Zeta Potential Of Nanoparticles Research Articles

Experimental Analysis of the Co-Deposition of Metal Cu and Nano-Sized SiC Particles with CTAB in Micro Via Filling

Micro via interconnection is the core of the three-dimensional (3D) packaging. The material property of the interconnection is the decisive factor of chip reliability. In this study, an innovative material modification method for micro via filling is proposed by adopting the co-deposition of metal copper (Cu) and SiC nanoparticles. Investigations focuse on defect-free filling of micro via with co-deposition method and the controllable nanoparticle amount in the nanocomposite. Cetyltrimethylammonium bromide (CTAB) is found having significant inhibition effect on Cu electrodeposition, and it is used as suppressor to avoid defects in micro via. By adjusting pH condition of the electrolyte, the absolute zeta potential of nanoparticles is increased, and agglomeration of nanoparticles is reduced. Experimental results indicate that the content of SiC nanoparticles incorporated in the nanocomposite is greatly enhanced by adding CTAB into the electrolyte, as the CTAB modified the zeta potential of these particles from negative into positive. Other factors affecting the content of SiC nanoparticle in the nanocomposite are investigated. Experimental results show that: 1) current density and duty cycle of pulse direct current (PDC) have great influence on the amount of nanoparticles in the nanocomposite; 2) ultrasound is an effective assistance facilitating the process of metal/nanoparticle co-deposition.

Deep Insight into PEGylation of Bioadhesive Chitosan Nanoparticles: Sensitivity Study for the Key Parameters Through Artificial Neural Network Model.

Ionically cross-linked chitosan nanoparticles have great potential in nanomedicine due to their tunable properties and cationic nature. However, low solubility of chitosan severely limits their potential clinical translation. PEGylation is a well-known method to increase solubility of chitosan and chitosan nanoparticles in neutral media; however, effect of PEG chain length and chitosan/PEG ratio on particle size and zeta potential of nanoparticles are not known. This study presents a systematic analysis of the effect of PEG chain length and chitosan/PEG ratio on size and zeta potential of nanoparticles. We prepared PEGylated chitosan chains prior to the nanoparticle synthesis with different PEG chain lengths and chitosan/PEG ratios. To precisely estimate the influence of critical parameters on size and zeta potential of nanoparticles, we both developed an artificial neural network (ANN) model and performed experimental characterization using the three independent input variables: (i) PEG chain length, (ii) chitosan/PEG ratio, and (iii) pH of solution. We studied the influence of PEG chain lengths of 2, 5, and 10 kDa and three different chitosan/PEG ratios (25 mg chitosan to 4, 12, and 20 μmoles of PEG) for the synthesis of chitosan nanoparticles within the pH range of 6.0-7.4. Artificial neural networks is a modeling tool used in nanomedicine to optimize and estimate inherent properties of the system. Inherent properties of a nanoparticle system such as size and zeta potential can be estimated based on previous experiment results, thus, nanoparticles with desired properties can be obtained using an ANN. With the ANN model, we were able to predict the size and zeta potential of nanoparticles under different experimental conditions and further confirmed the cell-nanoparticle adhesion behavior through experiments. Nanoparticle groups that had higher zeta potentials promoted adhesion of HEK293-T cells to nanoparticle-coated surfaces in cell culture medium, which was predicted through ANN model prior to experiments. Overall, this study comprehensively presents the PEGylation of chitosan, synthesis of PEGylated chitosan nanoparticles, utilizes ANN model as a tool to predict important properties such as size and zeta potential, and further captures the adhesion behavior of cells on surfaces prepared with these engineered nanoparticles.

Nicotine-loaded chitosan nanoparticles for dry powder inhaler (DPI) formulations – Impact of nanoparticle surface charge on powder aerosolization

The aim of this study is to demonstrate the role of surface charge of nicotine loaded or unloaded chitosan (CS) nanoparticles on the dispersibility from dry powder inhaler (DPI) formulations. The nanoparticles were prepared using glutaraldehyde crosslinking of the amino groups of chitosan in a water-in-oil emulsion. Using dynamic light scattering (DLS) the particle size, size distribution and the zeta potential of nanoparticles were measured. The morphological characteristics were studied using SEM. The fine particle fractions (FPFs) of nanoparticles were determined by a twin stage impinger (TSI) using a Rotahaler at 60 L/min flow rate. The FPF of nanoparticles could be correlated to the surface charge i.e., FPFs were increased with increasing surface charge, which reduced with increased concentration of the drug. The FPF from the large carrier (lactose) based formulations was significantly higher (p < 0.001) than those of formulations without carriers. The higher FPF from the large carrier-based formulations was independent of zeta potential and thought to be associated with high impaction. These results suggested the mechanism of nicotine loaded CS nanoparticle dispersion without large carriers was dependent on the zeta potential, which was linked to the agglomeration or deagglomeration behaviour of particles.

