Negative Surface Charge Research Articles

Efficacy of Ga3+ ions on structural, biological and antimicrobial activity of mesoporous lithium silicate bioactive glasses for tissue engineering

Mesoporous bioactive glass nanoparticles (MBGNPs) containing therapeutic ions have shown significant promise in the realm of hard and soft tissue repair and regeneration, owing to their multifunctional biological properties. In this study, gallium-incorporated silica-based gallium incorporated MBGNPs (Ga-MBGNPs) with fixed amount of Li2O (8 mol %) were synthesized using an emulsion-assisted sol-gel method. The impact of Ga2O3 integration into the silicate glass network was evaluated by investigating the microtextural properties. The results confirmed the production of spherical-shaped, nano-sized, amorphous particles with an enhanced specific surface area and ordered hexagonal meso-porosity (10–20 nm) in the developed Ga-MBGNPs. The in vitro bioactivity, assessed through hydroxyapatite (HAp) layer formation in simulated body fluid (SBF), over varying time intervals (0, 1, 3, 7, 14 & 21 days), revealed pronounced formation of short rod-like carbonated HAp with increasing immersion time and Ga3+ content in all glasses. However, a delayed apatite formation was observed for composition-dependent Ga-4 and Ga-5 MBGs during the initial incubation periods (1, 3, and 7 days). Further, the presence of Li + ions along with Ga3+ enhanced the apatite deposition when compared with the only Ga3+ inclusion. Evaluation of degradation rate and pH values indicated enhanced apatite formation with lower Ga ion content, while a slight reduction was noted with higher Ga ion content, attributable to the presence of reactive Si–O–Si bonds. Furthermore, analysis using a Zeta potential analyzer confirmed the dispersibility and bioreactivity of all glass powders owing to their higher negative surface charge. Moreover, Ga-MBGNPs exhibited notable antimicrobial effects against both E. coli and S. aureus bacteria due to the release of Ga3+ ions. Overall, the findings suggest that the incorporation of Ga in MBGNPs renders them potential multifunctional candidates for expediting the healing of bone tissue injuries in biomedical applications.

Synthesis of calix (4) resorcinarene based amphiphilic macrocycle as an efficient nanocarrier for Amphotericin-B to enhance its oral bioavailability

The supramolecular-based macrocyclic amphiphiles have fascinating attention and find extensive utilization in the pharmaceutical industry for efficient drug delivery. In this study, we designed and synthesized a new supramolecular amphiphilic macrocycle to serve as an efficient nanocarrier, achieved by treating 4-hydroxybenzaldehyde with 1-bromotetradecane. The derivatized product was subsequently treated with resorcinol to cyclize, resulting in the formation of a calix(4)-resorcinarene-based supramolecular amphiphilic macrocycle. The synthesized macrocycle and intermediate products were characterized using mass spectrometry, IR, and 1H NMR spectroscopic techniques. The amphotericin-B (Amph-B)-loaded and unloaded amphiphiles were screened for biocompatibility studies, vesicle formation, particle shape, size, surface charge, drug entrapment, in-vitro release profile, and stability through atomic force microscopy (AFM), Zetasizer, HPLC, and FT-IR. Amph-B -loaded macrocycle-based niosomal vesicles were investigated for in-vivo bioavailability in rabbits. The synthesized macrocycle exhibited no cytotoxicity against normal mouse fibroblast cells and was found to be hemocompatible and safe in mice following an acute toxicity study. The drug-loaded macrocycle-based vesicles appeared spherical, nano-sized, and homogeneous in size, with a notable negative surface charge. The vesicles remained stable after 30 days of storage. The results of Amph-B oral bioavailability and pharmacokinetics revealed that the newly tailored niosomal formulation enhanced drug solubility, protected drug degradation at gastric pH, facilitated sustained drug release at the specific target site, and delayed plasma drug clearance. Incorporating such advanced niosomal formulations in the field of drug delivery systems has the potential to revolutionize therapeutic outcomes and improve the quality of patient well-being.

