Transmission Electron Microscopy Micrographs Research Articles

Unraveling the Role of Deep Eutectic Solvents with Varying Hydrogen-Bond Acceptors on the Thermoresponsive Polymer Poly(N-isopropylacrylamide).

Deep eutectic solvents (DESs) have emerged as promising tools for crafting polymeric materials across diverse domains. This study delves into the impact of a series of DESs on the phase behavior of poly(N-isopropylacrylamide) (PNIPAM) in aqueous environments, presenting compelling insights into their performance. Specifically, we explore the conformational phase behavior of PNIPAM in the presence of four distinct lactic acid (LA)-based DESs: LA-betaine (LA-BET), LA-proline (LA-PRO), LA-choline chloride (LA-CC), and LA-urea (LA-U). By maintaining a consistent hydrogen-bond donor (HBD) while varying the hydrogen-bond acceptor (HBA), we unravel how different DES compositions modulate the phase transition behavior of PNIPAM. Our findings underscore the profound influence of DESs comprising LA as the HBD and diverse HBAs-BET, PRO, CC, and U on the thermoresponsive behavior of PNIPAM. Employing spectroscopic techniques such as ultraviolet-visible (UV-vis) spectroscopy, steady-state fluorescence, Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), ζ-potential, and transmission electron microscopy (TEM), we elucidate the preferential interactions between the HBA groups within DESs and the hydration layer of PNIPAM. Notably, temperature-dependent DLS analyses reveal a discernible decrease in the lower critical solution temperature (LCST) of PNIPAM with increasing DES concentration, ultimately disrupting the hydrogen-bond interactions and resulting in early hydrophobic collapse of the polymer, which can be clearly seen in the TEM micrographs. Furthermore, the formation of polymer composites within the mixed system leads to notable alterations in the physiochemical properties of PNIPAM, as evidenced by shifts in its LCST value in the presence of DESs. This perturbation disrupts hydrogen-bond interactions, inducing hydrophobic collapse of the polymers, a phenomenon vividly captured in TEM micrographs. In essence, our study sheds new light on the pivotal role of varying HBA groups within DESs in modulating the conformational transitions of PNIPAM. These insights not only enrich our fundamental understanding but also hold immense promise for the development of smart polymeric systems with multifaceted applications spanning bioimaging, biomedical science, polymer science, and beyond.

Effect of graphene addition on microstructure and wear behaviour of the A356-based composite fabricated by thixoforming process

Employing graphene as reinforcement in an aluminium matrix is a viable approach for developing composites with exceptional mechanical properties and wear resistance owing to its two-dimensional structure and high strengthening efficiency. This study aims to investigate the microstructure and wear behaviour of A356 aluminium matrix composites reinforced with different graphene nanoplatelets (GNPs) amounts (0.3, 0.5 and 1.0 wt%). The feedstock of composites underwent stir casting before being subjected to the thixoforming process. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy micrographs (TEM) demonstrated the microstructure transformation of the composites after fabrication and the presence of carbon elements in the A356 matrix composite, respectively. TEM micrographs also displayed the existence of aluminium carbide (Al4C3) compound in the composites due to the reaction of aluminium matrix and graphene during fabrication. The hardness testing results revealed the hardness of the composite with 0.3 wt% GNPs is higher than that of A356 alloy by showing an improvement of 51.4% after the thixoforming process. The wear resistance of the composites was enhanced by decreasing the wear rate. In comparison with the as-cast and thixoformed A356 alloys, the thixoformed composite reinforced with 0.3 wt% GNPs exhibited the lowest wear rate, demonstrating a reduction of 18.7% and 11.5%, respectively. These findings demonstrated the significance of GNPs as an effective self-lubricating and favourable reinforcement for A356 aluminium matrix composite in the automotive industry.