Chemical induced fabrication of silver nanoparticles (Ag-NPs) as nanocatalyst with alpha amylase enzyme for enhanced breakdown of starch

Abstract Silver nanoparticles (Ag-NPs) have been used as promising catalytic materials for various applications. The objective of the present study is the fabrication of silver nanoparticles by chemical method for nanocatalytic degradation of starch using alpha amylase enzyme. The present study demonstrates sodium borohydride is used for the fabrication of silver nanoparticles. The fabrication of the silver nanoparticles was monitored visually and using UV–visible absorption spectroscopy. Silver nanoparticles were characterized by UV–visible spectroscopy, FTIR, Zeta sizer, Zeta potential and antimicrobial efficacy. Silver nanoparticle with amylase enzyme is utilized for enhanced degradation of starch in a catalyzed reaction of starch hydrolysis by DNS assay method. UV–Vis spectroscopy revealed the fabrication of silver nanoparticles exhibiting the typical surface plasmon absorption at 430 nm. The three major functional moieties are proteins, aromatic groups and hydroxyl groups. These are responsible for the instant reduction of silver salts into silver ions recorded in FTIR spectra. The zeta potential of nanoparticle was found to be sharp peaked at − 31.7 mV. Antimicrobial activity of nanoprticles revealed more susceptible against Gram positive bacteria than Gram negative bacteria and Candida albicans. An increased formation of reducing sugar around 40 fold confirmed the catalytic activity of purified bacterial amylase enzyme mixed with Ag-NPs as nanocatalyst. The present study suggests that immobilization of amylase enzyme onto the surface of Ag-NPs as nanocatalyst can be a useful approach for increased degradation of complex starch molecules into simple sugars, which can be utilized for diverse industrial applications.

Poly (ε-caprolactone) nanoparticles loaded with indomethacin and Nigella Sativa L. essential oil for the topical treatment of inflammation

Indomethacin has a high anti-inflammatory potential and an acceptable efficiency for external application. However, indomethacin can cause several side effects. It is crucial to reduce the employed indomethacin dosage and accordingly associated side effects. Therefore, topical delivery of indomethacin is as an interesting strategy. Thus, we designed poly (ε-caprolactone) based nanoparticles loaded with the Nigella Sativa L. Seeds Essential Oil (NSSEO) and indomethacin to enhance analgesic and anti-inflammatory effects of indomethacin. Nanoparticles were prepared by nanoprecipitation method. Prepared nanoparticles pre-stability study was also carried out. Nanoparticles size was ranged between 230 nm and 260 nm and zeta potential of nanoparticles was between – 20 mV and – 30 mV at pH around 6. Encapsulation efficiency of indomethacin and NSSEO within nanoparticles was respectively 70% and 84% while drug loading of indomethacin and NSSEO were 14% and 5.63% respectively. The size and zeta potential of nanoparticles was not changed significantly within 30 days of pre-stability investigation. Nanoparticles had a size in nano scale with round shape and a proper stability. Indomethacin and NSSEO were successfully encapsulated that would boost the anti-inflammatory and analgesic effects of indomethacin.

Protein delivery nanosystem of six-arm copolymer poly(ε-caprolactone)-poly(ethylene glycol) for long-term sustained release.

