Stable Suspension Research Articles

Enhanced Stability and In Vitro Biocompatibility of Chitosan-Coated Lipid Vesicles for Indomethacin Delivery

Background: Lipid vesicles, especially those utilizing biocompatible materials like chitosan (CHIT), hold significant promise for enhancing the stability and release characteristics of drugs such as indomethacin (IND), effectively overcoming the drawbacks associated with conventional drug formulations. Objectives: This study seeks to develop and characterize novel lipid vesicles composed of phosphatidylcholine and CHIT that encapsulate indomethacin (IND-ves), as well as to evaluate their in vitro hemocompatibility. Methods: The systems encapsulating IND were prepared using a molecular droplet self-assembly technique, involving the dissolution of lipids, cholesterol, and indomethacin in ethanol, followed by sonication and the gradual incorporation of a CHIT solution to form stable vesicular structures. The vesicles were characterized in terms of size, morphology, Zeta potential, and encapsulation efficiency and the profile release of drug was assessd. In vitro hemocompatibility was evaluated by measuring erythrocyte lysis and quantifying hemolysis rates. Results: The IND-ves exhibited an entrapment efficiency of 85%, with vesicles averaging 317.6 nm in size, and a Zeta potential of 24 mV, indicating good stability in suspension. In vitro release kinetics demonstrated an extended release profile of IND from the vesicles over 8 h, contrasting with the immediate release observed from plain drug solutions. The hemocompatibility assessment revealed that IND-ves exhibited minimal hemolysis, comparable to control groups, indicating good compatibility with erythrocytes. Conclusions: IND-ves provide a promising approach for modified indomethacin delivery, enhancing stability and hemocompatibility. These findings suggest their potential for effective NSAID delivery, with further in vivo studies required to explore clinical applications.

Development of hemp seed (Cannabis sativa L.) beverages: Roasting effects and safety

AbstractThe aims of this study were to formulate 2% and 3% (w/v) hemp seed beverages and to evaluate chemical composition, colloidal stability, safety, and sensory profiles after roasting the seeds (150 °C, 15 min). Beverages with 2% and 3% roasted hemp seeds evidenced acceptable sensory attributes and nutritious profile, containing 0.6–1% protein, 0.4–0.6% dietary fibre, and 0.5–0.8% lipids –mainly unsaturated fatty acids–, respectively. The roasting treatment significantly increased the phenolic content by 49–55% and the antioxidant capacity by 15%, and improved the sensory attributes of the beverages. Low peroxide levels (<1 meq O2/kg) in roasted hemp seed beverages were detected up to five days in cold storage, with better capacity against oxidation at 2% seed content. The use of 0.03% gellan gum improved the physical stability of suspensions contributing to their overall acceptability. Roasted hemp seed beverages showed no cannabinoid and tetrahydrocannabinol (THC) content. The advantages observed after roasting the seeds on phenolic content, antioxidant activity, sensorial acceptability and safety provided better attributes for the feasibility of beverages formulated with hemp seeds. The results showed a formulation suitable for the development of potential industrial roasted hemp seeds beverages with promising compositional profiles.

Self-Similar Ligand for 2D Zr(IV)-Based Metal-Organic Frameworks: Fluorescent Sensing and Catalysis.

Two-dimensional (2D) metal-organic framework sheets, in comparison to the 3D analogues, offer potential advantages for intercalation of guest components between the layers, exfoliation/dispersion into solutions, and processing into thin films. As a versatile platform for leveraging organic functions, the 2D Zr(IV)-carboxylate net here features a dendritic Sierpinski tritopic linker with conjugated alkyne branches and a photoactive triphenylamine core. The 2D solid can be easily dispersed in water and many other solvents, resulting in stable and fluorescent suspension for sensing nitro aromatic compounds and Fe3+ ions with high quenching efficiencies and ultralow limits of detection. Also, the neighboring alkyne units of the coordination solid undergo thermal cyclization (e.g., at 320 °C) to form cross-linked nanographene-like components to afford robust porosity, which substantially takes up PdCl2 (atomic ratio of Zr/Pd, 2.4:1) to afford a heterogeneous catalyst for Suzuki-Miyaura coupling reactions─direct in air and without the need for phosphine ligands.