Architecture dependent transport behavior of iron (0) entrapped biodegradable polymeric particles for groundwater remediation

Polylactic acid based spherical particles with three architectural variations (Isotropic (P1), Semi porous (P2), and Janus (P3)) were employed to encapsulate zero valent iron nanoparticles (ZVINPs), and their performance was extensively evaluated in our previous studies. However, little was known about their transportability through saturated porous media of varying grain size kept under varying ionic strength. In this particular study, we aimed to investigate the architectural effect of polymeric particles (P1–P3) on their mobility through the sand column of varying grain size in presence of mono, di, and tri-valent ions of varying concentrations (25–200 mM (millimoles)). As per column breakthrough experiments (BTCs) using various types of sands, amphiphilic Janus type (P3) particles exhibited the maximum transportability among all the tested particles, irrespective of the nature of the sand. Owing to the narrower travel path, sands with lower porosity (31%) delayed the plateau by shifting it to a higher pore volume with a minimum retention of iron (C/Co: 0.94 for P3) in the column. The impact of mono (Na+, K+), di (Ca2+, Mg2+), and trivalent (Al3+) ions on their transportability was progressively increased from P3 to P1, especially at higher ionic concentrations (200 mM), with P3 being the most mobile particles (C/Co:0.54 for Al3+). Among all the ions, Al3+ exhibited maximum hindrance to their mobility through the sand column. This could be due to their strong charge screening effect coupled with cation bridging complex formation with moving particles. Experimental results obtained from BTCs were found to be well-fitted with a theoretical model based on advection-dispersion equation, showing minimum retention for P3 particles. Overall, it can be inferred that encapsulation of ZVINPs inside Janus particles (P3) with a right balance of amphiphilicity and highly negative surface charge would be required to achieve considerable transportability through sand aquifers to target contaminants in polluted groundwater existing under harsh conditions (high ionic concentrations).

Improving the stability and transdermal permeability of phycocyanin loaded cubosomes

Instability and low transdermal permeability of protein antioxidants are major obstacles to resist oxidative stress in transdermal drug delivery system. To overcome these shortcomings, cubosomes were developed as an advanced transdermal delivery system to improve stability and transdermal absorption of the model antioxidant phycocyanin in this study. Glyceryl monooleate and poloxamer 407 (P407) were used to prepare cubosomes as carrier matrix and stabilizer, respectively. Phycocyanin loaded cubosomes (PC-cubosomes) were prepared by the emulsification and homogenization method. A 33 full factorial design was used to optimize the cubosome formulations. The final optimal PC-cubosomes possessed an average particle size of 183.2 ± 0.5 nm and a negative surface charge as well as achieved a high encapsulation efficiency of 87.2% ± 2.7%. PC-cubosomes appeared as nano-sized and well-shaped spheres with highly ordered cubical structures. The residual amount of phycocyanin in PC-cubosomes was 3-fold higher than that in the free drug solution after 10 days ultraviolet radiation exposure. In vitro release kinetics of phycocyanin from PC-cubosomes fitted to the Higuchi kinetic model, indicating that phycocyanin released from cubosomes mainly attributed to drug diffusion and dissolution. PC-cubosomes also exhibited higher permeability (39.79 μg⋅cm−2⋅hour−1) across the rat skin than phycocyanin solution (16.33 μg⋅cm−2⋅hour−1). Furthermore, PC-cubosomes were easily taken up by keratinocytes, thereby achieving a prolonged anti-oxidative stress effect. These results therefore suggested that cubosomes could be a promising transdermal delivery system to improve the stability and transdermal permeability of phycocyanin.

Colloidal interaction of fly ash and soil clay

The combustion of coal worldwide creates a large quantity of fly ash (FA), and the application of FA to agricultural soils is being encouraged as a resource utilization strategy. While most of our attention has focused on positive aspects such as nutrient supplementation and pollution mitigation, the negative impacts of FA have likely been overlooked. In this study, we examined the colloidal properties of FA and soil clay, aiming to demonstrate the ability of FA to increase the dispersibility and transportability of soil clay. Dynamic light scattering technique was coupled with the test tube method to track the kinetics and pH-dependent changes in the zeta potential, hydrodynamic size and colloidal stability of FA, soil clay and their mixtures. We found that FA occurred in solution as “negatively charged balls”, and its negative surface charges increased with increasing pH. FA itself showed a low dispersibility; however, FA became more dispersive when it was introduced to clay suspensions. The mechanism is that the introduction of FA supplied more negative charges to the clay suspension, inducing electrostatic repulsion with soil clay, from which both FA and soil clay were favoured to disperse. Therefore, it can be inferred that off-site transport of FA is possible. More importantly, excessive application of FA can inadvertently intensify clay dispersibility, eventually resulting in soil clays together with FA being more vulnerable to leaching and/or surface run-off erosion. This suggests that the application of FA needs more careful consideration, and the development of more suitable techniques for the sustainable application of FA is still needed.

