Zeta Potential Values Research Articles

Combinational antimicrobial activity of biogenic TiO2 NP/ZnO NPs nanoantibiotics and amoxicillin-clavulanic acid against MDR-pathogens

The development of effective strategies against multidrug-resistant (MDR) pathogens is an urgent need in modern medicine. Nanoantibiotics (nABs) offer a new hope in countering the surge of MDR-pathogens. The aim of the current study was to evaluate the antibacterial activity of two attractive nABs, TiO2 NPs and ZnO NPs, and their performance in improving the antimicrobial activity of defined antibiotics (amoxicillin-clavulanic acid, amox-clav) against MDR-pathogens. The nABs were synthesized using a green method. The physicochemical characteristics of the synthesized nanoparticles were determined using standard methods. The results showed the formation of pure anatase TiO2 NPs and hexagonal ZnO NPs with an average particle size of 38.65 nm and 57.87 nm, respectively. The values of zeta potential indicated the high stability of the samples. At 8 mg/mL, both nABs exhibited 100 % antioxidant activity, while ZnO showed significantly higher activity at lower concentrations. The antibiofilm assay showed that both nABs could inhibit the formation of biofilms of Acinetobacter baumannii 80 and Escherichia coli 27G (MDR-isolates). However, ZnO NPs showed superior antibiofilm activity (100 %) against E. coli 27G. The MIC values were determined to be 8 (1), 2 (2), and 4 (4) mg/mL for amox-clav, TiO2 NPs, and ZnO NPs against A. baumannii 80 (E. coli 27G), respectively. The results showed that both nABs had synergistically enhanced antibacterial performance in combination with amox-clav. Specifically, an 8-fold reduction in MIC values of antibiotics was observed when they were combined with nABs. These findings highlight the potential of TiO2 NPs and ZnO NPs as effective nanoantibiotics against MDR-pathogens. The synergistic effect observed when combining nABs with antibiotics suggests a promising approach for combating antibiotic resistance. Further research and development in this area could lead to the development of more effective treatment strategies against MDR infections.

Synthesis of thermal and physical properties of biodegradable hybrid nano fluid using two step method

In the presence of green technology or biodegradable options, vegetable oils emerged as replacements for mineral oil as base oils due to their properties of high viscosity index, high flash point, low toxicity, low volatility, and high biodegradability. Nano fluids were a relatively new class of fluids that consisted of a base fluid with nano-sized particles (1–100 nm) suspended within them. The synthesis and characterization of biodegradable hybrid nano fluids and their combination with base materials were carried out in this paper, playing a vital role in machining operations. SiC and TiO2 were used as nano particles, with the base fluid being palm oil, and sodium dodecyl sulphate (SDS) was employed as a surfactant to maintain fluid stability. All samples were prepared in individual and hybrid modes, including palm oil as the base fluid without any emulsifier/surfactant, palm oil + SiC with nano particle concentrations of 0.1%, 0.2%, and 0.3% by volume, palm oil + TiO2 with nano particle concentrations of 0.1%, 0.2%, and 0.3% by volume, and palm oil + SiC + TiO2 with nano particle concentrations of 0.1%, 0.2%, and 0.3% by volume. The FTIR results showed that the SiC + palm oil and SiC + TiO2 + palm oil samples had better chemical composition and surface characterization as biodegradable hybrid nano fluids. The zeta potential values were observed to increase at volume concentrations of 1%, 2%, and 3%. Particularly, the biodegradable hybrid nano fluid samples (palm oil + 1% Vol. SiC + TiO2) and (palm oil + 2% Vol. SiC) demonstrated increased stability as well as enhanced physical, thermal, and rheological properties in machining applications.