BackgroundTo address the issue of delivery of proteins, a six-arm copolymer, six-arm poly (ε-caprolactone)–poly(ethylene glycol) (6S-PCL-PEG), was synthesized by a simple two-step reaction. Thereafter, the application of 6S-PCL-PEG as a protein carrier was evaluated.Materials and methodsA six-arm copolymer, six-arm poly(ε-caprolactone) (6S-PCL), was synthesized by ring-opening polymerization, with stannous octoate as a catalyst and inositol as an initiator. Then, poly(ethylene glycol) (PEG) was linked with 6S-PCL by oxalyl chloride to obtain 6S-PCL-PEG. Hydrogen-1 nuclear magnetic resonance spectrum, Fourier-transform infrared spectroscopy, and gel-permeation chromatography were conducted to identify the structure of 6S-PCL-PEG. The biocompatibility of the 6S-PCL-PEG was evaluated by a cell counting kit-8 assay. Polymeric nanoparticles (NPs) were prepared by a water-in-oil-in-water double emulsion (W1/O/W2) solvent evaporation method. The size distribution and zeta potential of NPs were determined by dynamic light scattering. Transmission electron microscopy was used to observe the morphology of NPs. Drug-loading capacity, encapsulation efficiency, and the release behavior of ovalbumin (OVA)-loading NPs were tested by the bicinchoninic acid assay kit. The stability and activity of OVA released from NPs were detected and the uptake of NPs was evaluated by NIH-3T3 cells.ResultsAll results indicated the successful synthesis of amphiphilic copolymer 6S-PCL-PEG, which possessed excellent biocompatibility and could formulate NPs easily. High drug-loading capacity and encapsulation efficiency of protein NPs were observed. In vitro, OVA was released slowly and the bioactivity of OVA was maintained for over 28 days.Conclusion6S-PCL-PEG NPs prepared in this study show promising potential for use as a protein carrier.

Effects of Interactions between ZnO Nanoparticles and Saccharides on Biological Responses.

Zinc oxide (ZnO) nanoparticles (NPs) are widely used as a Zn supplement, because Zn plays a role in many cellular and immune functions but public concern about their potentially undesirable effects on the human body is growing. When NPs are added in food matrices, interactions between NPs and food components occur, which can affect biological systems. In this study, interactions between ZnO NPs and saccharides were investigated by measuring changes in hydrodynamic radius, zeta potential and solubility and by quantifying amounts of adsorbed saccharides on NPs; acacia honey, sugar mixtures (containing equivalent amounts of fructose, glucose, sucrose and maltose) and monosaccharide solutions were used as model compounds. Biological responses of NPs dispersed in different saccharides were also evaluated in human intestinal cells and rats in terms of cytotoxicity, cellular uptake, intestinal transport and oral absorption. The results demonstrate that the hydrodynamic radii and zeta potentials of NPs were highly affected by saccharides. In addition, trace nutrients influenced NP/saccharide interactions and interactive effects between saccharides on the interactions were found. NPs in all saccharides increased inhibition of cell proliferation and enhanced cellular uptake. Oral absorption of NPs was highly enhanced by 5% glucose, which is in-line with intestinal transport result. These findings show that ZnO NPs interact with saccharides and these interactions affects biological responses.

Coating Chitosan Thin Shells: A Facile Technique to Improve Dispersion Stability of Magnetoliposomes.

Magnetoliposomes (ML) have been emerging as a novel multifunctional nanoparticle with a wide range of biomedical and therapeutic applications over the past decade. Although the ML system has shown excellent performances, the stability and lipid peroxidation of liposomal components are still remaining as key issues and need to be solved for intensive applications. Changing zeta potential of nanoparticles' surface can be seen as a potential way to achieve the stable dispersion. In this work, we have employed the positive charged, abundant and cheap chitosan to coat ML in order to change the zeta potential of the ML system and examined the stability of chitosan@magnetoliposomes (CML) in long-term storage. The combining of pH-sensitive chitosan with temperature-sensitive phospholipid formed a novel pH- and temperature-sensitive nanoparticles which can be promisingly used as controllable drug release applications. These novel CML with chitosan thin shells showed excellent stability in long-term storage; meanwhile, the bare ML sample showed aggregations and forming micrometer-size particles. The CML system can achieve a drug encapsulation efficiency of nearly 50% and an enhanced drug release behavior under pH 5 at 45 °C.