Synthesis of Polymeric Nanoparticles Using Fungal Biosurfactant as Stabilizer

Polymeric nanoparticles (PNPs) are highly valuable across various industries due to their advantageous properties, including biocompatibility and enhanced release control, which are particularly important for pharmaceutical and cosmetic applications. Fungi, through secondary metabolism, are capable of producing biosurfactants (BSs)—amphiphilic molecules that reduce surface tension and can therefore substitute synthetic surfactants in PNP stabilization. In this study, we investigated the production of biosurfactants by the endophytic fungus Aspergillus welwitschiae CG2-16, isolated from the Amazon region, as well as its use as a PNP stabilizer. The fungus exhibited a 36% reduction in the surface tension of the culture medium during growth, indicative of BS production. The partially purified biosurfactant demonstrated an emulsification of 24%, a critical micelle concentration (CMC) of 280 mg/L, and an FTIR spectrum suggesting a lipopeptide composition. The biosurfactant was employed in the synthesis of poly-ε-caprolactone (PCL) nanoparticles via nanoprecipitation and emulsion/diffusion methods. Nanoprecipitation yielded spherical nanoparticles with a low polydispersity index (0.14 ± 0.04) and a high zeta potential (−29.10 ± 8.70 mV), indicating suspension stability. These findings highlight the significant role of biosurfactants in polymeric nanoparticle formation and stabilization, emphasizing their potential for diverse applications in pharmaceutical, cosmetic, and other industrial sectors.

Optimization of preparation parameters and testing verification of carbon nanotube suspensions used in concrete

Abstract Carbon nanotubes (CNTs) have received extensive attention due to their exceptional properties and wide range of applications. However, the agglomeration of CNTs in aqueous solutions and organic solvents significantly limits their large-scale application. In this study, the microscopic morphology and dispersion stability of the CNT suspensions were analyzed, and the most suitable surfactant in this study was selected. The preparation parameters of the CNT suspensions were optimized, and uniaxial compression tests were conducted on carbon nanotube concrete (CNTC) prepared using the optimized parameters. Scanning electron microscope analysis was used to investigate the improvement in the microstructure of the concrete by CNTs. Transmission electron microscope micrographs of the polyvinyl pyrrolidone (PVP)-CNT suspensions exhibited a uniformly distributed CNT cross-linked network. The absorbance reduction ratio of PVP-CNT suspensions after standing for 90 days was 13.75 and 22.41%, respectively. The absorbance reduction ratio of the suspensions first increased and then decreased with increasing dispersant ratio and ultrasonic dispersion time and increased with increasing ultrasonic power ratio. Compared with that of plain concrete, the uniaxial compressive strength of CNTC significantly improved, with a maximum increase of 18.15% when the content was 0.10%, and the failure mode exhibited typical shear failure characteristics. The optimized preparation parameters for the CNT suspensions were a PVP-to-multiwalled carbon nanotube mass ratio of 4:1, an ultrasonic dispersion time of 20 min, and an ultrasonic power of 60%. These optimized parameters are ideal choices for preparing CNT cement-based composite suspensions.

Preparation of thickened P(AA-AMPS) copolymers by inverse emulsion polymerization and evaluation of fracturing and oil flooding performance

Polymer is an essential type of fracturing fluid. Nevertheless, issues such as slow dissolution, high initial viscosity, and challenges in storage, transportation and operation limit its application. To address these issues, a thickened copolymer P(AA-AMPS) was synthesized by inverse emulsion polymerization using acrylic acid (AA) and 2-acrylamide-2-methylpropanesulfonic acid (AMPS) as the monomers. Three P(AA-AMPS) copolymers were obtained by changing the weight ratio of AA and AMPS monomers. When the weight ratio of AA to AMPS monomers was 8.2:1.8, the P(AA-AMPS) copolymer solution exhibited the best interfacial activity, reducing the oil–water interfacial tension to 3.95 mN m−1. The initial viscosity of the copolymer was only 66 mPa s, but its solution could reach a high viscosity of up to 817 mPa s. P(AA-AMPS) copolymers demonstrated good resistance for temperature and shear. For instance, the viscosity of copolymer solution still remained 300 mPa s with a shear rate of 170 s−1 at 90 °C. Furthermore, P(AA-AMPS) copolymers had excellent gel-breaking capacity, sand suspension stability, wettability and oil displacement ability. Therefore, the integration of fracturing and oil flooding can be realized for the development of low permeability reservoirs by selecting appropriate copolymers. P(AA-AMPS) copolymers would play an important role due to their significant viscosity differences and easy operation on storage, transportation and application.