Understanding the sigmoidal primary creep behaviour in a multi-component solid-solution Co-base alloy between 700 – 850 °C

This investigation was motivated by the lack of understanding of the role of solid solution strengthening and substructure evolution during the creep of multi-component alloys. Thus, we studied the tensile creep behaviour of a multi-component solid-solution Co-base alloy (Co41-Ni23-Cr26-W4.7-Fe2-Mn1-C0.5) at 650 – 900 °C and stress (σApplied) range: 80 – 400 MPa. Uncommon sigmoidal primary creep (SPC) was witnessed at 700–850 °C and in the intermediate stress range. The stress exponent (∼5 – 7) and activation energy (∼270 kJ/mol ≈ Qlattice) suggest that dislocation creep controls the creep rate. Transmission electron microscopy (TEM) studies revealed substructural evolution with creep strain. At 750 °C and 160 MPa, at creep strain (ε) = 0.25 %, multiple pinning points along the dislocation length were seen, and a thorough analysis confirmed them as jogs. Friction stress estimation from dislocation curvature from multiple TEM micrographs revealed that effective stress on dislocations is high (>0.6σApplied) while solid solution strengthening is nominal during creep. Overall analysis suggests that the creep rate in the multi-component alloy is recovery controlled while jogs' motion determines the SPC creep rate.

Pulicaria gnaphalodes-assisted green synthesis of NiFe2O4@ZnO nanocomposites for sustainable remediation of an antibiotic from aqueous solution

In this study, the NiFe2O4@ZnO nanocomposite was synthesized in a simple, accessible and affordable method using Pulicaria gnaphalodes plant extract as a reducing agent. The structural characteristics of this nanocomposite were determined by transmission electron microscopy (TEM), X-ray diffraction, Fourier transform infrared spectroscopy, vibrating sample magnetometer, X-ray energy diffraction spectroscopy and dynamic light scattering. TEM micrograph confirmed the formation of spherical and cubic spinel ferrite with average dimensions of 75–85 nm. Some parameters such as pH, dose of NiFe2O4@ZnO nanocomposite, concentration of penicillin G and reaction time to reach optimal conditions were investigated. According to the results of the present research, the photocatalyst process along with the use of NiFe2O4@ZnO nanocomposite as an oxidizing agent is an effective method in degradation of the penicillin G antibiotic from aqueous solutions.

Application of cobalt-cerium-iron ternary layered double hydroxide for extraction of perfluorooctane sulfonate followed by HPLC-MS/MS analysis

Herein, Ce-doped CoFe layered double hydroxide (LDH), noted as CoCeFe ternary LDH, was prepared using the co-precipitation route. Prosperous synthesis of CoFe LDH and successful partial replacement of iron cations with cerium cations in CoCeFe ternary LDH were confirmed by X-ray diffraction patterns, energy-dispersive X-ray spectroscopy, and elemental dot-mapping images. Nanosheet morphology was recognized for both CoFe LDH and CoCeFe ternary LDH from scanning electron microscopy and transmission electron microscopy micrographs. In the following, a dispersive solid phase extraction (DSPE) method was developed using the synthesized CoCeFe ternary LDH as a sorbent for extracting perfluorooctanesulfonic acid (PFOS) from wastewater samples. For the selective analysis of PFOS, high-performance liquid chromatography-tandem mass spectroscopy (HPLC-MS/MS) in multiple reaction monitoring mode was used. Analytical parameters such as the limit of detection equal to 0.02 μg/L, with a linear range of 0.05–300 μg/L, the limit of quantification equal to 0.05 μg/L, and an enrichment factor equal to 23.3 were achieved for PFOS at the optimized condition (sorbent: 5 mg of CoCeFe ternary LDH, eluent type and volume: 150 μL mobile phase, pH: 3, adsorption time: 3 min, and desorption time: 5 min). The developed strategy for the analysis of PFOS was tested in real wastewater samples, including copper mine and petrochemical wastewater. The amount of analytes in real samples was calculated using the standard addition method, and good relative recovery in the range of 86%–105% was obtained. The main novelty of this research is the application of CoCeFe ternary LDH to extract the PFOS from wastewater using the DSPE method for determination by HPLC-MS/MS.

Effect of Phosphorus-Nitrogen based Flame-Retardant Combined with Zinc Borate on Thermal Stability and Flame Retardancy of Epoxy Clay Nanocomposites