Preparation and characterization of acetylsalicylic acid/chitosan nanoparticles and its antithrombotic effects

ABSTRACTChitosan (CS)-acetylsalicylic acid (ASA) nanoparticles, which are well dispersed and stable in aqueous solution, have been prepared by interpolymer complexation of ASA in CS solution. The physicochemical properties of nanoparticles were investigated by using FT-IR, 1H NMR, scanning electron microscope（SEM）, dynamic light scattering, and UV spectrophotometer. It was found that the carboxyl group of the ASA had firmly integrated on the amino group of CS and the ASA-CS nanoparticles were almost spherical in shape with an average diameter of less than (79.3 ± 24.6) nm in high reproducibility and showed high chemical stability against environmental changes. It was also found that the prepared nanoparticles carried a positive charge and showed the size in the range from 700 to 150 nm. The surface structure and zeta potential of nanoparticles can be controlled by different preparation processes. The factor experiment results indicated that the ASA-CS nanoparticles had satisfactory loading capacity (LC) and encapsulation efficiency (EE), 27.27% and 46.88% (data not shown), respectively. The experiments of in vitro ASA release showed that these nanoparticles provided a sustained and pH-dependent drug release manner, and the release behavior was influenced by the pH value of the medium. Preliminary pharmacology experiment exhibited prolonged circulation and higher bioavailability than that of ASA. All the results indicated that ASA/CS nanoparticles may have promising pharmaceutical application, and further pharmacological research is needed to confirm these beneficial effects.

Modeling of the Formation Processes of Nanocomposite Coatings by the Electrocodeposition

The coupled mathematical model of electrocodeposition process on the rotating cylinder electrode is presented. Low Reynolds k-e model with Abe-Kondoh-Nagano damping functions is used to describe mass transport of electrolyte. The cathodic and anodic processes are described by the tertiary current distribution theory. Mass transfer of electrolyte ions is described by diffusion-convection equation and is studied throughout the volume of the electrolyte cell. The simulation of electrocodeposition of Cu-Al2O3 nanoparticles on rotating cylinder electrode of are presented. It is found that the unsteady diffusion layer is formed close to the rotating electrode surface. Also it was found that the sign of the zeta potential of nanoparticles has a decisive influence on the possibility of forming the composite coatings. The results of mathematical modelling are in good agreement with the experimental data.

High-Resolution Single Particle Zeta Potential Characterisation of Biological Nanoparticles using Tunable Resistive Pulse Sensing

Physicochemical properties of nanoparticles, such as size, shape, surface charge, density, and porosity play a central role in biological interactions and hence accurate determination of these characteristics is of utmost importance. Here we propose tunable resistive pulse sensing for simultaneous size and surface charge measurements on a particle-by-particle basis, enabling the analysis of a wide spectrum of nanoparticles and their mixtures. Existing methodologies for measuring zeta potential of nanoparticles using resistive pulse sensing are significantly improved by including convection into the theoretical model. The efficacy of this methodology is demonstrated for a range of biological case studies, including measurements of mixed anionic, cationic liposomes, extracellular vesicles in plasma, and in situ time study of DNA immobilisation on the surface of magnetic nanoparticles. The high-resolution single particle size and zeta potential characterisation will provide a better understanding of nano-bio interactions, positively impacting nanomedicine development and their regulatory approval.

Formation of positively charged gold nanoparticle monolayers on silica sensors

Formation of positively charged gold nanoparticle monolayers on the Si/SiO2 was studied under in situ conditions using quartz microbalance (QCM). The gold nanoparticles were synthesized in a chemical reduction method using sodium borohydride as reducing agent. Cysteamine hydrochloride was applied to generate a positive surface charge of nanoparticles. The micrographs obtained from transmission electron microscopy (TEM) revealed that the average size of nanoparticles was equal to 12±3nm. The stability of nanoparticle suspensions under controlled pH and ionic strength was determined by dynamic light scattering (DLS). The electrophoretic mobility measurements showed that the zeta potential of nanoparticles was positive, decreasing with ionic strength and pH from 56mV at pH 4.2 and I=10−4M to 22mV at pH 8.3 and I=3×10−3M. The surface enhanced Raman spectroscopy (SERS) confirmed chemisorption of cysteamine on nanoparticles and the contribution of amine moieties in the generation of nanoparticle charge. The influence of suspension concentration, ionic strength and flow rate on the kinetics of nanoparticle deposition on the sensors was quantitatively determined. It was confirmed that the deposition for the low coverage regime is governed by the bulk mass transfer that results in a linear increase of the coverage with time. The significant increase in the maximum coverage of gold monolayers with ionic strength was interpreted as due to the decreasing range of the electrostatic interactions among deposited particles. Moreover, the hydratation of formed monolayers, their structure and the stability were determined by the comparison of the QCM results with those obtained by AFM and SEM. The experimental data were adequately interpreted in terms of the extended random sequential adsorption (eRSA) model that considers the bulk and surface transfer steps in a rigorous way. The obtained results are useful for a facile fabrication of gold nanoparticle-based biosensors capable to bind target molecules via available amine moieties.