Development and In Vivo Evaluation of Sustained Release Microparticles Loaded with Levothyroxine for Hypothyroidism Treatment

Hypothyroidism is a chronic condition combated by a daily oral supplementation of levothyroxine. In addition to the need for frequent dosing, oral administration may result in variable absorption of the drug leading to a failure in achieving normal thyroid function. Therefore, the development of a long-acting injectable system capable of delivering the drug is necessary. This work was aimed at developing sustained release microparticles loaded with levothyroxine. The microparticles were produced through the emulsification-solvent evaporation method using 2 grades of biocompatible and biodegradable polyesters: poly(ᴅ,ʟ-lactide-co-glycolide) (PLGA) and poly(ᴅ,ʟ-lactide) (PLA). Both polymers produced microparticles with very similar sizes (1.9 µm) and zeta potential values (around -22.0 mV). However, PLA microparticles had a significantly higher drug loading (6.1% vs. 4.4%, respectively) and encapsulation efficiency (36.8%, vs. 26.1%, respectively) when compared to PLGA counterparts. While both types of microparticles displayed a biphasic release pattern in vitro, a slower rate of release was observed with PLA microparticles. Moreover, a similar biphasic release pattern was found in vivo, with an initial phase of rapid release followed by a slower phase in the subsequent 10 days. These results indicate the possibility of developing levothyroxine loaded polyester microparticles as a potential long-acting thyroid hormone replacement therapy.

Stabilization of Al2O3 dispersed slurry by controlling pH

This study delves into the critical role of pH in modulating the dispersion and stabilization characteristics of Al2O3 slurries, emphasizing the interaction between the dispersant and Polyvinyl Alcohol (PVA) binder in terms of the system's adsorption behaviors and stability parameters. Zeta-potential measurements elucidate the substantial impact of slurry pH on stability, correlating low zeta potential values with accelerated sedimentation rates. Thermogravimetric and Fourier-Transform Infrared Spectroscopy (FTIR) analyses are conducted to elucidate the co-adsorption dynamics of the dispersant and binder on the Al2O3 surface. Our findings highlight pronounced adsorption of the polymer below the isoelectric point (IEP) of slurry and demonstrate the preferential adsorption of the ionic dispersant over the binder, indicative of chemical bond formation with the former and hydrogen bonding with the latter. These results not only shed light on the interaction mechanisms between the particles and reagents in the system but also pave the way for optimizing slurry formulations for enhanced stability and performance in industrial applications.

Synergistic effects of nano curcumin mediated photodynamic inactivation and nano-silver@colistin against Pseudomonas aeruginosa biofilms

BackgroundPatients with burn injuries colonized by multidrug-resistant Pseudomonas aeruginosa face increased mortality risk. The efficacy of colistin, a last-resort treatment, is declining as resistance levels rise. P. aeruginosa's robust biofilm exacerbates antibiotic resistance. Photodynamic Inactivation (PDI) shows promise in fighting biofilm. Materials and methodsNano curcumin (nCur) particles were synthesized, and their chemical characteristics were determined using zeta potential (ZP), dynamic light scattering analysis (DLS), energy-dispersive X-ray (EDX) analysis, and fourier transform infrared (FTIR). We conducted an MTT assay to assess the cytotoxicity of nCur-mediated PDI in combination with nanosilver colistin. The fractional biofilm inhibitory concentration (FBIC) of two P. aeruginosa clinical isolates and P. aeruginosa ATCC 27853 during nCur-mediated PDI@AgNPs@CL was determined using a 3-dimensional (3-D) checkerboard assay. To study the effect of nCur-mediated PDI@AgNPs@CL on lasI, lasR, rhlI, rhlR, pelA, and pslA gene expression, Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was conducted at each isolate's FBIC. The impact of treatments was also investigated using scanning electron microscopy (SEM). ResultsThe ZP and mean DLS values of the nCur were 10.3 mV and 402.6 ± 24.6 nm, respectively. The distinct functional groups of nCur corresponded with the peaks of FTIR absorption. Moreover, the EDX analysis showed the ratios of different metals in nCur. Cell viability percentages of nCur-mediated PDI@AgNPs@CL at FBIC concentrations of clinical isolates Nos. 30, 354, and P. aeruginosa ATCC 27853 were 91.36 %, 83.20 %, and 92.48 %, respectively. nCur-mediated PDI@AgNPs@CL treatment showed synergistic effects in clinical isolates and P. aeruginosa ATCC 27853 in a 3-D checkerboard assay. All six of the investigated genes showed down-regulation after nCur-mediated PDI@AgNPs@CL treatment. The most suppressed gene during nCur-mediated PDI@AgNPs@CL treatment was the rhlR gene (-11.9-fold) of P. aeruginosa ATCC 27853. The SEM micrographs further proved the connecting cement reduction and biofilm mass mitigation following nCur-mediated PDI@AgNPs@CL treatments. ConclusionsThe combined effect of nCur-mediated PDI and AgNPs@CL synergistically reduce the formation of biofilm in P. aeruginosa. This may be attributable to the suppression of the genes responsible for regulating the production of biofilms.