One Precursor, Two Different Outcomes: SnO-Graphite Composite and Anion-Doped SnO2 with Ester Surface Functionality.

The technological importance of SnO2 and SnO has invited scientists to explore various aspects, including their synthesis in the nanosize regime, surface functionalization, and composite formation. In the present work, a binuclear Sn2-EDTA complex has been demonstrated to produce a SnO-graphite composite and C, N-codoped SnO2 nanocrystals with ester functionality in quantitative yields by thermal and solvothermal dissociation processes. The products were characterized extensively. While SnO in the SnO-graphite composite exhibited tetragonal symmetry, graphitic carbon had defects. The composite had 12 wt % of graphitic carbon. The role of the SnO-graphite composite as an anode in lithium-ion batteries (LIB) has been evaluated. Solvothermal dissociation of the Sn2-EDTA complex in a propylene glycol medium yielded nanocrystalline SnO2 with yellow color. Agglomerated crystallites had ester functionality on their surfaces. The surface functionality was thermally stable up to 200 °C, and its complete removal yielded tetragonal white-colored SnO2. Co-doping of carbon and nitrogen in yellow SnO2 reduced its optical band gap (2.9 eV). Despite the negative surface charge of the functionalized SnO2, its affinity to rapidly adsorb anionic azo dyes (Congo red and Eriochrome black T) from aqueous solutions has been validated. Following pseudo-second-order kinetics, adsorption data analysis revealed chemisorption as the primary driving force in this process.

Synthesis and characterization of cellulose nanocrystals/Gd2O3 nanocomposite as a dual-mode contrast agent for MRI via gamma-ray irradiation

This study developed a biocompatible nanocomposite using cellulose nanocrystals (CNCs), polyethylene glycol (PEG), and sodium hydroxide (NaOH), combined with gadolinium oxide nanoparticles (Gd2O3-NPs) through gamma radiation to decrease the size of nanoparticles and increase their uniformity. This research found that the (CNCs-PEG/NaOH)/Gd2O3 nanocomposite exhibits notable characteristics, including high saturation magnetization (1.44 emu/g), remarkable colloidal stability with a highly negative surface charge of −31.4 mV, and a small hydrodynamic size of 5.5 ± 0.7 nm. Furthermore, the MTT assay conducted on HeLa cell lines revealed the excellent biocompatibility of the (CNCs-PEG/NaOH)/Gd2O3 nanocomposite. No cytotoxic effects were observed, and the nanocomposite exhibited adequate cellular uptake. Moreover, the (CNCs-PEG/NaOH)/Gd2O3 nanocomposite displayed a remarkable enhancement effect on both T1 and T2-weighted images, with high r1 and r2 relaxivity values of 21.694 mM−1 s−1 and 43.799 mM−1 s−1, respectively, resulting in a relaxivity ratio (r2/r1) of 2.02 when compared to clinical and commercial agents. This biocompatible nanocomposite holds promise as a dual contrast agent in MRI and various other biomedical applications. It is envisaged that gamma irradiation is a good method to produce nanoparticles within the nanoscale range.