The effect of cell penetrating peptides on transfection activity and cytotoxicity of polyallylamine.

Introduction: Cationic polymers have the potential to be modified to achieve an ideal gene vector lacking viral vector defects. The aim of the present study was to improve polyallylamine (PAA) transfection efficiency and to reduce cytotoxicity by incorporating of cell-penetrating peptides (CPPs). Methods: To prepare the peptide-based polyplexes, PAA (15 kDa) was modified with 2 peptides (TAT and CyLoP-1) by covering the 0.5% and 1% of amines. Buffer capacity and DNA condensation ability of modified polymer, particle size and zeta potential of nanoparticles, cell viability, and transfection activity of vectors were evaluated. Results: In low carrier to plasmid (C/P) weight ratios such as 0.5 and 1, the unmodified polymer was more capable to condense the DNA compared to the synthesized vectors. In C/P ratio of 2, the plasmid was fully condensed in all vectors. The size of polyplexes ranged from 195 to 240 nm. The zeta potential was almost as the same as PAA and varied from 25 to 27 mV. All polyplexes increased the buffer capacity compared to PAA. The transfection efficiency was improved compared to unmodified polymer especially in the vectors modified with 1% of TAT or CyLoP-1 peptides in C/P ratio of 2. The cytotoxicity of prepared vectors was less than PAA. In most ratios, the cytotoxicity of the CyLoP-1 modified samples was less than the TAT modified ones. Conclusion: Modification of PAA with CPPs improved the transfection activity of vector.

Transport of natural soil nanoparticles in saturated porous media: effects of pH and ionic strength

To understand the effects of ionic strength and pH on the transport of natural soil nanoparticles (NS) in saturated porous media, aeolian sandy soil nanoparticles (AS), cultivated loessial soil nano particles (CS), manural loessial soil nanoparticles (MS) and red soil nanoparticles (RS) were leached with solutions of varying pH and ionic strength. The recovery rate of soil nanoparticles decreased in the order AS > RS > MS > CS. Transport of soil nanoparticles was enhanced with increasing pH and decreasing ionic strength and was attributable to changes in the Zeta potential of NS. Deposition of NS was also affected by the composition of soil nanoparticles and the surface charge. Column experiments showed that the interaction between soil nanoparticles and saturated quartz sand was mainly due to the physical and chemical properties of soil nanoparticles. The Derjaguin–Landau–Verwey–Overbeek interaction energies between NS and sand were affected by pHs and ionic strengths. Soil nanoparticles transport through saturated porous media could be accurately simulated by the one-dimensional advection-dispersion-reaction equation.

Acute Toxicity Evaluation of Glycosylated Gd3+-Based Silica Nanoprobe.

Early stage diseases diagnosed using magnetic resonance imaging (MRI) techniques is of high global interest as a potent noninvasive modality. MRI contrast agents are improved through modifications in structural and physicochemical properties of the applied nanoprobes. But, the potential toxic effects of nanoprobes upon exposure to biological systems are still a major concern. In this study, the acute toxicity of glycosylated Gd3+-based silica mesoporous nanospheres (GSNs) as a MRI contrast agent was evaluated in Balb/c mice. In order to evaluate in vivo toxicity of GSN, preclinical studies, daily weight monitoring, hematological/blood chemistry tests, and histological assessment were conducted. Magnetic resonance relaxivities of GSN was determined using a MRI scanner. The obtained results suggest that in vivo toxicity of GSN was mostly influenced by nanoparticle surface area, functionality, and nanoparticle zeta potential. The maximum tolerated dose (MTD) increased in the following order: mesoporous silica nanospheres (MSNs) at 1mg/mice<GSN (aspect ratio 1, 2, 8) at 40mg/mice. The results also indicate GSN, one of the best cell imaging contrast agent, which does not show any significant toxicity on multiple vital organs following injection of 20mg/mice, while a significant T1-weighted enhancement was observed in whole body of a Balb/c mice 15min postinjection of (5μmol/kg) of body weight of GSN. These results shed light on the functionality of MSNs to minimize in vivo toxicity. Also, glyconanoprobe can be beneficially used for nanomedicine and cellular imaging applications without any significant toxicity.