Revolutionizing copper pipe durability: Shielding against corrosion with graphene oxide through electrophoretic application

This research endeavors to utilize electrophoretic deposition (EPD) to coat copper (Cu) pipes with graphene oxide (GO) nanosheets, aiming to bolster their resistance against corrosion. To achieve this, a stable aqueous colloidal suspension of GO was meticulously prepared via liquid exfoliation in deionized water. This suspension served as an electrolytic solution for EPD. The EPD process involved the meticulous application of varied operational parameters such as deposition time, applied voltage, and GO nanosheet concentration to facilitate anodic deposition on the copper pipe’s surface. To gauge the efficacy of the GO coating, evaluations were conducted to assess adhesive force and stabilization using specialized coating adhesion scratch testing equipment. Further analysis of the resulting film on the Cu pipe was executed employing X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, and Fourier transform infrared spectroscopy (FT-IR). These methods provided detailed insights into the characteristics and properties of the GO material post-deposition. The study yielded noteworthy outcomes, revealing the achievement of a uniform, unbroken, and consistent coating film on the Cu pipe. This was accomplished by employing specific parameters as 60 s of deposition time, a GO concentration of 0.5 mg/mL, and a voltage of 20 V. Impressively, when subjected to a corrosive solution containing 3.5% sodium chloride, the corrosion protection exhibited a remarkable twofold enhancement compared to untreated copper tubing, boasting an efficiency (η) of 90.48%. These findings suggest that the Cu pipe, coated with GO using the EPD technique, holds significant promise for utilization in demanding industrial settings susceptible to corrosion challenges.

Production of activated biocarbons by microwave-assisted chemical activation of hardwood sawdust and their application in the simultaneous removal of polymers of different origins from aqueous systems

Sawdust from deciduous trees was used as a raw material for the preparation of carbonaceous adsorbents. Microwave-assisted chemical activation with K2CO3 and H3PO4 was used to produce materials with a well-developed porous structure. The obtained activated biocarbons were characterized in terms of their porous structure, elemental composition, morphology, thermal stability, as well as surface and electrokinetic properties. The sorption abilities of both materials towards synthetic (poly(acrylic acid)) and natural (lysozyme) polymers in the process of their removal from aqueous systems were determined. Both single adsorbates and mixed solutions of two polymeric adsorbates were tested. The stability of aqueous suspensions containing activated biocarbons and one or two polymers was also determined. As a result of microwave-assisted chemical activation two carbonaceous adsorbents were obtained, characterized by a very well-developed specific surface area (1093–1777 m2/g), a completely different type of porous structure (mesoporous or microporous), and the acidic nature of the surface. The maximum adsorption of poly(acrylic acid) was obtained from a mixed solution of both polymers and it reached values of 379 mg/g (for the sample activated with H3PO4 with mean pore diameter 3.04 nm and minimal contribution of micropores—0.3%) and 259 mg/g (for K2CO3 activated material characterized by the mean pore diameter equal to 1.72 nm and large contribution of micropores—77.4%). In the case of lysozyme, the adsorption efficiency was two times lower (sorption capacity of 127–166 mg/g). Based on the collective data analysis, it can be stated that the most probable mechanisms of polymeric destabilization (highly desirable in separation from the multicomponent solutions) are surface charge neutralization at pH 3 and bridging flocculation at pH 11 (especially for the systems containing material activated with H3PO4 and poly(acrylic acid)).

Determination of Size, Size Distribution, and Concentration of Nanoparticles Using ICP‐MS in the Context of SERS Substrates

ABSTRACTSurface enhanced Raman scattering (SERS) is a widely used vibrational spectroscopic technique employing metallic nanostructures to enhance an inherent Raman signal. This study aimed to develop a method for the characterization of SERS substrates in a single analysis by inductively coupled plasma mass spectrometry (ICP‐MS) equipped with the single particle module (spICP‐MS). For this development, the well‐known Lee‐Meisel protocol was selected as starting point to synthesize gold nanoparticles (AuNps) and silver nanoparticles (AgNps). A spICP‐MS method was successfully developed and gave the mean size, size distribution, and concentration of nanoparticles in only one single analysis. Reference techniques were used to confirm these results namely dynamic light scattering, transmission electron microscopy, and UV–Visible spectroscopy. Thanks to the ICP‐MS characterization, it was observed that AgNps synthesized by chemical reduction presented more variability than the AuNps. The dissolved elements concentration in the suspension was investigated. It appeared that reaction yields were close to 100% for the six syntheses. This analysis may be repeated over time to evaluate the suspension stability and monitor any potential degradation of Nps. To conclude, ICP‐MS is a powerful technique to characterize SERS substrates and could be an interesting alternative to other characterization techniques.

