplifier to enhance electron transfer, which was essential for the detection of trace amounts of biological analytes, and were prepared via heating hydrolyzation-combustion calcination and trisodium citrate reduction. Meanwhile, aptamers bound to the as-prepared nanomaterial via Au-s bonds and specifically recognized VEGF165. The electrochemical properties of the aptasensor were evaluated with [Fe(CN)6]3−/4− as redox probes. When in optimal detection conditions, an excellent linear relationship (between 0.01 and 10 pg mL−1, R2 = 0.9973) was obtained for the electrochemical aptasensor. The limit of detection (LOD) and the limit of quantitation (LOQ) of the electrode were 0.01 and 0.03 pg mL−1. This proposed aptasensor exhibited favourable selectivity, stability, reproducibility, and regenerability. The results demonstrated that the sensor was promising to provide an efficient, accurate, and low-cost auxiliary detection method for the early screening of VEGF165-related diseases, which had important clinical practical value for the research of human precision medicine.

Octreotide-conjugated silver nanoparticles for active targeting of somatostatin receptors and their application in a nebulized rat model

Abstract Drug uptake and distribution through cell–receptor interactions are of prime interest in reducing the adverse effects and increasing the therapeutic effectiveness of delivered formulations. This study aimed to formulate silver nanoparticles (AgNPs) conjugated to somatostatin analogs for specific delivery through somatostatin receptors (SSTRs) expressed on cells and by nebulizing the prepared AgNPs formulations into lung cells for in vivo application. AgNPs were prepared using the citrate reduction method, yielding AgNPs–CTT, which was further chemically conjugated to octreotide (OCT) to form AgNPs–OCT through an amide linkage. The AgNPs–OCT formulation was coated using alginate to yield a carrier, AgNPs–OCT–Alg, feasible for drug delivery through nebulization. AgNPs were uniform in size with an acceptable range of zeta potential. Furthermore, the concentrations of AgNP formulations were found safe for the model cell lines used, and cell proliferation was significantly reduced in a dose-dependent manner (p < 0.05). In the healthy lung tissues, AgNPs–OCT–Alg accumulated at a concentration of 0.416 ± 5.7 mg/kgtissue, as determined via inductively coupled plasma optical emission spectrometry. This study established the accumulation of AgNPs, specifically the AgNPs–OCT–Alg, in lung tissues, and substantiated the active, specific, and selective targeting of SSTRs at pulmonary sites. The anticancer efficacy of the formulations was in vitro tested and confirmed in the MCF-7 cell lines. Owing to the delivery suitability and cytotoxic effects of the AgNPs–OCT–Alg formulation, it is a potential drug delivery formulation for lung cancer therapy in the future.

Ligand exchange reactions and PEG stabilization of gold nanoparticles

Gold nanoparticles (Au NPs) were synthesized by the citrate reduction method. Au NPs were aggregated when mixed with mercaptoethanol (ME), dopamine (DAH) and adenine (AD) as the surface passivating citrate molecules were incompletely but heavily replaced by them as supported by the occurrence of a new peak at a longer wavelength and eventual disappearance of the peak/s in the UV–Visible spectra due to the settlement of the aggregated NPs. Transmission electronic microscopic (TEM) images showed aggregated NPs. AD was increasingly replaced by an increasing concentration of dithiothreitol (DTT) in the range of 20 ​μM–10 ​mM, but an incomplete replacement was resulted even after using highly concentrated DTT (10 ​mM). mPEGSH passivates the gold surface where they bind to the gold surface via a mushroom-like configuration. mPEGSH stabilizes the Au NPs preventing aggregation upon mixing with ME, DAH and AD, as revealed by no change in the position and the absorbance of the localized resonance surface plasmon peak in the UV–Visible spectra and well-dispersed Au NPs in the TEM images. Mushroom-like arrangement of mPEGSH on the Au NPs allow adsorption of ME, DAH and AD as revealed by the surface enhanced Raman spectroscopic data.

Simple, rapid, portable and quantitative sensing of Fe3+ ions via analyte-triggered redox reactions mediating Tyndall effect enhancement of Au nanoparticles

This study initially describes a new nanosensing method for colorimetric detection of iron (III) (Fe3+) ions with high sensitivity and selectivity using one of the most basic optical properties of colloids (namely the Tyndall effect, TE). It adopts colloidal Au nanoparticles (AuNPs) prepared by sodium citrate reduction as the light scattering signaling probes, and 3,3′,5,5′ -tetramethylbenzidine (TMB) as recognition reagent. In the presence of Fe3+ ions, the TMB can be oxidized to its positively-charged product (TMBox) to induce the aggregation of the negatively-charged AuNP via electrostatic adsorption, leading to a significant enhancement in their TE which positively relies on the analyte concentration in the sample. The results demonstrate that this nanosensor is simple, rapid, low-cost, and portable, because it takes just 15 min to complete one assay run where only a laser pointer pen is utilized as the hand-held light source to stimulate the TE creation and a smartphone as the mobile quantitative TE reader. In particular, it can linearly detect the Fe3+ in a level range from 0.5 to 64 µM with a detection limit of ∼ 370 nM, offering a ∼ 37-fold improvement in sensitivity but with ∼ 9 times reduction in nanoprobe consumption per assay in comparison with the most common AuNP-based naked-eye method with surface plasmon resonance signaling strategy. Its accuracy and practicability are additionally validated by determining Fe3+ ions in real complex samples including tap water, commercially-available drinking water and human serum with acceptable recovery results between 85.96 and 115.52%. To the best of our knowledge, this is the first report of designing an equipment-free quantitative visual assay for the Fe3+ analysis by taking the advantage of the TE of colloids like AuNP tested herein.