A phosphorus-nitrogen containing 6,6'-(piperazine-1,4-diyl)bis(6H-dibenzo[c,e][1,2]oxaphosphinine 6-oxide) (DOPO-PZ) flame-retardant was synthesized and its effect combined with zinc borate (ZnB) and nanoclay (NC) on thermal stability and flame retardancy of epoxy resin was studied. Various epoxy composites containing DOPO, DOPO-PZ, ZnB and NC using curing agent diaminodiphenylsulfone (DDS) were prepared. The X-ray diffraction (XRD) and transmission electron microscope (TEM) micrographs of the composites showed intercalated nanostructure of epoxy-clay nanocomposites. In thermogravimetric analysis (TGA), pure epoxy gave 3.4% char yield at 700 ºC in nitrogen atmosphere, while in case of EP/DOPO-PZ/ZnB/NC sample having 1% phosphorus content, 5 wt.% zinc borate (ZnB) and 3 wt.% nanoclay (NC), the char yield is increased to 24.0%. Differential scanning calorimetry (DSC) study showed decrease in the glass transition temperature (Tg) on the addition of flame-retardant due to plasticization effect and increase in Tg on addition of nanoclay due to formation of nanostructure of epoxy composites. The EP/DOPO-PZ/ZnB/NC nanocomposite sample exhibited a limiting oxygen index (LOI) value of 29.2% and passed the UL-94 test with a V-0 rating and thus achieved a sufficient flame retardancy.

Malignance-restriction activity exhibited by bioactive compounds of selected actinobacteria as silver nanoparticles against A549 lung cancer cell lines.

This article deals with the antibacterial and anticancer potential of secondary metabolites produced by actinomycetes also reported as actinobacteria, Microbacterium proteolyticum (MN560041), and Streptomycetes rochei, where preliminary studies were done with the well diffusion method. These actinobacteria's silver nanoparticles were synthesized and characterized using transmission electron microscopy (TEM) and UV-Visible spectroscopy. Anticancer was measured using the MTT test, reactive oxygen species (ROS) generation measured with DCFDA, mitochondrial membrane potential (MMP) measurement, and DAPI fluorescence intensity activity was measured in treated and non-treated cancerous cells. The IC50 value for 5-FU (a), LA2(O) (b), LA2(R) (c), LA2(ON) (d), and LA2(RN) (e) was obtained at 3.91 μg/mL (52.73% cell viability), 56.12 μg/mL (52.35% cell viability), 44.90 μg/mL (52.3% cell viability), 3.45 μg/mL (50.25% cell viability), and 8.05 μg/mL (48.72% cell viability), respectively. TEM micrographs revealed discrete, well-separated AgNPs particles of size 7.88 ± 2 to 12.86 ± 0.24 nm. Gas chromatography-mass spectrometry was also performed to detect the compounds in bioactive metabolites where n-hexadecanoic acid was obtained as the most significant one. MTT test showed a substantial decline in A549 cell viability (up to 48.72%), 2.75-fold increase in ROS generation was noticed in comparison to untreated A549 lung cancer cells when measured with DCFDA. A total of 0.31-fold decrease in MMP and 1.74-fold increase in DAPI fluorescence intensity compared to untreated A549 lung cancer cells suggests that the synthesized nanoparticles promote apoptosis in cancerous cells. Our findings suggests that the secondary metabolites of M. proteolyticum and S. rochei in nanoparticle form can be used as a significant compound against lung cancers.

Elucidating the structural and spectroscopic attributes of titania-iron oxide (TiO2-([formula omitted]-Fe2O3)) nanocomposites: Showcasing a pulsed laser ablation in liquid approach

Various nanomaterials with tailored photo-electrochemical and physicochemical attributes became viable for the photo-catalysis and sensors applications. Thus, some new types of TiO2-(α-Fe2O3) nanocomposites were made via the pulse laser ablation in liquid method. These nanocomposites at each value of laser fluence were obtained by mixing the colloidal TiO2 nanoparticles and colloidal (α-Fe2O3) nanoparticles at equal ratio. The stability, structures, morphologies, and optical characteristics of the produced nanocomposites (suspended in deionized water) were customized by changing the laser fluence from 3.5–17.7 J cm−2. The high-resolution transmission electron microscopy micrographs showed the existence of homogeneous dispersion of spherical nanocrystallites (mean diameter 12.4 ± 6.0 nm) in the colloidal suspension. Both X-ray diffraction and Fourier transform infrared profiles of the specimen verified their purity and good nanocrystallinity. Two optical absorption peaks were probed in the range of 240 to 380 nm convoyed by a blue-shift. The spectral edge related to UV–Vis absorption was used to estimate the optical band gap of these nanocomposites. TiO2-(α-Fe2O3) nanocomposites made at optimum laser fluence (10.6 J cm−2) exhibited strong fluorescence with the life time decay of 3.64 μs, indicating the electronic density of states modification due to quantum size effects. The presence of Fe, Ti, and O in the X-ray photoelectron spectroscopy spectra reaffirmed the samples purity. The measured strong negative zeta potential (-33.1 mV) of the optimum TiO2-(α-Fe2O3) nanocomposites confirmed their excellent stability in the colloidal suspension. In short, these nanocomposites may be advantageous as good photo-catalysts for waste water treatment and photo-electrochemical uses.