Experimental measurement of track irregularities in EMS maglev systems using the mid-chord offset method and inverse filtering technology

Track irregularities are the main factors causing changes in suspension stability and vibrations in EMS (Electro-magnetic Suspension) maglev trains. Due to the scarcity of actual measurement data on EMS maglev track irregularities, this paper utilizes the principles of the mid-chord offset method to develop a track irregularity detector with a 1-m test chord length. Tests were conducted on the maglev line in Qingyuan, Guangdong. Based on the “using small to predict large” algorithm, data simulating a 3-m test chord length were output. The experimental data were processed to remove trend items and outliers, and an inverse filter was designed to counteract the amplitude gain error of the mid-chord offset method, obtaining accurate data on vertical and lateral track irregularities. The results show that the amplitude and power spectral density (PSD) fluctuations of track irregularities on the left and right rails of the measured line section are similar, with height irregularities of 2.5–3 mm and alignment irregularities of 1–1.5 mm. Periodic wavelength components related to the longitudinal spacing of sleepers, rail length, and beam span, such as 1.2 m, 6.5 m, 12.5 m, and 25 m, are evident, highlighting the need for enhanced inspection and maintenance of these structural components in engineering projects.

Improvement of dispersants on nano carbon black-modified cement paste: performance, microstructure and carbon footprint

The agglomeration of nano carbon black (NCB), driven by its high specific surface energy, limits the fundamental performance of cementitious materials and hinders the broader application of functional cementitious materials in engineering domains. NCB-modified cement (NC) has a low snow-melting efficiency, resulting in high energy consumption and excessive CO2 emissions. Herein, this study innovatively proposed a method of using dispersants to overcome the above issue and systematically introduced the effects of three dispersants, polycarboxylic acid superplasticizer (PCE), tannic acid (TA), and sodium dodecyl sulfate (SDS), on NC. The dispersity of dispersant-NCB suspension was analyzed firstly, and then the performance of fresh paste, mechanical properties, resistivity, snow-melting speed and LCA of NC were explored. Experimental results indicated that, in terms of suspension stability, SDS was the most effective, followed by TA, while PCE exhibited the least efficacy. Furthermore, all three dispersants improved the fluidity of NC to varying degrees. However, PCE and TA demonstrated a retardation effect on the setting time, whereas SDS facilitated a reduction in the setting time of NC. From the point of view of mechanical properties, the use of these dispersants not only augmented the mechanical strength of the NC but also decreased its electrical resistivity. The uniform dispersion of SDS at the microstructural level of NCB had also been found. When the PCE content is 0.2%, TA content is 0.4%, and SDS content is 0.4%, the mechanical strength and resistivity of NC were the best. NC with dispersant TA melted snow three times faster than the control group, reducing snow-melting energy consumption. Moreover, LCA analysis showed that the addition of dispersants also reduced carbon emissions.

Surface Modification of Cellulose Nanofiber (CNF) from Banana (<i>Musa paradisiaca</i>) Pseudo-Stem with Cetyltrimethylammonium Bromide (CTAB)

Modifying cellulose nanofiber (CNF) is necessary to improve its hydrophobic properties for broader applications. The surface of CNF from the banana pseudo-stem (Musa paradisiaca) was modified using a cationic surfactant, Cetyltrimethylammonium Bromide (CTAB). Principally, CNF surface sulfate ester group counterions are substituted for cetyltrimethylammonium (CTA+), which acts as a bulky, amphiphilic cation. Three steps produce CNF from banana pseudo-stem: delignification, bleaching, and acid hydrolysis. The acid hydrolysis process was optimized by adjusting the concentration of sulfuric acid. A 50% sulfuric acid concentration produced CNF with a size of 118 nm and the highest stability of its zeta potential value of -28.4 mV. The hydrophobicity of CNF increased after CTAB modification, as demonstrated by a change in surface charge from -28.4 mV to +3.63 mV. The modified CNF50-CTAB had a contact angle of 45.5º. In addition, CNF50-CTAB was unstable in water and formed stable colloidal suspensions in chloroform.