Phycocyanin-chitosan complex stabilized emulsion: Preparation, characteristics, digestibility, and stability

Phycocyanin is a natural pigment protein with antioxidant, anti-tumor, and anti-inflammatory properties, but its relatively poor emulsibility limits its use in the food industry. In order to improve the emulsifying capacity of phycocyanin, a novel phycocyanin-chitosan complex was prepared, and the characteristics, digestibility, and stability of emulsion containing oil droplets stabilized by the complex were investigated. The results showed that the phycocyanin-chitosan complex had better stability and lower interfacial tension at pH 6.5 than phycocyanin, and it significantly improved the stability of emulsion and inhibited the aggregation of oil droplets. The phycocyanin-chitosan complex stabilized emulsion showed better physical stability, digestibility, and oxidation stability than the phycocyanin emulsion. The particle size of the phycocyanin-chitosan complex stabilized emulsion was very small (from 0.1 to 2 μm), and its absolute value of zeta potential was high. Overall, this study suggests that the phycocyanin-chitosan complex effectively improved the emulsifying capacity of phycocyanin.

Improvement of the Antioxidant and Antitumor Activities of Benzimidazole-Chitosan Quaternary Ammonium Salt on Drug Delivery Nanogels.

The present study focused on the design and preparation of acid-responsive benzimidazole-chitosan quaternary ammonium salt (BIMIXHAC) nanogels for a controlled, slow-release of Doxorubicin HCl (DOX.HCl). The BIMIXHAC was crosslinked with sodium tripolyphosphate (TPP) using the ion crosslinking method. The method resulted in nanogels with low polydispersity index, small particle size, and positive zeta potential values, indicating the good stability of the nanogels. Compared to hydroxypropyl trimethyl ammonium chloride chitosan-Doxorubicin HCl-sodium tripolyphosphate (HACC-D-TPP) nanogel, the benzimidazole-chitosan quaternary ammonium salt-Doxorubicin HCl-sodium tripolyphosphate (BIMIXHAC-D-TPP) nanogel show higher drug encapsulation efficiency and loading capacity (BIMIXHAC-D-TPP 93.17 ± 0.27% and 31.17 ± 0.09%), with acid-responsive release profiles and accelerated release in vitro. The hydroxypropyl trimethyl ammonium chloride chitosan-sodium tripolyphosphate (HACC-TPP), and benzimidazole-chitosan quaternary ammonium salt-sodium tripolyphosphate (BIMIXHAC-TPP) nanogels demonstrated favorable antioxidant capability. The assay of cell viability, measured by the MTT assay, revealed that nanogels led to a significant reduction in the cell viability of two cancer cells: the human lung adenocarcinoma epithelial cell line (A549) and the human breast cancer cell line (MCF-7). Furthermore, the BIMIXHAC-D-TPP nanogel was 2.96 times less toxic than DOX.HCl to the mouse fibroblast cell line (L929). It was indicated that the BIMIXHAC-based nanogel with enhanced antioxidant and antitumor activities and acidic-responsive release could serve as a potential nanocarrier.

Investigating Baneh (Pistacia atlantica) gum properties and applying its particles for stabilizing Pickering emulsions

The purpose of this research was to investigate Baneh gum (BG) properties and prepare Pickering emulsion stabilized by BG particles at different concentrations (0.1, 0.3, 0.5, and 0.7 % (w/w)). Average size of the particles was 948 nm, and the SEM images confirmed the presence of the particles. Surface and interfacial tension of the BG particles were 48.39 and 15.36 (mN/m), respectively. Contact angle of water- and oil-BG particles was 99° and 42.68°, respectively, which can stabilize oil-in-water emulsions. Increment of the Pickering particles concentration decreased the size of the emulsion droplets and increased the emulsion stability (p ≤ 0.05). The size of emulsion droplets was in the range of 1.65–1.76 μm and the highest zeta potential value was obtained by 0.7 % (w/w) BG particles (−30.02 mV). It can be concluded that increasing BG particles to 0.7 % resulted in creating the most stable emulsion.