Folate-targeted doxorubicin delivery to breast and cervical cancer cells using a chitosan-gold nano-delivery system

Nanoparticles (NPs) are ideal candidates for safe, directed and effective delivery of chemotherapeutic agents to cancer cells. Herein, we report the synthesis of a gold NP (GNP) based delivery system as a platform for doxorubicin (DOX) delivery to cancer cells. GNPs synthesized by citrate reduction of the gold salt was used to encapsulate DOX, using sodium tripolyphosphate (TPP) as a linking agent. The subsequent functionalization of the DOX-GNP with chitosan (CS) and folate-linked chitosan (F-CS) resulted in the formation of CS-GNP-DOX and F-CS-GNP-DOX delivery systems. The synthesized DOX nanocarriers were characterized using UV–visible and ATR-FTIR spectroscopy, transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). Drug release and kinetic evaluations were done in simulated tumour and physiological microenviroments. The drug-nanocomplexes were evaluated in an in vitro MTT assay for their effect on cell proliferation with further assessments on the mechanisms associated with the toxicity. The NPs and nanocomplexes were spherically shaped, colloidally stable, and displayed a pH-dependent DOX release that closely followed a first or zero-order kinetic model. CS-GNP-DOX and F-CS-GNP-DOX displayed higher chemotherapeutic activity in the human breast (MCF-7), cervical (HeLa) and hepatocellular (HepG2) carcinoma cell lines when compared to free DOX. The lowest IC50 obtained for CS-GNP-DOX and F-CS-GNP-DOX in the cancer cells was significantly lower than that for free DOX. The F-CS-GNP-DOX nanocomplex displayed superior anticancer effects over CS-GNP-DOX in the breast and cervical cancer cells, predominantly due to enhanced cellular uptake via their over-expressed folate receptors (FRα). These nanocomplexes also induced mitochondrial membrane depolarization and activated downstream caspases during apoptotic induction in the breast and cervical cancer cells. Overall, these DOX-nanocomplexes have the potential for clinical application and are be promising lead candidates for further development.

Retention of Activity by Antibodies Immobilized on Gold Nanoparticles of Different Sizes: Fluorometric Method of Determination and Comparative Evaluation.

Antibody–nanoparticle conjugates are widely used analytical reagents. An informative parameter reflecting the conjugates’ properties is the number of antibodies per nanoparticle that retain their antigen-binding ability. Estimation of this parameter is characterized by a lack of simple, reproducible methods. The proposed method is based on the registration of fluorescence of tryptophan residues contained in proteins and combines sequential measurements of first the immobilized antibody number and then the bound protein antigen number. Requirements for the measurement procedure have been determined to ensure reliable and accurate results. Using the developed technique, preparations of spherical gold nanoparticles obtained by the most common method of citrate reduction of gold salts (the Turkevich–Frens method) and varying in average diameter from 15 to 55 nm have been characterized. It was shown that the number of antibodies (immunoglobulins G) bound by one nanoparticle ranged from 30 to 194 during adsorptive unoriented monolayer immobilization. C-reactive protein was considered as the model antigen. The percentage of antibody valences that retained their antigen-binding properties in the conjugate increased from 17 to 34% with an increase in the diameter of gold nanoparticles. The proposed method and the results of the study provide tools to assess the capabilities of the preparations of gold nanoparticles and their conjugates as well as the expediency of seeking the best techniques for various practical purposes.

Preparation of a sustainable Zeolite A using an agroindustry solid waste loaded with silver nanoparticles: Antimicrobial activity study

This paper reports the synthesis of a microporous sustainable Zeolite A material using an agroindustry solid waste (SZA) and its functionalization with silver nanoparticles. Silver nanoparticles with ca. 9.0 nm of diameter onto SZA where were obtained using a sodium citrate reduction route. The release transport properties of Ag+ ions from SZA were investigated. We found that silver ions released from the SZA is controlled by the pseudo-Fickian diffusion mechanism. Furthermore, its demonstrate that the Colony-Forming Units (CFU) of (L. monocytogenes; P. auriginosa; S. aureus; S. typhinimurium; E. coli and S. epidermidis) decreases significantly after exposure to the SZA loaded with silver nanoparticles. The antimicrobial activity of this SZA loaded with silver nanoparticles relies on the exposure time with microorganism and concentration of these materials.