Development of protein hydrolysate as a cost-effective and robust biodispersant: Investigating its performance in dispersing of carbon black pigment in water-based paints

Carbon black pigments hold significant importance as the primary representatives of black pigments in the industry today. The dispersibility of carbon black pigment (CB) in water is limited by the nonpolar and weakly hydrophilic characteristics of the pigment's surface. Therefore, there is a critical need to devise an economical and eco-friendly approach for creating a well-dispersed and stable suspension of carbon black in an aqueous medium. The primary focus of this study was to investigate the dispersion capabilities of protein hydrolysate (HP) derived from sheep wool on CB particles in a water-based pigment concentrate. The hydrolysis degree of protein source was determined by high-performance liquid chromatography and gel permeation chromatography. The dispersion performance was investigated by zeta potential, transmission electron microscopy, Fourier transform infrared spectroscopy, grindometer, spectrophotometer-colorimeter, viscometer, and cryptometer measurements. The HP solution containing amino acids, peptides, and polypeptides with low molecular weight can cover the surface of the CB particles, creating enough electrical repulsion and steric resistance. As a result, this phenomenon can inhibit the collision and interaction among the pigment particles caused by Brownian motion, making it less prone to aggregation. The protein hydrolysate demonstrated a higher capability in producing the stable CB dispersions compared to a commercial reference dispersant, highlighting the effectiveness of amino acids, peptides, and polypeptides as powerful CB dispersing agents.

Performance of delaying release and reducing adsorption of polyethyleneimine/poly(vinyl sulfonate) polyelectrolyte complex nanoparticles in polyacrylamide/polyethyleneimine gel system

Polyacrylamide/Polyethyleneimine (HPAM/PEI) is an environmentally friendly and promising gel system. However, inadequate gelation time and retention of the cross-linker (polyethyleneimine, PEI) during migration pose significant challenges for effective water control treatment in deep reservoirs. Polyelectrolyte complex nanoparticles (PECs) have demonstrated the ability to efficiently encapsulate PEI, facilitating for its gradual release. To achieve this, a cost-effective polyanionic complex, poly(vinyl sulfonate) (PVS), was employed to form PECs with PEI. By adjusting the mixing ratio of PEI and PVS, stable PECs suspensions with varying charges were successfully produced. These stable PECs exhibited spherical shapes with a particle size distribution ranging from 127.3–442.71 nm, and an average particle size of approximately 200 nm. The encapsulation efficiency of PEI by PECs varied from 64.56 % to 86.14 %. Under different conditions, 55.12 % to 90.26 % of PEI could be released from PECs. Increased temperatures, higher ionic strengths, and greater deviations in pH from the initial state of the PECs suspension all facilitated the release of PEI. The most stable PECs delayed the gelation time of the HPAM/PEI system to 9.5 days, which is twice the base gelation time of 4.5 days. The strength of mature HPAM/PEI (PECs) gels increased by 8.95 Pa in storage modulus (G′) compared to HPAM/PEI at the same concentration, albeit with a reduced linear viscoelastic region. And, the PECs-based delayed crosslinking method does not negatively affect the mechanical strength of the HPAM/PEI gel system, and thus its water control ability, under reservoir conditions. On the other hand, the static adsorption of PEI encapsulated by anionic PECs on sand decreased to one-fourth of that of free PEI (PEI solution). Additionally, the breakthrough of PEI encapsulated in anionic PECs in fractured sandstone cores was significantly advanced compared to free PEI.

Non-Polar Chain-Enabled Suspension of Carbon Nanoparticles in Base Oil

The transition to electric vehicles (EVs) has introduced new challenges in lubrication, demanding innovative solutions to ensure consistent performance. One promising approach is the use of nanoparticle additives, which have the potential to improve lubrication performance significantly. However, achieving a stable suspension of these nanoparticles in lubricating oils remains a critical challenge, as suspension stability is essential for maintaining consistent performance and maximizing the benefits of these advanced additives. In this study, carbon nanoparticles (CNPs) were modified with dodecylamine (DDA) to achieve stable suspension in nonpolar fluids. The successful functionalization was confirmed by the FTIR results, which showed characteristic peaks of various bonding. The suspension stability tests demonstrated that DDA-CNPs remained suspended for over 60 days in the Polyalphaolefin (PAO) oil, whereas unmodified CNPs were sedimented within 3–7 days. The rheological behavior was measured under different shear rates and temperatures. Viscosity measurements indicated that DDA-CNPs maintained a lower value compared to base PAO. The lubricants’ friction coefficient (COF) was also determined under various speeds and loads. The addition of DDA-CNPs at a concentration of 0.05 wt.% resulted in a significant reduction in COF, with values decreasing by 26% compared to base PAO oil under a load of 1 N. Additionally, the COF for DDA-CNPs was consistently lower than that of PAO, with reductions ranging from 15% to 18% across all tested speeds. The Stribeck curve further highlighted the improved performance of DDA-CNPs across boundary, mixed, and hydrodynamic lubrication regimes. These findings suggest that DDA-CNPs significantly improve the lubrication performance of PAO oil, making them suitable for advanced lubrication applications in automotive and industrial systems.