Bio-based nanomaterial suspensions as sprayable coatings for maintaining blueberry postharvest quality

The growing concerns about postharvest fruit spoilage demand sustainable active coating materials with high performance. In this work, bioactive spray coating suspensions were developed for the postharvest preservation of blueberries using chitosan, cellulose, and lignocellulose nanofibers (ChNFs, CNFs, and LCNFs), sodium alginate (SA), and tea tree essential oil (TTO). Characteristics, including the rheological properties of coatings and the effect on physicochemical postharvest quality parameters of blueberry fruit were investigated. The nanomaterials and SA were shown to make stable and sprayable coating suspensions with high surface charge (zeta potential value of −61.3 mV), shear thinning behavior, steady viscosity, and outstanding viscoelastic behavior from their ability to restore fibrous network structure and ion strength of SA to inhibit nanofibers aggregation. The coatings with LCNFs and SA were more effective in retarding moisture loss of postharvest blueberries during storage compared with coatings without LCNFs and SA. Blueberries coated with ChNF/LCNF/SA/TTO had a soluble solids content (SSC) increase of 16.2% after 15 storage days, while uncoated and other coated blueberries had more than a 21.7% SSC increase. In addition, the ChNF/LCNF/SA/TTO coating had an entangled matrix structure and enhanced hydrophobicity, improving gas barrier performance on the blueberry surface. As a result, the coating was able to preserve the moisture, stiffness, firmness, and individual sugar contents of blueberries during storage. Utilizing nanomaterials and other natural polysaccharides in coatings can offer an economically feasible and sustainable approach for functionalizing biomass materials to preserve fruits.

Honey mediated synthesis of zinc oxide nanoparticles, and evaluation of antimicrobial, antibiofilm activities against multidrug resistant clinical bacterial isolates

The present work aims to synthesize zinc oxide nanoparticles (ZnONPs) via a greener approach using honey as a bio-reductant and stabilizing agent. The prepared nanoparticles were analysed by using UV–visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), crystalline nature by X-ray diffraction (XRD), field electron scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), size distribution and zeta potential by dynamic light scattering (DLS) analysis. XRD patterns demonstrate the polycrystalline wurtzite structure for ZnONPs with an average zeta potential value of − 2.61 mV. Spherical and square-shaped nanostructures were affirmed using FE-SEM and TEM micrographs. The DPPH and ABTS assays revealed that ZnONPs possess antioxidant activity with an IC50 value of 38 µg/mL and 6.38 µg/mL, respectively. Additionally, the antimicrobial activity of ZnONPs performed against clinical strains of Gram negative bacteria such as Klebsiella pneumoniae (K. pneumoniae), Escherichia coli (E. coli), and Gram positive bacteria Methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa (P. aeruginosa), and Staphylococcus aureus (S. aureus) was assessed along with their antibiofilm activity. The evaluation of the integrity of the bacterial cell membrane with the leakge of cellular components, including nucleic acids and proteins, into the culture medium indicated that honey synthesized ZnONPs could function as potential antimicrobial agents.

Electrospherization of genistein@DNA core-shell nanospheres as a drug delivery system and theoretical study of the release mechanism