Preparation and Characterization of Atenolol Laden Nanoparticles

In the present study, an attempt was made to develop nanoparticles of Atenolol for effective treatment of Glaucoma. By developing the nanoparticulated delivery the required action of drug at the target site i.e. at eye can be provided. The nanoparticles were prepared by nano precipitation method. The formulation was subjected to different evaluation parameters like particle size, zeta potential, drug content uniformity, entrapment efficiency, in-vitro drug release study. The particle size range of nanoparticles was found to be 100-256 nm. The zeta potential of nanoparticles was found to be 55.87 to 64.87 mV. The drug content of different formulations F1 to F8 was calculated and the content was found to be in range of 95.98 TO 102.14 %. The entrapment efficiency was found to be in range of 45.76 to 72.98%. From the in-vitro drug release studies, it was found that the cumulative percent drug release for optimised formulation F5 found to be between 12.56 to 88.15 % respectively.

Preparation, characterization, and pharmacokinetics of tilmicosin‐ and florfenicol‐loaded hydrogenated castor oil‐solid lipid nanoparticles

To effectively control bovine mastitis, tilmicosin (TIL)- and florfenicol (FF)-loaded solid lipid nanoparticles (SLN) with hydrogenated castor oil (HCO) were prepared by a hot homogenization and ultrasonication method. In vitro antibacterial activity, properties, and pharmacokinetics of the TIL-FF-SLN were studied. The results demonstrated that TIL and FF had a synergistic or additive antibacterial activity against Streptococcus dysgalactiae, Streptococcus uberis, and Streptococcus agalactiae. The size, polydispersity index, and zeta potential of nanoparticles were 289.1±13.7nm, 0.31±0.05, and -26.7±1.3 mV, respectively. The encapsulation efficiencies for TIL and FF were 62.3±5.9% and 85.1±5.2%, and the loading capacities for TIL and FF were 8.2±0.6% and 3.3±0.2%, respectively. The TIL-FF-SLN showed no irritation in the injection site and sustained release invitro. After medication, TIL and FF could maintain about 0.1μg/mL for 122 and 6h. Compared to the control solution, the SLN increased the area under the concentration-time curve (AUC0-t ), elimination half-life (T½ke ), and mean residence time (MRT) of TIL by 33.09-, 23.29-, and 37.53-fold, and 1.69-, 5.00-, and 3.83-fold for FF, respectively. These results of this exploratory study suggest that the HCO-SLN could be a useful system for the delivery of TIL and FF for bovine mastitis therapy.

FORMULATION, OPTIMIZATION, AND CHARACTERIZATION OF BIOCOMPATIBLE INHALABLE D-CYCLOSERINE-LOADED ALGINATE-CHITOSAN NANOPARTICLES FOR PULMONARY DRUG DELIVERY