Aqueous dispersions of ‘green’ silver nanoparticles for eco-applications: Synthesis, structure and biosafety

Sustainable agriculture requires the use of intelligent compounds with multifaceted effect on soil and plants. Such conditioners can be hydrogels enriched with nanoparticles, but only those synthesized using ‘green chemistry’ methods. Therefore, the main aim of the study was to synthesize and characterize innovative ‘green’ silver nanoparticles (AgNPs) for agricultural applications. AgNPs were created using water or alcohol extracts of eucalyptus (Eucalyptus viminalisLabill) and aloe (Aloë arborescens Mill) as well as tannin to reduce silver ions (Ag+) to zero valent form (Ag0). The synthesis was conducted under autoclave conditions or at room temperature, in the presence of potassium carbonate. The AgNPs characterization was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS) method, whereas stability of the AgNPs suspensions under various conditions was estimated using turbidimetry. Biosafety of the formed species was determined based on genotoxicity (comet test) and cytotoxicity (study with crystal violet and MTT) assays. The obtained results confirmed the presence of zero valent silver phase in the nanoparticles and showed that their crystallite size was 14–24 nm, with different degrees of polydispersity depending on the synthesis conditions. Hydrodynamic diameter of AgNPs and their aggregates in the aqueous dispersions varied from 6 nm to 103 nm, and the smallest aggregation degree was noted for the nanoparticles synthesized using tannin. All synthesized nanoparticles were biosafe. Thus, they can be applied in agro-industrial processes without damaging the environment.

Development of Novel Biocomposites with Antimicrobial-Activity-Based Magnesium-Doped Hydroxyapatite with Amoxicillin.

Background/Objectives: A biocomposite based on magnesium-doped hydroxyapatite and enriched with amoxicillin (MgHApOx) was synthesized using the coprecipitation method and is presented here for the first time. Methods: The stability of MgHAp and MgHApOx suspensions was evaluated by ultrasound measurements. The structure of the synthesized MgHAp and MgHApOx was examined with X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The crystalline structure was determined by X-ray diffraction. The FTIR data were collected in the range of 4000-400 cm-1. The morphology of the nanoparticles was evaluated by scanning electron microscopy (SEM). Furthermore, the biocompatible properties of MgHAp, MgHApOx and amoxicillin (Ox) suspensions were assessed using human fetal osteoblastic cells (hFOB 1.19 cell line). The antimicrobial properties of the MgHAp, MgHApOx and Ox suspension nanoparticles were assessed using the standard reference microbial strains Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 and Candida albicans ATCC 10231. Results: X-ray studies have shown that the biocomposite retains the characteristics of HAp and amoxicillin. The SEM assessment exhibited that the apatite contains particles at nanometric scale with acicular flakes morphology. The XRD and SEM results exhibited crystalline nanoparticles. The average crystallite size calculated from XRD analysis increased from 15.31 nm for MgHAp to 17.79 nm in the case of the MgHApOx sample. The energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analysis highlighted the presence of the constituent elements of MgHAp and amoxicillin. Moreover, XPS confirmed the substitution of Ca2+ ions with Mg2+ and the presence of amoxicillin constituents in the MgHAp lattice. The results of the in vitro antimicrobial assay demonstrated that MgHAp, MgHApOx and Ox suspensions exhibited good antimicrobial activity against the tested microbial strains. The results showed that the antimicrobial activity of the samples was influenced by the presence of the antibiotic and also by the incubation time. Conclusions: The findings from the biological assays indicate that MgHAp and MgHApOx are promising candidates for the development of new biocompatible and antimicrobial agents for biomedical applications.