TiO2-NPs/ZnO-NPs@Co3O4 nanocomposite from natural extracts for the Rhodamine 6 G photodegradation

Socio-environmental issues are frequent in industrial growth, especially wastewater containing dyes resulting in toxic effects on fauna and flora. Parallelly, synthesizing nanomaterials using extracts allows for improved properties with fewer environmental effects. In this way, the present study aims to synthesize using natural extracts and characterize a ceramic nanocomposite containing titanium and zinc dioxide doped with tricobalt tetroxide nanoparticles (TiO2NPs/ZnONPs@Co3O4NPs) for the removal of Rhodamine 6 G under visible radiation. TiO2-NPs/ZnO-NPs@Co3O4-NPs ceramic nanocomposite showed a heterogeneous morphology with a negative charge surface of -16.73 mV, V-type isotherm and H1 hysteresis, surface area (SBET) of 62.2 m² g−1, pore diameter (Dp) of 10.41 nm and bang gap energy (Eg) of 2.98 eV. The ideal condition of photocatalytic heterogeneous was of [Rh 6 G] = 3.18 mg L−1, [NPs] = 1 g L−1 and pH = 7 with 99.97 % for the Rh 6 G photodegradation and the apparent rate of the pseudo first-order reaction (k) of 0.0193 min−1. After IV cycles of TiO2-NPs/ZnO-NPs@Co3O4-NPs, there was a small reduction in Rh 6 G dye removal (99.97 to 85.71 %), confirming the photocatalytic stability of the nanocatalyst. Ecotoxicity tests were carried out with Lactuca sativa seeds and demonstrated root radicular inhibition of 6.41 % to 20.73% ranging from 12.5 - 100 mg L−1. Machine Learning (ML) study was used to predict the Rh 6 G photodegradation mechanism, where the dye molecules successively cleavage such aromatic structure and carbonic acid to produce smaller fragments that are further form CO2 and H2O. Therefore, ceramic nanocomposite presents potential application as a nanocatalyst for the wastewater treatment.

Sonicated polyethylene terephthalate nano- and micro-plastic-induced inflammation, oxidative stress, and autophagy in vitro

The environmental presence of nano- and micro-plastic particles (NMPs) is suspected to have a negative impact on human health. Environmental NMPs are difficult to sample and use in life science research, while commercially available plastic particles are too morphologically uniform. Additionally, this NMPs exposure exhibited biological effects, including cell internalization, oxidative stress, inflammation, cellular adaptation, and genotoxicity. Therefore, developing new methods for producing heterogenous NMPs as observed in the environment is important as reference materials for research. Thus, we aimed to generate and characterize NMPs suspensions using a modified ultrasonic protocol and to investigate their biological effects after exposure to different human cell lines. To this end, we produced polyethylene terephthalate (PET) NMPs suspensions and characterized the particles by dynamic light scattering and scanning electron microscopy. Ultrasound treatment induced polymer degradation into smaller and heterogeneous PET NMPs shape fragments with similar surface chemistry before and after treatment. A polydisperse suspension of PET NMPs with 781 nm in average size and negative surface charge was generated. Then, the PET NMPs were cultured with two human cell lines, A549 (lung) and HaCaT (skin), addressing inhalation and topical exposure routes. Both cell lines interacted with and have taken up PET NMPs as quantified via cellular granularity assay. A549 but not HaCaT cell metabolism, viability, and cell death were affected by PET NMPs. In HaCaT keratinocytes, large PET NMPs provoked genotoxic effects. In both cell lines, PET NMPs exposure affected oxidative stress, cytokine release, and cell morphology, independently of concentration, which we could relate mechanistically to Nrf2 and autophagy activation. Collectively, we present a new PET NMP generation model suitable for studying the environmental and biological consequences of exposure to this polymer.

Green synthesis of zinc oxide/Allium sativum nano-composite and its efficacy against murine cryptosporidiosis.