Encapsulation of poor water-soluble drug was considered as one of the widely used approaches to overcome such obstacle. The goal of this research was in situ encapsulate the hydrophobic genistein (GEN) during the electrospherization (Es) of deoxyribonucleic acid (DNA) nanospheres as a delivery system with appropriate drug release properties. The prepared nanospheres (free GEN sample; Es DNA and GEN loaded DNA; Es GEN@DNA) were characterized using uv–visible spectroscopy (UV–vis), transmission electron microscope (TEM), zeta potential, Fourier transform infrared spectroscopy (FTIR), x-ray diffraction analysis (XRD), and stability test. In addition, the drug encapsulation % was studied, the drug release efficiency was recorded and theoretically visualized to understand the mechanism and kinetics of GEN drug release. The results revealed that GEN was successfully encapsulated during the DNA electrospherization as a core (GEN)/shell (DNA) like structure with a wonderful stability against time. The UV–vis patterns and their deconvolutions introduced that the emerged peak around 372–500 nm of Es GEN@DNA nanospheres has an area under curve larger than that of the free GEN sample. Zeta potential value decreased from −17.4 to −14.3 mV. In addition, TEM images confirmed the formation of a core/shell structure with average size 109.2 nm. XRD pattern of Es GEN@DNA revealed that GEN lost its crystalline phase, which indicated the incorporation of the drug. On the other hand, %Encapsulation of GEN within DNA nanospheres was found to be 89.62%. Es GEN@DNA release profile explored that the well entrapped GEN within the DNA nanospheres could be a promising for sustained drug release. Besides, the dilemma of using a fractal or fractional kinetics model was overcame by introducing a general fractional kinetic equation that involves a time-dependent rate coefficient, which introduced that the solution of the fractional kinetic model can fit the release data profiles.

Nanocomposite materials for decontamination of highly toxic acid dye from aqueous streams

ABSTRACT The rising issue of water pollution, driven by industry, urbanisation, and population increase, needs urgent action to address the release of contaminants. This study tackles the critical need for a low-cost, highly efficient adsorbent to extract toxic dyes from aqueous streams. The innovation lies in the synthesis of Cu/TiO2-CWSP composite, and composites with varying percentages of copper doping and comparing Cu/TiO2-CWSP composites with other nanocomposites, such as Li/TiO2-CWSP, Na₂SiO₃-CWSP, and various CaO-Fe-based composites. The works thoroughly optimised important parameters, including adsorbent dosage, pH, initial dye concentration, and exposure period, demonstrating their major influence on dye removal efficiency. Furthermore, the study assessed the effect of beginning pH on the adjustment of final pH, demonstrating variable efficiency levels depending on initial conditions. Recent research has evaluated numerous adsorbents, analysed by SEM. The highest % removal of acid green dye using Cu/TiO2-CWSP composite was at pH 7, dose of 0.5 g/L with a value of 99.12% achieved after 60 minutes only. The removal effectiveness of acid green dye improved as the percentage of Cu/TiO2 in the composite increased. Cu/TiO2-CWSP composite showed the presence of very fine particles at the surface of composite in SEM micrograph having a zeta Potential value of −20.9 mV. In conclusion, this study presents an innovative approach for efficiently removing acid green dye from aqueous solutions through adsorption-photocatalysis synergy. The findings contribute to addressing the critical issue of water pollution, especially in the textile industry, offering a sustainable path towards cleaner water resources.

Assessment of the correlation between optical properties and CQD preparation approaches

Various production procedures, for carbon quantum dots (CQDs), are still being extensively researched to understand the nature of CQD luminescence. This study compares and examines the impact of chemical as well as green methods on the structural and optical properties of CQDs. We present a straightforward, cost-effective bottom-up method for producing fluorescent CQDs from lemon peels (L-CQDs), orange juice (O-CQDs), and citric acid (C-CQDs) without having to deal with time-consuming or ineffective post-processing processes. The proposed green synthesis has no toxic by-products, and the residual resources utilized promote the large-scale production of CQDs. X-ray diffraction, high-resolution transmission electron microscopy, FTIR, Raman, DLS, and UV–Vis spectroscopy are utilized to investigate the structure and optical characteristics of the prepared CQDs. The as-prepared CQDS possess small particle sizes of 5.6 nm, 6.2 nm, and 1.1 nm for L-CQDs, O-CQDs, and C-CQDs samples, respectively. FTIR results reveal the coexistence of carboxylic and hydroxyl groups on the surface of the CQDs, as also supported by zeta-potential values. Maximal fluorescence intensity was reached at excitation wavelengths of 365, 250, and 280 nm with an emission color of blue, indigo, and light blue for L-CQDs, O-CQDs, and C-CQDs, respectively. The presented approaches show a high quantum yield of 88% for O-CQDs, 49% for L-CQDs, and 37% for C-CQDs. Due to their minuscule particle size, perfect water solubility, high stability, and tunable luminescence properties, the prepared CQDs are preferred for potential applications in multicolor imaging, metal ion sensing, and wastewater technologies.