Ultrasonic-Assisted Marine Antifouling Strategy on Gel-like Epoxy Primer

Ultrasonic technology has drawn extensive interests for its great potential in marine antifouling applications. However, its effects on the adhesion behavior of marine fouling organisms on marine structures remain underexplored. This work investigated how ultrasonic treatment impacted the adhesion of Pseudoalteromonas on a gel-like marine epoxy primer. And the process parameters for ultrasonic treatment were optimized using response surface analysis with Design-Expert software 11. The results revealed that ultrasonic treatment disrupted the cellular structure of Pseudoalteromonas, causing the deformation and fragmentation of the cell membrane, leading to bacterial death. Additionally, ultrasonic treatment reduced the particle size and Zeta potential value of Pseudoalteromonas, which disrupted the stability of bacterial suspensions. It also increased the relative surface hydrophobicity of Pseudoalteromonas cells, resulting in a reduction in adhesion to the gel-like marine epoxy primer. This study demonstrated that ultrasonic treatment significantly disturbed the adhesion behavior of microorganisms like Pseudoalteromonas on the gel-like marine epoxy primer, which provided an effective approach for controlling marine biofouling.

The Effect of Sodium Hexametaphosphate on the Dispersion and Polishing Performance of Lanthanum-Cerium-Based Slurry.

A lanthanum-cerium-based abrasive composed of CeO2, LaOF, and LaF3 was commercially obtained. The effect of sodium hexametaphosphate (SHMP) on powder dispersion behavior was systematically investigated using the combined techniques of liquid contact angle, turbidity, zeta potential (ZP), scanning electron microscopy (SEM), powder X-ray diffraction (XRD) combined with Rietveld refinements, X-ray photoelectron spectroscopy (XPS), and polishing tests. The results indicated that the addition of 0.5 wt.% SHMP dispersant to the 5 wt.% lanthanum-cerium-based slurry produced the most stable suspension with a high turbidity of 2715 NTU and a low wetting angle of 45°. The as-obtained slurry displayed good surface polishing quality for K9 glass, with low surface roughness (Ra) of 0.642 and 0.515 nm (in the range of 979 × 979 μm2) at pH = 6 and 11, respectively, which corresponds to the fact that it has local maximum absolute values of ZP at these two pH values. SEM images demonstrated that after appropriate grafting of SHMP, the particle aggregation was reduced and the slurry's dispersion stability was improved. In addition, the dispersion mechanism was explained based on the principle of complexation reaction, which reveals that the dispersant SHMP can increase the interparticle steric hindrance and electrostatic repulsions. In an acidic environment, steric hindrance dominates, while electrostatic repulsion prevails under alkaline conditions. As expected, this polishing slurry may find potential applications in manufacturing optical devices and integrated circuits.

Evaluation of protein-polysaccharide interactions through ζ-potential and particle size measurements to assess their functionality in wine.

Protein-polysaccharide-tannin interactions are important in every aspect of red wine production from physical stability to color, astringency, and body. For this model study, bovine serum albumin (BSA) was selected as the protein, while carboxymethyl cellulose (CMC), mannoproteins, and pectin were the model polysaccharides. Each protein-polysaccharide combination was analyzed for zeta (ζ) potential and particle size at neutral pH and within the wine-like solution. Mixtures were assessed regarding their protective, affinitive, and aggregative behaviors. Based on their individual ζ-potentials, pectin and mannoprotein were most stable at lower concentrations. At higher concentrations, they reduced the suspension's stability and increased the aggregate sizes. CMC consistently increased the stability of any solution under neutral pH conditions. However, with increasing concentrations, these large aggregates are expected to precipitate. Fruit pectin (FP) and BSA interactions seemed to be the main factors in the formation of visible precipitates at neutral pH. FP and the mannoprotein decreased stability enough to cause precipitation without haze formation. The mannoprotein decreased particle sizes, in both the suspension and precipitation, which may indicate greater selectivity toward proteins. FP also decreased the suspended particle sizes under wine conditions. These findings demonstrate the use of ζ-potential and particle size values to characterize macromolecular interactions in model systems and can also be used to indicate effective fining agents. PRACTICAL APPLICATION: This work demonstrates the capabilities of ζ-potential analysis paired with size particle measurements to predict and characterize the interactions between macromolecules in complex systems. The interactions between model wine macromolecules can be evaluated with this technology at a level that cannot be reached with any other analytical technique.