Cryptosporidiosis is a global health problem threats life of immunocompromised patients. Allium sativum (A. sativum) is one of the therapeutic options for cryptosporidiosis. This study develops green synthesized ZnO-NPs based on A. sativum extract, and assesses its therapeutic application in treating experimental cryptosporidiosis in immunosuppressed mice. FTIR, scanning electron microscopy, and zeta analyzer were used for characterization of bio ZnO-NPs. The morphology of prepared materials appeared as sponge with many pores on the whole surface that allows the feasibility of bio ZnO-NPs for different biological activities. Its structural analysis was highly stabilized with negative charge surface which indicated for well distribution into the parasite matrix. Twenty-five immunosuppressed Cryptosporidium parvum infected mice, classified into 5 groups were sacrificed at 21th day after infection with evaluation of parasitological, histopathological, oxidative, and proinflammatory biomarkers. Treated mice groups with 50 and 100 mg/kg of AS/ZnO-NPs showed a highly significant decline (79.9% and 83.23%, respectively) in the total number of expelled oocysts. Both doses revealed actual amelioration of the intestinal, hepatic, and pulmonary histopathological lesions. They also significantly produced an increase in GSH values and improved the changes in NO and MDA levels, and showed high anti-inflammatory properties. This study is the first to report green synthesis of ZnO/A. sativum nano-composite as an effective therapy in treating cryptosporidiosis which gave better results than using A. sativum alone. It provides an economical and environment-friendly approach towards novel delivery synthesis for antiparasitic applications. RESEARCH HIGHLIGHTS: Green synthesis of ZnO-NPs was developed using A. sativum extract. The morphology of prepared ZnO-NPs appeared as sponge with many pores on SEM The study evaluates its therapeutic efficacy against murine cryptosporidiosis The green synthesized ZnO-NPs significantly reduced percent of oocyst shedding, improved the pathological changes, and showed high antioxidant and anti-inflammatory potentials.

Incorporation of dendritic silica nanoparticles for the preparation of high‐performance thin‐film nanocomposite membranes

AbstractThe development of thin‐film nanocomposite (TFN) membranes with high performance is conducive to efficient desalination and wastewater treatment. In this work, dendritic mesoporous silica nanoparticles (DLSiO2) were synthesized by a dual‐templating strategy. Afterward, they were introduced into the aqueous phase to fabricate TFN membranes via in situ interfacial polymerization (IP) reaction. Powerful techniques as scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Nano zetasizer‐DLS, x‐ray photoelectron microscopy, electrokinetic analyzer, and contact angle were used in the characterization of dendritic structures and nanocomposite membranes. Results revealed that DLSiO2 with special structural characteristics can effectively regulate the IP process, promoting the enhancement of the crosslinking degree, surface hydrophilicity, and surface negative charge of polyaimde (PA) selective layers. It is also beneficial for constructing extra water channels within the PA selective layer to boost the transport of water molecules. As a consequence, the prepared TFN membrane with 0.3 mg/mL DLSiO2 exhibits optimal separation performance and good pressure resistance, acid–base resistance, and anti‐fouling properties. It also exhibited a water permeability of 4.17 L m−2 h−1 bar−1 (increased by 61.7% compared with thin film composites (TFC) membrane) and a NaCl rejection of 99.0%, which were better than those of TFN membranes prepared by introducing other types of silica in other studies.

Preparation of Edible Colorant Lake Using Calcium Carbonate and β-Carotene: Structural Characterization and Formation Mechanism Study.

This study prepared a novel β-carotene colorant lake using calcium carbonate (CaCO3) and investigated the lake formation process and its basic characteristics. Kinetic adsorption analysis confirmed that medium pH (9.3) and medium temperature (40 °C) were more suitable for lake preparation, while desorption occurred, possibly due to crystalline transformation of CaCO3. The isothermal analysis and model fitting results suggested that the β-carotene and CaCO3 particles combined via a monolayer adsorption process driven by physical force. Electrostatic attraction likely participated in the process due to the net negative surface charges of β-carotene dispersion and positively charged groups on the CaCO3 particle surfaces. Ethanol, ultrasonic treatment, and drying method significantly influenced the immobilization efficiency (IE) of β-carotene in the lake and light stability of the lake, without affecting its crystal form. The thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) curves confirmed absorption of β-carotene onto CaCO3. Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses indicated no obvious chemical bonds between β-carotene and CaCO3. Energy-dispersive spectroscopy (EDS) confirmed the presence of β-carotene on surfaces but not in the interior of the CaCO3 particles. The adsorption of β-carotene by calcium carbonate was further confirmed to be a physical adsorption on surface.