Quillaja and Sapindus saponins influence on effect on solubilization of Polymyxin B peptide antibiotic in aqueous solutions

Knowing and understanding the interactions between surfactants and pharmaceuticals is crucial for the proper and efficient design of drug delivery systems. The goal of such systems is to ensure that the drug is as bioavailable to cells as possible. The subject of this study was the effect of natural surfactants, saponins from Quillaja saponaria Mol. and Sapindus mukorossi L., on the behavior of the antibiotic Polymyxin B in aqueous solutions at 30 °C and atmospheric pressure. The conducted research showed that the tested surfactants in the concentration range up to 5 mg mL−1 did not affect the solubility of the antibiotic, but increased the value of the octanol–water partition coefficient (Kow). At concentrations of plant saponins from both sources, Kow slightly increased from 0.19 (control sample) to 0.40 (at 5 mg mL−1). The presence of surfactants also led to changes in the particle size distribution of Polymyxin B solutions and also in their zeta potential values. There was also a clear effect of saponins on the freezing point of the Polymyxin solution, but no significant changes in the melting point were observed. The collected results provide new knowledge about the interactions of plant surfactants and peptides based on the example of Polymyxin B, which opens wider possibilities for their use in drug delivery systems.

Exploration of properties (crystallographic, morphological, optical) of nano cobalt aluminate synthesized by facile sol–gel method: Effects of sintering temperature

The present work reports on the facile sol–gel synthesis of CoAl2O4 nanoparticles using cobalt nitrate and aluminum nitrate as the metal salts and citric acid and glycerol as chelating agents. The consequence of sintering temperature on the structure, particle size, morphology, composition, zeta potential, color, and reflectance spectra at neutral pH condition were explored with various instrumental techniques. The CoAl2O4 nanoparticles were characterized with Powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FT-IR), Field emission scanning electron microscopy (FESEM), Energy dispersive spectroscopy (EDS), Nanoparticle size analyzer, Ultraviolet–Visible Diffuse Reflectance Spectroscopy (UV–Vis-DRS) and CIE-Lab colorimetric method. From the data of PXRD, the crystallite size and peak profile analysis were investigated by four different models. It was found that the average crystallite size varied in the range of 28.01–320.97 nm and single-phase cubic CoAl2O4 was formed without any impurity. The average particle size of CoAl2O4 nanoparticles was discerned from the FESEM images using ImageJ software and from a nanoparticle size analyzer. The average particle sizes were increased with the increasing sintering temperature. The values of zeta potential found in all of the samples represented high dispersion stability. From the colorimetry of CoAl2O4 nanoparticles, the CIE-La*b* output illustrated high purity and brightness and the spectra.

SURFACE MODIFICATION OF ALUMINA-SILICA BY ADDITIVE AGENT USING SOL-GEL METHOD AS FILLER DENTAL COMPOSITE

Background: Macro-sized and inhomogeneous distribution of ceramic filer particles make it difficult to obtain smooth surfaces of dental composite after polishing. Objective. This study aims to synthesize alumina silica (Al2O3-SiO2) fillers using sol gel method with the additives agent chitosan 5%, 10% and polyethylene glycol (PEG) 5% to produce micro particle size and evenly distributed particle as filler dental composite. Methods. The type of research is descriptive explorative. The sol-gel process was utilized to synthesize filler particles of Al2O3-SiO2. TEOS was dissolved in ethanol and mixed with acetic acid as catalyts. Al2(NO3)3 was added into the solution and mixed homogenously. Subsequently, the additive agents (Chitosan 5%, chitosan 10% and PEG) were mixed into the mixture for 30 minutes. Drying the samples for 48 hours at 60°C in the oven. The Dynamic light scattering (DLS) SZ-1 was used to evaluate the size, particle distribution and zeta potential. Result. The results showed that the addition of chitosan 10% produced a smaller size of Al2O3-SiO2 compared to other samples. A homogeneous particle distribution is shown in the sample with PEG 5%. Meanwhile, zeta potential values of the filler particles Al2O3-SiO2 with the addition of chitosan 10% shows the biggest value. Conclusion: The additive agent of chitosan 10% can modify the surface of filler Al2O3-SiO2 in order to inhibit particle growth more effectively but better particle distribution is shown in samples with PEG 5% due to the lower viscosity than chitosan thus it is easily homogenized in the solution