&lt;p&gt;ABSTRACT&lt;br /&gt;Objective: To prepare Nanoparticulate dosage form having improved drug bioavailability and reduced dosing frequency of antitubercular drugs&lt;br /&gt;which will helps in improving patient compliance in the treatment of multi-drug resistant tuberculosis (MDR-TB).&lt;br /&gt;Methods: Ionotropic gelation method was used to prepare D-cycloserine (D-CS)-loaded alginate-chitosan nanoparticles, and the particles are&lt;br /&gt;characterized by their particle size and morphology using particle size analyzer and scanning electron microscopy (SEM). X-ray diffraction (XRD),&lt;br /&gt;differential scanning calorimetry (DSC), and Fourier-transformed infrared (FTIR) studies were used to determine drug-polymer interactions and drug&lt;br /&gt;entrapment. Entrapment efficiency, drug loading (DL), particle size, and zeta potential of nanoparticles were also studied. The 2&lt;br /&gt; factorial designs of&lt;br /&gt;experiments by Design-Expert&lt;br /&gt;®&lt;br /&gt; V9 were used to optimize the particle size and entrapment efficiency of nanoparticles.&lt;br /&gt;Results: The optimized batch had shown the entrapment efficiency of 98.10±0.24% and DL of 69.32±0.44% with particle size and zeta potential&lt;br /&gt;as 344±5 nm and −42±11.40 mV, respectively. DSC, FTIR, and XRD studies confirmed the drug entrapment within nanoparticle matrix. SEM results&lt;br /&gt;showed spherical-shaped particles. Sustained release of drug from the nanoparticles was observed for 24 hrs period. Respirable fraction up to&lt;br /&gt;52.37±0.7% demonstrates the formulation suitability for deep lung delivery. Lung inflammatory study showed a less inflammatory response.&lt;br /&gt;Conclusion: Ionotropic gelation method can be used to prepare biocompatible particles with a high entrapment efficiency, DL, optimum particle size,&lt;br /&gt;and controlled release characteristics, which can serve as a convenient delivery system for D-CS and could be a potential alternative to the existing&lt;br /&gt;conventional therapy in MDR-TB.&lt;br /&gt;Keywords: Nanoparticles, Alginate, Chitosan, Inhalation, Sustained release, Tuberculosis.&lt;br /&gt;3&lt;/p&gt;

Dense stable suspensions of medium-chain-length poly(3-hydroxyalkanoate) nanoparticles

This is the first study to examine the formulation (selection of ionic and nonionic surfactants and their concentrations) and processing conditions (ultrasonication time and amplitude, and selection of solvent) to make dense suspensions (10and30% (w/v)) of medium-chain-length poly(3-hydroxyalkanoate) (mcl-PHA) with particles less than 300nm. A two-stage emulsification-solvent evaporation process was used. Previous studies made suspensions at much lower solids content (up to 0.4% (w/v)). The dispersed phase was mcl-PHA initially dissolved in methylene chloride, while the continuous phase was water containing one or more surfactants. Water miscible solvents, such as acetone and tetrahydrofuran, could not make dense suspensions of PHA nanoparticles, while those with low water solubility were effective. Among the ionic surfactants, the anionic, sodium dodecyl sulfate (SDS), and the cationic, dodecyltrimethylammonium bromide, produced the smallest particle sizes (both ∼100nm). Nanoparticles were more stable when SDS was combined with any of the non-ionic surfactants tested. The zeta potential of nanoparticles stabilized with SDS and polyoxyethylene octyl phenyl ether (Triton X-100) or polyoxyethylene (20) sorbitan monooleate (Tween 80) increased slightly over 30days, indicating that they may be more effective than the other non-ionic surfactants stabilizers where a decrease was observed. Using the same surfactant formulation, similar size mcl-PHA stable nanoparticle suspensions were produced using either an ultrasonic probe or a more scalable high-shear microfluidic device.

Understanding ligand–nanoparticle interactions for silica, ceria, and titania nanopowders

We performed a systematic study on titania, ceria, and silica nanopowders, to investigate their interactions with ligands and the corresponding colloidal stability in aqueous solutions. Electrospray–differential mobility analysis (ES–DMA) was employed for characterization of particle size distributions (PSDs), including the peak diameter (dp,m∗) and the full width at half maximum (FWHM) of nanoparticle suspensions. Transmission electron microscopy and zeta potential analysis were employed orthogonally to provide information of particle imagery and surface charge, respectively. Bovine serum albumin, sodium dodecyl sulfate, and cetyltrimethylammonium bromide were chosen as representative ligands. Results show that we were able to successfully characterize the ligand–nanoparticle interaction including the aggregation, de-aggregation, and the surface dissolution of nanoparticle using ES–DMA. Based on the measured dp,m∗, FWHM, and the number concentrations over various experimental conditions, we observed that the colloidal stability was strongly dependent of the environmental pH, isoelectric point (IEP) of nanoparticle, and the acid dissociation constant (pKa) of ligand. Fast aggregation was found when the absolute zeta potential of nanoparticles was below 18mV and/or Ω (defined as ⌈(IEP+pKa)/2-pH⌉)<2. Our work demonstrates a prototype study for establishing the capability of characterizing ligand–nanoparticle interactions and developing a correlation to the corresponding colloidal stability in a variety of aqueous environments (e.g., formation chemistry, natural water system).