Pluronic F-127-coated ZnO nanoparticles as superior photosensitizers for effective bladder cancer photodynamic therapy: In-vitro evaluation

Bladder cancer is the most prevalent malignancy of the urinary system and ranks among the top ten most common cancers in humans. Photodynamic therapy (PDT) demonstrates significant promise in cancer treatment due to its high selectivity and minimal side effects. Zinc oxide nanoparticles (ZnO NPs) exhibit substantial potential in various biomedical applications, including cancer therapy. This study systematically investigates the potential of bare and Pluronic F-127-coated ZnO NPs as photosensitizers (PSs) for effective photodynamic therapy against the RT4 bladder cancer cell line, marking the first such exploration. Transmission electron microscopy (TEM) micrographs reveal the formation of a Pluronic F-127 coating layer with thickness ranging from approximately 3 nm–7 nm on the particle surface. The Pluronic coating process significantly enhances the cytotoxicity of ZnO NPs under dark conditions and during photodynamic therapy on the RT4 bladder cancer cell line. Additionally, the impact of PDT using bare and coated ZnO NPs is further evaluated through a 3D spheroid assay, which better replicates the real tumor environment for photodynamic therapy. Hoechst and rhodamine assays confirm the induction of apoptosis, characterized by nuclear condensation and disruption of mitochondrial membrane potential in the cells. This study advances the potential of ZnO NPs in bladder cancer photodynamic therapy and highlights the importance of Pluronic F-127 coatings, paving the way for more effective and targeted cancer treatments.

Deep learning-enabled probing of irradiation-induced defects in time-series micrographs

Modeling time-series data with convolutional neural networks (CNNs) requires building a model to learn in batches as opposed to training sequentially. Coupling CNNs with in situ or operando techniques opens the possibility of accurately segmenting dynamic reactions and mass transport phenomena to understand how materials behave under the conditions in which they are used. In this article, in situ ion irradiation transmission electron microscopy (TEM) images are used as inputs into the CNN to assess the defect generation rate, defect cluster density, and saturation of defects. We then use the output segmentation maps to correlate with conventional TEM micrographs to assess the model’s ability to detail nanoscale interactions. Next, we discuss the implications of preprocessing and hyperparameters on model variability, accuracy when expanded to other datasets, and the role of regularization when controlling model variance. Ultimately, we eliminate human bias when extrapolating physical metrics, speed up analysis time, decouple reactions that happen at 100 ms intervals, and deploy models that are both accurate and transferable to similar experiments.

Exploring the impact of pH and temperature on TiC nanopowders syntesized via sol-gel and subsequent crystallization by carbothermal reduction method

In the present study, titanium carbide powders with suitable morphology and nanometer particle size were synthesized by the sol–gel method to investigate the parameters affecting the properties of sol and the final powder. The initial sol was prepared in a four-component system of alkoxide-water-alcohol-citric acid based on the chemical process of sol–gel. The study of sol properties showed that pH was the most important factor in the control of sol conditions and particle size so that at low pHs, due to low concentration of OH− ions and reduced viscosity, it was easier to control the particles size. Accordingly, the results of the Dynamics Light Scattering (DLS) showed that at low pHs, the particles size was below 10 nm. According to the zeta potential diagram and by examining the conditions of sol at different pHs, 4.5 was determined as the optimal pH and to prevent the bonding of particles within the sol, ammonium polycarboxylate dispersant was used. The temperature at which particles were formed was determined using Differential thermal analysis (DTA) and Thermal gravimetric analysis (TG). X-ray diffraction (XRD) patterns showed the presence of a completely amorphous phase at 700 °C. It was also observed that with increasing temperature, TiC crystallization started from 1200 °C and ended at 1400 °C. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) micrographs at 1400 °C showed the completely spherical morphology of particles of nanometer size so that no agglomerate was observed.