Application of Corn Straw, an Agro-Waste, to Remove Dyes in an Aqueous Medium, Producing Blue or Red Fibers

The contaminant dyes that, even at low concentrations, may cause a series of adverse effects in humans and animals, and their removal by adsorption methods using alternative adsorbents as natural fibers, are regarded as a research topic that has become increasingly relevant. In this study, corn straw (CS), an agro-industrial residue, was used to remove dyes. The samples were characterized by ATR-FTIR, SEM-EDS, zeta potential, diffuse spectra, and colorimetry, before and after dye removal. The analyses allowed us to differentiate the morphology of CS after the treatment’s fiber on the adsorbent surface. The zeta potential showed a negative surface charge, but the acidic or alkaline treatment affected the surface charge of the sample, influencing the adsorption of cationic or anionic dyes. Adsorption data presented an increased removal when alkaline treatment was applied for the methylene blue (MB; qmax = 16.7 mg g−1), and the acid treatment was more effective for the Congo red (CR; qmax = 2.13 mg g−1). After color stability tests, it was observed that the anionic dye CR was more easily desorbed due to the surface charge of the adsorbent. Due to the chemical treatment, corn straw proved to be a good sustainable adsorbent for removing anionic or cationic dyes from aqueous media, contributing directly to the objective of sustainable development (#6—drinking water and sanitation) and with SDG numbers 3, 11, 12, 14, and 17.

Green synthesis of iron (III) oxide (Fe3O4) Nanoparticles Using Citrus sinensis Peel Extract for the Removal of Ciprofloxacin in Water

Ciprofloxacin is a widely used antibiotic that can contaminate water sources and pose environmental and health risks. Therefore, the objective of this paper is to explore the green synthesis of iron (III) oxide nanoparticles using Citrus sinensis peel extract for the removal of ciprofloxacin in water using standard techniques. The adsorption of ciprofloxacin on the nanoparticles was investigated under different conditions, such as pH, initial concentration of adsorbate, contact time, and different adsorbent doses. The adsorption data were fitted to different isotherm and kinetic models to understand the adsorption mechanism and parameters. The results of characterization revealed the particles to be of nanocrystalline structure with a cubic crystal shape, negative surface charge, and a high thermal stability with elemental composition primarily of Fe and O; it has z- average of 42.60, with Fe-O bond at 693.30cm-1 and UV-Visible absorbance at 221nm. The maximum adsorption capacity with ciprofloxacin was 29.21 mg/g (97.45%) at pH of 7 and room temperature of 25 °C. The results of the adsorption data indicated that the adsorption followed the Langmuir isotherm model and the pseudo-second-order kinetic model, suggesting a monolayer adsorption on a homogeneous surface with a finite number of identical sites. The synthesized nanoparticles showed a high efficiency and selectivity for the removal of ciprofloxacin from water, demonstrating it potential as an eco-friendly and low-cost adsorbent for water purification.

Amine functionalized graphene oxide decorated with ZnO-WO3 nanocomposites for remediation of organic dye from wastewater

Photocatalytic degradation is as an efficient technique to eradicate toxic chemical pollutants from contaminated water sources. However, the selectivity and photocatalytic activity are the challenging targets to explore the new photocatalysts. Therefore, our research goal is to develop a suitable photocatalyst to satisfy the recent photocatalytic degradation demand. In this work, amine functionalized graphene oxide (NH2-GO) supported heterojunction ternary novel nanocomposites (NH2-GO/ZnO-WO3) were prepared via simple solvothermal method. Structural and morphological investigations of the prepared composites are systematically observed by Field Emission Scanning Electron Spectroscopy (FE-SEM), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), and Ultraviolet–Visible (UV–vis) Spectroscopy. FT-IR analysis confirmed the effective functionalization of amine on graphene oxide. The XRD results indicated that the prepared nanocomposites were free from any impurities and the binary composite (NH2-GO/ZnO) showed hexagonal wurtzite structure, whereas the ternary composite (NH2-GO/ZnO-WO3) exhibited mix crystal structure of monoclinic and hexagonal phase of WO3 and ZnO, respectively. The synthesized ternary photocatalyst (NH2-GO/ZnO-WO3) demonstrated superior photocatalytic efficiency towards various organic dyes such as cationic dye methylene blue (MB, 85.89%) and anionic dye methyl orange (MO, 60.98%) compared to binary photocatalyst (NH2-GO/ZnO) that showed only 52.28% of MB and 25.8% of MO dye degradation under UV light irradiation. The enhanced photocatalytic performance was mainly due to the low recombination rate of photogenerated electron-hole pair, narrow band gap, and large surface area of ternary composite. The presence of lone pair electrons in amino group provides a negative-charged surface composite resulting good interaction with cationic dye is the key to upgrade the photocatalytic performance. The ternary nanocomposite NH2-GO/ZnO-WO3 has the capacity to be a competent and acceptable photocatalyst for the photodegradation of organic dyes used in industries.