A zero-waste one step method to produce carboxy nanocellulose from the untreated barley and wheat straws

A zero-waste simple method was developed to produce carboxy nanocellulose directly from the untreated barley and wheat straw by treating with nitric acid (55%) and sodium nitrite at 40 °C for 12 h. This method significantly reduced the need for toxic chemicals such as TEMPO ((2,2,6,6-tetramethylpiperidin-1-yl)-oxyl) and radical generating chemicals. The process also reduced the usage of corrosive bases and acids and energy demand during the pretreatment process for the multi-step acid hydrolysis of biomass. Moreover, the by-product can be easily neutralized with the addition of NaOH, and the neutralized solution can be concentrated to obtain sodium nitrate which can be utilized as a fertilizer. The current method produces rod shaped and spherical particles of carboxy nanocellulose from the barley and wheat straw respectively with lower crystallinity (ca. ⁓30% of crystallinity index) than the barley and wheat straw itself (ca. ⁓60% of crystallinity index) as evidenced from the grazing incidence X-ray diffraction (GIXRD) technique. The conductometric titration revealed a high concentration (ca. ⁓2.6 mmol/g) of surface carboxylic (-COOH) acid groups and this result is supported by the high zeta potential value (ca ⁓-40mV) for the synthesized carboxy nanocellulose.

Synthesis and in vitro assessment of gold nanoparticles conjugated with extracts, sterols and pure compounds derived from marine sponges from the Indian and Pacific Oceans.

Gold nanoparticles (AuNPs) exhibit different physical properties compared to small molecules, bulk materials and other nanoparticles. Their synthesis using plant extracts, particularly polyflavonoids as phytoreductants, for the conversion of Au(iii) into Au(0) has been reported. In this study, AuNPs were synthesized with extracts, sterols and pure compounds derived from marine sponges using gold(iii) chloride trihydrate. Extracts, hexane (JDH) and ethyl acetate (JDE), sterols (JC-2) and jaspamide were obtained from Jaspis diastra. Pure compounds, namely, contignasterol, ansellone A, motuporamines A and MN100 (a synthetic analog of pelorol), were also used. JC-2 was characterized using NMR and GC-MS, and the major constituent was determined to be β-sitosterol. β-Sitosterol has shown great promise as an anti-cancer molecule, but its poor aqueous solubility and bioavailability coupled with low targeting efficacy limit its therapeutic efficacy. Transmission electron microscopy (TEM) images revealed the formation of spherical AuNPs conjugated with JDH, JDE, JC-2, ansellone and contignasterol with average diameters of 21.1 ± 3.0 nm, 20.7 ± 2.1 nm, 26.2 ± 1.2 nm, 33.3 ± 5.1 nm and 30.8 ± 5.5 nm, respectively. No particle formation was seen with motuporamines A and MN100. Zeta potential values indicated that AuNPs-JC-2 was more stable than AuNPs-JDE, AuNPs-JDH and AuNPs-ansellone. Based on IC50 values, the cytotoxicity of AuNPs-JDH increased in A172, TERA, HeLa and HepG2 cells but showed similar activity in HaCaT cells compared to JDH. The cytotoxicity of AuNPs-JDE decreased in A172 and HaCaT cells but increased in TERA1, HeLa and HepG2 cells compared to JDE. AuNPs-JC-2 showed enhanced cytotoxicity with a decrease in IC50 values from 3.37 ± 0.19 μg mL-1 to 0.52 ± 0.09 μg mL-1 in A172 and from 2.28 ± 0.20 μg mL-1 to 0.78 ± 0.28 μg mL-1 in TERA1 compared to JC-2. The synergistic action of sterols in AuNPs-JC-2 seemed to favour enhanced anti-cancer activity. The presence of sterols increased the ability of transforming Au(iii) into Au(0) to form AuNPs and further enhancing cellular uptake and, thus, anti-cancer activity. AuNPs-contignasterol displayed lower activity than contignasterol in the A172 cell line. No significant difference in activity was observed with AuNPs-ansellone A in the A172 and HaCaT cell lines compared to ansellone A.