The intrinsic twinning and enigmatic twisting of aragonite crystals

It is generally accepted that aragonite crystals of biogenic origin are characterized by significantly higher twin densities compared to samples formed during geological processes. Based on our single crystal X-ray diffraction (SCXRD) and transmission electron microscopy (TEM) study of aragonite crystals from various localities, we show that in geological aragonites, the twin densities are comparable to those of the samples from crossed lamellar zones of molluscs shells. The high twin density is consistent with performed calculations, according to which the Gibbs free energy of twin-free aragonite is close to that of periodically twinned aragonite structure. In some cases, high twin densities result in the appearance of diffuse scattering in SCXRD patterns. The obtained TEM and optical micrographs show that besides the twin boundaries (TBs) of growth origin, there are also TBs and especially stacking faults that were likely formed as the result of local strain compensation. SCXRD patterns of the samples from Tazouta, in addition to diffuse scattering lines, show Debye arcs in the [Formula: see text] plane. These Debye arcs are present only on one side of the Bragg reflections and have an azimuthal extent of nearly 30°, making the whole symmetry of the diffraction pattern distinctly chiral, which has not yet been reported for aragonite. By analogy with biogenic calcite crystals, we associate these arcs with the presence of misoriented subgrains formed as a result of crystal twisting during growth.

Comparative genomic analysis of uropathogenic Escherichia coli strains from women with recurrent urinary tract infection.

Recurrent urinary tract infections (RUTIs) caused by uropathogenic Escherichia coli are costly public health problems impacting patients' quality of life. In this work, a comparative genomics analysis of three clinical RUTI strains isolated from bladder biopsy specimens was performed. One hundred seventy-two whole genomes of urinary tract E. coli strains were selected from the NCBI database. The search for virulence factors, fitness genes, regions of interest, and genetic elements associated with resistance was manually carried out. The phenotypic characterization of antibiotic resistance, haemolysis, motility, and biofilm formation was performed. Moreover, adherence and invasion assays with human bladder HTB-5 cells, and transmission electron microscopy (TEM) were performed. The UTI-1_774U and UTI-3_455U/ST1193 strains were associated with the extraintestinal pathotypes, and the UTI-2_245U/ST295 strain was associated with the intestinal pathotype, according to a phylogenetic analysis of 172 E. coli urinary strains. The three RUTI strains were of clinical, epidemiological, and zoonotic relevance. Several resistance genes were found within the plasmids of these strains, and a multidrug resistance phenotype was revealed. Other virulence genes associated with CFT073 were not identified in the three RUTI strains (genes for type 1 and P fimbriae, haemolysin hlyA, and sat toxin). Quantitative adherence analysis showed that UTI-1_774U was significantly (p < 0.0001) more adherent to human bladder HTB-5 cells. Quantitative invasion analysis showed that UTI-2_245U was significantly more invasive than the control strains. No haemolysis or biofilm activity was detected in the three RUTI strains. The TEM micrographs showed the presence of short and thin fimbriae only in the UTI-2_245U strain. The high variability and genetic diversity of the RUTI strains indicate that are a mosaic of virulence, resistance, and fitness genes that could promote recurrence in susceptible patients.

The high impact of zinc chromium oxide nanocombs on development of larvicidal and antimicrobial performance

Zinc chromium oxide (Cr/ZnO, 5wt.%) was prepared by a facile chemical co-precipitation route. The structure, composition, and chemical bonding were analyzed using X-ray diffraction (XRD), Energy dispersive X-ray spectroscopy (EDX), and Fourier-transform infrared spectroscopy (FTIR) indicating that chromium ions were integrated the host framework to form Cr/ZnO nanocomposite. Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) micrographs showed comb-shaped nanoparticles with an average size 20 nm and large surface area. The energy gap of the thin films was estimated from T% and R% measurements which exhibit a strong optical absorption edge close to the visible spectrum. The insecticidal activity of the synthesized nanocombs against C. pipiens larvae was evaluated with LC50 (30.15 ppm) and LC90 (100.22 ppm). Besides, the nanocomposite showed high antibacterial performance against gram-positive bacteria (Bacillus subtilis) and gram-negative bacteria (Proteus vulgaris) with inhibition zones 21.9 and 19 mm, respectively.