Strontium and Zinc Co-Doped Mesoporous Bioactive Glass Nanoparticles for Potential Use in Bone Tissue Engineering Applications.

Mesoporous bioactive glass nanoparticles (MBGNs) have attracted significant attention as multifunctional nanocarriers for various applications in both hard and soft tissue engineering. In this study, multifunctional strontium (Sr)- and zinc (Zn)-containing MBGNs were successfully synthesized via the microemulsion-assisted sol-gel method combined with a cationic surfactant (cetyltrimethylammonium bromide, CTAB). Sr-MBGNs, Zn-MBGNs, and Sr-Zn-MBGNs exhibited spherical shapes in the nanoscale range of 100 ± 20 nm with a mesoporous structure. Sr and Zn were co-substituted in MBGNs (60SiO2-40CaO) to induce osteogenic potential and antibacterial properties without altering their size, morphology, negative surface charge, amorphous nature, mesoporous structure, and pore size. The synthesized MBGNs facilitated bioactivity by promoting the formation of an apatite-like layer on the surface of the particles after immersion in Simulated Body Fluid (SBF). The effect of the particles on the metabolic activity of human mesenchymal stem cells was concentration-dependent. The hMSCs exposed to Sr-MBGNs, Zn-MBGNs, and Sr-Zn-MBGNs at 200 μg/mL enhanced calcium deposition and osteogenic differentiation without osteogenic supplements. Moreover, the cellular uptake and internalization of Sr-MBGNs, Zn-MBGNs, and Sr-Zn-MBGNs in hMSCs were observed. These novel particles, which exhibited multiple functionalities, including promoting bone regeneration, delivering therapeutic ions intracellularly, and inhibiting the growth of Staphylococcus aureus and Escherichia coli, are potential nanocarriers for bone regeneration applications.

Cold Emulsified Nanoemulsion: Enhancing Delivery and Stability of Thermolabile Acyclovir

Acyclovir is an acyclic purine nucleoside widely used as an antiviral agent with good topical efficacy. Acyclovir is a thermolabile drug, making it challenging to formulate a stable and effective emulsion via a conventional emulsification process. This study aims to develop, optimize, and characterize the nanoemulsion of thermolabile drug acyclovir, manufactured by adopting a cold emulsification process and compare the physicochemical properties and diffusion pattern with a leading marketed formulation. Diffusion studies were conducted using Franz diffusion cells. The optimized formulation was subjected to quantitative estimation of acyclovir, impurity profiling, viscosity, pH, vesicle size, shape, and polydispersibility index (PDI). In the current study, the particle size of the nanoemulsion varies from 66.25 to 244.40 nm, and the zeta potential revealed a high negative surface charge on the particles. Transmission electron microscopy images revealed spherical-shaped, non-aggregated, and discrete globules. The in-vitro diffusion study of acyclovir nanoemulsion showed enhanced penetration efficacy than the conventional emulsion. All these observations signified that the cold emulsification process for manufacturing nanoemulsion is appropriate for thermolabile and pH-sensitive drugs. The study demonstrates enhanced stability and efficacy of optimized acyclovir nanoemulsion through cold emulsification.

Computer-aided rational design strategy based on protein surface charge to improve the thermal stability of a novel esterase from Geobacillus jurassicus.

Although Geobacillus are significant thermophilic bacteria source, there are no reports of thermostable esterase gene in Geobacillus jurassicus or rational design strategies to increase the thermal stability of esterases. Gene gju768 showed a highest similarity of 15.20% to esterases from Geobacillus sp. with detail enzymatic properties. Using a combination of Gibbs Unfolding Free Energy (∆∆G) calculator and the distance from the mutation site to the catalytic site (DsCα-Cα) to screen suitable mutation sites with elimination of negative surface charge, the mutants (D24N, E221Q, and E253Q) displayed stable mutants with higher thermal stability than the wild-type (WT). Mutant E253Q exhibited the best thermal stability, with a half-life (T1/2) at 65°C of 32.4min, which was 1.8-fold of the WT (17.9min). Cloning of gene gju768 and rational design based on surface charge engineering contributed to the identification of thermostable esterase from Geobacillus sp. and the exploration of evolutionary strategies for thermal stability.