Dendrimer Induced Bilayer Disintegration of Hybrid Vesicles.

Physicochemical investigations on the inclusion of anionic polyamidoaminesuccinamic acid dendrimer, generation 5 (PAMAM-SA, G5) with positively charged hybrid vesicles (HCV), prepared using soylecithin, ion pair amphiphile (IPA), cholesterol and dihexadecyldimethylammonium bromide, were investigated by dynamic light scattering, transmission electron/atomic force microscopy (TEM/AFM), differential scanning calorimetry, fluorescence spectroscopy and surface pressure-time isotherm studies. Adsorption of dendrimer onto vesicle surface and subsequent bilayer disruption strongly depends on the bilayer composition and dendrimer concentration. Change in the zeta potential value with increasing dendrimer concentration suggests the dendrimer-vesicle interaction to be electrostatic in nature. AFM studies also confirm the adsorption of dendrimer as well as hole formation in the bilayer. Impact of the inclusion of dendrimer into the bilayer were further investigated through differential scanning calorimetry by monitoring the chain melting temperature and enthalpy of the chain melting processes. Dendrimer at low concentration does not alter bilayer integrity, while hole formations are noted at higher dendrimer concentration. Fluorescence anisotropy studies confirm the adsorption and subsequent bilayer disruption due to dendrimer inclusion. Dendrimer induced vesicle disintegration kinetics conclusively illustrate the transformation of cationic bilayer to monolayer and thereby exposing the role of IPA. In vitro cytotoxicity studies on PAMAM-SA, G5 and HCVs mixtures against human breast cancer cell line suggest that dendrimer-liposome aggregates (dendriosomes) exhibit substantial anticancer activities with insignificant side effects. It is expected that the dendriosomes may have application to host and deliver anticancer drug in the field of targeted drug delivery.

Delivery of siRNAs Against Selective Ion Channels and Transporter Genes Using Hyaluronic Acid-coupled Carbonate Apatite Nanoparticles Synergistically Inhibits Growth and Survival of Breast Cancer Cells.

Dysregulated calcium homeostasis and consequentially aberrant Ca2+ signalling could enhance survival, proliferation and metastasis in various cancers. Despite rapid development in exploring the ion channel functions in relation to cancer, most of the mechanisms accounting for the impact of ion channel modulators have yet to be fully clarified. Although harnessing small interfering RNA (siRNA) to specifically silence gene expression has the potential to be a pivotal approach, its success in therapeutic intervention is dependent on an efficient delivery system. Nanoparticles have the capacity to strongly bind siRNAs. They remain in the circulation and eventually deliver the siRNA payload to the target organ. Afterward, they interact with the cell surface and enter the cell via endocytosis. Finally, they help escape the endo-lysosomal degradation system prior to unload the siRNAs into cytosol. Carbonate apatite (CA) nanocrystals primarily is composed of Ca2+, carbonate and phosphate. CA possesses both anion and cation binding domains to target negatively charged siRNA molecules. Hybrid CA was synthesized by complexing CA NPs with a hydrophilic polysaccharide - hyaluronic acid (HA). The average diameter of the composite particles was determined using Zetasizer and FE-SEM and their zeta potential values were also measured. The stronger binding affinity and cellular uptake of a fluorescent siRNA were observed for HA-CA NPs as compared to plain CA NPs. Hybrid CA was electrostatically bound individually and combined with three different siRNAs to silence expression of calcium ion channel and transporter genes, TRPC6, TRPM8 and SLC41A1 in a human breast cancer cell line (MCF-7) and evaluate their potential for treating breast cancer. Hybrid NPs carrying TRPC6, TRPM8 and SLC41A1 siRNAs could significantly enhance cytotoxicity both in vitro and in vivo. The resultant composite CA influenced biodistribution of the delivered siRNA, facilitating reduced off target distribution and enhanced breast tumor targetability.