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

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

Revealing effect of cobalt dopant on crystallography and optical characteristics of nanostructured cupric oxide

Cupric oxide is an interesting semiconducting material that has the potential to be applied in various technological utilizations. To understand the modified structure, the effects of Co doping at different concentrations (0, 1, 3, and 5 mol%) on the crystal structure, morphology, and optical properties of CuO nanoparticles synthesized by the co-precipitation method through heating at 400 °C for 2 h have been investigated. Synthesized samples were characterized by various techniques. X-ray diffractometer (XRD) results showed a monoclinic structure of CuO and impurity phase Co2O3 appearing when doping 5 mol% Cobalt. The crystallite size was found in the range of 25–48 nm. The crystallinity, texture coefficient, crystallite size, lattice constants, strain, and some physical properties (stress, Young's modulus, and strain energy) were calculated from the obtained XRD data. As a result, the lower Young's modulus and strain energy values of (111) crystal plane promoted the preferable growth in the direction. Fourier transform infrared spectrometer (FT-IR) was used to understand the chemical structure and confirm the substitution of Co in the samples. Scanning electron microscopy technique (SEM) was used to study morphology, appearing in the micron irregular flat plates that change to spherical particles when cobalt addition increases. Transmission electron microscope (TEM) micrographs show that structures of CuO are highly crystalline in nature and also provide clear evidence of spherical nanostructures in the Co-doped CuO. The Brunau–Emmet–Teller analysis method (BET) depicts a surface area improvement, showing 6.532 m2/g for the CuO and 19.285 m2/g for the 5 mol% Co-doped CuO sample. As more Co content, the decreasing energy bandgap of 2.75 to 2.58 eV was approximated using the Ultraviolet–Visible spectroscopy (UV–Vis) result. Photoluminescence spectra (PL) were found at about 440 and 470 nm, replied to oxygen vacancy (Vo) and copper vacancy (VCu), which are a sublevel affecting energy bandgap change. The role of Co dopant in improving the morphology and optical properties was discussed, associating with the structural characteristics and emerging intrinsic defects.

Zinc phthalocyanine loaded- antibody functionalized nanoparticles enhance photodynamic therapy in monolayer (2-D) and multicellular tumour spheroid (3-D) cell cultures.

In conventional photodynamic therapy (PDT), effective delivery of photosensitizers (PS) to cancer cells can be challenging, prompting the exploration of active targeting as a promising strategy to enhance PS delivery. Typically, two-dimensional (2-D) monolayer cell culture models are used for investigating targeted photodynamic therapy. However, despite their ease of use, these cell culture models come with certain limitations due to their structural simplicity when compared to three-dimensional (3-D) cell culture models such as multicellular tumour spheroids (MCTSs). In this study, we prepared gold nanoparticles (AuNPs) that were functionalized with antibodies and loaded with tetra sulphonated zinc phthalocyanine (ZnPcS4). Characterization techniques including transmission electron microscopy (TEM) was used to determine the size and morphology of the prepared nanoconjugates. We also conducted a comparative investigation to assess the photodynamic effects of ZnPcS4 alone and/or conjugated onto the bioactively functionalized nanodelivery system in colorectal Caco-2 cells cultured in both in vitro 2-D monolayers and 3-D MCTSs. TEM micrographs revealed small, well distributed, and spherical shaped nanoparticles. Our results demonstrated that biofunctionalized nanoparticle mediated PDT significantly inhibited cell proliferation and induced apoptosis in Caco-2 cancer monolayers and, to a lesser extent, in Caco-2 MCTSs. Live/dead assays further elucidated the impact of actively targeted nanoparticle-photosensitizer nanoconstruct, revealing enhanced cytotoxicity in 2-D cultures, with a notable increase in dead cells post-PDT. In 3-D spheroids, however, while the presence of targeted nanoparticle-photosensitizer system facilitated improved therapeutic outcomes, the live/dead results showed a higher number of viable cells after PDT treatment compared to their 2-D monolayer counterparts suggesting that MCTSs showed more resistance to PS drug as compared to 2-D monolayers. These findings suggest a high therapeutic potential of the multifunctional nanoparticle as a targeted photosensitizer delivery system in PDT of colorectal cancer. Furthermore, the choice of cell culture model influenced the response of cancer cells to PDT treatment, highlighting the feasibility of using MCTSs for targeted PS delivery to colorectal cancer cells.

The application of bacteria-derived dehydrogenases and oxidases in the synthesis of gold nanoparticles.