DIFUCOSIN: DIclofenac sodium salt loaded FUCOidan-SericIN nanoparticles for the management of chronic inflammatory diseases

The current investigation emphasizes the use of fucoidan and sericin as dual-role biomaterials for obtaining novel nanohybrid systems for the delivery of diclofenac sodium (DS) and the potential treatment of chronic inflammatory diseases. The innovative formulations containing 4 mg/ml of fucoidan and 3 mg/ml of sericin showed an average diameter of about 200 nm, a low polydispersity index (0.17) and a negative surface charge. The hybrid nanosystems demonstrated high stability at various pHs and temperatures, as well as in both saline and glucose solutions. The Rose Bengal assay evidenced that fucoidan is the primary modulator of relative surface hydrophobicity with a two-fold increase of this parameter when compared to sericin nanoparticles. The interaction between the drug and the nanohybrids was confirmed through FT-IR analysis. Moreover, the release profile of DS from the colloidal systems showed a prolonged and constant drug leakage over time both at pH 5 and 7. The DS-loaded nanohybrids (DIFUCOSIN) induced a significant decrease of IL-6 and IL-1β with respect to the active compound in human chondrocytes evidencing a synergistic action of the individual components of nanosystems and the drug and demonstrating the potential application of the proposed nanomedicine for the treatment of inflammation.

Abstract 2029: Investigation of anti-tumor activity of porcine myeloperoxidase for urothelial carcinoma of the bladder

Abstract Introduction: Porcine myeloperoxidase (pMPO) is a cationic enzyme secreted by granulocytic leukocytes capable of selectively binding cancer cells due to their negative surface charge. In the presence of hydrogen peroxide (H2O2) and sodium chloride (NaCl), MPO catalyzes the production of electronically excited singlet molecular oxygen, which exerts focused cytotoxic activity against cancer cells. Methods: Human bladder non-cancer (SV-HUC1) and cancer cells (T24 and 5637) were used to assess differential cytotoxic activity of pMPO. pMPO was combined with associated reagents, including H2O2, NaCl, and L-proline and glycine for 45 minutes to support the generation of singlet oxygen. MTS assay was used to assessed cell viability at day 3 post-treatment. Non-cancer and cancer cells were labeled with GFP and mCherry, respectively, via infection with lentivirus and cultured in tandem to allow for simultaneous treatment of both cell types. After the treatment, flow cytometry and microscopy were used to monitor the growth of the cells. Results: No cytotoxicity was noted when SV-HUC1 cells were cultured with individual reagents pMPO, NaCl, L-Proline, or Glycine, and limited cytotoxicity was observed with H2O2. Notably, cell viability was nearly maximally preserved for SV-HUC1 cells. The combination of pMPO with associated reagents resulted in killing of 5637 and T24 cells, with tumoricidal activity maintained across increasing tumor cell density, with cell viability preserved for SV-HUC1 cells. Within the cell co-culture system, simultaneous treatment of both cell types with the pMPO treatment resulted in selective killing of tumor cells and preservation of SV-HUC1 cells. Mechanistic studies confirm specificity of pMPO binding to tumor cells, and further, high levels of expression of gammaH2AX and phospho-ATM in 5637 and T24 cells following treatment. Conclusion: pMPO demonstrates selective and efficient killing of bladder cancer cells with minimal cytotoxicity against non-cancer urothelial cells. Given its reliance on direct surface contact with tumor cells for activity, pMPO may be developed as an intravesical therapy for treatment of non-muscle invasive bladder cancers. Acknowledgements: This work was partially supported by Mayo funds provided to Dr. Haojie Huang. Citation Format: Junnan Liu, Robert C. Allen, Jackson T. Stephens, Paras Shah, Haojie Huang. Investigation of anti-tumor activity of porcine myeloperoxidase for urothelial carcinoma of the bladder [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2029.