In this work the green synthesis of gold nanoparticles (Au-NPs) using the oxidoreductive enzymes Myriococcum thermophilum cellobiose dehydrogenase (Mt CDH), Glomerella cingulata glucose dehydrogenase (Gc GDH), and Aspergillus niger glucose oxidase (An GOX)) as bioreductants was investigated. The influence of reaction conditions on the synthesis of Au-NPs was examined and optimised. The reaction kinetics and the influence of Au ions on the reaction rate were determined. Based on the kinetic study, the mechanism of Au-NP synthesis was proposed. The Au-NPs were characterized by UV-Vis spectroscopy and transmission electron microscopy (TEM). The surface plasmon resonance (SPR) absorption peaks of the Au-NPs synthesised with Mt CDH and Gc GDH were observed at 535nm, indicating an average size of around 50nm. According to the image analysis performed on a TEM micrograph, the Au-NPs synthesized with Gc GDH have a spherical shape with an average size of 2.83 and 6.63nm after 24 and 48h of the reaction, respectively. KEY POINTS: • The Au NPs were synthesised by the action of enzymes CDH and GDH. • The synthesis of Au-NPs by CDH is related to the oxidation of cellobiose. • The synthesis of Au-NPs by GDH was not driven by the reaction kinetic.

Multiscale modeling of hyperviscoelastic behavior of particulate rubber composites based on hybrid silica/carbon black filler system

AbstractThe present research outlines the novel finite element analysis of green tire tread compounds based on solution styrene‐butadiene rubber/butadiene rubber (SSBR/BR) reinforced with a hybrid silica/carbon black filler system. For this purpose, a series of micromodels using representative volume elements (RVEs) were developed. The silica/carbon black ratio with a constant value of the reinforcement and considering periodic boundary conditions (PBCs) were established. The distribution of the reinforcing fillers in the matrix was inspired by transmission electron microscope (TEM) micrographs. A nonlinear hyperviscoelastic model was considered for the matrix and interphase zones and a linear elastic model for the reinforcement phase to predict the dissipation behavior at a moderate to high strain regime. To confirm the accuracy of the proposed model, the RVEs of hybrid systems were simulated and then compared with experimental data. The results showed that the proposed model is capable to predict the mechanical properties of rubber compounds. The presence of agglomerated fillers resulted in an increase in the dissipation behavior. This was confirmed by rubber process analyzer (RPA) and dynamic mechanical thermal analysis (DMTA) results.Highlights Rubber compounds based on SSBR/BR reinforced with silica and/or carbon black were prepared by the melt mixing method. A multi‐scale finite element analysis of the particulate composites was developed using RVE. The distribution of reinforcing fillers in the matrix was inspired by TEM. The prediction of the stress–strain behavior of the hybrid composites was confirmed by the results of tensile tests. The simulated dissipation behavior of the composites was compared with RPA and DMTA analyses.

Limosomes versus hyalurolimosomes loaded with piperine for management of skin cancer

Skin cancer is considered the fifth most commonly occurring cancer worldwide hampering both health and economy. Piperine had proven efficacy in fighting skin cancer cells. Unfortunately, this natural agent had limited ability to penetrate the skin. The aim of the current study was to formulate piperine-loaded limosomes and hyalurolimosomes incorporating limonene as an edge activator and hyaluronic acid as bioactive gelling agent for managing skin cancer. Titration method followed by homogenization was adopted to prepare the nanoliposomal formulations. Characterization involved size, & zeta potential measurements, examination using transmission electron microscope (TEM) and stability study. Biological evaluation of the antitumor activity of piperine nanoliposomal formulations against Ehrlich’s (EAC) solid tumor was also performed. Drug loaded limosomes and hyalurolimosomes had particle size; 346.55 ± 8.55 & 372.70 ± 10.83 nm, respectively. Zeta potential was high enough to ensure their stability. TEM micrographs detected the surrounding layer of Hyaluronic acid formed around the spherical limosomal nano-carrier ensuring the formation of Hyalurolimosomes. All stored formulations showed non-significant differences compared with freshly prepared ones at p < 0.05. In addition, A DAD-HPLC method was developed and validated for Piperine analysis in the skin. Upon application of this method, it was found that hyalurolimosomes deliver double the concentration delivered by limosomes. The piperine hyalurolimosome group showed a significant reduction in tumor size with a smaller AUC compared to piperine gel, which was confirmed by in vivo studies. Consequently, hyalurolimosomes loaded with piperine is considered a promising nanocarrier system and a step forward better management of skin cancer introducing new hope in beating this deadly disease.